PATENT DOCUMENT

Abstract:
The invention comprises portable, rugged and relatively compact electrochemical cells. Each may be removably and nondestructively secured to one surface of a substrate of indefinite size. In-situ electrochemical measurements may be made on portions of existing structures such as ships, bridges, or buildings. An electrochemical cell is disclosed which comprises an analytical chamber which can be utilized with either on-board or external potentiostats. The electrochemical cell has a mounting means which permits the cell to be secured to substrates with irregular surface morphology and to horizontal, vertical or intermediately oriented surfaces. The electrochemical cell provides a means to control the temperature of the electrolyte and the substrate area of interest to permit more accuract and consistent elecrochemical measurements. Said probe is capable of performing electrochemical measurements such as a monitoring corrosion, effectiveness, or integrity of conductive and nonconductive coatings on bare and coated metallic or conductive substrates.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application 61/297,947, filed on Jan. 25, 2010. This application is also a Continuation-In-Part of U.S. patent application Ser. No. 13/522,524 filed on Jan. 24, 2011 as International Patent Application PCT/US2011/022286. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     This invention was made with government support under N00178-07-D-4078 DO EHP7 awarded by United States Navy. The government has certain rights in the invention. Per 48 CFR 52.227-11(b) the Federal Government shall have a nonexclusive, nontransferable, irrevocable, paid-up license. 
    
    
     SEQUENCE LISTING 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     The invention comprises six different but related types of electrochemical cell. The six electrochemical cells of the invention share several important common features. 
     In the first instance, they are all portable. That is, they can each be used in the field, e.g. outside the laboratory. They can be moved to any desired location to make electrochemical measurements on a wide variety of different sized and shaped substrates. Obviously, even though the electrochemical cells of the invention are designed to be usable outside the laboratory, they will work just as well in the laboratory, if desired. 
     Secondly, each electrochemical cell has the ability to be removably and nondestructively secured to one surface of a substrate of indefinite size. This feature derives from the attachment means used with each electrochemical cell of the invention. Removable and nondestructive attachment is defined herein to mean that the electrochemical cells of the invention may be attached and then easily removed from the substrate with no damage at all to the electrochemical cell and with only minimal damage to the substrate. For example, the substrate may require a small amount of cleaning because of spilled electrolyte. In addition, certain types of electrochemical measurements may require any coating of the substrate to be removed prior to taking the measurements. Obviously, this coating would have to be replaced in order to return the substrate to its original condition. 
     The attachment means permits the cells to be used to make electrochemical measurements on substrates of widely varying sizes and shapes. Since the attachment means will secure the electrochemical cells of the invention to substrates of widely varying sizes, in-situ electrochemical measurements may be made on portions of existing structures which may be quite large—for example ships, bridges, or buildings. 
     Prior art electrochemical cells typically are limited to making measurements on relatively small sized substrates, capable of being inserted into the cell interior. Some prior art cells have the ability to make measurements on larger substrates but require access to an edge of the substrate. Thus, most all of the prior art electrochemical cells are severely limited as to the size of the substrates they can work with. 
     Lastly, they are all relatively compact and rugged compared to existing electrochemical cells. For example, glass is often used in the construction of the prior art electrochemical cells and, for obvious reasons, a glass electrochemical cell cannot fairly be characterized as being “rugged”. The electrochemical cells of the invention are made primarily of modern polymeric materials which are much more rugged than glass. 
     The first and most basic electrochemical cell comprises an analytical chamber which can be utilized with existing prior art potentiostats. This chamber has means to contain the necessary electrolyte and means to secure a counter electrode and a reference electrode therein. The chamber also has an adjustable attachment means to permit the chamber to be removably and nondestructively attached to and then removed from the surface of a substrate of indefinite size. 
     The second electrochemical cell is a compact, rugged self-contained portable probe comprising an electrochemical cell and potentiostat to perform electrochemical measurements. The probe of the invention is particularly useful to monitor corrosion on bare and coated substrates. The probe of the invention is designed to work on metals and other conductive substrates. It is also designed to determine the effectiveness or integrity of conductive and nonconductive coatings on conductive substrates. 
     The third electrochemical cell is a modification of the second cell which retains the self-contained electronics component of the second electrochemical cell, but eliminates the fluidics handling portion of the second embodiment. 
     The fourth electrochemical cell is a modification of the first three cells which allows for more adjustment of the attachment means to permit the cell to be secured to substrates with irregular surface morphology, e.g. substrates which are not planar or have an irregular surface. 
     The fifth electrochemical cell is a modification of the third cell which retains the self-contained electronics component of the second embodiment and eliminates the fluidics handling portion of the second embodiment. In addition, the fifth electrochemical cell permits accurate temperature control of the electrolyte and of the local substrate area where the electrochemical measurements are being made. This cell also has an attachments means which permits the cell to be secured to substrates with a somewhat irregular surface morphology. 
     The sixth electrochemical cell is a modification of the fifth cell which eliminates the self-contained electronics component. 
     Corrosion is a wide-spread problem that affects nearly all industry and government sectors. A recent report determined that the direct cost of corrosion in the United States to be 3.1% of the Gross Domestic product (GDP) [G. H. Koch, et al. “Corrosion Costs and Preventive Strategies in the United States,” Report by CC Technologies Laboratories, Inc. to Federal Highway Administration (FHWA), Office of Infrastructure Research and Development, Report FHWA-RD-01-156, September 2001]. This corresponds to $300B annually or $1000 per person. This figure includes only the direct costs (e.g., corrosion prevention, corrosion inspection, and replacement or refurbishment of corroded structures). The indirect costs (e.g., lost productivity, taxes, and overhead) were conservatively estimated to be equal to the direct costs. 
     Thus, there is a pressing need to determine or monitor the susceptibility or rate of corrosion of critical structures and components in the field. Because corrosion is an electrochemical process, electrochemical measurements are the most effective means to determine if a material is corroding, is susceptible to corrosion, or is protected from corrosion. These measurements are generally acquired by placing the material being studied (the working electrode) in a liquid electrolyte along with reference and counter electrodes to form an electrochemical cell and using a potentiostat (a controlled power supply with a sensitive zero-resistance ammeter (ZRA) or other galvanometer) to apply a potential or voltage between the reference electrode and the material being studied and measuring the current induced between the material and the counter electrode. The potential can be constant or varying and it and the current can be either DC or AC. The relationship of the current to the potential or the impedance (potential divided by current for ac measurements) allows one skilled in the art to determine whether the material is corroding, susceptible to corrosion or protected from corrosion and if a coating is protective or not. The potentiostats are generally relatively large and heavy bench instruments that require standard electrical power. An example of a prior art potentiostat would be the Gamry Reference 3000 potentiostat that is approximately 20-cm×23-cm×30-cm and weighs approximately 6 kg. 
     In the procedure described above, the material or specimen must be relatively small with dimensions in inches or centimeters to allow the specimen to be immersed in a beaker or other container filled with a suitable electrolyte. For larger specimens or structures that are too large to immerse completely in an electrolyte, electrochemical measurements can sometimes be acquired if the desired area of the structure is horizontal or nearly horizontal by placing a bottomless cylinder (or similar construction) on the structure and sealing it to the structure with an o-ring, gasket, sealant, or other means so that the structure becomes the bottom of the container. Other configurations allow the material to be vertical and form the side of a horizontal cylinder with openings along the top of the cylinder to allow the electrolyte and electrodes to be added. The container is then filled with the appropriate electrolyte and counter and reference electrodes immersed into the electrolyte. A potentiostat is connected to the structures and the electrodes and the electrochemical measurements acquired. Once the measurements are completed, the setup must be reversed with the counter and reference electrodes removed and stored, the electrolyte drained and stored or disposed of, the bottomless cylinder removed, and the structure cleaned of any sealant. Examples of this type of apparatus include the Gamry Instruments PTC1 Paint Test Cell, the Princeton Applied Research Tait Cell K0307, and the Princeton Applied Research Flat Cell K0235. The PTC1 Paint Test Cell and the Flat Cell K0235 require the specimen to be clamped to the open end of the container and thus limit the size and configuration of specimens capable to be studied. The Tait Cell holds the specimen via threaded rods and a backing plate. It could be attached to a large structure provided that holes were drilled into the structure—a practice that is rarely allowed. All require a separate (large) potentiostat to be connected to the electrodes and specimen. 
     An analysis detected a number of documents of interest related to these patents and to the present invention. Table 1 identifies these patents. 
     
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Pat. 
                 Title 
                 Inventor 
               
               
                   
               
             
             
               
                 U.S. Pat. No. 7,265,559 
                 Self-calibrating corrosion measurement field device with improved 
                 Hladky, K. et al. 
               
               
                   
                 signal measurement and excitation circuitry 
               
               
                 U.S. Pat. No. 7,245,132 
                 Intrinsically safe corrosion measurement and history logging field 
                 Poirier, D. M. et 
               
               
                   
                 device 
                 al. 
               
               
                 U.S. Pat. No. 7,239,156 
                 Configurable corrosion measurement field device 
                 Hladky, K et al. 
               
               
                 U.S. Pat. No. 7,180,309 
                 Electronic system for multielectrode sensors and electrochemical 
                 Yang, X. S. 
               
               
                   
                 devices 
               
               
                 U.S. Pat. No. 7,148,706 
                 Embeddable corrosion rate meters for remote monitoring of 
                 Srinivasan, R. et 
               
               
                   
                 structures susceptible to corrosion 
                 al. 
               
               
                 U.S. Pat. No. 7,397,370 
                 Monitoring an environment using a RFID assembly 
                 Bratkovski, A 
               
               
                 US20060144719 
                 Quantitative, real time measurements of localized corrosion events 
                 Gill, R. P. et al 
               
               
                 U.S. Pat. No. 7,034,660 
                 Sensor devices for structural health monitoring 
                 Watters, D. G. et 
               
               
                   
                   
                 al. 
               
               
                 U.S. Pat. No. 6,776,889 
                 Corrosion monitoring 
                 Atherton, E. 
               
               
                 U.S. Pat. No. 6,683,463 
                 Sensor array for electrochemical corrosion monitoring 
                 Yang, L. et al. 
               
               
                 U.S. Pat. No. 6,611,151 
                 Coating assessment system based on electrochemical noise 
                 Ruedisueli, R. L. 
               
               
                   
                   
                 et al. 
               
               
                 U.S. Pat. No. 6,320,395 
                 Apparatus and method for electrochemical corrosion monitoring 
                 Bosch, R.-W et 
               
               
                   
                   
                 al. 
               
               
                 U.S. Pat. No. 6,294,074 
                 Electrode design for corrosion monitoring using electrochemical 
                 Lin, Y. P. J. et al,. 
               
               
                   
                 noise measurements 
               
               
                 U.S. Pat. No. 6,280,603 
                 Electrochemical noise technique for corrosion 
                 Jovancicevic, V. 
               
               
                 US20050122121 
                 Direct Resistance Measurement Corrosion Probe 
                 Gilboe, D. 
               
