Abstract: The present disclosure generally relates to methods of electro-depositing a crystalline layer of pure aluminum onto the surface of an aluminum alloy article. The methods may include positioning the article and an electrode in an electro-deposition solution. The electro-deposition solution includes one or more of an aluminum halide, an organic chloride salt, an aluminum reducing agent, a solvent such as a nitrile compound, and an alkali metal halide. The solution is blanketed with an inert gas, agitated, and a crystalline layer of aluminum is deposited on the article by applying a bias voltage to the article and the electrode.

Abstract: Electrodeposition bath compositions, additives, and maintenance methods are described. In one embodiment, an electrodeposition bath includes at least a first metal ionic species that reacts with a second metal ionic species to maintain either the first and/or second metal ionic species in a desired oxidation state for electrodeposition.

Abstract: This disclosure discloses a pollution-free electroplating solution for electroplating and its preparation method. The process of the preparation method includes: mixing choline chloride with nitrogenous compounds in molar ratio of 1:2, heating to 80° C. to form uniform ionic liquid, adding metal chloride into ionic liquid with molar concentration between 0.005M to 0.5 M, adding 7˜11 wt % of bio bacteria and 0.7M˜2M of inorganic acid agent into the mixed liquid. After been mixed thoroughly, this pollution-free electroplating solution is ready for the application in electroplating.

Abstract: A method for producing a sintered rare-earth magnet characterized by sintering a raw material that includes a ribbon-shaped polycrystalline phase with an average grain size of 10 to 200 nm fabricated by rapid solidification of an alloy melt having a rare-earth magnet composition, and a low-melting point phase formed on the surface of the polycrystalline phase and having a melting point lower than the polycrystalline phase.

Abstract: The present invention aims to provide an electrolyte solution for electrochemical devices, which has excellent thermal stability and high decomposition voltage and produces a small amount of evaporation at high temperatures. The present invention also aims to provide an aluminum electrolytic capacitor and an electric double layer capacitor, both of which include the electrolyte solution for electrochemical devices. The present invention relates to an electrolyte solution for electrochemical devices, the electrolyte solution including a solvent and an electrolyte, the solvent containing a sulfone compound represented by the formula (1): wherein R represents a C1-6 alkyl group.

Abstract: Techniques for electrodepositing selenium (Se)-containing films are provided. In one aspect, a method of preparing a Se electroplating solution is provided. The method includes the following steps. The solution is formed from a mixture of selenium oxide; an acid selected from the group consisting of alkane sulfonic acid, alkene sulfonic acid, aryl sulfonic acid, heterocyclic sulfonic acid, aromatic sulfonic acid and perchloric acid; and a solvent. A pH of the solution is then adjusted to from about 2.0 to about 3.0. The pH of the solution can be adjusted to from about 2.0 to about 3.0 by adding a base (e.g., sodium hydroxide) to the solution. A Se electroplating solution, an electroplating method and a method for fabricating a photovoltaic device are also provided.

Abstract: This method enables the use of nanowire or nano-textured forms of Polyaniline and other conductive polymers in energy storage components. The delicate nature of these very high surface area materials are preserved during the continuous electrochemical synthesis, drying, solvent application and physical assembly. The invention also relates to a negative electrode that is comprised of etched, lithiated aluminum that is safer and lighter weight than conventional carbon based lithium-ion negative electrodes. The invention provides for improved methods for making negative and positive electrodes and for energy storage devices containing them. The invention provides sufficient stability in organic solvent and electrolyte solutions, where the prior art processes commonly fail. The invention further provides stability during repetitive charge and discharge. The invention also provides for novel microstructure protecting support membranes to be used in an energy storage device.

Abstract: A surface preparation solution comprises an ionic liquid solvent and a water and oxygen scavenging species. Methods for making the solution, and methods for using the solution to prepare and activate a substrate surface for bulk electrodeposition are also disclosed.

Abstract: There is provided a mixture having a freezing point of up to 50° C., formed by reaction between: (A) one molar equivalent of a salt of formula I (Mn+)(X?)n I or a hydrate thereof; and (B) from one to eight molar equivalents of a complexing agent comprising one or more uncharged organic compounds, each of which compounds has (i) a hydrogen atom that is capable of forming a hydrogen bond with the anion X?; and (ii) a heteroatom selected from the group consisting of O, S, N and P that is capable of forming a coordinative bond with the metal ion Mn+, which reaction is performed in the absence of extraneous solvent, wherein M, X? mind a have meaning given in the description.

