Abstract: Provided are devices and methods for a rapid, non-perturbative and energy-efficient technique for pH sensing based on a flexible graphene electrode. This technique does not require the application of gate voltage or source-drain bias, and demonstrates fast pH-characterization with precision. The disclosed technology is suitable for in vivo monitoring of tumor-induced pH variation in tissues and detection of pH changes as required in a DNA sequencing system.

Abstract: There is described a method of reprocessing spent nuclear fuel. The spent nuclear fuel is added to an electro-reduction cell containing a halide salt electrolyte at a temperature above the melting point of the metallic form of uranium and higher actinides present in the spent nuclear fuel. The cell is operated so as to electrochemically reduce the spent nuclear fuel to an alloy of uranium and higher actinides present in the spent nuclear fuel, wherein electrochemical reduction is continued until a concentration of unreduced components of the spent nuclear fuel is sufficiently low for the ahoy to agglomerate.

Abstract: Devices and methods for electrochemical phase transfer utilize at least one electrode formed from either glassy carbon or a carbon and polymer composite. The device includes a device housing defining an inlet port (42), an outlet port (44) and an elongate fluid passageway (36) extending therebetween. A capture electrode (12) and a counter electrode are positioned within said housing such that the fluid passageway extends between the capture and counter electrodes.

Abstract: A process of incorporating technetium into an electroless deposit, forming an alloy that is extremely resistant to corrosion and reduces the mobility of technetium on a geologic time scale is disclosed and claimed. The process includes providing a liquid containing technetium, such as an aqueous waste stream generated during the used nuclear fuel reprocessing activities. The technetium is collected and concentrated, and provided into an electroless deposition bath. A substrate, such as suitably prepared zero valent iron or stainless steel, is introduced into the bath to initiate autocatalytic electroless deposition of the technetium onto the substrate due to the difference in electrochemical potential between the plating bath and the metals in solution. This causes a layer of technetium metal to form on the substrate.

Abstract: A gas purification apparatus, highly purifying gas containing salt derived from molten salt stored in a vessel (10), is provided with a reflux mechanism (35, 42) liquefying the salt, contained in the gas, for return to the molten salt in the vessel, and a filtration mechanism (39, 44) disposed in an exhaust flow path of the gas on a downstream stage of the reflux mechanism.

Abstract: A method for stabilizing a nuclear material may include electrolytically reducing the nuclear material in a first molten salt electrolyte of an electroreducer to produce a reduced material. A reducer waste may accumulate in the first molten salt electrolyte as a byproduct of the electroreduction. After the electroreduction, the reduced material may be electrolytically dissolved in a second molten salt electrolyte of an electrorefiner to produce a purified metal product on a refiner cathode assembly of the electrorefiner. As a result of the electrorefining, a first refiner waste may accumulate in the second molten salt electrolyte and a second refiner waste may accumulate in a refiner anode assembly of the electrorefiner. The reducer waste from the electroreducer and the first refiner waste from the electrorefiner may be converted into a ceramic waste form, while the second refiner waste from the electrorefiner may be converted into a metallic waste form.

Abstract: An in situ method for detecting alpha particles contained in a liquid medium, which uses a system which includes a counter-electrode and an alpha particle detector including a substrate made of an intrinsic semiconductor material sandwiched between two electrical contacts, wherein the contact intended to be in contact with the liquid medium is made of boron-doped diamond. By forming a particular electrolyte 8 and by causing a current to flow between counter-electrode and the boron-doped diamond contact in contact with the liquid medium, actinides or polonium present in the liquid medium may be concentrated on the boron-doped diamond contact, and by this means the detection limit of the alpha emitters may be lowered.

Abstract: An apparatus for real-time, in-situ monitoring of actinide ion concentrations which comprises a working electrode, a reference electrode, a container, a working electrolyte, a separator, a reference electrolyte, and a voltmeter. The container holds the working electrolyte. The voltmeter is electrically connected to the working electrode and the reference electrode and measures the voltage between those electrodes. The working electrode contacts the working electrolyte. The working electrolyte comprises an actinide ion of interest. The reference electrode contacts the reference electrolyte. The reference electrolyte is separated from the working electrolyte by the separator. The separator contacts both the working electrolyte and the reference electrolyte. The separator is ionically conductive to the actinide ion of interest. The reference electrolyte comprises a known concentration of the actinide ion of interest. The separator comprises a beta double prime alumina exchanged with the actinide ion of interest.