               
                   
               
             
          
         
       
     
     These patents involve a variety of different means to detect corrosion or the corrosivity of the environment, including fiber optic measurements, strain gauges, electrical resistance, electrochemical noise, current between two electrodes, and degradation of witness material. Some are valid only for metal surfaces; others only for painted surfaces. None include a self-contained electrochemical cell that directly measures electrochemical properties of the structure of interest, stores the results, and transfers them to a portable computer or similar device. 
     SUMMARY OF THE INVENTION 
     The first and most basic electrochemical cell comprises an analytical chamber which can be utilized with existing prior art potentiostats. This chamber has means to contain the necessary electrolyte and means to secure a counter electrode and a reference electrode therein. The chamber also has an adjustable attachment means to permit the chamber to be attached to and then removed from the surface of a substrate of indefinite size. The attachment means allows for nondestructive attachment and removal from a substrate and does not require access to an edge of the substrate to provide the necessary attachment. This feature allows for in-situ electrochemical measurements on portions of existing structures which may be quite large—for example, ships, bridges or buildings. 
     The second embodiment of the invention comprises a self-contained portable electrochemical cell and potentiostat probe which simplifies the steps of determining or monitoring the susceptibility or rate of corrosion of critical structures and components in the field. The probe comprises three components: 1) a miniature potentiostat; 2) a self-contained electrochemical cell; and 3) a means to firmly attach the apparatus to the structure. 
     The electrochemical cell comprises an electrolyte reservoir, a measurement or analytical compartment that is sealed to the substrate of interest via an o-ring or similar sealing means, counter and reference electrodes located in the measurement or analytical compartment, a means to make electrical contact to the structure, and the pump, valves and tubing necessary to transport the electrolyte from the reservoir to the measurement or analytical compartment and the reverse. 
     The probe is suitable for large and small structures and can be attached nondestructively. Measurements can be acquired in the field or in the laboratory. 
     The third embodiment of the invention is a modification of the second embodiment which retains the miniature potentiostat but does away with the fluid handling portions of the second embodiment electrochemical cell. 
     The fourth embodiment of the invention is a modification of the first embodiment which allows for more adjustment of the attachment means to permit the cell to be secured to substrates with irregular surface morphology, e.g. substrates which are not planar or have an irregular surface. 
     The fifth embodiment of the invention is a modification of the third embodiment which retains the self-contained electronics component of the second embodiment and eliminates the fluidics handling portion of the second embodiment. In addition, the fifth electrochemical cell permits accurate temperature control of the electrolyte and of the local substrate area where the electrochemical measurements are being made. This cell also has an attachments means which permits the cell to be secured to substrates with a somewhat irregular surface morphology. 
     The sixth embodiment of the invention is a modification of the fifth embodiment which eliminates the self-contained electronics component and is designed to be used with an external potentiostat. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a block diagram of a generic prior art potentiostat. 
         FIG. 2  shows a prior art electrochemical cell which works with an edge of a sample. 
         FIG. 3  shows a prior art electrochemical cell which can work with a substrate of indefinite size. 
         FIG. 4  shows the most basic electrochemical cell of the invention. 
         FIG. 5  shows a modification of the electrochemical cell shown in  FIG. 4 . 
         FIG. 6  shows a further modification of the electrochemical cell shown in  FIG. 4 . 
         FIG. 7  shows a further modification of the electrochemical cell shown in  FIG. 4 . 
         FIG. 8  shows an-isometric view of the probe of the second embodiment of the invention. 
         FIG. 9  shows a side view of the probe. 
         FIG. 10  shows a cross-sectional view along A-A of  FIG. 9 . 
         FIG. 11  shows another side view of the probe. 
         FIG. 12  shows a cross-sectional view along B-B of  FIG. 11 . 
         FIG. 13  shows a closer view of area C of  FIG. 12 . 
         FIG. 14  shows a block diagram of the electronics component. 
         FIG. 15  shows a block diagram of the fluidics component. 
         FIG. 16  shows the third embodiment of the invention mounted to a vertical substrate. 
         FIG. 17  shows an analytical chamber for use in a further embodiment of the invention shown in  FIG. 16 . 
         FIG. 18  shows an embodiment of the third modification of the invention with the analytical chamber of  FIG. 17  in place. 
         FIG. 19  shows a modification of the analytical chamber shown in  FIG. 17 . 
         FIG. 20  shows an embodiment of the third modification of the invention using the analytical chamber of  FIG. 19 . 
         FIG. 21  shows an embodiment of the cell of  FIG. 7  wherein the attachment means for biasing the cell towards a substrate has a modification to permit attaching the cell to substrates with widely varying surface morphology, e.g. substrates which are not planar or have an irregular surface 
         FIG. 22  shows a plan view of an embodiment of the invention utilizing temperature control and a somewhat more flexible attachment means than the attachment means of the first three embodiments. 
         FIG. 23  shows a side view of the embodiment shown in  FIG. 22 . 
         FIG. 24  shows a bottom view of the test fluid housing with the analytical chamber inserted therein. 
         FIG. 25  shows a cross section of the test fluid housing along section line A-A of  FIG. 24 . 
         FIG. 26  shows details of a coarse height adjustment for the electrochemical cell of  FIGS. 22 and 23 . 
         FIG. 27  shows details of the structure for mounting the electrolyte tank shown in  FIGS. 22 and 23  to the electrochemical cell. 
         FIG. 28  shows a modification of the embodiment of the cell of  FIGS. 22 and 23 , which eliminates the self-contained miniature potentiostat. 
     
    
    
