Abstract: Provided is a process for preparing an electrode comprising an iron active material. The process comprises first fabricating an electrode comprising an iron active material, and then treating the electrode with a gaseous oxidant to thereby create an oxidized surface. The resulting iron electrode is preconditioned prior to any charge-discharge cycle to have the assessable surface of the iron active material in the same oxidation state as in discharged iron negative electrodes active material.

Abstract: Provided is a black resin steel plate having superior drawing ability and glossiness and particularly to a black resin steel plate in which the coefficient of friction of a black resin film is adjusted so as to block the transfer of a resin layer due to a reduction in thickness of the resin layer, thereby improving blackness and drawing ability, and to a method of manufacturing the same.

Abstract: An alloy casting having a protective layer disposed on a surface of the casting is provided. The protective layer is resistant to liquid metal attack, and wherein the protective layer includes an oxide of an element present in the alloy. A method of forming a protective layer on a surface of the alloy casting is also provided. The method includes disposing the alloy in a mold, and oxidizing an element of the alloy to form a protective layer on the surface of the casting.

Abstract: A nickel powder with an average particle size of 0.05 to 1.0 ?m, which is composed of nickel particles having an oxidized surface layer and containing sulfur, wherein the sulfur content with respect to the total weight of the powder is 100 to 2000 ppm, and the intensity of a peak identified to sulfur bonded to nickel in surface analysis by ESCA of the nickel particles varies in a direction toward the center from the surface of the particles, and this intensity has its maximum at a location deeper than 3 nm from the particle outermost surface. This nickel powder is manufactured by bringing a nickel powder containing sulfur and dispersed in a non-oxidizing gas atmosphere into contact with an oxidizing gas at a high temperature.

Abstract: A process for treating a non-ferrous metal component, comprising placing the component into a process chamber at an elevated temperature, biasing the component to have a potential capable of attracting ions, introducing oxygen into the chamber at a pressure such that a glow discharge comprising oxygen ions is generated, the process chamber additionally comprising a glow discharge ionization enhancing means, and activating the glow discharge ionization enhancing means thereby increasing charged species density of the glow discharge, the oxygen ions flowing towards the component and colliding the surface thereof at least some of which diffuse into the component.

Abstract: A method for controlling microbial growth in potable water stored in a vessel having a metallic surface includes heating the metallic surface to a temperature between about 480° C. (900° F.) and about 870° C. (1600° F.), exposing the metallic surface to oxygen during heating to oxidize potential reduction sites on the metallic surface and charging potable water containing silver ions to the vessel. A vessel having a metallic surface is prepared for long-term storage of potable water containing silver ions by heating the metallic surface to a temperature between about 480° C. (900° F.) and about 870° C. (1600° F.) and exposing the metallic surface to oxygen during heating to oxidize electropositive metals on the metallic surface or by treating the metallic surface with an aqueous solution containing on oxidizing agent to oxidize potential reduction sites on the metallic surface.

Abstract: A bath containing nickel ions and formic acid is injected into a film-forming aqueous solution flowing in a circulation pipe connected to feed water pipe made of carbon steel in a BWR plant. This film-forming aqueous solution is supplied into the feed water pipe through the circulation pipe, and then, a nickel metal film is formed on an inner surface of the feed water pipe. After the nickel metal film is formed, a film-forming aqueous solution containing iron (II) ions, formic acid, nickel ions, hydrogen peroxide, and hydrazine is supplied to the feed water pipe. A nickel ferrite film is formed on the surface of the nickel metal film in the feed water pipe. Then, the nickel ferrite film is come into contact with water containing dissolved-oxygen at 150° C. or above to transform the nickel metal film into a nickel ferrite film. A thick nickel ferrite film is formed on the inner surface of the feed water pipe. Corrosion of the carbon steel member composing the plant can further reduce.

Abstract: A bath containing nickel ions and formic acid is injected into a film-forming aqueous solution flowing in a circulation pipe connected to a feed water pipe made of carbon steel in a BWR plant. This solution is supplied into the pipe through the circulation pipe, and a nickel metal film is formed on an inner surface of the pipe. After the film is formed, a film-forming aqueous solution containing iron (II) ions, formic acid, nickel ions, hydrogen peroxide, and hydrazine is supplied to the pipe. A nickel ferrite film is formed on the surface of the nickel metal film in the pipe. The nickel ferrite film comes into contact with water containing dissolved oxygen at or above 150° C. to transform the nickel metal film into a nickel ferrite film. A thick nickel ferrite film is formed on the inner surface of the feed water pipe.

