METHOD OF PREPARING ELECTRODES FOR USE IN HEAT-GENERATING APPARATUS

Abstract: An improved method of treating material for use in a heat generating method involving the absorption of isotopic hydrogen into the material. The method comprises treating the material to substantially remove impurities in the surface region and then depositing a thin film of a substance capable of absorbing isotopic hydrogen on the surface of the material. An optional additional treatment is to substantially remove hydrogen already absorbed in the material, then heat the material in an atmosphere of isotopic hydrogen in order to precharge the material with the isotopic hydrogen.

Description: METHOD OF PREPARING ELECTRODES FOR USE IN HEAT-GENERATING APPARATUS Methods of generating heat and power by contacting a material having a lattice structure capable of absorbing: hydrogen with low atomic weight nuclei have been disclosed in "Heat-Generating Method and Apparatus", U.S. Serial No. 323,513, filed March 13, 1989, and "Power- Generating Method and Apparatus", U.S. Serial No. 346079, filed May 2, 1989, assigned to the assignee of this application and incorporated herein by reference. The present invention provides an improved method of treating the lattice material so as to increase the capability of that material to absorb the low atomic weight nuclei. It has been discovered that very large amounts of excess heat can be generated when a material having a lattice structure capable of absorbing low molecular weight elements, primarily the isotopes of hydrogen, is exposed to a source of such elements under conditions which are effective to produce diffusion of these atoms into the metal lattice to a sufficient degree. In their paper entitled Electrochemically induced nuclear fusion of deuterium, J. Electroanal. Chem. 261 (1989) 301-308, Drs. Martin Fleisσhmann and Stanley Pons disclose a method of producing a sufficient compression of deuterium into palladium by a galvanostatic method in order to generate excess heat. This method uses a palladium cathode in a galvanic cell in which the electrolyte is a mixture of heavy water with small amounts of water and lithium deuteroxide. Palladium is well known to absorb very large amounts of hydrogen, in particular by use as a cathode in a dilute acid electrolyte. Impurities, such as platinum, in the bulk phase metal are known to tend to inhibit hydrogen charging of the lattice by promoting formation of hydrogen gas at the surface of the palladium cathode at the expense of diffusion into the lattice. When the metal cathode is formed by a process such as melting or is annealed when in solid form, these impurities tend to come to the surface, so these surface impurities can be removed by machining or grinding the metal prior to use as a cathode. Although the absorption of deuterium and tritium in palladium has not been so extensively studied, it is reasonable to assume that these impurities which inhibit the absorption of hydrogen will also inhibit the absorption of the higher isotopes. It is also well known, before studying the permeation of hydrogen into a metal, to remove as much of the existing absorbed hydrogen as possible by techniques such as melting and cooling or vacuum degassing. The inventors of the present invention have repeated the experiments described in the Fleischmann and Pons paper referred to above, using palladium rod cathodes in an electrolyte of heavy water with small amounts of water and lithium deuteroxide. This invention relates to an improved method of treating the cathode so as to enhance the absorption of deuterium into the metal lattice of the cathode and thereby improve the heat generating characteristics of the system. The present invention provides an improvement to a method of generating energy by subjecting a source of isotopes of hydrogen to a material having a lattice structure capable of absorbing hydrogen, the improvement being the treatment of the lattice material to oxidize a substantial proportion of the surface impurities and dissolve them in solution, and then depositing a thin film of a substance capable of absorbing hydrogen on the surface of the material. The material is preferably a metal, which may be selected from group VIII and group IVb metals and their alloys. One method of carrying out this