     DETAILED DESCRIPTION 
     It should be understood that the terms “voltage” and “potential” are used interchangeably herein and mean the same thing. 
       FIG. 1  shows a block diagram of a generic prior art potentiostat  10  comprising of a voltage/current generator  11 ; a electrometer  12  to measure the current induced by applied voltage or to measure the voltage induced by applied current; a means  13  to make electrical connection to the specimen being measured; a means  14  to make electrical connection to reference and counter electrodes immersed into an electrolyte along with the specimen; a means  15  to convert the measurement into an electrochemical impedance measurement; and a means for input/output  16 . 
       FIG. 2  shows a prior art electrochemical cell that is designed to grip a sample specimen at an edge thereof. Most prior art electrochemical cells are designed to make electrochemical measurements on small size samples or on samples which allow for the cell to be secured to one edge thereof. 
     In the first situation, the substrate of interest has to be small enough to fit within the electrochemical cell. If the substrate of interest is not small enough to fit within the electrochemical cell, the substrate would have to be partially destroyed by physically removing a suitably sized sample coupon. This sample coupon is then inserted into the cell in order to make the desired measurements. 
     In the second situation, the substrate of interest has to be small enough to be inserted into the sample slot in the electrochemical cell or the substrate of interest must have an edge of a limited size and orientation on which the cell can be fastened in order to make the desired electrochemical measurements. 
       FIG. 2  illustrates this latter type of prior art device. This figure corresponds to a commercially available electrochemical cell known as Princeton Applied Research Flat Cell Model K0235. Cell  70  comprises a glass cylinder  72  with ports  74  and  76  therein for receiving a counter electrode and a reference electrode (not shown). The cell is closed at one end by a plate  78  and at the other end by fixture  80 . Fixture  80  has a slot  82  to permit a portion of sample  92  to be inserted therein. Screw  88  is threaded into wall  86  of fixture  80  to bias the sample  92  against wall  84  of fixture  80 . Wall  84  of fixture  80  has an electrolyte opening  90  therein to permit electrolyte contained in cylinder  72  to contact the surface of sample  92 . Plate  78  and fixture  80  are secured at each end of cylinder  72  by threaded rods  94  which are secured to plate  78  and fixture  80  by nuts  96 . 
     In practice some sort of sealing means [not shown] would normally be provided around electrolyte opening  90  to seal opening  90  against the surface of sample  92 . This might take the form of an O-ring, gasket or other suitable device. Electrolyte is then poured into the cylinder  72  to a suitable level and a reference electrode and a counter electrode are mounted in ports  74  and  76  and suspended in the electrolyte within cylinder  72 . A known prior art potentiostat is connected to the working electrode [sample  92 ] and the reference and counter electrodes and any desired electrochemical measurements may be made. 
     Cell  70  is normally limited to handling samples of a limited size such that they can fit into the slot  82  in fixture  80  and such that they can be supported by cell  70 . If it is desired to fasten cell  70  to a larger sample, the orientation and size of the portion of the sample which must enter slot  82  becomes extremely important. This portion has to be generally vertical and sized and oriented such that cell  70  can be fastened thereto. Since ports  74  and  76  are not normally sealed, cell  70  is clearly designed to function only in a generally horizontal orientation. 
     In certain instances it is known in the prior art to adhere a cylindrical electrochemical cell to a generally horizontal substrate of interest. The cell may comprise a section of non-metallic tubing which is open at the top and wherein the bottom end of the tubing is fastened to the substrate with adhesive. The substrate of interest thus becomes the bottom wall of the cell. There is no intent with this type of device that the cell be easily removable and repositionable. The adhesive used is quite strong and would require serious force to be applied for removal. The forces involved usually cause damage to the tubing and to the substrate. 
       FIG. 3  illustrates this type of prior art device. Open cylinder  100  is adhered to substrate  102  by adhesive  104 . Cylinder  100  may be made from any suitable non-metallic material, such as glass, PVC or other suitable plastic. Electrolyte is then poured into the cylinder  100  to a suitable level and a reference electrode [not shown] and a counter electrode [not shown] are suspended within the electrolyte. A known prior art potentiostat is connected to the working electrode [substrate  102 ] and the reference and counter electrodes and any desired electrochemical measurements may be made. 
     In contrast to the prior art devices, the electrochemical cell of the present invention even in its most basic form does not required damage to be done to the cell or to the substrate in order to take the desired electrochemical measurements. A minor cleaning of the surface in the area affected by the cell mounting means may be required. This would comprise removal of any contaminants or loose material which could adversely affect the mounting. Depending upon the type of electrochemical measurements being taken, any coating material in the immediate vicinity of the testing area might have to be removed to secure access to the underlying metal, but this may not be necessary if the cell is used to make electrochemical measurements on the coating of the substrate. 
     In addition, the mounting means of the present invention permits electrochemical measurements to be made on substrates of indefinite size, such as ships, planes, bridges or buildings. The surfaces to be measured do not have to be strictly planar and may, indeed, be somewhat curved. 
       FIG. 4  shows an electrochemical cell  108  comprising a cylinder  110  which is open at the top end and has sealing means  112  attached to the bottom end. This may take the form of an O-ring, gasket or any other suitable sealing means. Ports  114  and  116  are provided for insertion of a reference electrode and a counter electrode (not shown). These ports are designed such that the port with an electrode inserted therein would be liquid tight. This could be accomplished, for example, by the use of a plug which held the electrode therein. The plug could be secured and sealed within port  114  and/or  116  using an O-ring, gasket, screw threads or any other suitable means. 
     At least one mounting means  118  is provided to removably and nondestructively secure call  108  to a surface of substrate  102 . In this figure mounting means  118  and an identical mounting means  118 ′ are shown. Mounting means  118 ,  118 ′ provide for adjustment of the cell  108  towards and away from substrate  102 . This allows for the bottom end of cylinder  110  to be biased against substrate  102  and permits sealing means  112  to seal cell  108  against substrate  102 . Mounting means  118 ,  118 ′ have a generally horizontal attachment arm  120 ,  120 ′ which secures the mounting means to cylinder  110 . In addition mounting means  118 ,  118 ′ have a generally vertical leg  122 ,  122 ′ to hold securing means  124 ,  124 ′. As shown, leg  122 ,  122 ′ can move vertically on arm  120 ,  120 ′. Securing means  124 ,  124 ′ may comprise a suction cup, a magnet, releasable adhesive means or any other device capable of releasably and nondestructively securing cell  108  to one surface of substrate  102 . Certain applications may be such that only one mounting means  118  is necessary, however two mounting means  118  will be necessary in many applications and three mounting means  118  is considered the optimal number for general usage, although more may be provided as the situation requires. Each mounting means is independently adjustable in the vertical direction. This permits the cell  108  to be used on non-planar surfaces. 
     Operation: 
     In operation, substrate  102  would be cleaned as necessary for the desired measurements. This would involve cleaning in the area where securing means  124 ,  124 ′ would contact substrate  102 . In addition, the area of substrate which would be directly under the footprint of cylinder  110  would be cleaned and any coating in this area may have to be removed in order to make the desired electrochemical measurements. Cell  108  would be then be secured to substrate  102  using mounting means  118 ,  118 ′. The mounting means would be adjusted to bias cell  108  against the surface of substrate  102  to seal cell  108  to substrate  102  by compressing sealing means  112 . A suitable reference electrode and suitable counter electrode would be secured in ports  114  and  116 . The cell would be filled with a suitable electrolyte. A conventional prior art potentiostat (not shown) would be electrically connected to the reference electrode and the counter electrode. In addition, the potentiostat would be electrically connected to the working electrode (substrate  102 ) and the desired electrochemical measurements taken. When the necessary electrochemical measurements are completed, the cell is emptied of electrolyte and sealing means  124 ,  124 ′ are removed from substrate  102 . The potentiostat would be disconnected from the cell and the reference and counter electrodes removed and stored for further use. Any spilled electrolyte would be cleaned up and the substrate  102  would be returned to its original condition. This might involve mild cleaning in the area of securing means  124 ,  124 ′ if a releasable adhesive is used in securing means  124 ,  124 ′ or an even more minimal cleaning if securing means  124 ,  124 ′ involve the use of suction cups or magnets. The surface of substrate  102  in the area of the bottom opening of cylinder  110  might have to be recoated if a coating was removed to make the desired measurements. 
       FIG. 5  shows a modification of the electrochemical cell of  FIG. 4 . The electrochemical cell  130  of  FIG. 5  comprises a cylinder  132  which is open at the top end and has a plate  138  closing its bottom end. Plate  138  may be removably secured to the bottom of cylinder  132  or it may optionally be integral with cylinder  132 . Plate  138  has an electrolyte opening  140  therein. This electrolyte opening  140  is provided with a sealing means  142  surrounding electrolyte opening  140  at the exterior surface of plate  138  to seal cylinder  132  and plate  138  to the surface of substrate  102 . Sealing means  142  may take the form of an O-ring, gasket or any other suitable means. Ports  134  and  136  are provided for insertion of a reference electrode and a counter electrode (not shown). These ports are designed such that the port with an electrode inserted therein would be liquid tight. This could be accomplished, for example, by the use of a plug which held the electrode therein. The plug could be secured and sealed within port  134  and/or  136  using an O-ring, gasket, screw threads or any other suitable means. 
     At least one mounting means  158  is provided to removably and nondestructively secure call  108  to a surface of substrate  102 . In this figure two mounting means  158 ,  158 ′ are shown. Mounting means  158 ,  158 ′ provide for adjustment of the cell  130  towards and away from substrate  102 . This allows for the electrolyte opening  140  in plate  138  to be biased against substrate  102  and permits sealing means  142  to seal cell  130  against substrate  102 . 
     Mounting means  158 ,  158 ′ has a generally horizontal attachment arm  160 ,  160 ′ which secures the mounting means to cylinder  132 . In addition mounting means  158 ,  158 ′ has a generally vertical leg  162 ,  162 ′ to mount securing means  164 ,  164 ′ to the mounting means. As shown, leg  162 ,  162 ′ can move vertically on arm  160 ,  160 ′. Securing means  164 ,  164 ′ may comprise a suction cup, a magnet, releasable adhesive means or any other device capable of releasably and nondestructively securing cell  108  to one surface of substrate  102 . 
     Certain applications may be such that only one mounting means  158  is necessary, however two mounting means  158 ,  158 ′ are considered necessary in most applications and three mounting means are considered the optimal number for general usage although more may be provided as desired. Each mounting means is independently adjustable in the vertical direction. This permits the cell  130  to be used on non-planar surfaces. 
     In operation, substrate  102  would be cleaned as necessary for the desired measurements. This would involve cleaning in the area where securing means  164 ,  164 ′ would contact the surface of substrate  102 . In addition, the area of substrate  102  which would be directly under the footprint of electrolyte opening  140  would be cleaned and any coating in this area may have to be removed in order to make the desired electrochemical measurements. Cell  130  would be then be secured to the surface of substrate  102  using mounting means  158 ,  158 ′. The mounting means would be adjusted to bias cell  130  against surface  102  to seal cell  130  to substrate  102  using sealing means  142 . A suitable reference electrode and a suitable counter electrode (not shown) would be secured in ports  134  and  136 . The cell would be filled with a suitable electrolyte. A conventional prior art potentiostat (not shown) would be electrically connected to the reference electrode and the counter electrode. In addition, the potentiostat would be electrically connected to the working electrode (substrate  102 ) and the desired electrochemical measurements taken. 
     When the desired electrochemical measurements have been collected, the electrolyte would be removed from cell  130 , the potentiostat disconnected, and the reference and counter electrodes removed from ports  134  and  136 . The cell  130  would then be removed from substrate  102  and any necessary cleaning of substrate  102  performed. Since the area of the electrolyte opening  140  is substantially less than the entire cross-section of cylinder  132 , replacement of any coating of substrate  102  would be simpler than when using the electrochemical cell of  FIG. 4 . 
       FIG. 6  shows an electrochemical cell which is a further modification of the electrochemical cell shown in  FIG. 4 . The electrochemical cell  130  of  FIG. 6  comprises a cylinder  172  which is closed at the top end by plate  174  and has a plate  178  closing its bottom end. Plates  174  and  178  may be removably secured to the cylinder  172  or they may optionally be integral with cylinder  172 . Plate  178  has an electrolyte opening  180  therein. This electrolyte opening  180  is provided with a sealing means  182  surrounding electrolyte opening  180  at the exterior surface of plate  178  to seal cylinder  172  and plate  178  to the surface of substrate  102 . Sealing means  182  may take the form of an O-ring, gasket or any other suitable means. 
     Ports  174  and  176  are provided for insertion of a reference electrode and a counter electrode (not shown). These ports are designed such that the port with an electrode inserted therein would be liquid tight. This could be accomplished, for example, by the use of a plug which held the electrode therein. The plug could be secured and sealed within port  174  and/or  176  using an O-ring, gasket, screw threads or any other suitable means. 
     Plate  174  has a filling/drain port  208  incorporated therein to permit the cell  170  to be filled with electrolyte. This filling/drain means incorporates a valve  210  to open and/or close port  208 . This will permit the cell  170  to be conveniently emptied of electrolyte when the desired measurements have been taken as will be discussed below in the operation section. 
