Method and apparatus for producing conductivity in materials

Abstract: A method of process for treating materials for making materials electrically conductive that are not naturally electrically conductive or for increasing and enhancing the electrical conductivity of materials that are naturally electrically conductive. The invention is carried out in processing apparatus or equipment. The apparatus includes a vessel containing a solution that is electrically conductive. The solution or bath contains salts including acid surfactant, acid and silver nitrate crystals. The apparatus includes electrical equipment which includes electrodes exposed to the soltuion in the vessel so that an alternating electrical current is caused to traverse the solution and the material being processed. Additionally, the apparatus includes an array of ultrasonic generators provided to cause ultrasonic sound vibrations to traverse through the solution and the material being processed simultaneously with the flow of current. The material is processed by being immersed in the solution while the flow of current through the solution and the material is produced simultaneously with the transmission of ultrasonic vibrations through the solution and the material to be processed. Continuous filtering and recirculation of the solution in the vessel is provided for.

Description: The present invention relates to a method and apparatus for making a solid state substrate ("material") conductive or for increasing the conductivity of such material. The field of this invention is that of static dissipative materials, that is, dissipation of static charge from materials. The field embraces not only static dissipative materials but includes the concept and implementation of the concept of increasing the electrical conductivity of materials or making materials electrically conductive that are not naturally electrically conductive. With respect to static dissipative materials or materials a providing static dissipative work surface reference is made to US-A-4,456,944; 4,525,398, 4,702,951. These patents relate primarily to materials useful for various purposes that provide a static dissipative surface. The materials of these patents provide static dissipative surfaces useful not only as work surfaces but floor surfaces, wall surfaces and various other types of surfaces. As explained in previous patents, in connection with working with and the handling of many types of electronic components, it is imperatively necessary that static charges in the environment be drained off to ground because otherwise they can have a very deleterious and even destructive effect upon such components. In the present day production of such components many different materials may be used including plastics, rubber, metals, and many, many other types of materials. It therefore becomes highly desirable that all of these materials that might be used in the production of such components and in other types of production be electrically conductive. This has of course not been possible and has not been a capability that has been present in the prior art. What has been available is that which is illustrated in the prior patents referred to. Thus it has become highly desirable as an achievement that materials that are not naturally electrically conductive be made conductive or that materials that are electrically conductive have their electrical conductivity increased or enhanced. "Metal Finishing Abstracts", vol. 25, no. 1, Jan.-Feb. 1983, p. 17, abstract E, reports a method for chemical deposition of metal coatings according to which a component is subjected to an alternating electromagnetic field and to mechanical vibrations. Coating a material with a metal attaches a conductive surface layer to what otherwise might be a poorly conductive material. The herein invention embraces exemplary embodiments which are disclosed in detail and which relate to method and apparatus for achieving the purpose of making materials electrically conductive that are not naturally electrically conductive and/or increasing or enhancing the electrical conductivity of materials that do naturally possess electrical conductivity. It is an object of the present invention to provide a method and an apparatus which are suitable to produce electrical conductivity in materials that are not naturally electrically conductive or to increase or enhance the electrical conductivity of materials that are naturally conductive. To solve this object the present invention provides a method and an apparatus as specified in claim 1 or 10, respectively. The method is carried out or executed in a preferred form of apparatus. The apparatus is in the form of a vessel or a tank containing a liquid solution, bath or medium. The vessel might be of any shape but in the preferred form of the invention disclosed herein, it is rectangular. The