Abstract: Uranic and transuranic metals and metal oxides are first dissolved in ozone compositions. The resulting solution in ozone can be further dissolved in ionic liquids to form a second solution. The metals in the second solution are then electrochemically deposited from the second solutions as room temperature ionic liquid (RTIL), tri-methyl-n-butyl ammonium n-bis(trifluoromethansulfonylimide) [Me3NnBu][TFSI] providing an alternative non-aqueous system for the extraction and reclamation of actinides from reprocessed fuel materials. Deposition of U metal is achieved using TFSI complexes of U(III) and U(IV) containing the anion common to the RTIL. TFSI complexes of uranium were produced to ensure solubility of the species in the ionic liquid. The methods provide a first measure of the thermodynamic properties of U metal deposition using Uranium complexes with different oxidation states from RTIL solution at room temperature.

Abstract: A method for recovery of residual actinide element from chloride molten salts that are formed after electro-refining and/or electro-winning of a spent nuclear fuel and include actinide elements and rare-earth elements is provided. The method comprises conducting electrolysis using a liquid cadmium cathode (LCC) in the chloride molten salt that is formed after electro-refining and/or electro-winning of a spent nuclear fuel and contains rare-earth elements and actinide elements; electro-depositing the actinide elements contained in the chloride molten salt on the LCC in order to reduce a concentration of the actinide elements; and adding a CdCl2 oxidant to the chloride molten salt containing the LCC-metal alloy in order to oxidize the rare-earth elements co-deposited on the LCC, thereby forming the rare-earth chlorides in the chloride molten salt.

Abstract: An in situ method for detecting alpha particles contained in a liquid medium, which uses a system which includes a counter-electrode and an alpha particle detector including a substrate made of an intrinsic semiconductor material sandwiched between two electrical contacts, wherein the contact intended to be in contact with the liquid medium is made of boron-doped diamond. By forming a particular electrolyte 8 and by causing a current to flow between counter-electrode and the boron-doped diamond contact in contact with the liquid medium, actinides or polonium present in the liquid medium may be concentrated on the boron-doped diamond contact, and by this means the detection limit of the alpha emitters may be lowered.

Abstract: The present invention relates to a portable device for generating ozone in water, purifying the water and making it drinkable. The device comprises a housing; at least two electrodes, including an anode and a cathode extending from the housing into the water and each having semi-rough or rough surfaces in contact with the water. The device also comprises a power supply operatively connected to the electrodes for generating between them a difference of potential creating a current and the hydrolysis of the water creating ozone that purifies the water. The electrodes may have a plate or a rode and tube configuration with a plurality of holes with rough edges. The roughness of the surfaces and of the edges of the holes leads to a coalescence of tiny hydrogen bubbles into larger hydrogen bubbles. The hydrogen may be also removed by absorption in a conductive material and regenerated for reuse.

Abstract: The present invention provides a method of simultaneously removing uranium and transuranics from metallic nuclear fuel in an electrorefiner. In the method, a potential difference is established between an anode basket containing the fuel and a solid cathode of the electrorefiner, thereby creating a diffusion layer of uranium and transuranic ions at the solid cathode, a first current density at the anode basket, and a second current density at the solid cathode. The ratio of anode basket area to solid cathode area is selected based on the total concentration of uranium and transuranic metals in a molten halide electrolyte in the electrorefiner and the effective thickness of the diffusion layer at the solid cathode, such that the established first and second current densities result in both codeposition of uranium and transuranic metals on the solid cathode and oxidation of the metallic nuclear fuel in the anode basket.

Abstract: A method for producing metal powder is provided the comprising supplying a molten bath containing a reducing agent, contacting a metal oxide with the molten bath for a time and at a temperature sufficient to reduce the metal in the metal oxide to elemental metal and produce free oxygen; and isolating the elemental metal from the molten bath.

Abstract: An anode and cathode for an electrolytic cell configured as a low inductance transmission line to enable control of an interphase at an electrode surface. The anode and cathode are coupled to a switched current source by a low inductance path that includes a parallel plate transmission line, a coaxial transmission line, or both. The switched current source provides fast switching between current sources to provide fast charging and discharging of the double-layer capacitance associated with the electrode surface so that an isotope may be selectively transported to the electrode surface for oxidation or reduction. A photon source may be used to create a population of isotope containing species within the electrolyte. An additional static magnetic field and/or an alternating current magnetic excitation source may be used to modify the composition of the population of species containing the isotope to be separated.