     At least one mounting means  198  is provided to removably and nondestructively secure cell  170  to a surface of substrate  102 . In this figure two mounting means  198 ,  198 ′ are shown. Mounting means  198 ,  198 ′ provide for adjustment of the cell  170  towards and away from substrate  102 . This allows for the electrolyte opening  180  in plate  178  to be biased against substrate  102  and permits sealing means  182  to seal cell  170  against substrate  102 . 
     Mounting means  198 ,  198 ′ have a generally horizontal attachment arm  200 ,  200 ′ which secures the mounting means to cylinder  172 . In addition mounting means  198 ,  198 ′ has a generally vertical leg  202 ,  202 ′ to mount securing means  204 ,  204 ′ to the mounting means. As shown, leg  202 ,  202 ′ can move vertically on arm  200 ,  200 ′. Securing means  204 ,  204 ′ may comprise a suction cup, a magnet, releasable adhesive means or any other device capable of releasably and nondestructively securing cell  170  to one surface of substrate  102 . 
     Certain applications may be such that only one mounting means  198  is necessary, however two mounting means  198 ,  198 ′ are considered necessary in most applications and three mounting means are considered the optimal number for general usage although more may be provided as desired. Each mounting means is independently adjustable in the vertical direction. This permits the cell  170  to be used on non-planar surfaces. 
     Operation: 
     In operation, substrate  102  would be cleaned as necessary for the desired measurements. This would involve cleaning in the area where securing means  204 ,  204 ′ would contact the surface of substrate  102 . In addition, the area of substrate  102  which would be directly under the footprint of electrolyte opening  180  would be cleaned and any coating in this area may have to be removed in order to make the desired electrochemical measurements. Cell  170  would be then be secured to the surface of substrate  102  using mounting means  198 ,  198 ′. The mounting means would be adjusted to bias cell  170  against surface  102  to seal cell  170  to substrate  102  using sealing means  182 . A suitable reference electrode and a suitable counter electrode (not shown) would be secured in ports  174  and  176 . The cell would be filled with a suitable electrolyte using filling/draining port  208 . A conventional prior art potentiostat (not shown) would be electrically connected to the reference electrode and the counter electrode. In addition, the potentiostat would be electrically connected to the working electrode (substrate  102 ) and the desired electrochemical measurements taken. 
     When the desired electrochemical measurements have been collected, the electrolyte can be removed from cell  170  by closing valve means  210  and then quickly removing cell  170  from substrate  102  and then inverting the cell  170 . A small amount of electrolyte would be spilled during this procedure, but most all of the electrolyte will be secured inside cell  170 . Then valve means  210  may be used to drain the used electrolyte where and when desired. The potentiostat (not shown) can be disconnected, and the reference and counter electrodes removed from ports  174  and  176 . At this time any necessary cleaning of substrate  102  performed. Since the area of the electrolyte opening  180  is substantially less than the entire cross-section of cylinder  172 , replacement of any coating of substrate  102  would be simpler than when using the electrochemical cell of  FIG. 4 . 
       FIG. 7  shows a further modification of the electrochemical cell shown in  FIG. 4 . The electrochemical cell  270  of  FIG. 7  comprises a cylinder  272  which is closed at the top end by plate  273  and has a necked-down portion  286  closing its bottom end. Plates  273  and necked-down portion  286  may be removably secured to the cylinder  272  or they may optionally be integral with cylinder  272 . Necked-down portion  286  has an electrolyte opening  280  therein. This electrolyte opening  280  is provided with a sealing means  282  surrounding electrolyte opening  280  at the exterior surface of necked-down portion  286  to seal cell  270  to the surface of substrate  102 . Sealing means  282  may take the form of an O-ring, gasket or any other suitable means. 
     Ports  274  and  276  are provided for insertion of a reference electrode (not shown) and a counter electrode (not shown). These ports are designed such that the port with an electrode inserted therein would be liquid tight. This could be accomplished, for example, by the use of a plug which held the electrode therein. The plug could be secured and sealed within port  274  and/or  276  using an O-ring, gasket, screw threads or any other suitable means. 
     Plate  273  has a filling/drain port  308  incorporated therein to permit the cell  270  to be filled with electrolyte. This filling/drain means incorporates a valve  310  to open and/or close port  308 . This will permit the cell  270  to be conveniently emptied of electrolyte when the desired measurements have been taken as will be discussed below in the operation section. 
     Necked-down portion  286  is provided with a valve  284  near electrolyte opening  280 . This permits the electrolyte opening  280  to be opened or closed. Valve  284  may be a rotary valve, a slide valve or any other suitable type of valve. 
     At least one mounting means  298  is provided to removably and nondestructively secure cell  270  to a surface of substrate  102 . In this figure two mounting means  298 ,  298 ′ are shown. Mounting means  298 ,  298 ′ provide for adjustment of the cell  270  towards and away from substrate  102 . This allows for the electrolyte opening  280  in necked-down portion  286  to be biased against substrate  102  and permits sealing means  282  to seal cell  270  against substrate  102 . 
     Mounting means  298  and  298 ′ have a generally horizontal attachment arm  300 ,  300 ′ which secures the mounting means to cylinder  272 . In addition mounting means  298 ,  298 ′ has a generally vertical leg  302 ,  302 ′ to mount securing means  304 ,  304 ′ to the mounting means. As shown, legs  302  and  302 ′ can move vertically on arms  300 ,  300 ′. Securing means  304 ,  304 ′ may comprise a suction cup, a magnet, releasable adhesive means or any other device capable of releasably and nondestructively securing cell  270  to one surface of substrate  102 . 
     Certain applications may be such that only one mounting means  298  is necessary, however two mounting means  298 ,  298 ′ are considered necessary in most applications and three mounting means are considered the optimal number for general usage although more may be provided if desired or necessary. Each mounting means is independently adjustable in the vertical direction. This permits the cell  270  to be used on non-planar surfaces. 
     Operation: 
     In operation, substrate  102  would be cleaned as necessary for the desired measurements. This would involve cleaning in the area where securing means  304 ,  304 ′ would contact the surface of substrate  102 . In addition, the area of substrate  102  which would be directly under the footprint of electrolyte opening  280  would be cleaned and any coating in this area may have to be removed in order to make the desired electrochemical measurements. Cell  270  would be then be secured to the surface of substrate  102  using mounting means  298 ,  298 ′. The mounting means would be adjusted to bias cell  270  against surface  102  to seal cell  270  to substrate  102  using sealing means  282 . A suitable reference electrode (not shown) and a suitable counter electrode (not shown) would be secured in ports  274  and  276 . The cell would be filled with a suitable electrolyte using filling/draining port  308 . During the filling process, valve  284  would be closed. A conventional prior art potentiostat (not shown) would be electrically connected to the reference electrode and the counter electrode. In addition, the potentiostat would be electrically connected to the working electrode (substrate  102 ). At this time valve  284  would be opened to permit electrolyte from the interior of the cell  270  to access the working electrode (substrate  102 ). The desired electrochemical measurements may then be taken. 
     When the desired electrochemical measurements have been collected, the cell  270  may be removed from substrate  102  after closing valve means  310  and  284 . Securing means  304 ,  304 ′ would be removed from substrate  102  and the cell  270  lifted off substrate  102 . A small amount of electrolyte might be spilled on the surface of substrate  102  in the removal process, but most all of the electrolyte will be secured inside cell  270 . The small amount spilled can be easily cleaned up. Once cell  270  is separated from substrate  102  and the potentiostat leads are disconnected, electrolyte may be drained from cell  270  using valves  284  and/or  310 . Then the reference and counter electrodes (not shown) may be removed from ports  274  and  276 . 
     At this time any necessary cleaning of substrate  102  performed. Since the area of the electrolyte opening  280  is substantially less than the entire cross-section of cylinder  272  and since valves  284  and  310  operate to secure most all of the electrolyte inside cell  270  during removal, clean-up of spilled electrolyte is minimal. At this time, any necessary cleanup of the areas of substrate  102  under securing means  304 ,  304 ′ can be performed and any coating of substrate  102  removed because of the electrochemical measurement process can be replaced in order to restore substrate  102  to its original condition. 
       FIG. 8  shows an isometric view of the probe  20  of the second embodiment of the invention. The probe housing  21  is shown with the electronics component housing  22  and the attachment mechanism  24 . In this drawing the attachment mechanism comprises suction cups, but it could also be magnets, clamps, screws, bolts, or other means of attachment. 
       FIG. 9  shows another view of the probe  20 . Electrical contact to a bare (uncoated) surface substrate is provided by springs  34 . These springs provide a means to apply a voltage or current to a substrate of interest. The springs also provide a means for making electrical measurements. For a coated substrate, electrical connection would be provided by a separate lead (not shown). The port  31  allows the reference electrode  32  in  FIG. 10  to be inserted into the probe and easily replaced from the outside of the probe. An air/liquid separator  38  allows the air to escape from the measurement chamber as it is being flooded. The thumb screw  52  holds in place an optional removable container filled with electrolyte. 
     The electronics component  50  ( FIGS. 12 and 14 ) is contained in housing  22 . The interface connector  56  allows for connection to a computer or other device to enable programming the electronics component  50  and to output data. In addition, the probe could be powered with electrical energy supplied via connector  56 . The data transfer and programming can be accomplished via connector  56  or by other means such as a wireless transmission. 
       FIG. 10  shows a cross-sectional view of the probe along line A-A of  FIG. 9 . It shows the probe housing  21  with the attachment mechanism  24 . The analytical chamber  30  is sealed to the substrate surface (not shown) by an o-ring  36 . Electrical contact to a bare (uncoated) surface is provided by springs  34 . For a coated substrate, electrical connection is would be provided by a separate lead (not shown). The reference electrode  32  and the counter electrode  33  are mounted in analytical chamber  30 . The electrolyte reservoir  44  holds the electrolyte until it is transferred to the analytical chamber  30  with the pumps and valves in the fluidics compartment  40 . The electrolyte reservoir  44  may be a refillable tank (not shown) which is integral with probe housing  21  or, more preferably, a removable container filled with electrolyte which can be held in place by thumb screw  52 . 
     Reference electrode  32  could be any of several commercially available reference electrodes such as a saturated calomel electrode (SCE) or any other electrode suitable for the type of electrochemical measurement desired. In  FIGS. 10 and 12 , reference electrode  32  is illustrated as a rod-type electrode. The counter electrode  33  is illustrated in  FIGS. 3 b  and 4 b    as a stainless steel mesh but it could take other forms such as a stainless steel or graphite rod or any other type of electrode suitable for the measurement desired. The choice of a suitable electrolyte would depend upon the exact type of measurement or test being performed. For example, in naval or marine corrosion tests, the electrolyte might be a saline solution to simulate sea water. Alternatively the electrolyte might be an acidic solution, an alkaline solution or a neutral solution depending upon the type of test being performed. 
       FIG. 11  shows a second view of the probe  20  showing the probe housing  21  with the attachment mechanism  24 . Control  42  allows adjustment of the probe height to assure sealing to the substrate. Electrical contact to a bare (uncoated) substrate is provided by springs  34 . For a coated substrate, electrical connection would be provided by a separate lead (not shown). Digital display  54  is mounted in electronics component housing  22 . 
       FIG. 12  shows a cross-sectional view of the probe along line B-B of  FIG. 11  showing the probe housing  21  with the attachment mechanism  24 . The electrolyte reservoir  44  holds the electrolyte until it is transferred to the analytical chamber  30  with the pumps and valves in the fluidics compartment  40 . 
       FIG. 13  shows a detail of area C of  FIG. 12  showing one spring  34  and o-ring  36 . 
       FIG. 14  shows a block diagram of the electronics component  50  comprising potentiostat  60 , fluidics control  62 , digital display  54 , and input/output means  66  all controlled by microprocessor  64 . Input/output means  66  enables programming instruction input and data output to an external computer or other device (not shown). An optional power supply  68  may be part of electronics component  50  or power may be supplied from a source external to the probe  20 . Input/output means  66  may also provide for wireless transfer of information. 
     Potentiostat  60  can apply a potential between reference electrode  32  and a surface of a substrate. It can also apply a current between counter electrode  33  and a surface of a substrate. Potentiostat  60  also has an electrometer capable of measuring the potential between a surface of a substrate and reference electrode  32  as a function of time or as a function of applied current and also capable of measuring a current between counter electrode  33  and a surface of a substrate as a function of time or as a function of applied voltage. The applied potential and/or current may be constant, they may vary (e.g. be ramped). The applied potential and/or current may be either AC or DC. When the applied potential and/or current are AC, the frequency may be varied. 
     Microprocessor  64  preferably includes a clock to provide time stamp information and storage means to store the collected data. 
       FIG. 15  shows a block diagram of the fluidics system including the reservoir tank  44 , the pumps and valves system  40 , the analytical chamber  30  sealed with o-ring  36  to the material of interest  60 . Also shown is the air separator and valve  38  to allow the air in the analytical chamber  30  to be exhausted during the filling operation. The air filter  46  allows air to be readmitted to the analytical chamber  30  during the draining operation. Emergency vent  52  allows air to enter or leave the analytical chamber in case of an under or over pressure event. 
     Operation: 