Abstract: A dry cleaning method of a substrate processing apparatus includes forming a metal oxide by oxidizing a metal film adhered to the inside of a processing chamber of the substrate processing apparatus; forming a complex by reacting the metal oxide with ?-diketone; and sublimating the complex to be removed. A cleaning gas containing oxygen and ?-diketone is supplied into the processing chamber while heating the inside of the processing chamber. A flow rate ratio of oxygen to ?-diketone in the cleaning gas is set such that a formation rate of the metal oxide is lower than a formation rate of the complex.

Abstract: There is provided a Cr-containing austenitic alloy tube, wherein a chromium oxide film with a thickness of 0.05 to 1.5 ?m having the relationship defined by Formula (i) is formed on the inner surface of the tube, wherein the average concentration of C in the depth range of 5 to 10 ?m from the inner surface is lower than the concentration of C in a base metal; 0.4??1/?2?2.5??(i) wherein ?1 and ?2 are thicknesses (?m) of the chromium oxide film at both ends of tube, respectively.

Abstract: A method of providing sulfidation corrosion resistance and corrosion induced fouling resistance to a heat transfer component surface includes providing a silicon containing steel composition including an alloy and a Si-partitioned non-metallic film formed on a surface of the alloy. The alloy is formed from the composition ?, ?,and ?, in which ? is a metal selected from the group consisting of Fe, Ni, Co, and mixtures thereof, ? is Si, and ? is at least one alloying element selected from the group consisting of Cr, Al, Mn, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Sc, La, Y, Ce, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au, Ga, Ge, As, In, Sn, Sb, Pb, B, C, N, P, O, S and mixtures thereof. The Si-partitioned non-metallic film comprises at least one of sulfide, oxysulfide and mixtures thereof.

Abstract: A method of providing sulfidation corrosion resistance and corrosion induced fouling resistance for a heat transfer component is disclosed. The heat transfer component includes a heat exchange surface formed from a chromium-enriched oxide containing material formed from the composition ?, ?, and ?, wherein ? is a steel containing at least about 5 to about 40 wt. % chromium, ? is a chromium enriched oxide (M3O4 or M2O3 or mixtures thereof) formed on the surface of the steel ?, wherein M is a metal containing at least 5 wt. % Cr based on the total weight of the metal M, and ? is a top layer formed on the surface of the chromium-enriched oxide ?, comprising sulfide, oxide, oxysulfide, and mixtures thereof. The top layer ? comprises iron sulfide (Fe1-xS), iron oxide (Fe3O4), iron oxysulfide, iron-chromium sulfide, iron-chromium oxide, iron-chromium oxysulfide, and mixtures thereof.

Abstract: A novel method of manufacturing a transition metal oxide having a spinel structure is provided. A mixture of powdery metals of metal elements constituting the transition metal oxide is heated in an oxidizing atmosphere to generate the transition metal oxide.

Abstract: An oxidation-resistant ferritic stainless steel comprising: a ferritic stainless steel comprising Cr, wherein a {110} grain orientation fraction of a surface of the ferritic stainless steel as measured using electron back scattered diffraction pattern (EBSD) is about 5% or more; and a chromium oxide layer formed on the surface of the ferritic stainless steel is provided.

Abstract: A method and device for reducing sulfidation corrosion and depositional fouling in heat transfer components within a refining or petrochemical facility is disclosed. The heat transfer components are formed from a corrosion and fouling resistant steel composition containing a Cr-enriched layer having a surface roughness of less than 40 micro inches (1.1 ?m) and a protective layer formed thereon.

Abstract: A nickel powder with an average particle size of 0.05 to 1.0 ?m, which is composed of nickel particles having an oxidized surface layer and containing sulfur, wherein the sulfur content with respect to the total weight of the powder is 100 to 2000 ppm, and the intensity of a peak identified to sulfur bonded to nickel in surface analysis by ESCA of the nickel particles varies in a direction toward the center from the surface of the particles, and this intensity has its maximum at a location deeper than 3 nm from the particle outermost surface. This nickel powder is manufactured by bringing a nickel powder containing sulfur and dispersed in a non-oxidizing gas atmosphere into contact with an oxidizing gas at a high temperature.

