JP5517024B2 - Mg-based structural member - Google Patents

Mg-based structural member

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JP5517024B2
JP5517024B2 JP2009021268A JP2009021268A JP5517024B2 JP 5517024 B2 JP5517024 B2 JP 5517024B2 JP 2009021268 A JP2009021268 A JP 2009021268A JP 2009021268 A JP2009021268 A JP 2009021268A JP 5517024 B2 JP5517024 B2 JP 5517024B2
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JP2010174363A (en )
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祥子 廣本
玲子 山本
典夫 丸山
敏司 向井
英俊 染川
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独立行政法人物質・材料研究機構
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    • C23C22/00Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
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    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
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    • C23C22/00Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/07Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing phosphates
    • C23C22/08Orthophosphates
    • C23C22/22Orthophosphates containing alkaline earth metal cations
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    • C23C22/00Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/60Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using alkaline aqueous solutions with pH greater than 8
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    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/68Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous solutions with pH between 6 and 8
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    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C30/00Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process

Description

本発明は、自動車などの輸送機器の部材、携帯電話、テレビなどのIT機器、家電製品の筐体等の所望の構造形状に形成されたマグネシウムおよびマグネシウム合金からなるMg基構造部材に関し、より詳しくは、その耐食性の向上に関するものである。 The present invention, members of the transportation equipment such as automobiles, mobile phones, relates Mg-based structural members made of IT equipment, magnesium is formed into a desired structural shape of the housing or the like of appliances and magnesium alloys, such as a television, and more detail relates to the improvement of the corrosion resistance.

マグネシウム合金は比強度が高く資源が豊富であることから、自動車や航空機の燃費を向上するための軽量化部材としての応用が検討されている。 Magnesium alloy because high resource specific strength is rich, application as lightweight member for improving the fuel efficiency of automobiles and airplanes have been studied. また、プラスチックよりも強度や電磁波遮蔽効果が高いことから、携帯電話やパソコン、テレビなどをはじめとするIT機器や家電品の筺体に利用されている。 In addition, due to its high strength and electromagnetic shielding effect than the plastic, mobile phones and personal computers, it has been used in IT equipment and consumer electronics products of the housing, including a TV. これらの部材には、多様な環境での高い耐食性が必要である。 These members are required to have high corrosion resistance in the environment.
一方、マグネシウムは化学的に活性な物質であるために、特に塩化物イオンを含む酸性・中性環境での耐食性が低いという欠点がある。 Meanwhile, magnesium chemically in order to be active substances, in particular there is a disadvantage that a low corrosion resistance in acidic-neutral environments containing chloride ions. 輸送機器や家電製品は、塩化物イオンを含む雨や海水の飛沫や人の汗に曝される。 Transport equipment and consumer electronics products, are exposed to splash and human sweat of rain and sea water containing chloride ions. このため、高耐食性皮膜の形成と、部材によっては高耐食性皮膜に加えて塗装が必要とされている。 Therefore, the formation of high corrosion resistance coating, painting in addition to high corrosion resistance coating is needed by the member.
従来のマグネシウム材の耐食性改善のための皮膜は、クロム、マンガンやフッ素などの環境負荷が高い元素を含むものが主流である。 Coatings for improving the corrosion resistance of conventional magnesium material, chromium, those environmental loads such as manganese and fluorine containing higher elements is the mainstream. このため、製造工程での環境負荷が小さく、使用中の環境への安全性も高い元素で構成されている耐食性皮膜が求められている。 Therefore, low environmental impact in the manufacturing process, corrosion-resistant coating is composed of highly safe to the environment during use elements are required.
リン酸を主成分とする環境負荷の低い元素で構成されている溶液中での陽極酸化により形成した高耐食性皮膜(特許文献1)の報告もあるが、陽極酸化は消費電力量が大きいという欠点がある。 Although some reports of highly corrosion-resistant coating formed by anodic oxidation in a solution that consists of a lower element environmental impact of the phosphoric acid as a main component (Patent Document 1), drawback anodization large power consumption there is.
また、リン酸、マンガン酸および酸化カルシウムを含む化成処理溶液および陽極酸化用電解液が開発されており(特許文献1〜5)、製造された皮膜は高い耐食性および塗料との密着性を示している。 Further, phosphoric acid, and the chemical conversion treatment solution and for anodizing electrolyte containing manganate and calcium oxide have been developed (Patent Documents 1 to 5), manufactured coating shows the adhesion between the high corrosion resistance and paint there. しかし、マンガン酸は廃液処理が必要な物質であることから、さらに環境負荷の低い耐食性皮膜およびその製造方法が望まれている。 However, manganate since it is a necessary material waste liquid treatment, it is desired lower corrosion barrier coating and a method of manufacturing the same environmental impact.