solution or bath is preferably a liquid which may be simply water that has been filtered to remove iron. Essentially the water has been deionized or distilled water may be used. The filter may be a known type of carbon filter. Removing the iron deionizes the water sufficiently for the purpose of the method. Chemical ingredients are introduced into the water and mixed into it. The chemicals include acids which provide a vehicle for electrical current which is passed through the liquid bath and which passes through the molecular structure of the materials introduced into the liquid bath which are to be made electrically conductive or to have their electrical conductivity increased or enhanced. The chemical ingredients are caused to intrude into the molecular structure, which is loosened (or "relaxed", so that the distance between molecules is increased) by the process as explained more in detail hereinafter. With the aid of ultrasonic vibrations which are passed through the liquid bath, the molecular structure, after being loosened, closes in or comes back at the termination of the processing resulting in a homogenous material which is electrically conductive or possesses increased electrical conductivity. The chemical ingredients are mixed into the liquid bath simply by stirring and preferably this is done with the liquid bath, that is, the water, heated to substantially 26.7°C (80° F), which causes the chemicals to mix faster while stirring. The ingredients introduced into the liquid include a surfactant in an amount of 5% to 15% for example, by weight. Preferably the surfactant is a liquid. It is a non-ionized surfactant liquid. This surfactant is a product that is used to make soap with. Other surfactants are commercially available that might be used including the product known by the trade name "MAZOX CAPA". The surfactant is a salt. The precise surfactant used is not critical. There is also added hydrochloric acid in a range of substantially 5-15% by weight. There is also added substantially 1/2 of 1% of silver nitrate by weight. Preferably the silver nitrate is in the form of silver nitrate crystals. This product is commercially available. This is a product that may be used in certain photographic processes. During the process the liquid bath or solution is continually circulated and filtered by circulating means provided in association with the said vessel or tank. The apparatus in which or by which the process is executed includes a plurality of electrodes at opposite positions with respect to the vessel, the electrodes being exposed to the liquid so as to cause an alternating electrical current to traverse through the liquid solution and through the materials being processed. Preferably the electrodes include a plurality of pairs of electrodes that all have an alternating voltage impressed between them which may be preferably in the range of 60-120 volts or on the other hand it is possible that the applied voltage may run as high as 800 volts AC depending on the materials to be processed particularly their density and the desired conductivity to be realized. Additionally, the apparatus includes a plurality of ultrasonic sound generators arranged in positions opposite to each other to cause ultrasonic vibrations to traverse through the liquid solution and the materials in the solution to be processed. The ultrasonic generators may simply be arranged at opposite sides of the vessel, that is, opposite sides of the rectangular tank when it has that configuration. A preferred form of ultrasonic generator is provided for purposes of practicing the invention although commercially available types of ultrasonic generators might be used. The preferred form of ultrasonic generator is constructed of tubular parts preferably in a U-shaped configuration. The ultrasonic generator as stated herein is preferably formed of tubular parts connected together by elbows. The tubular parts are filled with barium titanate or on the other hand they may be filled with quartz crystals. Electrodes are provided at the ends of the legs of the U-shaped configuration and a voltage supplied in a range of 60-120 volts AC. Because of the configuration of the parts, ultrasonic vibrations are dispersed in all directions as a result of the reversing flow of the alternating current. Within each unit, disposed within the barium titanate or the quartz crystals is a coil of wire the ends of which are not connected to the electrodes at the ends of the legs of the unit. The purpose of the coil of wire is to facilitate or enhance the flow of current through the material in the ultrasonic unit. The ultrasonic unit could be said to be a form of sound oscillator. The same voltage is applied to all of the plurality of ultrasonic generators in a configuration as referred to in the foregoing. The range of frequencies in the preferred form of the process might be from 40,000 