JP2008208446A - Composite surface treatment method of aluminum or aluminum alloy and product thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic treatment method by which the heat dissipation of aluminum or an aluminum alloy is improved and other metallic or metal oxide properties are added and a novel product obtained by the method. <P>SOLUTION: Aluminum or the aluminum alloy is DC-electrolyzed in an acidic electrolyte containing a silicone resin to fill air reservoir on the surface with the silicone resin and to form a silicone resin composite coating film on the air reservoir and the surface layer to improve the heat dissipation. If need, the product obtained by the treatment is secondarily AC-electrolyzed in an acidic electrolyte containing a metal or metal oxide to replace the silicone resin filled in the air reservoir in the primary treatment by the metal or the metal oxide in the electrolyte to provide the novel aluminum or the aluminum alloy provided multiply with the properties of the metal or the metal oxide and the properties of the silicone resin in the silicone resin composite coating film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

        The present invention relates to a surface treatment method for aluminum or an aluminum alloy, and more particularly to a treatment method for improving heat dissipation and characteristics and a product thereof.

        In general, aluminum or an aluminum alloy is anodized with an electrolyte of a strong acid aqueous solution containing nitric acid, sulfuric acid, chromic acid, etc., and an alumite film is formed on the surface to improve hardness, corrosion resistance, etc. Widely used for surface treatment of aircraft, automobiles, ships, optics, chemical equipment, etc.

        However, this type of treatment at room temperature alone generates extremely fine and fine pores (commonly referred to as air traps) in the surface layer of the material to be treated, thereby providing corrosion resistance, wear resistance, heat and electrical conductivity, etc. The problem of being inferior to the problem remained.

In view of such drawbacks, the material to be treated was further subjected to secondary surface treatment with tetrafluoroethylene resin, etc., and the air reservoir was covered and filled to improve the above disadvantages. Since the diameter of tetrafluoroethylene resin (Teflon) particles is larger than the diameter of the former, the former cannot be filled, and only the surface is covered.
Therefore, it was impossible to perform machining after dredging, and it had to be used as it was with the above-mentioned defects.

Therefore, the use of an acidic electrolyte containing an acrylic resin composition having a low polymerization degree as a composition to replace the tetrafluoroethylene resin is proposed, and the member to be treated is energized as an anode at a temperature of 0C or more and 5C or less. The following two documents disclose a technique in which the surface layer portion containing air pockets is impregnated with an acrylic resin composition to form a composite anodized film to improve the disadvantages of the Teflon treatment.
Japanese Patent Publication No. 1-19479 JP-A-2-97698

Further, in the following patent document disclosed recently, the surface oxide film material of aluminum or aluminum alloy obtained as described above is further exchanged in an electrolyte composed of sulfuric acid, boric acid, metal salt and water. Electrolyzed with an electric current, impregnated with metal ions of the metal salt in the primary-treated film, substituted with the acrylic resin in the air pocket, together with the acrylic resin composite film on these surfaces present in the primary treatment A technique has been proposed in which a new composite metal film is secondarily formed, the characteristics of this metal are newly added to the base material to be processed, and the added value is increased.
JP 2005-264290 A

        However, the techniques of Patent Documents 1 and 2 of these prior arts are such that the air pool of the aluminum or aluminum alloy surface layer is impregnated and filled with acrylic resin in the electrolyte during electrolysis. At the same time, the surface is composite-coated with acrylic resin, so it is obvious to add the characteristics of acrylic resin, that is, light guide, corrosion resistance, or wear resistance, but on the other hand, From the nature of organic synthetic resin, it is also clear that it is not a material that improves heat dissipation because it inhibits conductivity such as heat and electricity.

        Accordingly, the aluminum or aluminum alloy obtained by such a technique is further subjected to AC electrolysis in an acidic electrolyte containing a metal salt, and the acrylic resin composite film is replaced with metal ions of the metal salt. Even if the secondary composite film is formed, the influence of the properties of the primary film of the previously treated acrylic resin is inevitable. For example, the metal coated with the secondary process has good heat and electrical conductivity such as silver. Even if it is a conductive metal, it is impossible to improve the heat dissipation and electrical conductivity of the mother body.

導体の熱を引き出すＣｕ板をその下部に敷くと共に、更にその下に放熱性並びに摺動性の良好なＳｉシートを重ねた上で、最終的に熱伝導性に優れたＡｌ板から矢印（Ｔ）（ｔ）方向に放熱する様に構成する事を常套手段としている。
然しながら、この方法に於いても、各部材の境界表層面上の多孔質の空気だまりの熱抵抗により、放熱アルミ板からの放熱効率は、此等各面を適当に加工しても、満足すべき効果は得られないのが実情である。

A Cu plate that draws the heat of the conductor is laid underneath, and a Si sheet with good heat dissipation and slidability is further stacked thereunder, and finally an arrow (T ) (T) It is a conventional means that the heat is dissipated in the direction (t).
However, even in this method, due to the thermal resistance of the porous air pool on the boundary surface of each member, the heat dissipation efficiency from the heat dissipation aluminum plate is satisfied even if these surfaces are appropriately processed. The actual situation is that the desired effect cannot be obtained.

