Abstract: To provide an aluminum surface treatment method for manufacturing a polymer-aluminum joint structure having excellent bond strength. An aluminum surface treatment method for bonding with a polymer composite which is characterized in that it includes (a) a primary anodizing treatment step wherein the aluminum surface is treated by anodic oxidation; (b) a step wherein the aluminum oxide film is removed from the aluminum that has undergone the primary anodizing treatment; and (c) a secondary anodizing treatment step wherein the aluminum from which the aluminum oxide film is removed following the primary anodizing treatment is treated by anodic oxidation again.

Abstract: The present disclosure generally relates to methods of electro-chemically forming aluminum or aluminum oxide. The methods may include the optional preparation of a an electrochemical bath, the electrodepositon of aluminum or aluminum oxide onto a substrate, removal of solvent form the surface of the substrate, and post treatment of the substrate having the electrodeposited aluminum or aluminum oxide thereon.

Abstract: The described embodiments relate generally to aluminum films and methods for forming aluminum films. Methods involve providing aluminum films having increased hardness. Methods involve using higher than conventional current densities during plating of aluminum on substrates. The higher current density plating creates aluminum films with grain structures that are different from conventional plated aluminum films. In some embodiments, the average grain sizes are smaller in the hard aluminum films than conventional plated aluminum films. In some embodiments, the plated aluminum layer is anodized. In some embodiments, a multi-layered aluminum coating is formed using a combination of high current density and low current density plating. In some embodiments, a current filter is used to provide uniform plating across a part.

Abstract: A method for manufacturing a mold includes (a) anodizing an aluminum substrate at a voltage of 60 V to 120 V in an electrolytic solution in which two or more species of acid are mixed, and forming an oxide film having a plurality of minute holes on a surface of the aluminum substrate; and (b) removing at least a portion of the oxide film. The electrolytic solution used in (a) satisfies the relation (D1)/2<D2, where D1 is the current density when the aluminum substrate is anodized under the same conditions as in (a) in an electrolytic solution of only the acid (A) having the highest acid dissociation constant (Ka) of the two or more species of acid, and D2 is the current density when the aluminum substrate is anodized under the same conditions (a) in the same electrolytic solution as that of (a).

Abstract: A method for producing a cast component may include providing an insert part including an insert body having a circumferential face; coating the circumferential face with an adapter layer made of silicon oxide; arranging the insert part in a casting mold; and positively locking a casting encapsulation of the insert part and the adapter layer with an aluminum alloy to produce the cast component, wherein the aluminum alloy has a magnesium proportion of at least 0.3% by weight.

Abstract: One aspect relates to an electrical bushing for use in a housing of an implantable medical device. The electrical bushing includes at least one electrically insulating base body and at least one electrical conducting element. The conducting element is set up to establish, through the base body, at least one electrically conductive connection between an internal space of the housing and an external space. The conducting element is hermetically sealed with respect to the base body. The at least one conducting element includes at least one cermet. The electrical bushing includes an electrical filter structure. The at least one conducting element forms at least one electrically conducting surface of the filter structure.

Abstract: A method of depositing nickel on a surface of an object, the method including the steps of providing a source of direct current having a positive and a negative terminal; connecting the object to the negative terminal; connecting an anode to the positive terminal; and submerging the object and anode in a solution comprising nickel. The anode is positioned at a distance equal to or less than 2 mm from the surface of the object and when the source of direct current is switched on, nickel in the solution comprising nickel is deposited on the surface of the object.

Abstract: A method for treating the surface of aluminum components or components comprising aluminum includes anodizing the surface. Anodizing includes introducing at least one pigmenting substance, particularly fully pigmenting substance, into depressions or pores open toward the surface of a comb or pore structure of the surface created by the anodizing process, and/or introducing oxidizable substances into depressions or pores open toward the surface of a comb or pore structure of the surface created by the anodizing process and oxidizing these substances. The method further includes applying a ceramic thin-film coating or siliceous sol-gel coating onto the surface. The ceramic thin-film coating or the sol-gel coating comprises a pigment particularly serving refraction purposes.

Abstract: A method comprising providing an insert having a portion capable of being oxidized and electrochemically anodizing the portion capable of being oxidized to provide a layer comprising an oxidized material thereon.