Abstract: Disclosed herein is a method for coating a metallic interconnect of a solid oxide fuel cell. The method for coating a metallic interconnect of a solid oxide fuel cell includes generating a cobalt compound solution using lithium cobalt oxide (LiCoO2) that is an anodic material of a lithium ion battery; immersing the metal interconnect in a plating solution in which the generated cobalt compound solution is contained; and forming cobalt (Co) on the immersed metal interconnect by performing electroplating.

Abstract: The present invention relates to a method to electroplate or electropolish a metal on a substrate wherein an ionic liquid is selected from the group of N+R1R2R3R4 X? or N+R5R6R7R8 Y? is employed as electrolyte, and a metal salt added to the ionic liquid is employed as the metal source or a metal anode is used as the metal source, wherein any one of R1 to R8 independently represents a hydrogen, alkyl, cycloalkyl, aryl, or aralkyl group that may be substituted with a group selected from OH, Cl, Br, F, I, phenyl, NH2, CN, NO2, COOR9, CHO, COR9, or OR9, at least one of R5 to R8 is a fatty alkyl chain, and one or more of R5 to R8 can be a (poly)oxyalkylene group wherein the alkylene is a C1 to C4 alkylene and the total number of oxyalkylene units can be from 1 to 50 oxyalkylene units, and at least one of R1 to R8 is a C1 to C4 alkyl chain, R9 is an alkyl or cycloalkyl group, X? is an anion having an N-acyl sulphonylimide anion (—CO—N?—SO2—) functionality, Y? is an anion compatible with the N+R5R6R7R8 ammonium cati

Abstract: A metal oxide film suitable for protection of metals, composed mainly of aluminum. A metal oxide film includes a film of an oxide of a metal composed mainly of aluminum, having a thickness of 10 nm or greater, and exhibiting a moisture release rate from the film of 1E18 mol./cm2 or less. Further, there is provided a process for producing a metal oxide film, wherein a metal composed mainly of aluminum is subjected to anodic oxidation in a chemical solution of 4 to 10 pH value so as to obtain a metal oxide film.

Abstract: The present invention relates to the electrodeposition of elemental zirconium at a temperature of less than 100° C. from a mixture of a Lewis acid, a zirconium salt and an ionic liquid.

Abstract: Proposed are an iridium plating solution capable of easily forming an iridium plating coat in which the occurrence of cracks is suppressed as much as possible and an iridium plating method. In the present invention, the iridium plating solution uses an iridium compound obtained by adding, to an iridium (III) complex salt containing a halogen as an anionic component, one or more compounds selected from the following group and by stirring the resulting mixture, the group consisting of a saturated monocarboxylic acid, a saturated monocarboxylic acid salt, a saturated dicarboxylic acid, a saturated dicarboxylic acid salt, a saturated hydroxycarboxylic acid, a saturated hydroxycarboxylic acid salt, an amide and urea, wherein the iridium plating solution includes at least one or more of Fe, Co, Ni and Cu.

Abstract: A method of anodizing non-stainless steel, wherein a non-stainless steel object is connected to a positive terminal of a power supply, a counter electrode or vessel is connected to a negative terminal of the power supply, the non-stainless steel object and counter electrode are placed into a solution of NaOH, and a voltage is applied across the terminals to anodize the non-stainless steel object by forming an adherent blue-black or semi-adherent dichroic, colored oxide coating thereon.

Abstract: Disclosed is a solution for an electrochemical process, the solution containing a sulfonic acid and having a low concentration of sulfur compounds, either low or high valence, that are susceptible to reduction and which is intended for use in electrodeposition, batteries, conductive polymers and descaling processes.

Abstract: Provided is an Al alloy member with an excellent mechanical strength that is sufficient for use in large-scale manufacturing apparatuses. The Al alloy member is characterized in that, in mass %, Mg concentration is 5.0% or less, Ce concentration is 15% or less, Zr concentration is 0.15% or less, the balance comprises Al and unavoidable impurities, the elements of the unavoidable impurities are respectively 0.01% or less, and the Vickers hardness of the Al alloy member is greater than 30.