treatment involves using the metal as an electrode in an electrolytic cell, and first taking it anodic to a voltage sufficient to substantially oxidize and dissolve the impurities in the surface region of the metal, and then taking it cathodic to reduce the palladium oxide formed and deposit a fresh layer of palladium. Preferably, the electrolyte contains a salt of the substance to be deposited on the surface of the metal, so that the deposition takes place while the metal electrode is cathodic. This substance is preferably palladium, and the salt may be palladium chloride or palladium nitrate. The material may be treated further by substantially removing the hydrogen previously absorbed, heating it in an atmosphere of isotopic hydrogen gas, preferably deuterium, and holding it at a temperature which enhances the absorption of deuterium for a period of time. The isotopic hydrogen gas will be at a pressure greater than atmospheric. Figure 1 shows an electrolytic cell in which a palladium cathode, treated in accordance with the present invention, is exposed to electrolytically generated deuterium. Figure 2 shows an alternative embodiment of the electrolytic cell. The first part of this description relates to the improved methods of the present invention for preparing the metal cathodes before they are charged with isotopic hydrogen. The second part describes the way that the present inventors used cathodes prepared according to this invention to generate heat. 1. Preparation of Metal Cathodes The cathode must be prepared from a material that is capable of absorbing isotopic hydrogen to a sufficient degree to produce the heat-generating events. The preferred material is palladium, but many other metals and alloys have been previously shown to absorb hydrogen. In particular, the group VIII metals, which besides palladium include rhodium, ruthenium, iridiu , osmium, nickel, cobalt, iron, and alloys of those metals, in particular palladium/silver and palladium/cerium alloys, are known to readily absorb hydrogen. Other suitable materials are the group IVb metals, titanium, zirconium and hafnium and alloys of those metals. In the preferred embodiment, the cathode is in the form of a rod. However, there are many other suitable forms, such as a plate, tube, thin sheet (which may be planar or curved) , or the material capable of absorbing isotopic hydrogen may be in the form of a thin film on a substrate, which may be inactive or may itself be capable of absorbing hydrogen, or the material may be generally spherical in shape. For cathodes in bulk form, such as rods, plates or tubes, the first preparation step is to mechanically remove the surface layer of material, which is likely to contain significant quantities of impurities when the cathode form has been prepared by casting or has been annealed. The amount to be removed will depend upon the diameter of the rod or tube or the thickness of the plate and the degree of purity of the material. In the preferred embodiment the palladium rod was machined to approximately two thirds of its original diameter. The cathode is then cleaned to remove any surface contamination. Preferably, this is done by first grinding the surface using increasingly fine grades of abrasive, and then cleaning the surface using a suitable solvent. In the preferred embodiment, the grinding was done using carborundum papers of grades ranging between 320 and 600 Grit, and the cleaning done in distilled and deionized water and .then in acetone. The cathode is then cleaned again, preferably by immersing in aqua regia followed by washing in distilled and deionized water. For sheet or thin film cathodes, solvent cleaning is generally the only practicable cleaning step. The cathode is then annealed in ultra high purity argon. The annealing step is to reduce the dislocation density and point defect concentration and to remove hydrogen whose solubility in the lattice decreases with increasing temperature and lower hydrogen partial pressure. Preferably, the annealing temperature is about 600 degrees celsius, and the annealing time is about four hours. The cathode is then allowed to cool to room temperature before being removed from the annealing chamber. The surface may then be polished, for example by abrasion in fine alumina powder, and then further