Abstract: A method for the formation of a paint film in which an aluminum or aluminum alloy part is subjected to an anodic oxidation treatment and an anodic oxide film is formed on the surface of the aluminum or aluminum alloy part, an anti-rust primer is coated on said anodic oxide film and an anti-rust primer paint film is formed and, as required, a top-coat paint is coated on said anti-rust primer paint film and a top-coat paint film is formed in which said anti-rust primer includes a base resin comprising hydroxyl group containing epoxy resin and a hardening agent, selected from among melamine resin and polyisocyanate, and barium sulfate, and the proportion of said barium sulfate included is a proportion within the range from 20 to 70 parts by mass per 100 parts by mass in total of the solid fractions of the base resin and the hardening agent.

Abstract: A process of hard anodizing or Type III anodizing an aluminum article creates a heat stable, hard anodized, color surface on the exterior of the article. The process includes anodizing the aluminum article to achieve a hard anodized base layer on a surface of the article. A copper layer is deposited after the exterior is hard anodized. A tin layer is deposited after the step of depositing the copper layer.

Abstract: An aluminum alloy member includes a main body including an aluminum alloy serving as a base material, and an electrolytic oxidation ceramic coating coated at a portion of a surface of the main body and including a most outer layer and an inner layer which is arranged close to the main body relative to the most outer layer, the inner layer in which an aluminum oxide is richer than the most outer layer, the most outer layer in which a volume of a titanium oxide or a total volume of the titanium oxide and a zirconium oxide is richer than the inner surface.

Abstract: Disclosed herein are a heat-radiating substrate and a method of manufacturing the same. The heat-radiating substrate includes: a core layer including a core metal layer and a core insulating layer formed on the core metal layer and divided into a first region and a second region; a circuit layer formed in the first region of the core layer; a build-up layer formed in the second region of the core layer and including a build-up insulating layer and a build-up circuit layer; an adhesive layer formed between the second region of the core layer and the build-up layer; and an impregnation device mounted on the build-up layer to be impregnated into the adhesive layer. A heat generating element is mounted on the circuit layer and a thermally weakened element is mounted on the build-up layer, thereby preventing the thermally weakened element from being damaged by heat of the heat generating element.

Abstract: Provided are a heat radiation board and a method of manufacturing the same, and more particularly, to a heat radiation board formed using electro-deposition coating, in which a circuit is formed by forming a first insulating layer through anodizing and forming a second insulating layer through electro-deposition coating, and a method of manufacturing the same. The method of manufacturing the heat radiation board using electro-deposition coating includes preparing a metal core, forming a first insulating layer on the metal core by anodizing, forming a second insulating layer on the metal core, on which the first insulating layer is formed, by the electro-deposition coating, and forming a circuit layer. Therefore, since the first insulating layer is formed by anodizing and the second insulating layer is formed by electro-deposition coating, thermal conductivity is increased and thus radiation effect is improved.

Abstract: Aluminum-plated components of semiconductor material processing apparatuses are disclosed. The components include a substrate and an optional intermediate layer formed on at least one surface of the substrate. The intermediate layer includes at least one surface. An aluminum plating is formed on the substrate, or on the optional intermediate layer. The surface on which the aluminum plating is formed is electrically-conductive. An anodized layer can optionally be formed on the aluminum plating. The aluminum plating or optional the anodized layer comprises a process-exposed surface of the component. Semiconductor material processing apparatuses including one or more aluminum-plated components, methods of processing substrates, and methods of making the aluminum-plated components are also disclosed.

Abstract: The disclosure relates to a chamber component or a method for fabricating a chamber component for use in a plasma processing chamber apparatus. The chamber component includes a polished high purity aluminum coating and a hard anodized coating that is resistive to the plasma processing environment.

Abstract: A Clad material superimposed aluminum materials on stainless steel materials forms coating film by the electrodeposition coating on each whole surface of stainless steel material and aluminum material. A film of the aluminum material is removed by the irradiation of the laser beam, and the aluminum material of this region is exposed. Aluminum material is introduced into an injection molding machine after forming anodizing film. The synthetic resin part is formed with invading a synthetic resin to aperture of anodizing film. Then the composite component of clad material and synthetic resin part is produced.