to 280,000 Hz. In performing the process the material to be treated is immersed in the solution. The electrodes as described are energized with the AC voltage to cause current to traverse the solution and the materials being processed and simultaneously the ultrasonic generators are energized to provide for a traversal of ultrasonic vibrations through the solution and the material being processed. The process is applicable to increasing the conductivity of many, many different materials including such materials as rubber, canvas (tennis shoes), vinyls, high-pressure laminate, synthetic carpeting and other materials as identified more in detail hereinafter. Other materials include metals, such as brass, copper, steel, concrete, polycarbonate, acrylic, styrene, polypropylene, polyethylene, leather, styrene, and others. A method for the stated purpose which includes immersion of the material to be treated in a solution or bath of liquid containing ingredients in the form of chemicals which provide a vehicle for carrying electrical current comprises steps of providing for a flow of electrical current through the bath or solution and through the material being processed and simultaneously providing for transmission of ultrasonic vibrations through the liquid solution and the material being processed; and causing the molecular structure of the material being processed to be loosened to allow the chemicals to be introduced into the molecular structure and after terminating the process, allowing or causing the molecular structure to reclose or come back together making the material being processed into a homogenous electrically conductive material or material with increased electrical conductivity. The voltage applied to the electrodes producing the alternating current flow is in the range of 60 - 120 volts A.C., and the voltage applied to the ultrasonic generators is in the range of 60 - 120 volts A.C., the voltages for producing current flow and for producing ultrasonic vibrations being applied simultaneously, causing them to produce the effects described of loosening the molecular structure of the material being processed so as to introduce the chemicals into the molecular structure and to allow the molecular structure to reclose or come back to the original state. An apparatus as identified in the foregoing is in the form of a vessel containing a solution with chemical ingredients as identified in the foregoing, with electrodes oppositely positioned with respect to the vessel of solution, with means for applying a voltage to provide an alternating current flow through the solution, and the vessel having oppositely disposed a plurality of ultrasonic generators whereby to provide for simultaneous traversal of ultrasonic vibrations through the solution and the material being processed. An improved form of ultrasonic sound or vibration generator has a unique configuration to provide the capability of dispersing sound vibrations in all directions. The ultrasonic sound generator is formed of tubular parts, preferably in a U-shape, the unit containing barium titanate or, alternatively, quartz crystals, with an alternating current voltage being applied to the unit so as to pass - through the material in the unit, and the material in the unit having a coil of wire disposed in it to facilitate or enhance the flow of alternating current through the material. Further objects and additional advantages of the invention will become apparent from the following detailed description and the annexed drawings, wherein: Fig. 1 is an isometric view of a preferred form of the apparatus, illustrating the tank or vessel, the electrodes for providing for flow of alternating currents, and the array of ultrasonic generators; Fig. 2 is a cross-sectional view taken along the line 2-2 of Fig. 1; Fig. 3 is a cross-sectional view taken along the line 3-3 of Fig. 1; Fig. 4 is a schematic or diagrammatic view of a preferred form of ultrasonic vibration generator. Fig. 5 is a schematic circuit diagram of the circuit for the electrodes that produce the electric field; and Fig. 6 is a schematic circuit diagram of the circuit for the each individual sonic generator. Referring to Figs. 1, 2 and 3 of the drawings, numeral 10 designates generally a vessel which is a rectangular tank for containing the processing solution or bath. The walls of the vessel are formed from plastic sheets of materials, including a side wall 12 and an end wall 14. The sides of the vessel are exactly alike, as are the ends of the vessel. Numeral 18 designates a framework structure which may be made of metal to provide support for the wall 12. Numeral 20 designates a similar supporting framework for the end wall 14. Similar supporting frameworks are provided at the other side of the tank and at the other end. Supporting legs are provided for the tank itself, as shown at 24a, 24b and 24c. The