     An operator or inspector will prepare the surface to be examined in a manner suitable for the measurement to be made. This preparation could include a simple cleaning of the surface, light abrasion to expose a fresh surface, heavy abrasion or grit blasting to remove material such as a paint coating if the underlying metal is to be examined. The operator would mount the apparatus onto the surface using suction cups, magnets, or other attachment means. The operator would then program the unit to take whatever electrochemical measurements are desired. These measurements could include a potential sweep or hold with the current being measured as a function of potential or of time, a current sweep or hold with the voltage being measured as a function of current or time, an oscillatory (ac) potential with the frequency being swept or held with the current being measured as a function of frequency, or the open circuit potential and current being measured as a function of time. The electrolyte would be transferred from the reservoir to the analysis chamber and the measurements being acquired either immediately or after an appropriate hold time. After the measurements are completed, the electrolyte would be transferred back to the reservoir and the unit removed from the structure. Data could then be transferred to a portable computer or similar device for analysis. 
       FIG. 16  shows the third embodiment of the electrochemical cell of the invention mounted to a generally vertical surface  103 . The previous electrochemical cells have all been illustrated as taking electrochemical measurements on horizontal substrates. The electrochemical cell of this invention may be used to make electrochemical measurements on substrates which are not horizontal. In particular the closed cell embodiments as shown in  FIGS. 6 and 7  are suitable for making measurements on vertical substrates. Since the mounting means will mount the cell to essentially any substrate, measurements can even be made on substrates which are inclined past vertical. In addition, the previous embodiments were designed for use with a conventional prior art potentiostat. It is possible to provide an electronics package to the previous embodiments and give them the capability to function without an external potentiostat. The embodiment shown in  FIG. 16  is particularly suited for making such measurements. 
     The electrochemical cell  370  of  FIG. 16  comprises a cylinder  372  which is closed at one end by plate  373  and has a necked-down portion  386  closing the other end. Plate  373  and necked-down portion  386  may be removably secured to the cylinder  372  or they may optionally be integral with cylinder  372 . Necked-down portion  386  has an electrolyte opening  380  therein. This electrolyte opening  380  is provided with a sealing means  382  surrounding electrolyte opening  380  at the exterior surface of necked-down portion  386  to seal cell  370  to the surface of a substrate  103 . Sealing means  382  may take the form of an O-ring, gasket, releasable adhesive or any other suitable means. 
     Ports  374  and  376  are provided for insertion of a reference electrode (not shown) and a counter electrode (not shown). These ports are designed such that the port with an electrode inserted therein would be liquid tight. This could be accomplished, for example, by the use of a plug which held the electrode therein. The plug could be secured and sealed within port  374  and/or  376  using an O-ring, gasket, screw threads, releasable adhesive or any other suitable means. 
     A filling/drain port  408  is incorporated into a suitable portion of cylinder  372  in order to permit the cell  370  to be filled with electrolyte when cylinder  372  is disposed in a generally horizontal position as it would be if cell  370  was secured to a generally vertical substrate  103 . This filling/drain means incorporates a valve  410  to open and/or close port  408 . A similar filling/drain port  408 ′ is provided at a suitable location on cylinder  372  generally opposite to filling/drain port  408 . Filling/drain port  408 ′ has a valve  410 ′ which permits filling/drain port  408 ′ to be opened or closed. This provision of a filling/drain port  408 ′ will permit the cell  370  to be conveniently emptied of electrolyte while cell  370  remains mounted to the generally vertical substrate  103 . This will be further discussed below in the operation section. 
     An air-liquid separator  311  is provided in a portion of cylinder  372  near port  408 . This permits gasses (e.g. air) trapped inside cell  370  to escape while the cell  370  is being filled with electrolyte. Air-liquid separator  311  does not have to be near the port  408 . Other locations could be used as desired. The air-liquid separator simply has to be in suitable position so as to permit gasses to be exhausted from cell  370  as electrolyte is introduced therein. It is assumed, herein, that cell  370  would usually be mounted to the generally vertical substrate prior to filling the cell with electrolyte although this is not absolutely necessary. 
     Necked-down portion  386  is provided with a valve  384  near electrolyte opening  380 . This permits the electrolyte opening  380  to be opened or closed. Valve  384  may be a rotary valve, a slide valve or any other suitable type of valve. 
     Housing  412  is secured to plate  373 . This housing contains electronics component  420  which comprises a miniature potentiostat and the necessary means to initiate, monitor and control the electrochemical measurement process. Electronic component  420  also has means therein to store the electrochemical measurements when they are taken and means to output said stored measurements when desired. This electronics component is similar to electronics component  50  shown in  FIGS. 12 and 14  and described earlier. Jack  424  is provided in housing  412  to permit an electrical connection from the electronics component  420  to a counter electrode (not shown). Jack  426  is provided in housing  412  to enable electrical connection between the electronic component  420  and the working electrode (in this instance, generally vertical substrate  103 ). Jack  428  is provided to enable electrical connection between electronics component  420  and a reference electrode (not shown). 
     At least one mounting means  398  is provided to removably and nondestructively secure cell  370  to a surface of generally vertical substrate  103 . In this figure two such mounting means  398 ,  398 ′ are shown. Mounting means  398 ,  398 ′ provide for adjustment of the cell  370  towards and away from generally vertical substrate  103 . This allows for the electrolyte opening  380  in necked-down portion  386  to be biased against substrate  103  and permits sealing means  382  to seal cell  370  against substrate  103 . 
     Mounting means  398  and  398 ′ have an attachment arm  400 ,  400 ′ which secures the mounting means to cylinder  372 . In addition mounting means  398 ,  398 ′ have a leg  402 ,  402 ′ to mount securing means  404 ,  404 ′ to the mounting means. As shown, legs  402  and  402 ′ can move along the longitudinal axis of cylinder  372  across arms  400 ,  400 ′. Securing means  404 ,  404 ′ may comprise suction cups, magnets, releasable adhesive means or any other device capable of releasably and nondestructively securing cell  370  to one surface of generally vertical substrate  103 . 
     It is possible that two mounting means  398 ,  398 ′ would be sufficient to mount cell  370  to generally vertical substrate  103  but it is more likely that three such mounting means would be considered the optimal number for a vertical measurement. Obviously, more than three mounting means could be used, if desired. Each mounting means is independently adjustable along the longitudinal axis of cylinder  372  in order to permit the cell  370  to be used on non-planar surfaces. 
     Operation: 
     In operation, substrate  103  would be cleaned as necessary for the desired measurements. This would involve cleaning in the area where securing means  404 ,  404 ′ would contact the surface of substrate  103 . In addition, the area of substrate  103  which would be directly under the footprint of electrolyte opening  380  would be cleaned and any coating in this area may have to be removed in order to make the desired electrochemical measurements. 
     Cell  370  would then be secured to the surface of generally vertical substrate  103  using mounting means  398 ,  398 ′. The mounting means would be adjusted along the longitudinal axis of cylinder  372  to bias cell  370  against surface  103  in order to seal cell  370  to substrate  103  using sealing means  382 . A suitable reference electrode (not shown) and a suitable counter electrode (not shown) would be secured in ports  374  and  376 . 
     Electrical connections between electronics component  420  and the reference and counter electrodes would be made using jacks  428  and  424 . In addition, electronics component  420  would be electrically connected to the working electrode (generally vertical substrate  103 ) using jack  426 . The cell would be filled with a suitable electrolyte using filling/draining port  408 . During the filling process, valves  384  and  410 ′ would be closed. When the cylinder  372  is filled with electrolyte, valve  384  would be opened to permit electrolyte from the interior of the cell  370  to access the working electrode (generally vertical substrate  103 ). The desired electrochemical measurements may then be taken. 
     When the measurements have been collected, the cell  370  may be removed from generally vertical substrate  103  after making sure that valve means  410 ,  410 ′ and  384  are closed. Securing means  404 ,  404 ′ would be removed from generally vertical substrate  103  and the cell  370  lifted off. A small amount of electrolyte might be spilled in the removal process, but most all of the electrolyte will be secured inside cell  370 . The small amount spilled can be easily be cleaned up. Once cell  370  is separated from generally vertical substrate  103  and the electronic component leads are disconnected, electrolyte may be drained from cell  370  using valves  234 ,  410  and  410 ′. Then the reference and counter electrodes (not shown) may be removed from ports  374  and  376 . 
     At this time any necessary cleaning of generally vertical substrate  103  may be performed. Since the area of the electrolyte opening  380  is substantially less than the entire cross-section of cylinder  372  and since valves  384 ,  410  and  410 ′ operate to secure most all of the electrolyte inside cell  370  during removal, clean-up of spilled electrolyte is minimal. At this time, any necessary clean up of the areas of generally vertical substrate  103  under securing means  404 ,  404 ′ can be performed and any coating previously removed from the surface of generally vertical substrate  103  prior to initiating the electrochemical measurement process can be replaced in order to restore generally vertical substrate  103  to its original condition. 
       FIG. 17  illustrates an analytical chamber  471  designed to be used with another embodiment of the electrochemical cell of the invention illustrated in  FIG. 18 . 
     The analytical chamber  471  of  FIG. 17  comprises a cylinder  473  which is closed at the top end by removable portion  475  and closed at the bottom by plate  477 . Plate  477  may be removably secured to the cylinder  473  (not shown) or it may be integral with cylinder  473  as shown. Removable portion  475  is removably secured to cylinder  473  by any suitable means. For example, an O-ring (not shown) could be used to removably secure portion  475  to cylinder  473  or screw threads could be used or any other suitable means. An electrolyte opening  479  is provided in the bottom plate  477 . A slide valve  485  is secured to the bottom portion of plate  477  at the external side thereof. Slide valve  485  permits electrolyte opening  479  to be open or closed depending upon the position of slide valve  485 . Sealing means  487  is provided between electrolyte opening  479  and slide valve  485  to prevent electrolyte leakage when slide valve  485  is closed. Sealing means  487  may take the form of an O-ring, gasket, releasable adhesive or any other suitable means. 
     The analytical chamber  471  also has openings  481  and  483  in plate  477 . These openings permit a reference electrode (not shown) and a counter electrode (not shown) to penetrate to the interior of analytical chamber  471  when the analytical chamber is inserted into the electrochemical cell  490  shown in  FIG. 18   
     A resealable elastomeric material  488 ,  488 ′ is placed inside openings  481  and  483  to seal them. This material permits the electrodes to penetrate into the analytical chamber and then seals itself when the electrodes are removed. 
     This resealable elastomeric material may be similar to the type of material used to seal multi-dose vials in the medical arts. These vials hold multiple doses of medicines which are intended to be injected into a patient. The needle of a hypodermic syringe penetrates the elastomeric material permitting a single dose of the medicine to be withdrawn into the hypodermic syringe and the needle is then withdrawn from the vial. As the needle leaves the elastomeric material, it seals itself. 
     It is also possible (although not shown in  FIG. 17 ) to use a pressure sensitive adhesive tape to seal openings  481 ,  483 . The tape could cover the electrode openings at the inner or outer surface of plate  477  and thus seal them prior to use. When the reference and counter electrodes penetrate into openings  481  and  483 , they will easily puncture the pressure sensitive tape and the cell would be ready to use. 
       FIG. 18  illustrates another embodiment of the electrochemical cell of the invention. Unlike the previous embodiments this embodiment has a removable analytical chamber. It also has an electronics component similar to the one shown at  50  in  FIG. 11  and shown at  420  in  FIG. 16 . 
     The electrochemical cell  490  shown in  FIG. 18  comprises a separate analytical chamber  471  as shown in  FIG. 17  and a base fixture  472 . Analytical chamber  471  comprises a cylinder  473  which is closed at the top end by removable portion  475  and closed at the bottom by bottom plate  477 . Bottom plate  477  may be removably secured to the cylinder  473  or it may be integral with cylinder  473  as shown. Removable portion  475  is removable secured to cylinder  473  by any suitable means. For example, an O-ring (not shown) could be used to removably secure portion  475  to cylinder  473  or screw threads could be used or any other suitable means. An electrolyte opening  479  is provided in the bottom plate  477 . A slide valve  485  is secured to the bottom portion of plate  477  at the external side thereof. Slide valve  485  permits electrolyte opening  479  to be open or closed depending upon the position of slide valve  485 . Sealing means  487  is provided between electrolyte opening  479  and slide valve  485  to prevent electrolyte leakage when slide valve  485  is closed. Sealing means  487  may take the form of an O-ring, gasket, releasable adhesive or any other suitable means. 
     The analytical chamber  471  also has openings  481  and  483  in bottom plate  477 . A resealable elastomeric material  488 ,  488 ′ is placed inside openings  481  and  483  to seal them. This material permits the electrodes to penetrate into the analytical chamber and then seals itself when the electrodes are removed. Openings  481  and  483  permit a reference electrode  505  and a counter electrode  507  to penetrate to the interior of analytical chamber  471  when the analytical chamber is inserted into the base fixture  472  shown in  FIG. 18 . 
     Base fixture  472  comprises a cylinder  492  closed at the top end by plate  493  and closed at the bottom by plate  497 . Plate  493  has a large opening therein to receive the analytical chamber  471 . Bottom plate  497  has an electrolyte opening  498  therein designed to permit electrolyte from the analytical chamber to flow onto the surface of substrate  102 . Cylinder  492  has a slot  495  on one side thereof which slot is designed to receive slide valve  485  of analytical chamber  471 . The slot extends from the top portion of cylinder  492  to the bottom thereof and extends thru plate  493 . 