        Therefore, the problem of the present invention is improved with reference to such a conventional semiconductor heat dissipation method and the technology disclosed in the above-mentioned patent document, and aluminum or aluminum having high heat and electrical conductivity and extremely good slidability. It is an object of the present invention to provide a composite electrolytic treatment method for producing an aluminum alloy and the novel product produced by the method.

In order to solve such problems, in the present invention, instead of the acrylic resin-containing acidic electrolyte disclosed in the above-mentioned patent document, an electrolyte containing a silicon resin with good thermal conductivity is used, Impregnating and filling the air reservoir in the surface layer with silicon resin, and expelling the air in it, at the same time, the surface is compositely coated with silicon resin to increase the thermal conductivity and improve the heat dissipation effect from the base material It is improved.
Thus, the present invention provides a novel aluminum or aluminum having good heat dissipation, conductivity, slidability, etc. in addition to the properties of acrylic resin, that is, light guiding properties, abrasion resistance, and corrosion resistance. Succeeded in providing alloys.

        Furthermore, the aluminum or aluminum alloy obtained by such treatment is used in an electrolyte containing other metals or metal oxide salts (salts such as gold, platinum, titanium dioxide, etc.), sulfuric acid, and boric acid. The silicon resin in the air reservoir is impregnated and replaced with the metal or metal oxide ion in the electrolyte, and the properties of these metals are added in a secondary and complex manner, thereby further adding value. It is characterized by enhancing.

        According to the present invention, a fine and dense air pocket existing in the surface layer of aluminum or aluminum alloy electrolytically treated by a conventional method is synthesized from a metal belonging to Group 4 of the periodic table such as silicon. While being impregnated and filled with a resin, a composite film is formed on the surface to eliminate the thermal resistance of air pockets, and at the same time, the characteristics of this metal, that is, the slidability (lubricity) and the thermal conductivity, are made of the base material aluminum. As shown in FIG. 4, the heat dissipation Cu plate and Si sheet are compared with the conventional heat dissipation system for semiconductor devices (see FIG. 3). Since it is not used and can be used directly as a material directly connected to semiconductors, both the capacity and weight of the product are reduced, miniaturization and weight reduction are achieved, and the assembly process can be reduced by two processes. In It is possible to refer to reduction.

        Furthermore, the aluminum or aluminum alloy obtained by the primary treatment in this way is subjected to secondary AC electrolysis of the silicon resin filling portion in an acidic metal or metal oxide aqueous solution, In addition to the thermal conductivity added by impregnation with a metal or metal oxide, such as gold, platinum, titanium dioxide, etc., and by the primary treatment, the characteristics of the metal ions or metal oxide ions in the aqueous solution, For example, characteristics such as light guiding properties, heat, electrical conductivity, corrosion resistance, disinfection, sterilization, antibacterial properties, and the like can be added secondarily to further increase the industrial value.

        The best mode for carrying out the present invention as described above is that, in the processing method of the above-mentioned patent document, instead of the low-polymerization acrylic resin used for the primary electrolytic treatment, it is possible to obtain a thermally conductive material that is inexpensive and easily available. The first feature is to use a good silicon resin by dissolving it in weakly alkaline carbon water. This resin blocks fine and dense air pockets on the surface of the base material, and the surface of the resin is filled with silicon resin. The composite film is formed to eliminate the heat resistance of the air pocket and improve the heat dissipation effect of the base material.

Furthermore, the primary processing base material with good heat dissipation obtained in this way is further excellent in other metals or metal oxides such as gold, platinum, titanium dioxide, etc., that is, good electrical and thermal properties. Properties such as conductivity, gloss, corrosion resistance, and antibacterial properties are added in a complex manner by secondary electrolytic treatment, further increasing its industrial value, for example, heat dissipation from the above semiconductor devices, precision machines, etc. It is very advantageously used as a conductive material.
The preferred embodiments of the present invention will be described below with reference to the drawings.

この様な電解処理条件下での所定時間の通電により、図１に示す如く、処理母材（２）の表層（１）に形成されていた問題の熱抵抗性の空気だまりは、シリコン樹脂（３）（３）（３）に依って含浸充填されると共に、前記表層上面及び各空気だまりの内面には、（４）（４）・・で示すシリコン樹脂の複合皮膜が形成されるので、当該表層の熱伝導性は著しく向上し、母材本体（２）を経由する熱伝導性（放熱性）は、極めて良好な状態へと改善される。
尚、上記電解水溶液中のシリコン樹脂は、弱アルカリ性（ＰＨ９−１０）の水、特に炭素水に溶解して有利に使用される。
又、図面中の符号（３）は、当該電解中に形成されたバリヤー層を示し、符号（５）は同質のアルミナ表層部を示している。In the direct current electrolytic surface treatment in the acidic electrolytic aqueous solution of aluminum or aluminum alloy of the present invention, the above-mentioned aluminum matrix is used as the anode in an electrolytic cell filled with the electrolytic aqueous solution as usual. This was carried out under the following conditions using an aluminum material as a cathode.