supporting framework 18 has legs or uprights as designated at 26a, 26b, 26c and 26d. Numerals 28 and 30 designate elongated side members at the upper ends of the legs 26. The end frame 20 has similar legs 34a and 34b. This framework has transverse members at the upper ends of the legs, as designated at 36 and 38. As previously indicated, the structure at both sides of the tank and the structures at the ends of the tank are alike. As one end of the tank is a trough, as designated at 44a, and at the other end is a similar trough 44b. The trough 44a may be seen in Fig. 3, and the trough 44b may be seen in Fig. 2, these troughs having bottom and side walls as shown and being identical in construction. Within the tank 44b is a wire-mesh screen forming a filter, as designated at 46, and within the tank 44a is a similar screen. The tank 44b and the filtering screen 46 are shown in cross-section in Fig. 2. As previously stated, the structure at the two ends is identical. Apparatus is provided for producing a continuous circulation and filtering of the solution within the tank. The circulating means at one end includes a circulating pump, as designated at 50 in Fig. 1. Positioned at the top of the tank 44b are brackets 52a, 52b, 52c and 52d, each having a notch at the top edge. Held in the notches is a distributing pipe or header 58 having elbows at its ends, as designated at 60 and 62, positioned to allow solution to flow out of the ends into the trough 44b through the wire mesh filtering screen 46. Preferably, the tube 58 has perforations in its underside to allow the liquid solution to drain down into the trough 44b, as illustrated in Fig. 2. The trough 44b has openings at the bottom, as illustrated at 66, to allow the solution to drain back down into the tank. See Fig. 3. The circulating pump connects by a tubular line 70 to a "T" fitting 72 in the pipe or tube 58 for conveying solution to the distributing tube. The pump draws solution from the bottom of the tank through pipe connection 74. Numerals 76, 78, 80 and 82 designate manual valves for manually controlling the flow of circulating solution and for draining solution from the tank, if desired. Electrical apparatus, including electrodes, are provided at the ends of the tank so that an alternating voltage can be applied to cause alternating current to traverse through the solution in the tank and the material being processed. Fig. 3 illustrates the electrodes at one end of the tank. The structure is the same at both ends of the tanks. Three of the electrode units are indicated in Fig. 3 at 84a, 84b and 84c. Each of these electrode units is of similar construction including a bottom part, as shown at 86, and upright connector or contact parts 88 and 90. Voltage is applied by way of electrical connections to the upper ends of the connector or contact parts 88 and 90. An alternating current voltage of 60 - 120 volts, by way of example, is applied between the electrodes, although at times, this voltage may be raised to as much as 800 volts, depending upon the density and other characteristics of the materials being processed and the particular degree of electrical conductivity that may be desired. The parts 84a, 84b and 84c extend or are positioned to be in contact with the solution in the vessel or tank. The electrode array is the same at both ends so that the alternating current is caused to traverse through the solution and through the material being processed. As stated, the structure at both ends of the vessel or tank is the same as is the structure at both sides of the tank. Fig. 5 shows the electrical circuitry for applying the voltage to the electrodes at opposite ends of the tank. Numeral 85 designates a variable transformer which is provided for purposes of controlling the alternating current voltage that is applied to the electrodes. The figure also shows the circuitry for providing voltage to the ultrasonic generators, as further shown in Fig. 6. The numeral 85 designates the secondary of the variable transformer which is connected to the power supply as shown. The power supply is connected to terminals 1 and 4 at the ends of the secondary 85. A slider 85a is provided which can be adjusted along the secondary 85. The parts of the secondary on different sides of the slider are designated at 2 and 4. The slider is connected to terminal 3. The letter "V" designates volt meters connected to the circuit. Numeral 85b designates a control switch. Numeral 3 is connected through a fuse as shown and an indicator light to the terminal box of "J" box 89. A plug-in connector as shown connects the "J" box to the electrodes as shown at 84a and 87, which are electrodes at opposite ends of the vessel containing the solution. Plural electrodes at each end may of course be connected in parallel. The meter connected between terminals 1 and 3 gives the voltage applied to the circuit as