     Cylinder  492  has a rod-like reference electrode  505  and a rod-like counter electrode  507  mounted on bottom plate  497 . The electrodes extend vertically upwards from bottom plate  497  and are longer than the thickness of bottom plate  477  of analytical chamber  471 . The electrodes are positioned on bottom plate  477  so as to be capable of passing through openings  481  and  483  in the bottom of analytical chamber  471  when the analytical chamber is inserted into base fixture  472 . 
     Sealing means  499  is provided on the upper portion of plate  497  and so positioned as to surround the electrolyte opening  479  of analytical chamber  471  and the electrolyte opening  498  of bottom plate  497 . Sealing means  499  is also in contact with the bottom of slide valve  485 . Sealing means  499  helps to prevent the escape of electrolyte from analytical chamber  471  during operation of electrochemical cell  490 . 
     Sealing means  505  is provided at the external side of plate  487  and surrounds electrolyte opening  498  therein. This permits the cell  490  to be sealed to the surface of substrate  102  in operation. Sealing means  487 ,  499  and  505  are shown as O-rings but they could easily be any other suitable type of sealing means such as a gasket, etc., etc. 
     Housing  513  is fastened to cylinder  492  and contains electronics component  520 . As noted above, electronics component  520  is similar in design and function to electronics component  50  in  FIG. 12  and electronics component  420  in  FIG. 16 . Electrical connections  509  and  511  connect counter electrode  07  and reference electrode  505 , respectively, to electronics component  520 . Jack  515  is provided in housing  513  to electrically connect electronics component  520  with the working electrode ((substrate  102 ). 
     Electrochemical cell  490  has a mounting means  500 ,  500 ′ for removably and nondestructively securing the cell to substrate  102 . Mounting means  500 ,  500 ′ comprises a generally horizontal arm  501 ,  501 ′ which is fastened to cylinder  492 . Generally vertical legs  502 ,  502 ′ ride on the ends of arms  501 ,  501 ′ and carry securing means  504 ,  504 ′. Vertical legs  502 ,  502 ′ ride up and down on arms  501 ,  501 ′ so as to permit cell  490  to be biased against one surface of substrate  102 . Securing means  504 ,  504 ′ could be suction cups, magnets, plates with releasable adhesive thereon or any other type of securement means which would permit the cell  490  to be removably and nondestructively secured to substrate  102 . 
     Operation: 
     Separate analytical chamber  471  would be filled with a suitable electrolyte before use of the cell  490 . Analytical chamber  471  could be closed by positioning slide valve  485  to close electrolyte opening  479 . Elastomeric seal means  488  and  489  are provided inside openings  481  and  483  to seal them prior to use. When the reference and counter electrodes penetrate into openings  481  and  483 , they will easily puncture the elastomeric means  488 ,  489  and the cell would be ready to use. 
     Separate analytical chamber  471  could be assembled to base fixture  472  prior to fastening the base fixture  472  to substrate  102  or it could be inserted after the base fixture  472  has been fastened to substrate  102 . Once the base fixture  472  has been secured to the surface of substrate  102  by securing means  500 ,  500 ′, and once analytical chamber  471  has been inserted fully into base fixture  472 , the necessary electrical connection between electronics component  520  and the working electrode (substrate  102 ) may be made using jack  515 . Slide valve  485  would be opened to permit electrolyte from the interior of analytical chamber  471  to contact the working electrode (substrate  102 ) and the necessary electrochemical measurements could be made. 
     After the desired electrochemical measurements have been taken, slide valve  485  would be closed and the cell  490  removed from the substrate  102 . The connection between the electronics component  520  and the working electrode (substrate  102 ) would be removed and the analytical chamber  471  would be removed from base fixture  472 . A fresh analytical chamber  471  could be inserted into base fixture  472  in order to make further electrochemical measurements, as desired. 
     It is noted that the connection to the working electrode (substrate  102 ) may be made using springs (not shown) fastened to the bottom of plate  487  and electrically connected to electronics component  520 . This would be similar to the springs  34  shown in  FIGS. 12 and 13 . 
       FIG. 19  illustrates an analytical chamber designed to be used with another embodiment of the electrochemical cell of the invention illustrated in  FIG. 20 . 
     The analytical chamber  517  of  FIG. 19  comprises a cylinder  512  which is closed at the top end by top plate  519  and closed at the bottom end by bottom plate  522 . Plates  519  and  522  may be removably secured to the cylinder  512  (not shown) or they may be integral with cylinder  512  as shown. An electrolyte opening  524  is provided in bottom plate  522 . A rotating valve  530  is secured to chamber  517 . Rotation of this valve  530  opens or closes electrolyte opening  524  located in bottom plate  522 . Rotating valve  530  comprises a rod  533  which penetrates top plate  519  and is rotatable and secured in bottom plate  522 . Plate  535  is secured to rod  533  and rotates with rod  533 . Knob  537  is provided to permit rotating valve  530  to be rotated. Sealing means  523  is provided at the top of electrolyte opening  524  to prevent electrolyte leakage when rotating valve  530  is closed. Sealing means  525  is provided at the external side of electrolyte opening  524  to seal analytical chamber  517  into the body of the electrochemical measurement means illustrated in  FIG. 20 . Sealing means  523  and  525  may take the form of an O-ring, gasket, releasable adhesive or any other suitable means. 
     The analytical chamber  517  also has openings  526  and  527  in bottom plate  522 . These openings permit a reference electrode (not shown) and a counter electrode (not shown) to penetrate to the interior of analytical chamber  517  when the analytical chamber is inserted into the electrochemical measurement means shown in  FIG. 20   
     A small strip  528  of pressure sensitive adhesive tape is applied on the exterior side of bottom plate  522  to seal openings  526 ,  527 . Optionally, the pressure sensitive adhesive tape could be applied on the inner surface of bottom plate  522  and thus seal openings  526 ,  527  prior to use. When the reference and counter electrodes penetrate into openings  526  and  527 , they will easily puncture the pressure sensitive adhesive tape and the cell would be ready to use. 
     An alternate to the strip  528  of pressure sensitive adhesive tape would be to use a resealable elastomeric material inside openings  526  and  527  to seal them. This would be very similar to what is shown in  FIG. 17  and described above. This material would permit the electrodes to penetrate into the analytical chamber and then would seal itself when the electrodes are removed. 
     This resealable elastomeric material may be similar to the type of material used to seal multi-dose vials in the medical arts. These vials hold multiple doses of medicines which are intended to be injected into a patient. The needle of a hypodermic syringe penetrates the elastomeric material permitting a single dose of the medicine to be withdrawn into the hypodermic syringe and the needle is then withdrawn from the vial. As the needle leaves the elastomeric material, it seals itself. 
       FIG. 20  illustrates another embodiment of the electrochemical cell of the invention similar to that shown in  FIG. 18 . This embodiment also has a removable analytical chamber and an electronics component similar to the one shown at  50  in  FIG. 12  and shown at  420  in  FIG. 16 . 
     The electrochemical cell  590  shown in  FIG. 20  comprises a separate analytical chamber  517  as shown in  FIG. 19  and a base fixture  518 . Analytical chamber  517  comprises a cylinder  512  which is closed at the top end by plate  519  and closed at the bottom by bottom plate  522 . Bottom plate  522  may be removably secured to the cylinder  512  or it may be integral with cylinder  512  as shown. An electrolyte opening  524  is provided in the bottom plate  522 . A rotating valve  530  runs from top plate  519  into the analytical chamber and is secured to the bottom plate  522 . Rotating valve  530  comprises a generally vertical rod  533 , a bottom flap  535  and a knob  537 . Knob  537  permits rod  533  to be rotated causing flap  535  to rotate over the top of electrolyte opening  524  closing the electrolyte opening. This permits electrolyte opening  524  to be open or closed depending upon the position of rotating valve  530 . Sealing means  523  is provided between electrolyte opening  524  and bottom flap  535  to prevent electrolyte leakage when rotating valve  535  is closed. Sealing means  523  may take the form of an O-ring, gasket, releasable adhesive or any other suitable means. 
     The analytical chamber  517  also has openings  526  and  527  in bottom plate  522 . A small strip  528  of pressure sensitive tape emplaced on the exterior side of bottom plate  522  covers openings  526 ,  527  and seals them. These openings permit a reference electrode  597  and a counter electrode  596  to penetrate to the interior of analytical chamber  517  when the analytical chamber is inserted into the base fixture  518 . When the electrodes begin to enter openings  526  and  527  they will easily penetrate the strip  528  of pressure sensitive adhesive tape. 
     Base fixture  518  comprises a cylinder  592  closed at the top end by plate  593  and closed at the bottom by plate  594 . Plate  593  has a large opening therein to receive the analytical chamber  517 . Bottom plate  594  has an electrolyte opening  529  therein designed to permit electrolyte from the analytical chamber to flow onto the surface of substrate  102 . 
     Cylinder  592  has a rod-like reference electrode  597  and a rod-like counter electrode  596  mounted on bottom plate  522 . The electrodes extend vertically upwards from bottom plate  522  and are longer than the thickness of bottom plate  522  of analytical chamber  517 . The electrodes are positioned on bottom plate  522  so as to be capable of passing through openings  527  and  526  in the bottom of analytical chamber  517  when the analytical chamber is inserted into base fixture  518 . 
     Sealing means  525  is provided on the upper portion of plate  594  and so positioned as to surround the electrolyte opening  524  of analytical chamber  517  and the electrolyte opening  526  of bottom plate  594 . Sealing means  525  helps to prevent the escape of electrolyte from analytical chamber  517  during operation of electrochemical cell  590 . 
     Sealing means  595  is provided at the external side of plate  594  and surrounds electrolyte opening  529  therein. This permits the cell  590  to be sealed to the surface of substrate  102  in operation. Sealing means  523 ,  525  and  595  are shown as O-rings but they could easily be any other suitable type of sealing means such as a gasket, releasable adhesive or any other suitable means. 
     Housing  621  is fastened to cylinder  592  and contains electronics component  620 . As noted above, electronics component  620  is similar in design and function to electronics component  50  in  FIG. 12 , electronics component  420  in  FIG. 16  and electronics component  520  in  FIG. 18  Electrical connections  599  and  605  connect counter electrode  596  and reference electrode  597 , respectively, to electronics component  620 . Jack  622  is provided in housing  621  to electrically connect electronics component  620  with the working electrode (substrate  102 ). 
     Electrochemical cell  590  has a mounting means  600 ,  600 ′ for removably and nondestructively securing the cell to substrate  102 . Mounting means  600 ,  600 ′ comprises a generally horizontal arm  601 ,  601 ′ which is fastened to cylinder  592 . Generally vertical legs  602 ,  602 ′ ride on the ends of arms  601 ,  601 ′ and carry securing means  604 ,  604 ′. Vertical legs  602 ,  602 ′ ride up and down on arms  601 ,  601 ′ so as to permit cell  590  to be biased against one surface of substrate  102 . Securing means  604 ,  604 ′ could be suction cups, magnets, plates with releasable adhesive thereon or any other type of securement means which would permit the cell  590  to be removably and nondestructively secured to substrate  102 . 
     Operation: 
     Separate analytical chamber  517  would be filled with a suitable electrolyte before use of the cell  590 . Analytical chamber  517  would be closed by using rotating valve  530  to close electrolyte opening  524 . The strip  528  of pressure sensitive adhesive tape covers electrode openings  526  and  527  and seals them prior to use. When the reference and counter electrodes penetrate into openings  526  and  527 , they will easily puncture the strip  528  of pressure sensitive adhesive tape and the cell would be ready to use. 
     Separate analytical chamber  517  could be assembled to base fixture  518  prior to fastening the base fixture  518  to substrate  102  or it could be inserted after the base fixture  518  has been fastened to substrate  102 . Once the base fixture  518  has been secured to the surface of substrate  102  by securing means  600 ,  600 ′, and once analytical chamber  517  has been inserted fully into base fixture  518 , the necessary electrical connection between electronics component  620  and the working electrode (substrate  102 ) may be made using jack  622 . Rotating valve  530  would be opened to permit electrolyte from the interior of analytical chamber  517  to contact the working electrode (substrate  102 ) and the necessary electrochemical measurements could be made. 
     After the desired electrochemical measurements have been taken, rotating valve  530  would be closed and the cell  590  removed from the substrate  102 . The connection between the electronics component  620  and the working electrode (substrate  102 ) would be removed and the analytical chamber  517  would be removed from base fixture  518 . A fresh analytical chamber  517  could be inserted into base fixture  518  in order to make further electrochemical measurements, as desired. 
     It is noted that the connection to the working electrode (substrate  102 ) may be made using springs (not shown) fastened to the bottom of plate  594  and electrically connected to electronics component  620 . This would be similar to the springs  34  shown in  FIGS. 12 and 13 . 
     In the embodiment shown in  FIG. 18  and  FIG. 20  two mounting means are shown attached to the base fixture. In certain environments, one mounting means may be sufficient to properly secure electrochemical cell  490  and  590  to the substrate. It is thought that most situations would require two mounting means. Obviously more than two such mounting means may be used. It is envisaged that three mounting means is the optimal number of mounting means for electrochemical cell  490  and  590 , however more than three mounting means may be used if desired and/or necessary. Since each mounting means is individually adjustable, the provision of three mounting means permits the electrochemical cell  490  and  590  to be used on non-planar surfaces. In addition, even though electrochemical cells  490  and  590  have been illustrated as being used to make measurements on generally horizontal surfaces, they could obviously be used to make electrochemical measurements on vertical substrates as well. 
       FIG. 21  illustrates another embodiment of the electrochemical cell of the invention similar to that shown in  FIG. 7 .  FIG. 21  shows an embodiment wherein the attachment means for biasing the cell towards a substrate is modified to permit attaching the cell to substrates with widely varying surface morphology, e.g. substrates which are not planar or have an irregular surface. The elements of  FIG. 21  that are similar to those in  FIG. 7  have similar numbering. 