washed in distilled and deionized water and dried under argon. The surface of the cathode is then prepared to enhance the absorption of the isotopic hydrogen at the surface, and to remove impurities that could hinder that absorption. This is done by placing it in an electrolytic cell with an electrolyte composed of a solution containing a palladium salt and sodium chloride. The preferred palladium salts are palladium chloride and palladium nitrate. Platinum is the preferred counter electrode. The cathode is first taken anodic, with the voltage gradually increasing from zero to a voltage sufficient to oxidize surface impurities. In the preferred embodiment, the voltage is increased at about 5mv/sec to a maximum positive voltage in the region of 250 mv. The current is then decreased at the same rate, and then taken cathodic at the same rate to a negative voltage of about 250mv. During the cathodic part of the treatment, a fine surface film of palladium is deposited on the surface. The cathode is then removed from the cell, washed in distilled and deionized water, and immediately transferred to the heat-generating electrolytic cell. In an alternative preferred embodiment, after the first annealing period at the higher temperature, the temperature is then reduced to about 400 degrees celsius, oxygen is introduced, and the temperature held for about 10 minutes. The annealing chamber is then purged with argon, deuterium gas is introduced, and the temperature held for a further period of about 30 minutes. The cathode is then allowed to cool to room temperature before being removed, and then immersed in aqua-regia followed by washing in distilled and de-ionized water. In addition to the above preparation methods, the cathode may be optionally pretreated with isotopic hydrogen in order to decrease the time needed to charge the cathode to a sufficient concentration for the heat- generating events to occur. Hydrogen already absorbed in the lattice structure of the cathode is preferably removed, for example by degassing in a vacuum. The cathode is then introduced into an autoclave under argon cover, and the autoclave is flushed with high purity argon. Deuterium gas under pressure is introduced, and the cathode heated to a suitable temperature for the diffusion of deuterium into the metal lattice structure. In the preferred embodiment, the deuterium gas is maintained at a pressure of over 120 psi, and the cathode is held at a temperature of about 125 degrees celsius for about two hours. It is then cooled to about 80 degrees, and held at that same temperature under the same deuterium gas pressure for about 12 hours. The Cathode is then cooled to room temperature, removed under argon cover and immediately transferred to the heat-generating cell. 2. Use of Prepared Cathodes Figure l shows a palladium cathode 2, prepared in accordance with the present invention, in an electrolytic cell 4. The outer cell wall 6 is preferably made of glass. The palladium cathode 2 is mounted at the top end in a glass tube 8 with a liquid-tight glass seal 10. An electrically conductive wire lead 12, preferably made of palladium, is connected to the cathode 2 to conduct the cathodic current to the cathode. The anode 14 consists of wire 16, in this embodiment platinum wire, wound around a series of glass rods 18 encircling the cathode 2. Wire leads 20 to the anode are brought to the outside of the cell to connect with the source of anodic current. The lower end of the cathode 2 and the anode winding rods 18 are fixed in a spacer 22, in this embodiment made of teflon. The electrolyte 24 is a solution of 0.1 molar LiOD in heavy water, with a preferred composition of 99.9% D 2 0 and 0.1% H 2 0. The electrolyte level is adjusted by adding more electrolyte solution through the tube 26 to maintain the level 28 above the glass seal 10. The temperature of the cell is measured with a thermocouple 30 enclosed in a thin walled glass tube 32. Gas is generated by the electrolysis. This can be vented from the cell through outlets 34 and 36 connecting to the center and the outer part of the cell respectively. As a further means of limiting the explosive potential of an accumulation of gas in the cell, the various leads and tubes from the cell to the outside are taken through a glass cap 38, connected to the