referred to hereinafter, and the voltage across the lines connecting to the terminals 84a and 87 indicates the voltage applied across the length of the solution in the vessel. A circuit similar to or like that of Fig. 5 is used to provide the voltage to each of the ultrasonic generators, such as indicated at 98, all of which can be connected in parallel. In addition to the electrical apparatus for providing an alternating current to produce a flow of current through the solution in the tank, arrays of ultrasonic sound or vibration generators are provided to produce ultrasonic vibrations that traverse through the solution in the tank and through the material being processed. Referring to Fig. 1 of the drawings, numeral 90a designates a transverse member which supports the ultrasonic units and the electrodes by which electrical power is supplied to the individual ultrasonic units. The member 90a is supported by upright bracket members 92a, 92b, 92c, 92d, 92e and 92f from the elongated member 28, previously described. Numeral 90b designates a similar support member at the other side of the tank, showing the upper ends of the individual ultrasonic units supported from the member 90b. One of the ultrasonic units is designated at 96 in Fig. 3, this figure showing one of the electrodes 100 connecting to the ultrasonic unit. Fig. 2 shows another of the ultrasonic units, as designated at 98, these units being of course identical in construction. Fig. 4 is a schematic view of a preferred form of ultrasonic unit, identified by the numeral 98. The unit 98 is constructed of tubular parts, as designated at 102, 104 and 106, the parts including the upright legs 102 and 104 and the transverse lower part 106 which is joined to the upright parts by way of elbows 108 and 110. As may be seen in Fig. 2, elbows preferably are provided at the upper ends of the tubular parts 102 and 104, as designated at 116 and 118. Electrodes are provided at the upper ends of the parts 102 and 104, as designated at 120 and 122, the alternating current voltage being applied to these electrodes. A variable transformer is provided for controlling the voltage supplied to these electrodes. Figs. 5 and 6 illustrate preferred circuitry for the ultrasonic generators. The tubular parts of the ultrasonic generator are filled with material which may preferably be barium titanate or, alternatively, quartz crystals. These materials are commercially available materials for the purpose of generating ultrasonic vibrations when a current is passed through them. Disposed within the material is an electrical coil, as designated at 126, the ends of which are not connected to the electrodes 120 and 122. The purpose of the electrical coil is to facilitate the flow of current through the material in the tubular parts. The construction of the ultrasonic generator is unique in that due to its configuration, it has the capability of transmitting and dispersing sound vibrations in all directions through the solution, the ultrasonic generators of course being exposed to the solution within the tank or vessel 10. The construction of all of the individual ultrasonic generators is the same. The generators are arranged or arrayed as illustrated in Fig. 1 at opposite sides of the tank or vessel to provide for the dispersion and transmission of the ultrasonic vibrations through the solution tank and through the material being processed. A preferable range of frequencies generated by the ultrasonic generators may be from 40,000 to 280,000 Hz. Referring to the solution or bath that is used in the processing tank, preferably it is a water solution of water that has been filtered or distilled water. The water is filtered to remove the iron from the water through a carbon filter of a type that is commercially available. The removal of iron from the water deionizes the water sufficiently for purposes of the process. Distilled water may be used. Certain ingredients or chemicals are introduced into the water, that is, mixed into it, by simple mixing. Preferably, however, the mixing is done with the water heated to substantially 26.7° C (80° F). which causes the chemicals to mix faster while being stirred. Surfactant is introduced into, that is, mixed into, the water, and this ingredient may be in a range from about 5% to about 15% by weight, depending upon how much increase of conductivity is wanted or needed in the material being processed. The surfactant is a liquid. It is a non-ionized surfactant liquid. This is a product that is used to make soap with. The surfactant may be a product marketed under the trade name "MAZOX CAPA". Other surfactants may be used, which are surfactants that are commercially available. The particular surfactant used is not critical. The surfactant is a salt. Also, there is mixed into the solution hydrochloric acid in an amount from 5% to 15% by weight. The ingredients can be mixed