       FIG. 21  shows a modification of the electrochemical cell shown in  FIG. 7 . The electrochemical cell  270 ′ of  FIG. 21  comprises a cylinder  272 ′ which is closed at the top end by plate  273 ′ and has a necked-down portion  286 ′ closing its bottom end. Plate  273 ′ and necked-down portion  286 ′ may be removably secured to the cylinder  272 ′ or they may optionally be integral with cylinder  272 ′. Necked-down portion  286 ′ has an electrolyte opening  280 ′ therein. This electrolyte opening  280 ′ is provided with a sealing means  282 ′ surrounding electrolyte opening  280 ′ at the exterior surface of necked-down portion  286 ′ to seal cell  270 ′ to the surface of substrate  102 ′. Sealing means  282 ′ may take the form of an O-ring, gasket or any other suitable means. 
     Ports  274 ′ and  276 ′ are provided for insertion of a reference electrode (not shown) and a counter electrode (not shown). These ports are designed such that the port with an electrode inserted therein would be liquid tight. This could be accomplished, for example, by the use of a plug which held the electrode therein. The plug could be secured and sealed within port  274 ′ and/or  276 ′ using an O-ring, gasket, screw threads or any other suitable means. 
     Plate  273 ′ has a filling/drain port  308 ′ incorporated therein to permit the cell  270 ′ to be filled with electrolyte. This filling/drain means incorporates a valve  310 ′ to open and/or close port  308 ′. This will permit the cell  270 ′ to be conveniently emptied of electrolyte when the desired measurements have been taken. 
     Necked-down portion  286 ′ is provided with a valve  284 ′ near electrolyte opening  280 ′. This permits the electrolyte opening  280 ′ to be opened or closed. Valve  284 ′ may be a rotary valve, a slide valve or any other suitable type of valve. 
     At least one mounting means is provided to removably and nondestructively secure cell  270 ′ to a surface of substrate  102 ′. In this figure two mounting means  315 ,  315 ′ are shown. Mounting means  315 ,  315 ′ provide for adjustment of the cell  270 ′ towards and away from substrate  102 ′. This allows for the electrolyte opening  280 ′ in necked-down portion  286 ′ to be biased against substrate  102 ′ and permits sealing means  282 ′ to seal cell  270 ′ against substrate  102 ′. 
     Mounting means  315  and  315 ′ have an attachment arm  300 ″,  300 ′ which extends generally perpendicular to the longitudinal axis of cylinder  272 ′ and which secures the mounting means to cylinder  272 ′. In addition mounting means  315 ,  315 ′ has legs  302 ,  302 ′ which extend generally perpendicular to attachment arms  300 ″ and  300 ′″ respectively. One end of locking universal joints  317  and  317 ′ are attached to legs  302  and  302 ′. The other end of locking universal joints  317  and  317 ′ is attached to a first end of leg portions  325  and  325 ′ respectively. Securing means  304 ″,  304 ′″ are attached to the other end of leg portions  325  and  325 ′. As shown, legs  302  and  302 ′ can move generally perpendicular to arms  300 ″,  300 ′″. Locking universal joints  317  and  317 ′ permit leg portions  325  and  325 ′ to be independently adjusted to allow securing means  304 ″ and  304 ′″ to secure cell  270  to a substrate with irregular surface morphology. As shown, surface  102 ′ contains a substantial bend. The modified attachment means of this embodiment permits the cell  270 ′ to be securely mounted to this type of irregular surface. Securing means  304 ″,  304 ′″ may comprise a suction cup, a magnet, releasable adhesive means or any other device capable of releasably and nondestructively securing cell  270 ′ to one surface of substrate  102 ′. 
     Certain applications may be such that only one mounting means  315  is necessary, however two mounting means  315 ,  315 ′ are considered necessary in most applications and three mounting means are considered the optimal number for general usage although more may be provided if desired or necessary. 
     Any suitable type of joining member could be used to join legs  302  and  302 ′ to leg portions  325  and  325 ′ instead of a locking universal joint. The main requirement would be the locking capability and the ability to angularly adjust the legs  302 ,  302 ′ and leg portions  325 ,  325 ′. 
     Operation: 
     In operation, substrate  102 ′ would be cleaned as necessary for the desired measurements. This would involve cleaning in the area where securing means  304 ″,  304 ′″ would contact the surface of substrate  102 ′. In addition, the area of substrate  102 ′ which would be directly under the footprint of electrolyte opening  280 ′ would be cleaned and any coating in this area may have to be removed in order to make the desired electrochemical measurements. Cell  270 ′ would be then be secured to the surface of substrate  102 ′ using mounting means  315 ,  315 ′. Mounting means  315 ,  315 ′ would be adjusted to compliment the morphology of surface  102 ′. For example, in the situation shown in  FIG. 21 , the angular orientation of leg portion  325 ′ and leg  302 ′ would be adjusted to permit mounting means  304 ′″ to be securely attached to the left side of substrate  102 ′ [as show] while mounting means  304 ″ is securely attached to the right side of substrate  102 ′. Further adjustment of legs  302 ,  302 ′ in relation to arms  300 ″ and  300 ′″ may be necessary in order to enable the cell  270 ′ to be securely mounted to substrate  102 ′. 
     Once cell  270 ′ has been securely mounted to substrate  102 ′, the remainder of the operation to take an electrochemical measurement with Cell  270 ′ is the same as that described above for cell  270  of  FIG. 7 . It should be noted that cell  270 ′ is adapted to make electrochemical measurements on horizontal surfaces, sloped surfaces, and even on surfaces that are vertical. 
       FIGS. 22 and 23  show the fifth embodiment of the invention. The structure of electrochemical cell  700  permits accurate temperature control of the electrolyte and of the local substrate area where the electrochemical measurements are being made. This cell also has an attachments means which permits the cell to be secured to substrates with a somewhat irregular surface morphology. It is noted that cell  700  is adapted to make electrochemical measurements on horizontal surfaces, sloped surfaces, vertical surfaces, and even on surfaces that are slightly beyond vertical. 
       FIG. 22  shows a plan view of cell  700  and  FIG. 23  shows a side view of cell  700 . These two figures will be described together as they are different views of the same cell with some common components hidden in one view but visible in the other. 
     Cell  700  comprises a base  726  which is shown with the shape of an irregular hexagon. Obviously, other shapes could be used. Base cover  732  is mounted to the upper portion of base  726 . Also mounted to base  726  are leg base mounts  712 ,  712 ′ and  712 ″. These leg base mounts provide the mounting means for the suction cup assemblies  701 ,  701 ′ and  701 ″. 
     Each suction cup assembly comprises a large bellows-type pneumatic suction cup  703 ,  703 ′ and  703 ″ with a coaxial venturi  702 ,  702 ′ and  702 ″ mounted to the upper portion thereof. Venturi mount assemblies  708 ,  708 ′ and  708 ″ attach coaxial venturis  702 ,  702 ′ and  702 ″ to adjustment screws  704 ,  704 ′ and  704 .″ Adjustment screws  704 ,  704 ′ and  704 ″ are carried in adjustment screw mounts  710 ,  710 ′ and  710 ″. Adjustment nuts  706 ,  706 ′ and  706 ″ permit fine height adjustment of adjustment screws  704 ,  704 ′ and  704 ″ with respect to the adjustment screw mounts  710 ,  710 ′ and  710 ″. 
     Adjustment screw mounts  710 ,  710 ′ and  710 ″ are attached to base  726  by leg base mounts  712 ,  712 ′ and  712 ″. The means attaching the adjustment screw mounts to the leg base mounts permits a coarse height adjustment of adjustment screw mounts  710 ,  710 ′ and  710 ″ with respect to the leg base mounts  712 ,  712 ′ and  712 ″ as will be further described below. 
     Electronics component  734  is attached to base  726  between suction cup assemblies  701  and  701 ″. This electronics component comprises a miniature potentiostat similar to electronics component  50  shown and described above with respect to  FIGS. 12 and 14 . Digital display  736  is similar to digital display  54  described above and shown in  FIG. 11 . Electronics component  734  may also comprise temperature control circuitry whose function will be further discussed below. In addition, electronics control  734  may interact with one or more electro-mechanical interlock switches as described below. 
     Electrolyte tank  716  is mounted to cell  700  at a slight angle to the vertical to avoid problems with air bubbles in the electrolyte solution in the electrochemical analytical chamber  724  which will be further described below. The particular angle shown in  FIGS. 22 and 23  is 10° from the vertical although other angles obviously may be suitable. Electrolyte tank  716  is connected to base cap  732  by quick-disconnect fittings  718  and  720  and positioned on base cap  732  by means of fluid tank base  714 ,  714 ′. Fluid tank base  714 ,  714 ′ is mounted on base cap  732  and comprises a curved wing on each side which receives the outer portion of fluid tank  716 . 
     As shown in  FIG. 27 , an electro-mechanical interlock switch  739  is mounted on shelf  714 ″ which connects wings  714 ,  714 ′. Electro-mechanical interlock switch  739  prevents operation of electrochemical cell  700  if the electrolyte tank  716  is not properly mounted to base  726  by means of quick-disconnect fittings  718  and  720 . The electro-mechanical interlock switch may control circuitry in electronics component  734  to prevent operation of cell  700  when electrolyte tank  716  is not properly positioned on the fluid tank base  714 , 714 ′. Electrolyte tank  716  is vented at the top portion thereof by vent means  738 . 
     Reference electrode  729  is mounted on one side of base  726  and slightly angled downwards from the horizontal. This is to avoid problems with air bubbles in the electrochemical analytical chamber  724  which will be discussed further below. 
     An important feature of the invention is control of the temperature of the substrate surface where the electrochemical measurements are being taken. Another important feature of the invention is control of the electrolyte solution temperature. It is well-known that the rate of almost every chemical reaction is dependent upon the temperature of the reactants. It is also true that the rate of electrochemical reactions is, in like manner, dependent upon the temperature of the reactants. It has been discovered that, by eliminating the influence of temperature on the reaction rate, more consistent and reliable results can be obtained when making electrochemical measurements with the electrochemical cells disclosed herein. 
     With this in mind, the electrochemical cell of the invention has a means to control the temperature of the substrate of interest in the area where the electrochemical measurements are being made and a means to control the temperature of the electrolyte solution. It is noted that the embodiments disclosed herein all use heating means to control the temperature of the local substrate area and the electrolyte; however, it is recognized that some situations might call for a cooling means to control these temperatures. 
     The temperature control features of the instant invention involve the use of heating elements in thermal contact with the substrate of interest near the area where the electrochemical measurements are being made and with the electrolyte solution. Each of these temperature control features will be further discussed below. 
     While some previous embodiments have been designed such that all power necessary for operation of the cell is provided by an on-board battery, this embodiment requires substantially greater amounts of power for the temperature control mechanisms. To this end, it is envisaged that external power will be supplied via connector  740  [shown in  FIG. 22 ] when cell  700  is in operation. In addition, this embodiment requires compressed air to power the coaxial venturi assemblies  702 ,  702 ′ and  702 ″ in order to provide a vacuum in suction cup assemblies  701 ,  701 ′ and  701 ″. 
     The temperature control means for the substrate of interest is heating pad  730 . Heating pad  730  is a large annular heater which is mounted to the lower surface of base  726  by annular heater pad mount  728 . Heating pad  730  and heater pad mount  728  surround analytical chamber  724 . Heating pad  730  has a resistive temperature device [RTD]  733  or another suitable temperature measurement device embedded therein or attached thereto to shut down operation of heating pad  730  when a predetermined maximum temperature is exceeded. Hex adjustment screws  722  and  722 ′ permit the heater pad mount  728  and thus heating pad  730  to be moved towards or away from base  726 . Analytical chamber  724  has a gasket  736  mounted to the lower end thereof which gasket serves to seal the analytical chamber to the substrate of interest when electrochemical measurements are being made. Analytical chamber  724  is shown in  FIG. 23  as extending slightly below the lower surface of heating pad  730 . However, in normal operation of cell  700  this would not be the case as heating pad  730  would have been lowered to contact the surface of the substrate of interest prior to taking any electrochemical measurements. Analytical chamber  724  will be further described below. 
       FIG. 24  shows a bottom view of test fluid housing  750 .  FIG. 25  shows a cross-section view of test fluid housing  750  along section A-A of  FIG. 24 . These two figures will be described together as they are different views of the same elements with some common components hidden in one view but visible in the other. It is noted that test fluid housing  750  is primarily contained within base  726  with portions thereof extending into base cap  732  and below base  726 . 
     Test fluid housing  750  comprises three cylindrical portions,  751 ,  752  and  754  made of a polymeric material. Test fluid housing portion  752  has the smallest portion  751  mounted to its upper surface. Portion  754  is intermediate in size between portions  751  and  752  and is mounted to the lower surface of test fluid housing portion  752 . Quick-disconnect fitting  720  is mounted to test fluid housing portion  751 . Electrolyte fluid feed bore  778  starts in portion  751  and extends through portion  752  to analytical chamber  724  which is contained within test fluid housing portion  754  as shown in  FIG. 25 . A reference electrode bore  776  for mounting reference electrode  729  [shown in  FIG. 23 ] extends from an outer surface of portion  752  to intersect electrolyte fluid feed bore  778 . A vent pipe  772  extends from the upper surface of portion  752  to intersect electrolyte fluid feed bore  778  at the lower portion thereof as shown in  FIG. 25 . Vent pipe  772  has a valve  774  in the upper portion thereof to allow gas to escape from the analytical chamber  724 , from the reference electrode bore  776  and from the electrolyte fluid feed bore  778 . During operation of cell  700 , vent pipe  772  prevents gas bubbles in the electrolyte fluid from interfering with accurate electrochemical measurements. This feature is important because cell  700  can be used to make electrochemical measurements on substrates with many different orientations from generally horizontal to vertical and even to somewhat past vertical. 
     Analytical chamber  724  as noted above is mounted within test fluid housing portion  754 . Chamber  724  comprises a passive metallic cylinder  766  which is surrounded by a heating coil  768  and has a gasket  736  extending from the lower portion thereof. Heating coil  768  has a resistive temperature device [RTD]  769  or another suitable temperature measurement device embedded therein or attached thereto to shut down operation of heating coil  768  when a predetermined maximum temperature is exceeded. 