Abstract: An anode for a lithium ion secondary battery includes an anode, and a LiF-based coating layer formed with LiF-based particles on a surface of the anode. The LiF-based coating layer has a thickness of 0.05 to 1 ?m. The anode allows the LiF-based coating layer created by side reaction of LiPF6 during a battery charging/discharging process to be relatively uniformly formed on the anode surface, thereby elongating the life cycle of a lithium ion secondary battery.

Abstract: A high-quality oxide film which is free from a pinhole and surface roughing caused by anodic oxidation and which has surface smoothness on a surface of a material to be treated containing a metal as a principal component. An electrolyte solution which is used for forming an oxide film on a surface of a material to be treated containing a metal as a principal component by anodic oxidation, the electrolyte solution containing a non-aqueous solvent containing an alcoholic hydroxyl group and having 4 or more carbon atoms as a main solvent. This non-aqueous solvent preferably contains two or more alcoholic hydroxyl groups and is especially preferably one or two or more members selected from the group consisting of diethylene glycol, triethylene glycol and polyethylene glycol. A method of forming an oxide film including a step of anodically oxidizing a material to be treated containing a metal as a principal component in this electrolyte solution.

Abstract: A capacitor comprising an aluminum anode and a dielectric layer comprising phosphate doped aluminum oxide and process for making the capacitor. The capacitor has a CV Product of at least 9 ?F?V/cm2 at 250 volts. Furthermore, the capacitor is formed by the process of: forming an aluminum plate; contacting the plate with an anodizing solution comprising glycerine, 0.1 to 1.0%, by weight, water and 0.01 to 0.5%, by weight, orthophosphate; applying a voltage to the aluminum plate and determining an initial current; maintaining the first voltage until a first measured current is no more than 50% of the initial current; increasing the voltage and redetermining the initial current; maintaining the increased voltage until a second measured current is no more than 50% of the redetermined initial current, and continuing the increasing of the voltage and maintaining the increased voltage until a final voltage is achieved.

Abstract: There is provided a mixture having a freezing point of up to 50° C., formed by reaction between: (A) one molar equivalent of a salt of formula I (Mn+)(X?)n I or a hydrate thereof; and (B) from one to eight molar equivalents of a complexing agent comprising one or more uncharged organic compounds, each of which compounds has (i) a hydrogen atom that is capable of forming a hydrogen bond with the anion X?; and (ii) a heteroatom selected from the group consisting of O, S, N and P that is capable of forming a coordinative bond with the metal ion Mn+, which reaction is performed in the absence of extraneous solvent, wherein M, X? mind a have meaning given in the description.

Abstract: The invention relates to a process for the electrochemical deposition of grey selenium on a substrate in an ionic liquid, where the electrochemical deposition can be carried out at temperatures of greater than 10000.

Abstract: A system and a method for electroplating a metal component, comprising rotating the metal component and electroplating the rotating metal component.

Abstract: A gold plating solution comprising iodide ions, gold iodide complex ions and a non-aqueous solvent, which is less toxic and stable, while having a performance comparable to a cyanide type gold plating solution. The present invention further provides a gold plating solution comprising iodide ions, gold iodide complex ions, a non-aqueous solvent and a water-soluble polymer, which is less toxic and stable, while having a performance comparable to a cyanide type gold plating solution and which is capable of forming a gold plating film in which gold crystal particle sizes are very fine and grain boundaries are dense. The present invention further provides a gold plating method employing such a gold plating solution.

Abstract: The metal oxide surface coating of an anodized valve metal may be made conductive under certain conditions so that conductive coatings can be electrolytically deposited on the surface of the oxide. When a dry polar aprotic electrolyte solution is used at a reduced temperature and a relatively high field is applied, the oxide ceases to be insulative. The process is reversible, meaning that there is no permanent change in the oxide.

Abstract: Non-aqueous electrolytic solutions suitable for anodizing valve metal derivative anodes, methods of anodizing using non-aqueous electrolytic solutions, and capacitors prepared with non-aqueous electrolytic solutions. The non-aqueous electrolytic solution comprises glycerine and at least one soluble salt formed by the neutralization of at least one non-halogen-containing organic or inorganic acid anion with at least one alkali metal, ammonium, or protonated amine cation; wherein the acid anion is derived from an acid having a pKa lower than phosphoric acid.