Abstract: A method for recovery of residual actinide element from chloride molten salts that are formed after electro-refining and/or electro-winning of a spent nuclear fuel and include actinide elements and rare-earth elements is provided. The method comprises conducting electrolysis using a liquid cadmium cathode (LCC) in the chloride molten salt that is formed after electro-refining and/or electro-winning of a spent nuclear fuel and contains rare-earth elements and actinide elements; electro-depositing the actinide elements contained in the chloride molten salt on the LCC in order to reduce a concentration of the actinide elements; and adding a CdCl2 oxidant to the chloride molten salt containing the LCC-metal alloy in order to oxidize the rare-earth elements co-deposited on the LCC, thereby forming the rare-earth chlorides in the chloride molten salt.

Abstract: Provided is a submerged-type, electrosorption-based desalination apparatus for water purification and method, comprising applying a DC voltage of 0.1 to 2.0 volts to a carbon electrode of the reactor to thereby adsorb inorganic ions on the carbon electrode, and reversely applying the same DC voltage having opposite polarity to recycle regeneration solution to the outside of the apparatus or into the treatment tank, thereby enhancing a recovery rate. In addition, in order to improve desalination efficiency, the reactor used in the desalination apparatus may be embodied in various forms of T-shaped, linear type, single, composite, and ion exchange membrane electrodes. Therefore, the present invention may be applied to remove inorganic ions from industrial wastewater, sea water, and brackish water, which contain large amounts of inorganic ions.

Abstract: A system for automatically producing radioisotopes, and including a target carrier; an electrodeposition unit for electrodepositing a target in the target carrier; an irradiation unit for irradiating the target in the target carrier; first transfer means for transferring the target carrier from the electrodeposition unit to the irradiation unit; an electrodissolution unit for electrodissolving the irradiated target; second transfer means for transferring the target carrier from the irradiation unit to the electrodissolution unit; a purifying unit for purifying the radioisotope of the non-reacting target and impurities; third transfer means for transferring the electrodissolved irradiated target from the electrodissolution unit to the purifying unit; and a central control unit for controlling the operating units and transfer means to automate the entire process. The electrodissolution of the irradiated target is carried out without corroding said target carrier.

Abstract: This is a single stage process for treating spent nuclear fuel from light water reactors. The spent nuclear fuel, uranium oxide, UO2, is added to a solution of UCl4 dissolved in molten LiCl. A carbon anode and a metallic cathode is positioned in the molten salt bath. A power source is connected to the electrodes and a voltage greater than or equal to 1.3 volts is applied to the bath. At the anode, the carbon is oxidized to form carbon dioxide and uranium chloride. At the cathode, uranium is electroplated. The uranium chloride at the cathode reacts with more uranium oxide to continue the reaction. The process may also be used with other transuranic oxides and rare earth metal oxides.

Abstract: A method of electrochemically reducing a metal oxide to the metal in an electrochemical cell is disclosed along with the cell. Each of the anode and cathode operate at their respective maximum reaction rates. An electrolyte and an anode at which oxygen can be evolved, and a cathode including a metal oxide to be reduced are included as is a third electrode with independent power supplies connecting the anode and the third electrode and the cathode and the third electrode.

Abstract: Disclosed is a method of in-situ monitoring a reduction process of uranium oxides by lithium metal, wherein a conversion yield of uranium metal from uranium oxides upon production of uranium metal through a reaction of uranium oxides (UOx, x?3) with lithium metal in the presence of a high-temperature molten salt is measured according to an electrochemical analysis based on an oxidation of an oxygen ion and a reduction of a lithium ion dissociated from lithium oxide obtained as a by-product of the reaction, by use of a measuring device composed of a potentiostat/galvanostat and a reactor provided with an anode and a cathode. The in-situ monitoring method of the current invention is advantageous in terms of fast and simplified measuring techniques, by directly measuring the reduction process of uranium oxides at the anode and cathode connected to the potentiostat/galvanostat in the presence of the high-temperature molten salt.