Abstract: An insulated light-reflective substrate, comprising a substrate and an anodized film provided on the surface of the substrate, wherein: the substrate has at its surface an aluminum alloy layer of a thickness of not less than 10 ?m; the aluminum alloy layer has an aluminum purity of 99.9% by weight or higher, with the total content of Si and Fe in the layer being not more than 0.005% by weight, and the content of inevitable impurities in the layer as components other than Al, Si, Fe, Ga and Zn being not more than 0.01% by weight; the anodized film has micropores each extending from the surface of the film in the direction of thickness; and the ratio of center line length to depth of the micropores is 1.0 to 1.2.

Abstract: [Task] In a method, in which a plain bearing alloy layer 3 is bonded to a surface of a backing steel sheet 1, and, a Bi-based overlay layer 10 is then deposited on the plain bearing alloy layer 3 by electroplating, replacement of Bi with the backing steel sheet 1 and deposition of Bi on the backing steel sheet 1 are prevented. [Solution Means] Prior to the step of electroplating of said Bi-based overlay layer 10, the following metals and the like are formed on at least the back surface of said backing steel sheet 1. An electrochemically more noble metal 2 than Bi, an electrochemically more base metal 2 than Bi and capable of forming a passivation state, or resin 4.

Abstract: There is provided a method of manufacturing a tantalum condenser, in which a high-performing tantalum condenser is manufactured through a more simplified and higher-efficient process using simpler and economical equipment. The method of manufacturing a tantalum condenser including: preparing a tantalum pellet by sintering a tantalum powder; oxidizing the tantalum pellet to form a dielectric layer on a surface thereof; forming a polymer layer on the tantalum pellet having the dielectric layer formed on the surface thereof; and immersing the tantalum pellet having the polymer layer formed on the surface thereof in a polymer suspension to be subjected to chemical reformation.

Abstract: Disclosed is a microstructure comprising an aluminum anodized film bearing through micropores, wherein a surface of the microstructure is covered with a protective film for preventing hydration of the aluminum anodized film. The microstructure may be used as a porous alumina membrane filter excellent in filtration rate and its stability with time.

Abstract: This invention involves the technological field of electroplating, chemical plating, specially involves a method for partially plating aluminum and aluminum copper radiators. A radiator is conducted partial chemical oxidation and enclosure before undergoing galvanization. Firstly oxidize the non-plate surface of the radiator by chemical oxidation, then utilize a sealing compound to fill up tiny holes of the porous layer to make a film thereon against the erosion of acid and alkali, and then process common chemical plating or electroplating. Only plate a weldable nickel-phosphorus alloy on the touching parts at where the aluminum radiator or the aluminums and copper radiator connect with the main frame.

Abstract: A microstructure includes an anodized aluminum layer that has on a surface thereof micropores, at least some of which contain a catalyst, in a micropore array with a degree of ordering of at least 40%. A method of manufacturing the microstructure includes anodizing an aluminum member to form on its surface an anodized layer having micropores, removing the aluminum member, and supporting a catalyst on at least part of the anodized layer. The microstructure is excellent in heat resistance.

Abstract: A method of manufacturing a microstructure wherein an aluminum member having an aluminum substrate and a micropore-bearing anodized film present on a surface of the aluminum substrate is subjected at least to, in order, a pore-ordering treatment which involves performing one or more cycles of a step that includes a first film dissolution treatment for dissolving the anodized film until a barrier layer has a thickness of 3 to 50 nm, and an anodizing treatment which follows the first film dissolution treatment; and a second film dissolution treatment for dissolving the anodized film so that a ratio of a diameter of a micropore opening “a” to a micropore diameter at a height “a/2” from a micropore bottom “b” (a/b) is in a range of 0.9 to 1.1, whereby the microstructure having micropores formed on a surface thereof is obtained. The manufacturing method enables microstructures having an ordered array of pits to be obtained in a short period of time.

Abstract: Disclosed is a method of manufacturing a microstructure, wherein an aluminum substrate is subjected to, in order, (1) a step of subjecting a surface of the aluminum substrate to a first anodizing treatment to form an anodized film having micropores on the surface of the aluminum substrate; (2) a step of partially dissolving the anodized film using an acid or alkali; (3) a step of performing a second anodizing treatment to grow the micropores in their depth direction; and (4) a step of removing a part of the anodized film above inflection points in cross section of the micropores, whereby the microstructure having the micropores formed at a surface of the anodized film is obtained and a microstructure manufactured by the method. The method is capable of obtaining in a short period of time a microstructure having an ordered array of pits without using highly toxic chromic (VI) acid.