cell by a ground glass joint 40. In the event of a rapid build up of gas, this cap will be popped off by the pressure before the cell wall is ruptured, thus avoiding a serious explosion and loss of electrolyte. An alternative embodiment of an electrolytic cell is shown in Figure 2. The cell 50 is a quartz tube, with a pyrex glass top 52 connected to the tube with a ground joint 54. The palladium cathode rod 56 is connected at the top to a glass tube 58 through which the platinum lead 60 to the cathode 56 extends. The anode is platinum gauze or wire 62 wound around a cage of glass rods 64. The anode cage rods 64 are supported at the top by anode cage support 66 and at the bottom by anode cage support 68, preferably made of teflon. Glass tube 58 passes through a hole in he center of the upper anode cage support 66, and the cathode 56 os supported at the bottom by lower anode cage support 68. In this embodiment three separate thermocouples in thin-walled glass tubes are used to measure the cell temperature, near the top 70, at the middle 72 and near the bottom 74. The same electrolyte is used as in the previously described embodiment. However, in this embodiment the electrolyte level 76 is maintained by a continuous metered addition of electrolyte by syringe pump 78 through the glass tube 80. A gas outlet 82 is provided in the top 52 to vent the electrolysis gases. SPECIFIC EXAMPLES EXAMPLE 1: A palladium rod of about 99.95% purity obtained from Johnson Matthey PLC was machined from 6.25 mm to 4 mm, polished with 600 Grit SiC paper and then annealed at 600 C for 1 hour in ultrahigh purity argon gas atmosphere. The rod was subsequently washed in distilled and deionized water, then taken first anodic and then cathodic in a solution of palladium chloride (saturated) and sodium chloride (20 mg/cc) in heavy water for 20 minutes. The run was started on April 24, 1989, and operated at a current density of about 115 mA/cm 2 . Electrolyte was 0.1 molar LiOD in heavy water. The anode was platinum wire, 0.5 mm in diameter. The cell top was found outside of the cell on the early morning of May 2, 1989, apparently popped out by an explosion, which was presumed to be hydrogen/oxygen recombination. The cell was reconnected and started. On the night of 5-2- 89, at 10:15 pm, a small explosion was observed and the cell top was popped out. The top was put back in the cell and the cell reconnected quickly. The temperature of the cell had gone up from about 25 degrees C to 54 degrees C and had stayed at around 48 degrees C for over forty minutes. During this period of increased temperature, termed a heat burst, the power output was 70 watts and the gross power input was 9.6 watts. The input voltage and currents were 7.4 volts and 1.3 amperes. The burst lasting 40 minutes was interrupted by the mild explosive pop. The cell was quickly reassembled and connected. The cell continued to show higher temperature corresponding to an output of about 24 watts for about 10 watts input. The voltage and currents were 7.7 volts and 1.3 amperes. This continued for another 30 hours after which the cell exploded and could not be reassembled. This electrode was removed, retreated and used again. The total excess energy produced during this heat burst was 1.4 million joules. Example 2; The Johnson Matthey rod from Example 1 was retreated by abrading in 0.3 micron alumina powder and washed in distilled and deionized water. The cathode was reassembled in a new cell. The run was started on May 7, 1989. The current density was maintained around 100 mA/cm 2 . Early in the morning of May 21, 1989, a heat burst was observed. The temperature rose in the cell from 31 degrees C to 47 degrees C peak temperature and then dropped to a steady state temperature of about 42 degrees C. The input voltage and currents were 9.76 volts and 0.95 amperes. The input power was 9.3 watts and the conservative estimate of power output was 44 watts. This burst lasted 90 minutes. The burst was interrupted by heavy water addition to the cell to make up for the loss due to electrolysis. The total heat generated during this burst was 187,000 joules. The cell electrolyte taken two days after the burst showed tritium at levels of about 3 to 4 times the background. The cell was shut down on June 2, 1989, for metallurgical analysis of