     The passive metallic cylinder  766  serves as a counter electrode when making electrochemical measurements with cell  700 . 
     The purpose of gasket  736  is to seal analytical chamber  724  to the substrate of interest. Stainless steel is an example of a passive metal which is very suitable for the cylinder  766  although other passive metals may be used which would be suitable chambers for the specific types of electrochemical measurements desired. O-ring  770  is placed around the upper portion of cylinder  766  to seal analytical chamber  724  and to prevent electrolyte contact with heating coil  768 . Bore  762  is provided in test fluid lousing portion  752  to permit resistive thermal device [RTD]  764  or another suitable temperature-measuring device to access the electrolyte within analytical chamber  724 . The RTD  764  [or other suitable temperature measurement device] permits the electronics component  734  to control the electrolyte fluid temperature by controlling the operation of heating coil  768 . 
     Bore  756  extends through test fluid housing portions  752  and  754  to permit an electro-mechanical interlock device  758  to access the substrate of interest when cell is in operation. Spring loaded contact  760  is contained within the bottom portion of electro-mechanical interlock device  758 . In operation, the electro-mechanical interlock device  758  may control circuitry in electronics component  734  to prevent operation of cell  700  when spring loaded contact  760  is not depressed by the substrate as it would be when cell  700  is properly mounted on the substrate of interest. 
     Bores  780  and  784  [shown in  FIG. 24 ] also extend through test fluid housing portions  752  and  754 . Bore  780  permits working electrode probe  782  to make electrical contact with the working electrode which is the substrate of interest upon which the electrochemical measurements are being made. Bore  784  permits RTD  786  [or another suitable temperature measurement device] to measure the temperature of the working electrode [the substrate of interest]. This connection permits electronics component  734  to control the temperature of the substrate within the measurement area by controlling the operation of heating pad  730  [shown in  FIG. 23 ]. 
       FIG. 26  shows the means which attaches adjustment screw mount  710  to leg base mount  712  and provides a coarse height adjustment as discussed above. Obviously, similar means are provided to attach adjustment screw mounts  710 ′ and  710 ″ to leg base mounts  712 ′ and  712 ″. In  FIG. 26  adjustment screw mount  710  is shown with five linearly spaced holes  740 ,  740 ′,  740 ″,  740 ′″ and  740 ″″ bored into the right side of adjustment screw mount  710 . Each hole  740 ,  740 ′,  740 ″,  740 ′″ and  740 ″″ has a smaller perpendicular hole bored there through to permit a push pin [not shown] to be inserted into the holes. 
     Leg base mount  712  has a corresponding set of linearly spaced holes [not shown] bored therein. Pins  742 ,  742 ′ are removably secured in two of the corresponding holes in leg base mount  712 . Pins  742  and  742 ′ have transverse bores  744  and  744 ′ there through. In operation, leg base mount  712  would be assembled to adjustment screw mount  710  with pins  742 ,  742 ′ being inserted into corresponding holes  740  and  740 ″ in adjustment screw mount  710 . When assembled, the perpendicular holes in adjustment screw mount  710  align with the transverse bores  744 ,  744 ′ of pins  742 ,  742 ′. Push pins [not shown] are inserted through the aligned perpendicular holes and transverse bores  744 ,  744 ′ to secure the assembly. In order to adjust the relative vertical position of adjustment screw mount  710  and leg base mount  712 , the push pins would be removed, adjustment screw mount  710  and leg base mount  712  would be separated, and pins  742  and  742 ′ could then be inserted into different holes, for example  740 ′ and  740 ′″. This would give a different relative position between adjustment screw mount  710  and leg base mount  712 . In addition, pins  742 ,  742 ′ could be removed from their holes in leg base mount  712  and placed in other holes achieve different relative positioning of adjustment screw mount  710  and leg base mount  712 . 
     Operation: 
     Once the substrate surface is suitably prepared, cell  700  is positioned such that the analytical chamber  724  is over the substrate area of interest and the suction cup assemblies  701 ,  701 ′ and  701 ″ are positioned on the substrate surface. 
     Compressed air from a suitable source [not shown] is provided to each of the coaxial venturi assemblies  702 ,  702 ′ and  702 ″ allowing the suction cup assemblies  701 ,  701 ′ and  701 ″ to secure cell  700  to the substrate surface. The construction of suction cups  703 ,  703 ′ and  703 ″ and the independent height adjustment at each suction cup permit the cell to be secured to a substrate surface that is moderately irregular, e.g. not planar or a moderately rough surface. 
     The distance between analytical chamber  724  and the substrate surface is adjusted to the optimal distance for a good seal between the analytical chamber  724  and the substrate surface using the coarse height adjustments means illustrated in  FIG. 26  and/or using the fine height adjustment provided by adjustment nuts  706 ,  706 ′ and  706 ″. The heater pad  730  will then be adjusted, as necessary, via hex adjustment screws  722  and  722 ′. Heater pad  730  should then be in close contact with the substrate surface. It is noted that heater pad  730  is somewhat flexible to allow for a suitable thermal connection to moderately irregular surfaces. Electrical connections [using a cable, not illustrated] are made between the reference electrode  729  and the electronics component  734 . Electrical power from an external source is provided to cell  700  via connector  740 . 
     A full electrolyte tank  716  is connected to cell  700  via quick-disconnect fittings  718  and  720 . Wings  714 ,  714 ′ guide electrolyte tank  716  into place and the bottom end of electrolyte tank  716  contacts electro-mechanical interlock switch  739  when the tank is fully seated. Power is applied to the heating pad  730  and heating coil  768 , as necessary, to assure that the electrolyte fluid and the substrate surface area of interest achieve the optimum temperature. Once the optimum temperatures are achieved, electronics component  734  will make and store the desired electrochemical measurements. 
       FIG. 28  shows the sixth embodiment of the invention. Cell  799  similar to the construction of cell  700  shown in  FIGS. 22 and 23  but without the electronics component  734  of cell  700 . Cell  799  is designed to be connected to an external potentiostat [not shown] and external circuitry which would control the analytical chamber heating elements and the heating pad. 
     The structure of electrochemical cell  799  also permits accurate temperature control of the electrolyte and of the local substrate area where the electrochemical measurements are being made. This cell also has an attachments means which permits the cell to be secured to substrates with a somewhat irregular surface morphology. It is noted that cell  799  is adapted to make electrochemical measurements on horizontal surfaces, sloped surfaces, vertical surfaces, and even on surfaces that are slightly beyond vertical. 
     Cell  799  comprises a base  826  which is shown with the shape of an irregular hexagon. Obviously, other shapes could be used. Base cover  832  is mounted to the upper portion of base  826 . Also mounted to base  826  are leg base mounts  812 ,  812 ′ and  812 ″. These leg base mounts provide the mounting means for the suction cup assemblies  801 ,  801 ′ and  801 ″. 
     Each suction cup assembly comprises a large bellows-type pneumatic suction cup  800 ,  800 ′ and  800 ″ with a coaxial venturi  802 ,  802 ′ and  802 ″ mounted to the upper portion thereof. Coaxial venturis  802 ,  802 ′ and  802 ″ are mounted to the upper portion of suction cups  800 ,  800 ′ and  800 ″. Venturi mount assemblies which are not shown in  FIG. 28  but which are similar to venturi mount assemblies  708 ,  708 ′ and  708 ″ of  FIG. 23  attach to adjustment screws which also are not shown in  FIG. 28  but which are similar to adjustment screws  704 ,  704 ′ and  704 ″ shown in  FIG. 23 . These adjustment screws are carried in adjustment screw mounts  810 ,  810 ′ and  810 ″. Adjustment nuts  806 ,  806 ′ and  806 ″ permit fine height adjustment of the adjustment screws with respect to the adjustment screw mounts  810 ,  810 ′ and  810 ″. 
     Adjustment screw mounts  810 ,  810 ′ and  810 ″ are attached to base  826  by leg base mounts  812 ,  812 ′ and  812 ″. The means attaching the adjustment screw mounts to the leg base mounts permits a coarse height adjustment of adjustment screw mounts  810 ,  810 ′ and  810 ″ with respect to the leg base mounts  812 ,  812 ′ and  812 ″ in the same manner as shown in  FIG. 26 . 
     Electrolyte tank  816  is mounted to cell  799  at a slight angle to the vertical to avoid problems with air bubbles in the electrolyte solution as discussed above with respect to  FIGS. 22 and 23 . Electrolyte tank  816  is connected to base cap  832  by quick-disconnect fittings not shown in  FIG. 28  but which are similar to quick disconnect fittings  718  and  720  shown in  FIG. 23 . Electrolyte tank  816  is positioned on base cap  832  by means of fluid tank base  814 ,  814 ′. Fluid tank base  814 ,  814 ′ is mounted on base cap  832  and comprises a curved wing on each side which receives the outer portion of fluid tank  816 . 
     An electro-mechanical interlock switch is mounted on a shelf portion of fluid tank base  814 , 814 ′. Neither the interlock switch or shelf portion is shown in  FIG. 28  but they are identical to the showing in  FIG. 27 . As shown in  FIG. 27 , an electro-mechanical interlock switch  739  is mounted on shelf  714 ″ which connects wings  714 ,  714 ′. Electro-mechanical interlock switch  739  prevents operation of electrochemical cell  700  if the electrolyte tank  716  is not properly mounted to base  726  by means of quick-disconnect fittings  718  and  720 . The interlock switch of cell  799  operates in the same manner as that shown in  FIG. 27 . This electro-mechanical interlock switch controls circuitry in an external electronics package [not shown] to prevent operation of cell  799  when electrolyte tank  816  is not properly positioned on the fluid tank base  814 , 814 ′. Electrolyte tank  816  is vented at the top portion thereof by vent means  836 . 
     Reference electrode  829  is mounted on one side of base  826  and slightly angled downwards from the horizontal. This is to avoid problems with air bubbles as discussed above in regard to  FIGS. 22 and 23 . 
     An important feature of the invention is control of the temperature of the substrate surface where the electrochemical measurements are being taken. Another important feature of the invention is control of the electrolyte solution temperature. It is well-known that the rate of almost every chemical reaction is dependent upon the temperature of the reactants. It is also true that the rate of electrochemical reactions is, in like manner, dependent upon the temperature of the reactants. It has been discovered that, by eliminating the influence of temperature on the reaction rate, more consistent and reliable results can be obtained when making electrochemical measurements with the electrochemical cells disclosed herein. 
     With this in mind, the electrochemical cell of the invention has a means to control the temperature of the substrate of interest in the area where the electrochemical measurements are being made and a means to control the temperature of the electrolyte solution. It is noted that the embodiments disclosed herein all use heating means to control the temperature of the local substrate area and the electrolyte; however, it is recognized that some situations might call for a cooling means to control these temperatures. 
     The temperature control features of the instant invention involve the use of heating elements in thermal contact with the substrate of interest near the area where the electrochemical measurements are being made and with the electrolyte solution. Each of these temperature control features will be further discussed below. 
     The temperature control means for cell  799  is identical to the temperature control means for cell  700  except that it is achieved with external control circuitry [not shown] instead of an onboard electronics component. Thus the temperature of the substrate of interest is controlled by a heating pad identical to heating pad  730  shown in  FIG. 23 . The heating pad is a large annular heater which is mounted to the lower surface of base  826  by annular heater pad mount not shown in  FIG. 28  but identical to heater pad mount  728  shown in  FIG. 23 . The heating pad and heater pad mount surround the analytical chamber and have hex adjustment screws  822  and  822 ′ permit the heater pad mount and thus heating pad to be moved towards or away from base  826  as described and shown above with respect to  FIG. 23  and cell  700 . 
     Reference electrode  829  is mounted to base  826  in the same manner as reference electrode  729  is mounted to base  726  for cell  700  described above and shown in  FIG. 23 . 
     Since cell  799  does not have an on-board electronics component, plugs  834 ,  836  and  840  provide electrical connection between the electrodes, the temperature control devices and interlocks and the heating elements of cell  799  and the external control means. They also provide for a source of external power for the heating pad and the heating coil. 
     Operation: 
     Once the substrate surface is suitably prepared, cell  799  is positioned such that the analytical chamber is over the substrate area of interest and the suction cup assemblies  801 ,  801 ′ and  801 ″ are positioned on the substrate surface. 
     Compressed air from a suitable source [not shown] is provided to each of the coaxial venturi assemblies  802 ,  802 ′ and  802 ″ allowing the suction cup assemblies  801 ,  801 ′ and  801 ″ to secure cell  799  to the substrate surface. The construction of suction cups  800 ,  800 ′ and  800 ″ and the independent height adjustment at each suction cup permit the cell to be secured to a substrate surface that is moderately irregular, e.g. not planar or a moderately rough surface. 
     The distance between the analytical chamber and the substrate surface is adjusted to the optimal distance for a good seal between the analytical chamber and the substrate surface using the coarse height adjustments means illustrated in  FIG. 26  and/or using the fine height adjustment provided by adjustment nuts  806 ,  806 ′ and  806 ″. The heater pad will then be adjusted, as necessary, via hex adjustment screws  822  and  822 ′. The heater pad should then be in close contact with the substrate surface. It is noted that the heater pad is somewhat flexible to allow for a suitable thermal connection to moderately irregular surfaces. Electrical connections [using cables, not illustrated] are made between the reference electrode  829 , connectors  834 ,  836  and  840  and the external electronics [not shown]. The external electronics would comprise a control system and a potentiostat. Electrical power from an external source is provided to cell  799  via connector  840 . 
     A full electrolyte tank  816  is connected to cell  799 . Wings  814 ,  814 ′ guide electrolyte tank  816  into place and the bottom end of electrolyte tank  816  contacts an electro-mechanical interlock switch [not shown] when the tank is fully seated. Power is applied to the heating pad and heating coil, as necessary, to assure that the electrolyte fluid and the substrate surface area of interest achieve the optimum temperature. Once the optimum temperatures are achieved, the external electronics will make and store the desired electrochemical measurements.