in by stirring with a paddle, the actual acts of mixing not being critical. There is added 1/2 of 1% to 1% substantially of silver nitrate by weight. The silver nitrate is in the form of crystals. This is a product that is commercially available. The effect of the solution during the process with the other steps will be referred to more in detail presently. As has been pointed out above, there is a continuous circulation and filtering of solution within the tank or vessel by way of the circulating pump at each end. The following is a description of the process. This description constitutes a specific example of the process, the specific example including the particular equipment or apparatus that has been described in the foregoing. In carrying out the process, the solution may be that described in the foregoing. In performing the process, the voltage as described is provided through the circuitry described to the electrodes at opposite ends of the tank. To identify a specific example, the data are as follows: material - vinyl sheet surfactant 15% by weight hydrochloric acid 15% by weight silver nitrate 1% by weight voltage (for current) 107 volts A.C. voltage (for ultrasonics) 110 volts A.C. The alternating voltage provides for a flow of alternating current through the solution in the vessel and through the materials being processed. Simultaneously, the voltage as described above is applied to all of the individual ultrasonic generators at opposite sides of the tank so as to provide for sonic vibrations to traverse through the solution in the tank and through the material (vinyl) being processed at frequencies as have been indicated, that is, in the range of 40,000 to 280,000 Hz. A typical frequency of the ultrasonic vibrations is 60,000 Hz; for example, the material is a rectangular sheet of vinyl material, such as a vinyl, which is placed in the tank and immersed in the solution. The material may be any material or piece of material that is immersible in the solution. The exemplary piece of material being processed is a sheet of laminate having a thickness of, for example, 1.0 mm (0.040 inches). The material can be immersed in the solution one sheet at a time, or it is possible to process a large number of sheets at one time with spacers placed in between the sheets of material. Various types of handling equipment can be provided for placing material, such as, for example, sheets of laminate, into the solution in the tank and providing spacers between the sheets. Such equipment, that is, handling equipment, is of course auxiliary to the method, and the equipment or apparatus for practicing the method. In the process, the flow of alternating current and the sonic vibrations loosen the molecular structure of the material being processed so that the chemicals are carried into and through the material into the molecular structure, making the material electrically conductive or enhancing the electrical conductivity. The surfactant and silver nitrate are conductive materials which are caused by the current and the vibrations to intrude directly into the molecular structure. When the process is terminated and the ultrasonic generators are turned off, the molecular structure then closes or comes back together again, resulting in the material being processed being a homogeneous conductive material or electrically conductive material that has had its conductivity increased or enhanced. A number of different types of material have been successfully processed by the process, including rubber and canvas (that is, tennis shoes), and also vinyls, synthetic carpeting and other materials. In observing the process and its effect, there has been used a surface resistivity meter, that is, Model 262A marketed by Monroe Electronics, Inc. This instrument is capable of testing the surface resistance of sheets of material and also the resistance to ground of pieces of material that have been processed. The resistivity meter is an instrument with parallel electrodes at the bottom which are placed in contact with the material to be tested, the instrument giving a reading of the electrical resistivity of the area encompassed between the electrodes. A reading can be had as to the resistivity per square, that is, the area between the electrodes and/or the resistance to ground. By way of example, an unprocessed material may show a resistance of 10¹² or 10¹³ ohms. After processing, by way of example of one material processed, the reading of the ohms resistance went down from these figures to 10⁶ and 10⁷. The resistivity in ohms is of course an indication of the increase in electrical conductivity of the material processed. The electrical conductivity can be increased or enhanced to a greater extent by leaving the material to be processed in longer and by increasing the voltage and the frequency of the vibrations generated by the ultrasonic generators.