the electrode. Example 3: A Johnson Matthey palladium rod 1 (JM1) , that had been machined to 4 mm, polished with 600 Grit SiC paper, annealed 900 C for 1 hour in ultra high purity argon and run between April 10, 1989 and May 1, 1989, was used again. The electrode was remachined to 3 mm. The electrode was further treated at 275 degrees C for 2 hours under vacuum on May 1, 1989. The electrode was immersed in aqua regia for 3 minutes. The electrode was cleaned in water and dried. The electrode was taken anodic and then cathodic in a palladium chloride and sodium chloride solution in heavy water. The electrode was placed in a cell again and the next run was started on the same day. The nominal current density was 100 mA/cm 2 . After 20 days, on May 21, 1989, at around 20:00 hours, a small sustained burst of heat was observed, which continued for several days. Examole 4 : A 4 mm diameter and 9 cm long electrode (PD 3) of approximately 99.995% purity palladium obtained from Metallor was used as received in this run. The cell was started on April 26, 1989. The current density used was 100 mA/cm 2 . On May 4, 1989, the cell experienced a mild explosion, with destruction of the cell. An increase in cell temperature was observed around 8 pm on May 2, 1989 to a level of about 2 degrees above normal operating temperature. The input voltage and currents were 8 volts and 1 ampere corresponding to a power input of 8 watts. The estimated heat output during the burst is 11.5 watts. The heat burst lasted 32 hours before the cell destruction by explosion on the morning of may 4, 1989. Example 5: The palladium electrode previously used in Example 4 was heat treated in air at 300 degrees C for 1 hour, then treated at 275 degrees C for 2 hours in ultra high purity argon. The electrode was reassembled in a new cell and the second run was started on May 6, 1989. The cell was reconfigured again on June 23, 1989 and restarted with an interruption of about 2 hours. A small heat burst was observed on July 1, 1989, over a 60 minute period. The voltage and current inputs were 9.7 volts and 1.0 amperes corresponding to power input of 9.7 watts. The power output during the burst was about 13.5 watts with an excess of about 3.7 watts. Example 6: A 4 mm diameter and 7 cm long palladium rod of 99.995% purity from Metallor was immersed in aqua regia for 3 minutes, washed in distilled and deionized water and abraded with 0.3 micron alumina powder. The electrode was taken anodic and then cathodic in a PdCl plus NaCl solution in heavy water. The electrode was subsequently assembled in a cell having a 3-electrode system, with a facility to monitor cathodic overvoltage. The reference electrode was a Calomel electrode. The electrolyte had chloride ion contamination from the reference electrode solution. The cell was run from April 9, 1989 to May 23, 1989, with a platinum sheet anode at current densities varying from 100 to 350 mA/cm 2 . On May 23, 1989, the cell was destroyed by a powerful explosion. The electrode was reconfigured in a new cell with palladium sheet anode and the same electrolyte. A small heat burst was observed on June 2, 1989, for a very short time of about 10 minutes. The voltage and currents were 9.7 volts and 1.6 amperes corresponding power input of 15.5 watts. The average output during the burst was about 25 watts over " a 10 minute period. Example 7: A palladium electrode 4 mm in diameter and 8 cm long of about 99.995% purity from Metallor was pre-deuterated in D 2 gas at 110 psi first at 125 C for 1 hour and then at 80 C for 2 hours and cooled slowly overnight at 110 psi gas pressure to room temperature on April 25, 1989. The palladium rod cathode was then assembled in a cell with a platinum sheet anode. The experiment was started on April 26, 1989. The current densities used varied from 160 mA/cm 2 to 280 mA/cm 2 . After 5 days, on May 1, 1989, a heat burst was observed. The voltage and current input during the burst were 8 volts and 2.6 amperes, corresponding to a power input of about 21 watts. The average output was about 25 watts. The burst was interrupted after 25 hours by an explosion. Although preferred embodiments of the invention have been described, it will be apparent that a variety of modifications and changes may be made without departing from the invention.