Abstract: Non-aqueous electrolytic solutions suitable for anodizing valve metal derivative anodes, methods of anodizing using non-aqueous electrolytic solutions, and capacitors prepared with non-aqueous electrolytic solutions. The non-aqueous electrolytic solution comprises glycerine and at least one soluble salt formed by the neutralization of at least one non-halogen-containing organic or inorganic acid anion with at least one alkali metal, ammonium, or protonated amine cation; wherein the acid anion is derived from an acid having a pKa lower than phosphoric acid.

Abstract: Carbon nanoparticles including both nanofilaments and nanotubes produced by an electrochemical deposition method from organic solutions at room temperature, in which the formation and growth of carbon nanoparticles are stimulated by the catalyst, such as iron and nickel. It has been found that the electrochemical deposition conditions have a strong influence on the growth phenomenon of the carbon nanotubes. Scanning electron microscope (SEM) and transmitting electron microscope (TEM) characterizations show that the diameter of nanotubes is of the order of approximately 100 nm, and the length of filaments can be up to approximately 50 &mgr;m, depending on the size of catalyst particles.

Abstract: Non-aqueous electrolytic solutions suitable for anodizing valve metal derivative anodes, methods of anodizing using non-aqueous electrolytic solutions, and capacitors prepared with non-aqueous electrolytic solutions. The non-aqueous electrolytic solution comprises glycerine and at least one soluble salt formed by the neutralization of at least one non-halogen-containing organic or inorganic acid anion with at least one alkali metal, ammonium, or protonated amine cation; wherein the acid anion is derived from an acid having a pKa lower than phosphoric acid.

Abstract: Separator paper comprising paper impregnated with soluble silicate. The soluble silicate may be applied to the separator paper by immersing the paper into an aqueous solution of the soluble silicate or by spraying with an aqueous solution of the soluble silicate. In a preferred embodiment, the soluble silicate is sodium silicate. An electrolytic capacitor comprising an electrolytic solution, at least one anode foil, at least one cathode foil, and separator paper between the at least one anode foil and at least one cathode foil, wherein the separator paper comprises paper impregnated with a soluble silicate.

Abstract: A non-aqueous electrolyte comprises an organic solvent and a solute, and also has an electrolytic conductivity that is greater than or equal to 1 mS/cm but less than or equal to 100 mS/cm. This solute preferably includes at least one of a carboxylate and a salt of inorganic oxoacid. In addition, the non-aqueous electrolyte preferably comprises water in a proportion of 1 to 10 wt %. In an MIM nonlinear element (20), an insulated film (24) is formed by anodic oxidation using the above non-aqueous electrolyte. In addition, the insulated film comprises at least one of carbon atoms and atoms of families 3 to 7 that were originally the central atoms of the salt of inorganic oxoacid, and has a relative permittivity of 10 to 25. With this MIM nonlinear element, the capacitance is sufficiently small, the steepness of the voltage-current characteristic is sufficiently large, and also the resistance is sufficiently uniform over a wide area.

Abstract: An electrolyte comprising a polyester condensation product of 2-methyl-1,3-propane diol and boric acid; and further comprising dimethyl amino ethoxy ethanol in an amount to reduce the resistance of the electrolyte. The electrolyte may further comprise ortho-phosphoric acid and at least one substituted pyrrolidone or lactone, such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-hydroxy ethyl-2-pyrrolidone or 4-butyrolactone. The ortho-phosphoric acid prevents hydration of anodic aluminum oxide in contact with the solution. The pyrrolidone or lactone reduce the resistance of the electrolyte. The electrolyte may also comprise sodium silicate.

Abstract: Light weight, low resistance electrode plates for lead-acid batteries are formed from a highly conductive non-lead substrate such as aluminum or copper, coated with a continuous layer of a corrosive resistant conductive materials, such as lead, applied from a fused salt bath.

Abstract: Non-aqueous electrolytic solutions suitable for anodizing valve metal derivative anodes, methods of anodizing using non-aqueous electrolytic solutions, and capacitors prepared with non-aqueous electrolytic solutions. The non-aqueous electrolytic solution comprises glycerine and at least one soluble salt formed by the neutralization of at least one non-halogen-containing organic or inorganic acid anion with at least one alkali metal, ammonium, or protonated amine cation; wherein the acid anion is derived from an acid having a pKa lower than phosphoric acid.

Abstract: A method of anodizing comprising suspending at least one aluminum substrate into an electrolyte solution and applying an anodizing current to the electrolyte solution, wherein the electrolyte solution comprises from about 5 to about 99.5 wt % glycerine, about 0.05 to about 5.0 wt. % of at least one orthophosphate salt selected from the group consisting of ammonium phosphates, alkali metal phosphates, amine phosphates, or mixtures thereof, and water.