Abstract: A nickel powder with an average particle size of 0.05 to 1.0 ?m, which is composed of nickel particles having an oxidized surface layer and containing sulfur, wherein the sulfur content with respect to the total weight of the powder is 100 to 2000 ppm, and the intensity of a peak identified to sulfur bonded to nickel in surface analysis by ESCA of the nickel particles varies in a direction toward the center from the surface of the particles, and this intensity has its maximum at a location deeper than 3 nm from the particle outermost surface. This nickel powder is manufactured by bringing a nickel powder containing sulfur and dispersed in a non-oxidizing gas atmosphere into contact with an oxidizing gas at a high temperature.

Abstract: In this method, the inner surface of a metal pipe containing, by mass percent, 20 to 55% of Cr and 20 to 70% of Ni is subjected to mechanical treatment, the metal pipe is subjected to heat treatment such as to be held in a temperature range of 1050 to 1270° C. for 0.5 to 60 minutes, and thereby an oxide scale layer consisting mainly of Cr is formed on at least the inner surface of the metal pipe. A metal pipe excellent in carburization resistance and coking resistance in a carburizing gas environment can be obtained by the method.

Abstract: The object of the present invention is to form a chromium-oxide film excellent in corrosion resistance without containing an oxide film of other metal onto the optional metallic material. The chromium-oxide passivation film excellent in corrosion resistance without containing the oxide film of other metal can be formed inexpensively and in a short time, and a fluid supplying system for supplying fluid hard in corrosivity in safety is able to be provided. This invention comprises a step of forming the passivation film consisting of a chromium oxide by giving heat treatment in an oxidizing atmosphere after coating chromium on metallic material of which surface roughness (Ra) of a coat surface is not more than 1.

Abstract: The present invention provides a ferromagnetic/antiferromagnetic coupling film structure and a fabrication method thereof. The structure includes an antiferromagnetic layer of cobalt oxide having a thickness of 2 to 15 monolayers and formed on a substrate at a temperature ranging from 700K to 900K; and a ferromagnetic layer of cobalt having a thickness of at least one monolayer for being formed on the antiferromagnetic layer of cobalt oxide.

Abstract: Alloys containing aluminium are characterised by an outstanding oxidation resistance at high temperatures, that is based on, inter alia, the formation of a thick and slow-growing aluminium oxide layer on material surfaces. If the formation of the aluminium oxide layer reduces the aluminium content of the alloy so far that a critical aluminium concentration is not reached, no other protective aluminium oxide layer can be formed. This leads disadvantageously to a very rapid breakaway oxidation, and the destruction of the component. This effect is stronger at temperatures above 800° C. due to the fact that, often at this point, metastable Al2O3 modifications, especially ?- or ?-Al2O3, are formed instead of ?-Al2O3 that is generally formed at high temperatures. The above-mentioned oxide modifications are disadvantageously characterised by significantly higher growth rates.

Abstract: Shape Memory Alloy tube is protected from damage during drawing, caused by galling-type interaction between the tube and high-carbon dies, by forming an oxide surface layer. This invention protects the tube internal diameter from oxidation while allowing the tube outside diameter to be oxidised, by using an oxygen getter located within the tube during the oxidation step. The method yields a higher quality internal diameter and improves productivity.

Abstract: A metal coated with ceramic and a method manufacturing the same. The metal contains chromium. A buffer layer is disposed on the metal, and a silicon carbide (SiC) coating layer is disposed on the buffer layer. The buffer layer has a thermal expansion coefficient between those of the metal and the SiC coating layer. The method includes annealing a metal containing chromium to form a chromium oxide layer on the metal, dissolving polycarbosilane (PCS) in a solvent to form a PCS coating solution, coating the chromium oxide layer with the PCS solution, and annealing the to form an SiC coating.

Abstract: A method for manufacturing a Ni-based alloy article which elutes little Ni even when used in a high-temperature water environment for a long period comprises heating the Ni-based alloy in a carbon dioxide-containing atmosphere for a set period of time at an elevated temperature to form an oxide film comprising chromium oxide on a surface thereof. Using carbon dioxide as an oxidizing gas produces an oxide film of generally uniform thickness along a length of the article being treated so that resistance to nickel elution is more uniform over the entire article.

Abstract: Substrates comprising a surface comprising chromium, said surface being adapted to exhibit reduced coefficient of friction and/or increased hardness.