Claims: CLAIMS : 1. In a method of generating energy by subjecting a source of isotopic hydrogen to a material having a lattice structure capable of absorbing isotopic hydrogen and causing isotopic hydrogen to permeate into the lattice structure to a concentration sufficient to induce the generation of energy, the improvement comprising: treating the material so as to oxidize a substantial proportion of the impurities in the surface region of the material; treating the material so as to substantially remove the oxidized impurities; and depositing a thin film of a substance capable of absorbing isotopic hydrogen on the surface of the material. 2. The method of claim 1, wherein the material is a metal. 3. The method of claim 2, wherein the metal is selected from the group consisting of palladium, rhodium, ruthenium, iridium, osmium, nickel, iron, cobalt, titanium, zirconium, hafnium and alloys thereof. 4. The method of claim 2, wherein the treatment of the metal so as to oxidize a substantial proportion of the impurities in the surface region comprises using the metal as an anode in an electrolytic cell and gradually increasing the electrode potential to a more positive level sufficient to cause the impurities in the surface region to be substantially oxidized and go into solution. 5. The method of claim 2, wherein the treatment of the metal so as to remove the oxidized layer on the metal surface comprises using the metal as a cathode in an electrolytic cell and gradually decreasing the electrode potential to a more negative level sufficient to cause the oxidized surface to be substantially reduced. 6 The method of claim 2, wherein the deposition of the thin film of the substance capable of absorbing isotopic hydrogen comprises using the metal as a cathode in an electrolytic cell containing a solution of a salt of the substance to be deposited on the surface of the metal. 7. The method of claim 6, wherein the substance capable of absorbing isotopic hydrogen is palladium and the electrolytic cell contains a solution of sodium chloride and a palladium salt selected from the group comprising palladium chloride and palladium nitrate. 8. The method of claim 1, further comprising; substantially removing the hydrogen already absorbed in the material; heating the material in an atmosphere of isotopic hydrogen gas to a temperature at which absorption of the isotopic hydrogen is enhanced; and holding the material at such temperature in the atmosphere of isotopic hydrogen gas for a period sufficient to permit diffusion of isotopic hydrogen into the material to reach steady state. 9. The method of claim 8, wherein the isotopic hydrogen gas is deuterium gas. 10. The method of claim 8, wherein the atmosphere of isotopic hydrogen gas is at a pressure greater than atmospheric. 11. A method of preparing an electrode for use in a heat generating method involving the absorption of isotopic hydrogen from a solution containing a source of the isotopic hydrogen, comprising the steps of: placing the electrode in an electrolytic cell containing a solution of a salt of a substance capable of absorbing isotopic hydrogen; passing current through the cell in such a way that the electrode is anodic; gradually increasing the electrode potential to a more positive level sufficient to oxidize a substantial proportion of the impurities in the surface region of the electrode and dissolve them in solution; gradually decreasing the electrode potential to zero, then reversing the flow of current through the cell so that the electrode becomes cathodic; gradually decreasing the electrode potential to a more negative value sufficient to reduce the palladium oxide film and sufficient to deposit a layer of the substance capable of absorbing isotopic hydrogen on the surface of the electrode. 12. The method of claim 11, wherein the electrode is made from a metal selected from the group consisting of palladium, rhodium, ruthenium, iridium, osmium, nickel, iron, cobalt, titanium, zirconium, hafnium and alloys thereof. 13. The method of claim 11, wherein the substance capable of absorbing isotopic hydrogen is palladium and the salt is selected from the group comprising palladium chloride and palladium nitrate. 14. The method of claim 11, further comprising; substantially removing the hydrogen already absorbed in the material; heating the material in an atmosphere of isotopic hydrogen gas to a temperature at which absorption of the isotopic hydrogen is enhanced; and holding the material at such temperature in the atmosphere of isotopic hydrogen gas for a period sufficient to permit diffusion of isotopic hydrogen into the material to reach steady state. 15. The method of claim 14, wherein the isotopic hydrogen gas is deuterium gas. 16. The method of claim 14, wherein the atmosphere of isotopic hydrogen gas is at a pressure greater than atmospheric. 17. A method of enhancing the ability of a material to absorb isotopic hydrogen, comprising the steps of; removing the outer surface of the material; then treating the material so as to oxidize a substantial proportion of the impurities in the surface region of the material; then treating the material so as to substantially remove the oxidized impurities; and then depositing a thin film of a substance capable of absorbing isotopic hydrogen on the surface of the material. 