Abstract: Disclosed is a forming electrolyte for forming metal oxide coating films which comprises one or more kinds of solutes selected from the group consisting a salt of inorganic acid and salt of organic carboxylic acid dissolved in a solvent having analcoholic hydroxyl group or aprotic organic solvent, provided that, when the solvent having an alcoholic hydroxyl group is selected, the salt of organic carboxylic acid is selected from salts of aromatic carboxylic acids, salts of aliphatic polycarboxylic acid having 3-5 carbon atoms with no hydroxyl groups, salts of monohydroxy carboxylic acid having 2-5 carbon atoms, and salts of amino acid. By anodically oxidizing metal using the forming electrolyte, there can be formed an oxide coating film of high insulation property with a high throughput, in which hillocks are effectively suppressed.

Abstract: A method of non-thickness-limited anodizing for valve metals and alloys which are resistant to the non-thickness-limited growth of anodic oxide, such as niobium and high niobium content alloys. Non-thickness-limited anodic oxide film growth is produced on such valve metals by employing a first glycerine-based electrolyte containing about 1 to about 3 wt % water for the initial production of anodic oxide. After the substrate is anodized using the first electrolyte, it is immersed in a second glycerine-based electrolyte having less than about 0.1 wt % water. The second electrolyte may be produced by allowing water to evaporate from the first electrolyte solution until the solution contains less than about 0.1 wt. % water.

Abstract: A method of anodizing a metal comprising immersing a metal substrate into an a glycerine-based electrolytic solution and applying a constant current to produce a uniform film. The electrolytic solution additionally comprises at least one acidic organic salt, inorganic salt, or mixtures thereof. Suitable salts include dibasic potassium phosphate, P-toluene sulfonate, potassium hydrogen sulfate and monobasic potassium tartrate. The electrolytic solution may be prepared by mixing glycerine and the salt or salts, and then heating the solution to about 150 to 180° C. for about 1 to 12 hours. The prepared solution preferably has a water content of less than 0.1 wt %. Anodizing may be performed in the electrolytic solution at temperatures above about 150° C. to achieve non-thickness-limited film growth. Temperature fluctuations within the solution are reduced by the use of impellers or ultrasonic agitation.

Abstract: Thin, light weight bipolar plates for use in electrochemical cells are rapidly, and inexpensively manufactured in mass production by die casting, stamping or other well known methods for fabricating magnesium or aluminum parts. The use of a light metal, such as magnesium or aluminum minimizes weight and simultaneously improves both electrical and thermal conductivity compared to conventional carbon parts. For service in electrochemical cells these components must be protected from corrosion. This is accomplished by plating the surface of the light weight metal parts with a layer of denser, but more noble metal. The protective metal layer is deposited in one of several ways. One of these is deposition from an aqueous solution by either electroless means, electrolytic means, or a combination of the two. Another is deposition by electrolytic means from a non-aqueous solution, such as a molten salt.

Abstract: In one embodiment, the present invention relates to a method of making a catalytic film comprising: applying an electric current to an electrochemical cell comprising an anode, a cathode and a solution comprising a film forming compound and a nitrate ion source thereby forming the catalytic film.

Abstract: An electrolytic solution comprising glycerine and an organic salt, an inorganic salt, or mixtures thereof, and having a pH of less than about 7. The electrolytic solution has a water content of less than 0.1 weight percent and is prepared by mixing the glycerine and the salt or their acidic and basic ionogen components and heating to above 150.degree. C. A method of anodizing a metal comprising forming a film on the metal with said electrolytic solution. The metal is preferably a valve metal, such as tantalum, and the film is formed at a temperature of 150.degree. C. or higher.

Abstract: An electrolytic solution comprising glycerine and dibasic potassium phosphate. The electrolytic solution has a water content of less than 1000 ppm and is prepared by mixing the glycerine and the dibasic potassium phosphate and then heating to about 150 to 180.degree. C. for about 1 to 12 hours. A method of anodizing a metal comprising forming a film on the metal with an electrolytic solution comprising glycerine and dibasic potassium phosphate. The metal is preferably a valve metal, such as tantalum, and the film is formed at a temperature of 150.degree. C. or higher.