Abstract: A decontamination method for stripping radionuclides from the surface of stainless steel or aluminum material comprising the steps of contacting the metal with a moderately acidic carbonate/bicarbonate electrolyte solution containing sodium or potassium ions and thereafter electrolytically removing the radionuclides from the surface of the metal whereby radionuclides are caused to be stripped off of the material without corrosion or etching of the material surface.

Abstract: An apparatus for concentration and deactivation of actinide nuclear materials having a pair of spaced apart electrodes made of a composite material including at least one oxide, at least one carbon-containing material and lead, a nuclear waste water stream flowing between the electrodes, and a DC power supply operably connected with the electrodes. When a voltage is applied to the spaced apart electrodes, nuclear cations in the nuclear waste water stream are attracted to one of the electrodes and anions in the nuclear waste water stream are attracted to the other of the electrodes, forming a substantially deionized water stream and a concentrated nuclear waste stream.

Abstract: The invention relates to a flow cell, a method for separating carrier-free radionuclides from a liquid or liquefiable target material, and the radiochemical reaction thereof. According to prior art, flow cells are known which require reaction volumes corresponding to the volume of the target material in order to carry out the desired reactions. The inventive flow cell (1) and method enable the reaction volume, and thus the quantity of starting material, to be reduced by a multiple by reducing the cylinder volume (=reaction volume). As the radioactively marked product is present in very small quantities (picomole to nanomole), the HPL-chromatographic separation of the non-reacted starting material is significantly improved. The economic efficiency of the method is increased due to the fact that small quantities of starting material can be used.

Abstract: A negative ion generating medium for generating negative ions from the surface of a mother material made of aluminum or aluminum alloy. The negative ion generating medium has the mother material of aluminum or aluminum alloy covered at the surface with an anodized layer on which a rare metal separated from a rare metal solution such as zirconium salt is deposited. As the rare metal is deposited in the pores provided in the anodized layer, its negative ion generating area can be increased thus releasing a large number of negative ions. The negative ion generating medium is manufactured by electrolytically processing the mother material in an electrolyte solution of sulfuric acid doped with a rare metal salt such as lithium salt to develop the anodized layer on the surface of the mother material and deposit the rare metal on the anodized layer.

Abstract: A method of electrochemically reducing a metal oxide to the metal in an electrochemical cell is disclosed along with the cell. Each of the anode and cathode operate at their respective maximum reaction rates. An electrolyte and an anode at which oxygen can be evolved, and a cathode including a metal oxide to be reduced are included as is a third electrode with independent power supplies connecting the anode and the third electrode and the cathode and the third electrode.

Abstract: Radioactive material can be processed by an apparatus that includes at least a cylindrical outer shell electrode, an inner electrode, and a plurality of prism-shaped ferromagnetic elements positioned between the outer and inner electrodes. The prism-shaped ferromagnetic elements are positioned around the inner circumference of the metal cylinder. The inner electrode component is located within the metal cylinder and is configured to cover the inwardly-pointing portions of the prism-shaped ferromagnetic elements. Radioactive material in a container is placed into the apparatus, and an AC voltage excitation signal is applied to the electrodes of the apparatus during treatment of the material. The frequency of the excitation signal is selected according to the frequency of structurization or the frequency of destructurization of the ferromagnetic material. The process can be monitored and controlled with the use of alpha, beta, and gamma radiation intensity measuring instruments.

Abstract: This invention relates to radioactively coated devices, preferably radioactively coated medical devices. These coated devices are characterized as having a low rate of leaching of the radioisotope from the surface of the coated device and a uniform radioactive coating, and are therefore suitable for use within biological systems. Methods for coating a device with a radioisotope comprising are also disclosed. One method comprises immersing the device within a solution containing a &Ugr;, &bgr;+, &agr;, &bgr;− or &egr; (electron capture) emitting radioisotope, then exposing the immersed substrate to tuned vibrational cavitation to produce a coated substrate. A second method involves coating a substrate using electroless plating, and yet a third method involves the use of electroplating a radioisotope onto a substrate of interest. With these methods, the coating procedures are followed by baking the coated substrate at a temperature below the recrystallization temperature of the substrate.

Abstract: A new process for recycling spent nuclear fuels, in particular, mixed nitrides of transuranic elements and zirconium. The process consists of two electrorefiner cells in series configuration. A transuranic element such as plutonium is reduced at the cathode in the first cell, zirconium at the cathode in the second cell, and nitrogen-15 is released and captured for reuse to make transuranic and zirconium nitrides.