As shown in FIG. 1, when the energization is performed for a predetermined time under such electrolytic treatment conditions, the problematic heat-resistant air pocket formed on the surface layer (1) of the treatment base material (2) becomes silicon resin ( 3) Since (3) and (3) are impregnated and filled, and on the upper surface of the surface layer and the inner surface of each air pool, a composite film of silicon resin shown in (4), (4),. The thermal conductivity of the surface layer is remarkably improved, and the thermal conductivity (heat dissipation) via the base material body (2) is improved to a very good state.
The silicone resin in the electrolytic aqueous solution is advantageously used after being dissolved in weakly alkaline (PH9-10) water, particularly carbon water.
Reference numeral (3) in the drawing represents a barrier layer formed during the electrolysis, and reference numeral (5) represents a homogeneous alumina surface layer.

The aluminum or aluminum alloy thus modified further undergoes secondary electrolysis under the following conditions by an alternating current, and a specific metal ion or metal oxide contained in the electrolyte. Ions and silicon resin in the aluminum base air reservoir are impregnated and replaced, and in addition to the heat dissipation characteristics of the primary treatment base material, the characteristics of these metals such as titanium dioxide (photocatalyst) such as the above-mentioned corrosion resistance and antibacterial properties To add industrial properties and improve industrial added value.

As shown in FIG. 2, by alternating current electrolysis under the above-described conditions, the air pocket of the porous surface layer (1) on the secondary treatment base material (2) is impregnated with a titanium resin impregnated with silicon resin (7). (4) heat dissipation of the silicon resin film that has been composite-coated by the primary treatment, and the above characteristics of titanium dioxide, that is, corrosion resistance, antibacterial properties, etc. New aluminum or aluminum alloy is being produced.
Furthermore, if it is necessary to add properties of other metals such as gold, platinum, silver, copper, etc. to the primary or secondary processing matrix, these metal salts are added to the electrolyte. By doing so, it is possible to provide a novel aluminum or aluminum alloy having a composite of the respective characteristics by substituting and impregnating the silicon resin or titanium dioxide in the air.

It is explanatory sectional drawing which shows the surface layer part of the aluminum or aluminum alloy by which heat dissipation was improved by the primary direct current electrolysis process of this invention. Description showing a surface layer portion of a product obtained by subjecting aluminum or aluminum alloy obtained by the above-mentioned primary direct current electrolytic treatment to secondary alternating current electrolytic treatment in an electrolytic aqueous solution further containing a metal or a metal oxide. It is sectional drawing. It is explanatory drawing about the heat dissipation system of the conventional semiconductor which uses aluminum or aluminum alloy. It is description which shows the thermal radiation system of the semiconductor device using the aluminum or aluminum alloy plate processed by the method of this invention.

Explanation of symbols

(1) Surface layer portion of primary electrolytic treatment aluminum or aluminum alloy of the present invention (2) Aluminum or aluminum body (3) Silicon resin (4) Silicon resin composite coating (5) Alumina surface layer portion (6) Barrier layer (7 ) titanium dioxide

Claims (6)

    A predetermined amount of an aqueous silicone resin solution is added to an electrolytic solution containing sulfuric acid, dissolved aluminum, and water, and a workpiece made of aluminum or an aluminum alloy is used as an anode to be energized with a direct current in the solution. A composite surface treatment method comprising: forming a silicon resin composite film in which a silicon resin is impregnated in a porous material formed on a surface of a processed body.     The composite surface treatment method according to claim 1, wherein the aqueous silicone resin solution is prepared by adding (carbon water) having a pH of 9 to 10 to the silicone resin.     The aluminum or aluminum alloy provided with the silicon resin composite film produced | generated by the composite surface treatment method of Claim 1.     An aluminum or aluminum alloy workpiece obtained by the composite surface treatment method according to claim 1 or 2 and provided with a silicon resin composite film, an acid containing sulfuric acid, boric acid, an ionized metal or metal compound, and water. A composite surface treatment method characterized in that the silicon resin in the porous layer of the silicon resin composite film is replaced with the ionized metal or metal compound by energizing with an alternating current in the electrolyte solution.     5. The composite surface according to claim 4, wherein the ionized metal or metal compound added to the acidic electrolyte is any one of titanium oxide, platinum, silver, or a similar metal or metal compound. Processing method.     Aluminum or an aluminum alloy composite-coated with any of titanium oxide, platinum, silver, or a similar metal produced by the surface treatment method of claim 5.

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