Abstract: In a method of manufacturing a microstructure, an aluminum member having an aluminum substrate and a micropore-bearing anodized layer present on a surface of the aluminum substrate is subjected at least to, in order, a pore-ordering treatment which involves performing one or more cycles of a step that includes a first film dissolution treatment for dissolving 0.001 to 20 wt % of a material constituting the anodized layer and an anodizing treatment which follows the first film dissolution treatment; and a second film dissolution treatment for dissolving the anodized layer, thereby obtaining the microstructure having micropores formed on a surface thereof. This method enables a microstructure having an ordered array of pits to be obtained in a short period of time.

Abstract: This invention provides a casing for storing MEA, which has satisfactory corrosion resistance to formic acid produced in an electrode reaction of MEA. There is also provided a casing formed of a material having the lowest possible specific gravity that can apply a suitable pushing pressure to MEA and a current collector without increasing the thickness dimension and is suitable for a power supply mounted, for example, in small portable electronic equipment. The casing is a casing for use in a fuel battery in which a hydrogen electrode, an oxygen electrode, and a film-electrode joint product formed of a proton conductive film held between the hydrogen electrode and the oxygen electrode are housed within the casing and, in removing water produced in an oxygen electrode reaction, the above water comes into contact with the casing. The casing for a fuel battery comprises a base material (2a) formed of a magnesium alloy and a film (2b) provided on the base material (2a).

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: Aluminium alloy sheet having on a surface anodic oxide film and an overlying coating consisting essentially of at least one adhesion promoter excluding silanes. Sheet for architectural use carries a paint layer over the adhesion promoter coating. Sheet for automobile use may carry an electroconductive paint primer layer over the adhesion promoter coating. Preferred adhesion promoters are polyacrylic acid and pretreatments containing Cr, Mn, Mo, Si, Ti, Zr and F values.

Abstract: A process for the production of wear-resistant, coated surfaces includes the use of at least two electrodes connected to a voltages source which are mounted in, or border, a reaction space through which an electrolyte flows in which the surface to be coated is located. The process is distinguished by the fact that the direction of the flow of the electrolyte is selectively reversed at least once during the coating process to enable better control of the formation of the oxide layer.

Abstract: A method of high-k gate dielectrics prepared by liquid phase anodic oxidation, which first produces a metallic film on the surface of a clean silicon substrate, next to oxidize said metallic film to form a metallic oxide as a gate oxidizing layer by liquid phase anodic oxidation, then to promote quality of said gate oxidizing layer by processing a step of thermal annealing. With this oxidation, a gate dielectric layer of high quality, high-k and ultrathin equivalent oxide thickness (EOT) can be produced, which can be integrated to complementary metal oxide semiconductor (CMOS) process directly.

Abstract: Aluminum or aluminum alloys are surface-treated by anodic oxidation (anodization) in an electrolyte containing from 3 to 30% by weight of an alkanesulfonic acid. Workpieces based on aluminum or aluminum alloys and produced by this process can be used in building and construction, in automobile or aircraft construction and in the packaging industry.

Abstract: The invention relates to a process for obtaining gold-colored aluminum oxide layers in which the coloring of the oxidized surface of the aluminum or aluminum alloys is carried out by an electrolytic process in an electrolyte comprising an alkanesulfonic acid and an alkanesulfonate of silver, and to the use of the gold-colored workpieces based on aluminum or aluminum alloys produced by this process for decorative purposes.

Abstract: A method for coating a light metal alloy component to form a protective layer comprising Sn. First, a surface of the light metal alloy component is cleaned and passivated. A layer comprising Zn is formed on the surface, and a layer comprising Sn is deposited. An intermediate layer is preferably deposited between the Zn-containing layer and the Sn containing layer. The Sn-containing layer may additionally be varnished.

Abstract: An external component of an endoscope includes an aluminum alloy base member whose surface is subjected to anodic oxidation, and thereafter, is subjected to an electrolytic deposition thereon.

Abstract: A process of producing an aluminum beverage can body having a decorative surface exhibiting a dichroic effect when observed in white light. In the process, a can body is formed from a sheet of metal selected from aluminum and aluminum alloy by drawing and ironing, surfaces of the can body are cleaned to produce a cleaned can body, a decorative structure exhibiting a dichroic effect is applied to a surface of the cleaned can body, and the can body is subjected to finishing operations. The decorative structure is applied by the steps of: applying a layer of dielectric material directly onto the metal of the cleaned can body without pre-treatment of the metal with a metal brightener, and forming a semi-transparent metal layer on or within the dielectric layer.