Abstract: A method for producing with a high yield a high performance non-aqueous electrolyte secondary cell with a reduced cost is provided. The method includes the steps of: a baking step of baking a positive electrode active material precursor containing a lithium source and a nickel source in order to render the positive electrode active material precursor a lithium nickel composite oxide; a measuring step of measuring the amount of carbon dioxide gas occurring when the lithium nickel composite oxide is heated to 200° C. or higher and 1500° C. or lower in an inactive gas atmosphere; a selecting step of selecting a lithium nickel composite oxide satisfying the following formulas: y<(0.27x?51)/1000000(200?x<400)??formula 1 y<57/1000000(400?x?1500)??formula 2 where x is a heating temperature (° C.

Abstract: An active material for a non-aqueous electrolyte secondary battery including a lithium-containing transition metal oxide containing nickel and manganese and having a closest-packed structure of oxygen, wherein an atomic ratio MLi/MT between the number of moles of lithium MLi and the number of moles of transition metal Mt contained in the lithium-containing transition metal oxide is greater than 1.0; the lithium-containing transition metal oxide has a crystal structure attributed to a hexagonal system, and the X-ray diffraction image of the crystal structure has a peak P003 attributed to the (003) plane and a peak P104 attributed to the (104) plane; an integrated intensity ratio I003/I104 between the peak P003 and the peak P104 varies reversibly within a range from 0.7 to 1.5 in association with absorption and desorption of lithium by the lithium-containing transition metal oxide; and the integrated intensity ratio varies linearly and continuously.

Abstract: Alloys containing aluminium are characterised by an outstanding oxidation resistance at high temperatures, that is based on, inter alia, the formation of a thick and slow-growing aluminium oxide layer on material surfaces. If the formation of the aluminium oxide layer reduces the aluminium content of the alloy so far that a critical aluminium concentration is not reached, no other protective aluminium oxide layer can be formed. This leads disadvantageously to a very rapid breakaway oxidation, and the destruction of the component. This effect is stronger at temperatures above 800° C. due to the fact that, often at this point, metastable Al203 modifications, especially ?- or ?-Al203, are formed instead of ?-Al203 that is generally formed at high temperatures. The above-mentioned oxide modifications are disadvantageously characterised by significantly higher growth rates.

Abstract: Martensitic stainless steel whose steel composition is restricted within a specific range for each element is provided. The scale layer formed on the surface of the base material consists of an inner layer scale mainly including FeCr2O4 and an outer layer scale having a thickness of not more than 20 ?m, which outer layer is deposited on the inner layer scale at a surface coverage of not less than 1% and not more than 15%. The application of rust preventive oil onto the surface of the steel ensures an excellent weather resistance during a long term, and therefore a martensitic stainless steel forming no rust either in the outdoor depository or in the indoor depository can be provided. The steel can be used to manufacture, not only steel pipes, but also steel plates, steel rods and others in a wide application field.

Abstract: In a rolling bearing put under a working circumstance in which water tends to intrude into lubricants, it has been known such a phenomenon that hydrogen ions formed by decomposition of the lubricants are adsorbed to raceway surfaces and accumulated as hydrogen atoms in highly strained sites (in the vicinity of the position for maximum shearing stress), to cause stress corrosion cracking type peeling. The present invention provides a rolling bearing in which an oxide layer of an iron/chromium oxide series is formed at a thickness of from 1 to 1000 nm to at least one of raceway surfaces of bearing rings or rolling contact surfaces of rolling elements and a manufacturing method thereof.

Abstract: A method for forming a chromium-rich layer on the surface of a nickel alloy workpiece containing chromium includes heating the workpiece to a stable temperature of about 1100° C., and then exposing the workpiece to a gaseous mixture containing water vapor and one or more non-oxidizing gases for a short period of time. The process conditions are compatible with high temperature annealing and can be performed simultaneously with, or in conjunction with, high temperature annealing.

Abstract: A process for treating a chromium coating and/or the surface of a chromium alloy to increase hardness, and/or to decrease coefficient of friction; chromium alloys and/or chromium coatings with surfaces having increased hardness and/or decreased coefficient of friction; and, components comprising chromium alloys and/or chromium coatings with surfaces having increased hardness and/or decreased coefficient of friction.

Abstract: The invention includes a composition of matter which is resistant to metal dusting and a method for preventing metal dusting on metal surfaces exposed to carbon supersaturated environments.

Abstract: Furnace run length extension by fouling control utilizing a pigging-passivation process.