Abstract: A non-aqueous electrolyte secondary battery having a long cycle life and a high reliability with substantially no internal short-circuit is provided by incorporating crystalline metal lithium as its negative electrode. The crystalline metal lithium is electrochemically deposited on a metal substrate in an electrolyte including a tetrahydrofran derivative or a 1,3-dioxolan derivative as a solvent.

Abstract: An organic solvent electrolyte is provided for electrolytically forming a plating film on the surface of a R.sub.2 T.sub.14 B intermetallic compound permanent magnet. The organic solvent electrolyte comprises a metallic salt including at least one metalic element with a supporting electrolyte, the balance being an organic solvent for forming a plating film on the surface of a R.sub.2 T.sub.14 B intermetallic compound permanent magnet, wherein R denotes a rare earth element including Y and T denotes a transition metal including R, Fe and B as main components. The supporting electrolyte includes at least one selected from a group consisting of:(1) a boric acid compound including at least one of R'.sub.3 BO.sub.3 methyl, ethyl, propyl, butyl group, MBO.sub.2 (in which M denotes H or Na, K, Li metal), M'BO.sub.3 (M' denotes B or Na, K, Li metal), M'"BO.sub.x O.sub.(3x+2)/2 (X is an even number of more than 2).(2) a C10.sub.4 salt of an alkali metal or tetraalkylammonium including at least one of M'C10.sub.

Abstract: Surface treated titanium and titanium alloy articles having a thin anodized film substantially of TiO.sub.2 and characterized by a leakage current of less than about 25 microamps per square centimeter and a dielectric strength of at least one million volts per square centimeter, together with a high breakdown potential and high corrosion resistance, is disclosed. The process for forming such titanium and titanium alloy articles is also disclosed and is characterized by anodizing the articles in a substantially non-aqueous solution of a mineral acid and an organic solvent at a formation current above 0.1 microamps per square centimeter.

Abstract: The invention provides a method for forming deposits of superconducting ceramics by sequentially electrodepositing layers of metals, of a type and in proportion suitable for forming a superconducting ceramic, to form a precursor metal deposit, followed by oxidizing the precursor deposit to form a superconducting ceramic deposit. Optionally, the electroplating steps are conducted in such a manner that a patterned precursor deposit results, to obtain a patterned superconducting deposit after oxidation.

Abstract: The invention relates to a catalytic process for the synthesis of an alcohol by reaction of an epoxide with a nucleophilic compound containing a labile hydrogen, such as an alcohol, a phenol, a primary amine or a carboxylic acid.The catalyst is a metal complex of general formula (I)[M[Co(CO).sub.4 ].sub.2 ].sub.x in which x is equal to 1 or 2 and M denotes tin, lead and cadmium.The reaction preferably takes place in the presence of carbon monoxide.This process makes it possible to increase the yield and the selectivity of the reaction and the stereoselectivity for alcohol in the case of which the hydroxyl formed is attached to the least hindered carbon atom of the epoxide.The invention also relates to the new complexes of formula (I) in which x equals 2.It also relates to a process for the electrosynthesis of these new compounds by electroreduction of Co.sub.2 (CO).sub.

Abstract: In a method of trapping ions in a silicon oxide film or a silicon oxy-nitride film, silicon or silicon nitride as an electrode is first immersed in a nonaqueous solvent containing an electrolyte. Then, a voltage is applied between the electrode and a counter electrode so as to oxidize the surface of the silicon or silicon nitride to form a silicon oxide film or a silicon oxy-nitride film. At the same time, the ions contained in the electrolyte are caused to permeate into the silicon oxide film or the silicon oxy-nitride film and trapped therein. The method is thus capable of trapping ions in a silicon oxide film or a silicon oxy-nitride film for a short time without using any evaporation apparatus and of shifting the flat band potential of the silicon.

Abstract: There is disclosed a non-aqueous electrolytic aluminum plating bath composition comprising an aluminum halide and a nitrogen-containing heterocyclic onium halide compound and containing an additive selected from the group consisting of an inorganic halide compound, aromatic aldehyde, ketone or carboxylic acid, an unsaturated heterocyclic compound containing more than one nitrogen atom, an unsaturated heterocyclic compound containing a sulfur atom, an aromatic hydrocarbon compound containing a sulfur atom, an aromatic hydrocarbon compound containing an amino group and an aromatic amine; and further optionally an organic polymer. The bath composition is easy in maintenance, has good covering power, and enables smooth plating with low current density.