Abstract: Disclosed are a method of reducing spent oxides nuclear fuel to nuclear-fuel metal, in which metal oxides are reduced to metals using an electrochemical reduction device with LiCl—Li2O salt as an electrolyte, a cathode electrode assembly used in the method, and a reduction device including the cathode electrode assembly. The method is advantageous in that the process of reducing the spent oxide nuclear fuel to the nuclear-fuel metal and another process of recovering Li are united to simplify the whole processes, direct use of high oxidative Li metals is excluded to secure safety, and conversion efficiency of the spent oxide nuclear fuel is 99% or more.

Abstract: Described is a process for the separation of americium metal from spent fuel or chlorinated high level waste of fuel reprocessing by using a liquid electrode whereby americium will be obtained in high yields.

Abstract: The invention relates to a process for purifying and concentrating charge-bearing first molecules 9, such as proteins, nucleic acids and the like, comprising the following steps: a) preparation of a solution containing the first molecules 9, b) contacting the solution with an electrode 2 which is directly provided with a coating of second molecules 4 having affinity for the first molecules 9, and c) connecting the electrode 2 to a means 11 for generating an electric field to bring about a movement of the first molecules 9 in the solution directed relative to the electrode 2.

Abstract: A process for the electrochemical dissolution of a metallic structure having a plurality of electrically conducting components comprises utilising the structure as a sacrificial electrode in an electrochemical cell so as to dissolve at least part of the strcuture. The process is characterised in that, prior to the use of the structure as a sacrificial electrode, molten metal is allowed to solidify about the structure so as electrically to connect together the components.

Abstract: A waste treatment apparatus treats radioactive contaminated waste from a nuclear fuel material handling facility to decontaminate the radioactive contaminated waste by using an electrolytic molten salt, and reuses the electrolytic molten salt so that any effluents are not produced. Radioactive contaminated waste (10) from a nuclear fuel material handling facility is subjected to electrolysis by a molten salt electrolysis unit (20) to decontaminate the waste (10). The used salt (16) used for decontaminating the waste (10) is filtered to separate nuclear fuel materials (19) from the used salt (16). The filtered salt (18) is reused by the molten salt electrolysis unit (20). The salt adhering to the decontaminated waste (12) is recovered by an evaporating unit (59), and the recovered salt (15) is reused by the molten salt electrolysis unit (20).

Abstract: The present invention relates to a process for separating technetium from a nitric solution of technetium through cathodic electrodeposition of said technetium by electrolysis. According to the process of the invention, the nitric solution of technetium is denitrified and its pH is adjusted to a value of approximately 5.5 to 7.5 before electrolysis. Electrolysis is conducted at galvanostatic rate, and the cathode potential is approximately −1.36 V/SHE to −1.16/SHE. The ratio of the cathode surface area (S) to the volume of the technetium solution to be electrolyzed may be in the region of 0.25 to 0.50 cm−1.

Abstract: Magnetic composites exhibit distinct flux properties due to gradient interfaces. The composites can be used to improve fuel cells and batteries and effect transport and separation of different chemical species. Devices utilizing the composites include an electrode and improved fuel cells, batteries. Some composites, disposed on the surface of electrodes, prevent passivation of those electrodes and enable direct reformation of liquid fuels. Methods involving these composites provide distinct ways for these composites to be utilized.

Abstract: Apparatus and methods for decontaminating surfaces are disclosed. A housing is configured with first and second channels and first and second fluid pathways in fluid communication therewith, respectively. First and second applicators are positioned within respective first and second channels and electrodes are electrically connected with the applicators. Electric current of a first polarity is supplied to a first applicator via the first electrode, and electric current of a second polarity is supplied to a second applicator via the second electrode. Decontaminating a surface comprises supplying a first fluid to a first applicator, supplying a second fluid to a second applicator, generating an electrical potential between the first and second applicators, and contacting the contaminated surface with the first and second applicators.

Abstract: Ionizable or polarizable, carrier-free radionuclides may be separated by electrofixation, from a low electric conductivity liquid target material in a flow cell fitted with a permanent electrode arrangement. The target liquid is separated while the fixing voltage is maintained; then the fixed radionuclide is removed again from the electrode, if required by heating, after switching off or reversing the poles of the field, after an optional intermediate rinsing.