Abstract: A sintered rare earth magnet consisting essentially of 20-30% by weight of R (wherein R is Sm or a mixture of Sm and another rare earth element), 10-45% by weight of Fe, 1-10% by weight of Cu, 0.5-5% by weight of Zr, and the balance of Co has on its surface a composite layer containing Sm2O3 and/or CoFe2O4 in Co or Co and Fe. The magnet is resistant to hydrogen embrittlement.

Abstract: A method for forming an oxidation-passive layer having high corrosion resistance to highly oxidizing materials such as ozone; a stainless steel and a titanium base alloy having corrosion resistance to an ozone containing fluid; and a fluid containing part, a process apparatus, and a fluid feed/discharge system made by using the same. The method comprises the steps of heat-treating the surface of a stainless steel or titanium-base alloy having an Al content of 0.5 percent by weight to 7 percent by weight either at 300° C. to 700° C. in a mixed gas atmosphere composed of an inert gas and 500 ppb to 1 percent H2O gas or 1 ppm to 500 ppm oxygen gas, or alternatively at 20° C. to 300° C. in a mixed gas atmosphere composed of an oxygen gas and at least 100 ppm ozone gas to form an oxidation-passive layer containing an aluminum oxide or a titanium oxide.

Abstract: The present invention relates to structures within an x-ray device including an x-ray can, an x-ray can window frame insert, a rotor sleeve, and a bearing support assembly for a rotor structure. The various structures are fabricated from a chromium alloy of copper that is essentially oxygen free copper having a minor amount of chromium, the combination of which imparts desirable qualities to the x-ray device structures, including efficient heat sink and emissivity qualities that are beneficial in an x-ray device environment. In one preferred embodiment of the present invention, oxygen free high conductivity (OFHC) copper is melted in an RF furnace in the presence of a minor amount of chromium and is either ingot cast or powder metallurgically cast into a desired article and further fabricated into a finished article.

Abstract: The present invention provides a rolling bearing in which an oxide layer of an iron/chromium oxide series is formed at a thickness of from 1 to 1000 nm to at least one of raceway surfaces of bearing rings or rolling contact surfaces of rolling elements and a manufacturing method thereof. The oxide layer can inhibit hydrogen formed by decomposition of water incorporated in the lubricants from intruding into the matrix of the bearing members, thereby preventing early peeling for the raceway surfaces of the bearing rings or the rolling contact surfaces of the rolling elements and, thus, greatly improving the rolling life. The oxide layer can be formed simply by merely tempering the bearing member and then applying a re-heating treatment in air at a temperature lower than the tempering temperature.

Abstract: A method for forming a chromium-rich layer on the surface of a nickel alloy workpiece containing chromium includes heating the workpiece to a stable temperature of about 1100° C., and then exposing the workpiece to a gaseous mixture containing water vapor and one or more non-oxidizing gases for a short period of time. The process conditions are compatible with high temperature annealing and can be performed simultaneously with, or in conjunction with, high temperature annealing.

Abstract: A method for producing oxidation-resistant austenitic alloys for use at temperatures below 800° C. comprising of: providing an alloy comprising, by weight %: 14-18% chromium, 15-18% nickel, 1-3% manganese, 1-2% molybdenum, 2-4% silicon, 0% aluminum and the balance being iron; heating the alloy to 800° C. for between 175-250 hours prior to use in order to form a continuous silicon oxide film and another oxide film. The method provides a means of producing stainless steels with superior oxidation resistance at temperatures above 700° C.

Abstract: (1) A nickel-base alloy product having, on the surface thereof, an oxide film comprising at least two layers, namely a first layer mainly composed of Cr2O3 and having a chromium content of not less than 50% relative to the total amount of metal elements and a second layer occurring outside the first layer and mainly composed of MnCr2O4, wherein the grain size of Cr2O3 crystals in the first layer is 50 to 1,000 nm and the total oxide film thickness is 180 to 1,500 nm.

Abstract: A method for forming a chromium oxide film on the surface of a stainless steel sample. The method includes: (a) placing a sample having stainless a steel surface into a vacuum furnace, evacuating the vacuum furnace to a pressure of 2×10−7 to 3×10−7 Torr, and heating the vacuum furnace to 450 to 600° C. at a rate of 5 to 10° C./min; (b) maintaining the vacuum furnace for 10 to 20 minutes at a temperature of 450 to 600° C. to remove foreign materials from the surface of the stainless steel sample and to extract chromium atoms from the stainless steel substrate; and (c) supplying oxygen to the vacuum furnace while maintaining the temperature until oxygen partial pressure reaches 1×10−9 to 2.5×10−7 Torr, so the extracted chromium atoms react with oxygen, producing a chromium oxide (Cr2O3) film on the surface of the stainless steel.