Abstract: Methods of producing aluminum picture frames having two regions of different colors. Aluminum frame stock is coated with a colored maskant or paint. Selective regions of the coated frame stock are abraded, and then anodized and dyed a second color absorbed by the exposed regions. In a second embodiment, aluminum frame stock is etched, anodized, and dyed a first color. The frame stock is then selectively abraded to remove regions of the first color, and then anodized and dyed a second color so the abraded regions absorb the second color. In a third embodiment, the frame stock is first etched, anodized, and dyed a first color. Selective areas of the frame stock are protected using an etch-resistant mask and is then etched stripping the unmasked regions of the first color and then anodized again and dyed a second color absorbed by the unmasked regions. The mask is then chemically removed.

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: A corrosion-resistant and electrically conductive connector shell includes a shell member formed of an aluminum alloy; an anodic surface coating formed on and extending into the shell member, having an approximate thickness between 0.0008 inch and 0.0018 inch; and a conductive metal plating covering and sealing the anodic surface coating. The metal plating can be a single layer of high purity aluminum having a thickness of 0.0002 inch. Alternatively, the metal plating can include a layer of a first metal on the anodic surface coating and having a thickness of at least approximately 0.00002 inch, and a layer of a second metal such as cadmium having a thickness of approximately 0.0002 inch on the layer of first metal.

Abstract: A method for applying a zinc layer onto an aluminum or aluminum alloy sheet, comprising pretreating the surface and applying the layer by electrolytic galvanizing, the pretreating comprises electrochemical graining of the surface, for example in a solution having a pH less than 3 with an alternating current applied between the sheet and an electrode. In an alternative method, the pretreating includes applying a preliminary zinc layer by immersing the surface in a zinc-containing alkaline solution, applying a potential to the sheet and reversing the polarity of said potential at least once. The sheets are useful for building cladding sheets and automotive panels.

Abstract: An inventive method of preparing an aluminum foil used in a high voltage aluminum electrolytic capacitor is disclosed. The method involves:(a) immersing an aluminum foil in a first forming solution,(b) applying a first voltage to said aluminum foil immersed in said first forming solution,(c) immersing said aluminum foil to which said first voltage is applied in a second forming solution, without passing current, and(d) applying a second voltage to said aluminum foil immersed in said second forming solution.Also disclosed is an aluminum foil that renders an electrolytic capacitor having properties of both high electrostatic capacity and small leak current.

Abstract: Disclosed is a method of surface-roughening an aluminum support comprising the step of electrolytically surface-roughening an aluminum support in an electrolyte solution, supplying an alternating current with an alternating waveform having a positive polarity period and a negative polarity period in one cycle, and comprising arriving at the largest current value from a zero current value in the positive polarity period of one cycle and then falling, followed by rising to a current maximum in one cycle, wherein the time t.sub.1, which is required to arrive at the largest current value, has the following relationships:1 millisecond<t.sub.1 .ltoreq.10 milliseconds, and1 millisecond<t.sub.1 .ltoreq.one third of the positive polarity period time.

Abstract: The present invention relates to a vacuum chamber and chamber parts made of aluminum or its alloys which exhibit excellent corrosion resistance to a corrosive gas or plasma introduced into the vacuum chamber, the surface treatment, and material for the vacuum chamber. The vacuum chamber has a porous layer with a structure in which a pore diameter at the top thereof is small, while a pore diameter at the bottom thereof is large. In order to give such a structure to the porous layer, a final anodizing voltage is set to be higher than an initial anodizing voltage when the surface of the base material is anodized. After the porous-type anodizing is completed, non-porous type anodizing may be conducted so as to grow a barrier layer. Furthermore, the base material made of aluminum alloy preferably has particles such as precipitates and/or deposits with a diameter of 10 .mu.m or less in average, and the precipitates and/or deposits are arranged in parallel with a largest surface of the base material.