Claims: A method for making a solid substrate electrically conductive or for increasing the electrical conductivity of the solid substrate, characterized by the following steps: a) preparing a liquid bath including treatment agents in solution, with the treatment agents including at least one conduction agent; b) immersing the solid substrate in the liquid bath; c) subjecting the liquid bath and the solid substrate to ultrasonic vibrations, whereby the molecular structure of the solid substrate is loosened or relaxed; and d) simultaneous with step c), passing an alternating electric current through the liquid bath and the solid substrate, whereby molecules of the conduction agent enter into the relaxed molecular structure of the solid substrate and thereby increase its electrical conductivity. A method according to claim 1, characterized by passing the alternating electrical current laterally through the liquid bath, and by applying the ultrasonic vibrations so that they pass laterally through the liquid bath. A method according to claim 1, characterized by the treatment agents including a salt that make the liquid bath electrically conductive. A method according to claim 3, characterized by: a) the salt being a surfactant; and b) the treatment agents including hydrochloric acid, and a small percentage by weight of silver nitrate crystals. A method according to claim 4, characterized by introducing the surfactant in a range of substantially 5 to 15 % by weight, the hydrochloric acid being in a range of 5 to 15 % by weight, and the silver nitrate crystals in an amount of substantially 1/2 % to 1 % by weight. A method according to claim 1, characterized by applying the ultrasonic vibrations at a frequency in the range of 40,000 to 280,000 Hz. A method according to claim 1, characterized by applying the alternating electric current to the bath and treatment material with a voltage in the range of 60 - 120 volts AC. A method according to any of the preceding claims, characterized by the liquid bath including deionized water as a base. A method according to any of the preceding claims, characterized in that the increase in electrical conductivity is an increase in surface electrical conductivity. An apparatus for carrying out a process for making a solid substrate electrically conductive or for increasing its electrical conductivity characterized by: a) a vessel (10) adapted to contain the solid substrate and a liquid bath including treatment agents in solution, with the treatment agents including at least one conduction agent; b) electrodes (84a, 84b, 84c) positioned with respect to the vessel (10) in electrical contact with the liquid, whereby the electrodes (84a, 84b, 84c) apply an alternating electrical current through the liquid in the vessel (10), c) a plurality of ultrasonic generators (98) mounted on the vessel (10), whereby the ultrasonic generators (98) apply ultrasonic vibrations at a predetermined frequency to the liquid throughout the vessel (10) at the same time that the electrodes (84a, 84b, 84c) apply alternating electric current to the liquid, whereby the molecular structure of the solid substrate is loosened or relaxed and molecules of the conduction agent enter into the relaxed molecular structure of the solid substrate and thereby increase its electrical conductivity. An apparatus according to claim 10, characterized by a mixing device that continuously circulates the liquid in the vessel. An apparatus according to claim 10, characterized by each individual ultrasonic generator (98) being configured to disperse ultrasonic vibrations in all directions from the generator. An apparatus according to claim 10, characterized by the vessel (10) being generally rectangular, with ends and having sides, whereby the electrodes (98) are in contact with the liquid and are disposed at opposite ends of the vessel (10), and whereby the ultrasonic generators (98) are disposed at opposite sides of the vessel (10) and transmit the ultrasonic vibrations between the sides of the vessel (10). An apparatus according to claim 10, characterized by the electrically conductive liquid includes water mixed with the conduction agent. An apparatus according to claim 14, characterized by the liquid bath including a surfactant, an acid, and silver nitrate crystals. An apparatus according to claim 15, characterized by the surfactant being included in a range of 5 % to 15 % by weight, the acid is hydrochloric acid in a range of 5 % to 15 % by weight, and the silver nitrate is substantially 1/2 % to 1 % by weight. An apparatus according to claim 16, characterized by the ultrasonic vibrations having a frequency in the range of 40,000 to 280,000 Hz. An apparatus according to claim 12, characterized by each ultrasonic generator (98) having: tubular parts (102, 104, 106) containing barium titanate or quartz crystals; electrodes (120, 122) through which an alternating electric current is applied to the barium titanate or quartz crystals; and a coil of wire (126) disposed within the barium titanate or quartz crystals, whereby the ends of the coil (126) are spaced from the electrodes (120, 122). An apparatus according to any one of the claims 10 to 18, characterized in that the increase in electrical conductivity is an increase in surface electrical conductivity.

Inventors: ROOKLYN JACK, ROOKLYN, JACK
Applicants: IND MANAGEMENT CO, INDUSTRIAL MANAGEMENT CO.
Application year: 1989
Main classification: C23C18
IPC codes: H01B1, H05F1, C23C18