Abstract: An improved process that is commercially practical for forming an oxide film cobalt conversion coating exhibiting corrosion resistance and paint adhesion properties on a substrate, where the substrate is aluminum or aluminum alloy, the process including the steps of: (a) providing an oxide film forming cobalt conversion solution comprising an aqueous reaction solution, containing no triethanolamine (TEA), prepared by reacting the following starting materials: (1) a water soluble cobalt-II salt CoX2 where X=Cl, Br, NO3, CN, SCN, ⅓PO4, ½SO4, ½CO3, formate, or acetate; (2) a water soluble complexing agent selected from the group consisting of MeNO2, MeAc, MeFm, NH4Ac, and NH4Fm where Me is Na, K, or Li; Ac is acetate; and Fm is formate; (3) an accelerator selected from the group consisting of NaClO3, NaBrO3, and NaIO3; (4) water; and (b) contacting the substrate with the aqueous reaction solution for a sufficient amount of time to oxidize the surface of the substrate, whereby the oxid

Abstract: A method of making a spinner disc for a rotary fiberization process, such as but not limited to a glass fiberization process, includes: forming a spinner disc from an alloy that forms a protective oxide film on surfaces of the spinner disc exposed to the atmosphere; forming fiberizing holes in an annular peripheral sidewall of the spinner disc; and applying a plasma to a surface of the spinner disc to remove hydrocarbons and sulfurous compounds from the surface of the spinner disc which would otherwise reduce and/or react with and degrade the protective oxide film forming on the surface of the spinner disc when the spinner disc is exposed to the atmosphere.

Abstract: The known flourinated layer has usually a thickness of from 1000 to 3000 angstroms. After the forced oxidation of metal, the forcibly oxidized surface is flourinated. As a result of the preceding forcing oxidation, a 1 &mgr;m or more thick fluorinated layer is formed on the surface of the metal.

Abstract: This invention relates to equipment for treating the aforesaid waste plastics directly with supercritical water, and an object thereof is to provide a method for the anticorrosive treatment of waste plastics treating equipment which makes it possible to use inexpensive stainless steel. Waste plastics treating equipment made of stainless steel is charged with a predetermined amount of an aqueous solution containing at least one alkali metal salt, and this aqueous solution is deaerated until its dissolved oxygen content is reduced to 0.5 mg/L or less. After the temperature and pressure of the equipment are raised until supercritical conditions are established, these temperature and pressure are maintained for a predetermined period of time.

Abstract: The present invention provides a stainless steel having by far higher corrosion resistance than those of the prior art and a method of forming an oxide passivation film having a chromium oxide layer on the surface thereof.

Abstract: A treated stainless steel is used as the material of construction for parts of an apparatus exposed to an organic amine. The stainless steel is treated by cleaning the stainless steel, forming a colored oxide film on the surface of the cleaned stainless steel by heating the cleaned stainless steel in an oxidizing atmosphere, and removing a portion of the colored oxide film to expose a passivating oxide film.

Abstract: A pure steam-related apparatus, which is one of apparatus in the group of pure steam generators generating pure steam from purified water, pipelines for pure steam and sterilizers using pure steam, is protected from discoloration, so-called "fouling", to red or black caused by contact with the pure steam. The apparatus is manufactured by using an austenitic stainless steel sheet as the material, by taking the blanks from the material which received no mechanical surface polishing, by deforming and welding, without electrolytic polishing customarily done, and by passivating the surface to contact pure water to increase Cr-content in the passivation film to such extent as 45 atomic % or higher, preferably 55 atomic % or higher. Better results will be obtained by ensuring Cr/Fe ratio in the passivation film at the level of 1.45 or higher, preferably, 1.70 or higher.

Abstract: Steam is contacted with a hydrogen absorbing alloy in a temperature range from 200.degree. C. to 400.degree. C. With a contact catalytic reaction of water, a metal contained in the hydrogen absorbing alloy is changed to an oxide or a hydroxide. Hydrogen produced causes the Ni compound to be reduced and thereby the Ni metal that is catalytically active is produced. Thus, the surface of the hydrogen absorbing alloy is activated. The steam is contained in an inert gas or a reductive gas. This treatment method is suitable as an activation treatment for a hydrogen absorbing alloy used as an active material of a negative electrode of a secondary battery.