18. The method of claim 17, wherein the material is a metal. 19. The method of claim 18, wherein the metal is selected from the group consisting of palladium, rhodium, ruthenium, iridium, osmium, nickel, iron, cobalt, titanium, zirconium, hafnium and alloys thereof. 20. The method of claim 18, wherein the treatment of the metal so as to oxidize a substantial proportion of the impurities in the surface region comprises using the metal as an anode in an electrolytic cell and gradually increasing the electrode potential to a level sufficient that the impurities in the surface region are substantially oxidized and go into solution. 21. The method of claim 18, wherein the treatment of the metal so as to remove the oxidized impurities comprises using the metal as a cathode in an electrolytic cell and gradually decreasing the cathodic potential to a level sufficient that the oxidized impurities are substantially reduced. 22. The method of claim 18, wherein the deposition of the thin film of the substance capable of absorbing isotopic hydrogen comprises using the metal as a cathode in an electrolytic cell containing a solution of a salt of the substance to be deposited on the surface of the metal. 23. The method of claim 22, wherein the substance capable of absorbing isotopic hydrogen is palladium and the electrolytic cell contains a solution of sodium chloride and a palladium salt selected from the group comprising palladium chloride and palladium nitrate. 24. The method of claim 17, further comprising; substantially removing the hydrogen already absorbed in the material; heating the material in an atmosphere of isotopic hydrogen gas to a temperature at which absorption of the isotopic hydrogen is enhanced; and holding the material at such temperature in the atmosphere of isotopic hydrogen gas for a period sufficient to permit diffusion of isotopic hydrogen into the material to reach steady state. 25. The method of claim 24, wherein the isotopic hydrogen gas is deuterium gas. 26. The method of claim 24, wherein the atmosphere of isotopic hydrogen gas is at a pressure greater than atmospheric. 27. In a method of generating energy by subjecting a source of isotopic hydrogen to a cathodic material capable of absorbing hydrogen in an electrolytic cell, the improvement comprising: treating the material so as to oxidize a substantial proportion of the impurities in the surface region of the material; treating the material so as to substantially remove the oxidized impurities; and depositing a thin film of a substance capable of absorbing isotopic hydrogen on the surface of the material. 28. The method of claim 27, wherein the material is a metal. 29. The method of claim 28, wherein the metal is selected from the group consisting of palladium, rhodium, ruthenium, iridium, osmium, nickel, iron, cobalt, titanium, zirconium, hafnium and alloys thereof. 30. The method of claim 28, wherein the treatment of the metal so as to oxidize a substantial proportion of the impurities in the surface region comprises using the metal as an anode in an electrolytic cell and gradually increasing the anodic potential to a level sufficient that the impurities in the surface region are substantially oxidized and go into solution. 31. The method of claim 28, wherein the treatment of the metal so as to remove the oxidized layer comprises using the metal as a cathode in an electrolytic cell and gradually decreasing the cathodic potential to a level sufficient that the oxidized impurities are substantially reduced. 32. The method of claim 28, wherein the deposition of the thin film of the substance capable of absorbing isotopic hydrogen comprises using the metal as a cathode in an electrolytic cell containing a solution of a salt of the substance to be deposited on the surface of the metal. 33. The method of claim 32, wherein the substance capable of absorbing isotopic hydrogen is palladium and the electrolytic cell contains a solution of sodium chloride and a palladium salt selected from the group comprising palladium chloride and palladium nitrate. 34. The method of claim 27, further comprising; substantially removing the hydrogen already absorbed in the material; heating the material in an atmosphere of isotopic hydrogen gas to a temperature at which absorption of the isotopic hydrogen is enhanced; and holding the material at such temperature in the atmosphere of isotopic hydrogen gas for a period sufficient to permit diffusion of isotopic hydrogen into the material to reach steady state. 35. The method of claim 34, wherein the isotopic hydrogen gas is deuterium gas. 36. The method of claim 34, wherein the atmosphere of isotopic hydrogen gas is at a pressure greater than atmospheric.

Inventors: BYRNE J GERALD, GURUSWAMY SIVARAMAN, LI JUN, WADSWORTH MILTON E, BYRNE, J., GERALD, GURUSWAMY, SIVARAMAN, LI, JUN, WADSWORTH, MILTON, E.
Applicants: UNIV UTAH, UNIVERSITY OF UTAH
Application year: 1990
Main classification: G21B1
IPC codes: C25B5, C25B11, G21B3