Abstract: A process for treating a radioactive waste, includes drying a radioactive waste containing a radioactive substance(s) and a sodium compound(s), to convert it into a dried material, heating the dried material to convert it into a molten salt, and subjecting the molten salt to electrolysis using the salt as an anolyte and .beta.-alumina as a sodium ion-permeable membrane. This process can recover metallic sodium or sodium hydroxide, each of extremely low radioactivity from a radioactive waste containing a radioactive substance(s) and a sodium compound(s), at a high purity at a high current efficiency.

Abstract: A process of remediation of cationic heavy metal contamination from soil utilizes gas phase manipulation to inhibit biodegradation of a chelating agent that is used in an electrokinesis process to remove the contamination, and further gas phase manipulation to stimulate biodegradation of the chelating agent after the contamination has been removed. The process ensures that the chelating agent is not attacked by bioorganisms in the soil prior to removal of the contamination, and that the chelating agent does not remain as a new contaminant after the process is completed.

Abstract: An electrolytic cell, system and method for producing excess heat for use and for deactivation an actinide series metal by electrolysis in an aqueous media. The electrolytic cell includes a non-conductive housing having an inlet and an outlet and spaced apart first and second conductive grids positioned within the housing. A plurality of preferably cross linked polymer non-metallic cores each having an improved conductive exterior metallic surface formed of one or more of the actinides or daughter elements therefrom to form a bed of conductive beads are positioned within the housing in electrical contact with the first grid adjacent the inlet. The non-conductive cores are preferably sulfonated and then evaporation loaded with an actinide salt solution, dried and fired at decomposition temperature of the salt. An electric power source in the system is operably connected across the first and second grid whereby electrical current flows between the grids within the aqueous media flowing through the cell.

Abstract: According to the invention, a consumable anode constituted by a metal alloy incorporates between 20 and 70 wt. % iron, between 20 and 40 wt. % cobalt and between 5 and 30 wt. % aluminium. To these basic constituents can optionally be added elements such as nickel and/or titanium and/or copper and/or niobium. The decontamination process involves an electrodissolution of said anode.

Abstract: The invention relates to a process for the electrochemical oxidation of Am(III) to Am(VI), usable for separating americium from spent nuclear fuel reprocessing solutions.The process consists of adding to the aqueous nitric solution (17) containing the Am(III) a) heteropolyanion able to complex the americium, such as potassium phosphotungstate and b) the Ag(II) ion for oxidizing Am(III) being converted into Ag(I), and subjecting the solution to an electrolysis under conditions such that electrochemical regeneration takes place of the Ag(II) ion from the Ag(I) ion obtained during said oxidation.After oxidizing Am(III) to Am(VI), it is possible to extract the latter in an appropriate organic solvent.

Abstract: A pyrochemical process is utilized to recover 99% of the remaining transuranium materials from plutonium-uranium extraction waste. One step of the overall pyrochemical process involves the electrochemical separation of the waste components. A solid anode and a solid cathode are used in this electrochemical separation step to electrorefine in single or multiple steps. The solid anode and solid cathode are selected from certain preferred anodic and cathodic materials. Where multiple electrorefining steps are used to obtain more complete electroseparation, this is achieved by employing in the multiple electrorefining steps both a solid anode, suitably graphite, and a molten metal anode containing a mixture of the actinide and rare earth elements. This results in greater separation than can be realized through electroseparation by use of either anode alone.

Abstract: A metal catalyst carried on a carrier material is provided, the carrier material being selected from the group consisting of a powder of fine tourmaline crystals possessing polarity and a formed body containing a plurality of fine tourmaline crystals possessing polarity. The catalyst is prepared by immersing the carrier material in an aqueous solution containing at least one metal salt, mixing and stirring the aqueous solution until the at least one metal ion is deposited on poles of the tourmaline crystals of the carrier material, separating the carrier material from the aqueous solution, evaporating off traces of the aqueous solution from the carrier material, and drying the carrier material. The metal catalyst may be prepared by immersing the carrier material in an aqueous solution containing two or more metal ions, wherein the metal ions are deposited on said carrier material in an inverse proportion to the magnitude of the deposition ionization tendencies of the metal ions.