Abstract: The invention relates to a process for equipping a kitchenware object, for example a pan, a pot, roasters or the like, comprising metal, for example aluminum, an aluminum alloy, magnesium or a magnesium alloy, with an anti-adhesion coating in the stressed surface regions, for example, on the inside, in which onto the metal surface of the object, for example after roughening, a mechanically-resistant layer, such as a mechanically-resistant anodization layer or similar mechanically-resistant layer is provided, and subsequently the stressed surface regions are provided with the anti-adhesion layer, wherein, before providing the mechanically-resistant layer, a durable surface layer is applied onto the surface regions, not to be provided with the coating system (mechanically-resistant layer or the like with or without anti-adhesion layer), of the object.

Abstract: An iron immersion composition of matter is disclosed comprising a compound having a divalent or trivalent iron ion, a compound having a fluoride ion, and a compound having an acid hydrogen ion. A process for treating an aluminum substrate to improve the adhesion of metal layers to the substrate is also disclosed comprising contacting the substrate with the acidic iron immersion composition to produce an iron immersion coating on the alloy, and contacting the iron immersion coating with an etchant to substantially remove the coating and produce a microporous surface on the substrate.

Abstract: According to the present invention, an aluminum alloy containing silicon is anodized using an electrolyte including a compound containing an anion having complexing capability such as sodium hydrogenphosphate or tribasic sodium phosphate, a salt of an organic acid containing an oxyacid anion such as sodium citrate or sodium tartrate or an alcohol such as sorbitol, and a halide such as potassium fluoride or sodium fluoride. The use of such an electrolyte results in a reduced amount of silicon being incorporated in the anodic oxide film. When the resulting oxide film is subjected to an electrodeposition treatment such as electroplating or electrolytic coloring, wasteful consumption of electrodeposition current can be inhibited. An aluminum alloy decorative cover is produced by buffing the surface of an aluminum alloy containing silicon, forming the anodized film on the buffed surface, and subjecting the anodized film to sequential nickel and chromium plating.

Abstract: Process for the electrolytic deposition of composite nickel onto the face of a part of a motor vehicle, in particular the bore of a casing or engine block of an internal combustion engine comprising at least three successive stages, the first being an electrochemical activation stage where the part is brought to anodic polarity in a bath containing a halogenated acid salt of nickel, the second being a stage of superactivation of the surface and the third being a stage of electrolytic deposition of a nickel layer containing particles of solid substances where the part is brought to cathodic polarity in a nickel-plating bath containing a charge of solid particles of which the diameter is advantageously between 0.5 and 5 microns and which can be of silicon carbide or any other hardening element, optionally mixed with particles of graphite.

Abstract: The invention provides a peelable laminated structure suitable for use in a peelable seal joining a flexible closure element (23) to a container (20) or in foil/polymer laminates used for packaging and the like. The structure comprises a porous-anodizable metal substrate (11) and a porous anodic film (12) overlying and attached to a surface of the substrate. The porous anodic film (12) has a weakened stratum (19) positioned between an outer film part and an underlying structure including the metal substrate (11). The weakened stratum (19) is strong enough in use of said structure to prevent detachment of the outer film part from the underlying structure, except by deliberate peeling of the flexible closure element (23). The invention also relates to a process for producing the structure and to peelable containers and recyclable laminates incorporating the structure.

Abstract: A machine part comprises: a base part formed of a titanium alloy or an aluminum alloy and having a roughened surface of Ra 0.5 .mu.m or above and PPI.sub.50 or above; and a Ni--P electrodeposit layer formed over the surface of the base part by an electroplating process using a Ni--P plating bath containing a stress relaxing agent, and having a stress of 20 kgf/mm.sup.2 or below. The machine part has a small specific gravity, excellent seizure resistance, wear resistance and fatigue strength.

Abstract: A magnetic recording medium having a substrate made of aluminum or aluminum alloy and an anodic-oxide film, e.g., alumite film, formed by effecting the anodic oxidation process, wherein the surface of the alumite film has protruding portions formed in addition to micro-irregularities which are formed in response to the cell-pore structure of the alumite film and height of the protruding portions is higher than that of the micro-irregularity, and density of the protruding portions is ranging from 10.sup.2 to 10.sup.7 per one square millimeter, these protruding portions are formed by processing the alumite film in the fluorine-contained solution (e.g., hydrofluoric acid) or in solution containing one of the acid (HCl), base (NaOH) and strong-acid salt ((NH.sub.4)SO.sub.4), Cr film and magnetic film are sequentially formed on the alumite film by the sputtering process.