本発明は、このような実情に鑑み、環境に安全な元素で構成された耐食性皮膜を有するMg基構造部材を提供することを目的とする。 In view of such circumstances, and an object thereof is to provide an Mg base structural member having a corrosion barrier coating composed of a secure element environment. また、その製造方法においても製造工程での環境負荷が低いものを提供することを目的とする。 Also it aims to environmental impact in the manufacturing process to provide a low in the manufacturing process.

本発明は、上記目的を達成するために、環境負荷が低いリン酸カルシウムの中でも熱力学的安定性が高いアパタイトを主成分とする皮膜を耐食性膜とすることとした。 The present invention, in order to achieve the above object, and the film composed mainly of thermodynamic stability is high apatite among environmental load is low calcium and be corrosion-resistant film. 具体的には以下の通りである。 More specifically, it is as follows.
発明1のMg基構造部材は、基材の表面がアパタイト結晶を主成分とする皮膜により覆われており、前記皮膜と基材とが水酸化マグネシウム層を介して一体化されてなり、 Invention 1 of Mg-based structural member is covered with a film surface of the substrate is composed mainly of apatite crystals, and the coating and the substrate is being integrated via a magnesium hydroxide layer,
前記皮膜の厚さが1〜5μmであることを特徴とする The thickness of the coating, characterized in 1~5μm der Rukoto.
は、発明1の Mg基構造部材において、前記皮膜の表面が、樹脂塗料により塗装されてなることを特徴とする。 Inventions 2, in Mg group structural member of the invention 1, the surface of the coating, characterized by comprising been coated with a resin coating.

発明は、発明1 又は2のMg基構造部材の製造方法であって、所望の形状に成形された前記基材を、リン酸イオンおよび過飽和状態で溶解している非塩化物系カルシウムイオンを含む水溶液中に浸漬して、前記基材の表面にアパタイト結晶を主成分とする皮膜を析出させることを特徴とする。 Invention 3 is a manufacturing process of the first or second aspect of the Mg-based structural members, the desired the base material molded into a shape, a non-chloride-based calcium ions dissolved in the phosphate ion and supersaturated It was immersed in an aqueous solution containing, characterized in that to deposit a film composed mainly of surface apatite crystals of the substrate.
発明は、発明のMg基構造部材の製造方法において、前記水溶液のカルシウムイオンはカルシウムキレート化合物の溶解により得られたものであることを特徴とする。 Invention 4 provides a method of manufacturing a Mg based structural member of the invention 3, the calcium ions of the aqueous solution is characterized by is obtained by the dissolution of the calcium chelate compound.

アパタイトをはじめとするリン酸カルシウムは、中性環境での溶解度は低く、塩化物イオンによる腐食を受けない。 Calcium phosphate, including apatite solubility at neutral environment is low, not subject to corrosion by chloride ions. アパタイトはリン酸カルシウムがとりうる種類の結晶構造の中で、熱力学的安定性が高い結晶構造であるため、他のリン酸カルシウムよりも水溶液中での溶解度が低い。 Apatite in different crystal structures calcium phosphate can take, for thermodynamic stability is highly crystalline structure, low solubility in aqueous solutions than the other calcium phosphates. また、リン酸カルシウムは、生体骨の主成分であることが示しているように、環境負荷の低い元素で構成されている環境安全性の高い材料である。 Also, calcium phosphate, as it has shown a major component of living bone, a high environmental safety is configured with a low environmental impact element material.
以上の特性より、アパタイトをはじめとするリン酸カルシウム、特にアパタイトをマグネシウム表面に析出させることで、低環境負荷の高耐食性マグネシウム材を提供することができる。 From these characteristics, by precipitating calcium phosphate, including hydroxyapatite, especially apatite magnesium surface, it is possible to provide a highly corrosion resistant magnesium material of a low environmental impact. さらに、アパタイトを主成分とする皮膜の作製を水溶液中で行うことができれば、製造過程の環境負荷を軽減することができる。 Further, if it is possible to carry out the fabrication of the film mainly composed of apatite in aqueous solution, it is possible to reduce the environmental impact of the manufacturing process.
ところが、マグネシウムは、アパタイトの結晶化を阻害する元素であるため、マグネシウム材表面に水溶液中から直接アパタイトを析出させることは不可能とされていたのが従来技術常識であった。 However, magnesium is an element that inhibits crystallization of apatite, the it had been impossible to precipitate directly apatite from an aqueous solution of magnesium material surface is a conventional technical common knowledge.
本発明は、このような技術常識を打破したものである。 The present invention has overcome these technical knowledge.

本発明のマグネシウム材は、アパタイトを主成分とする皮膜が存在することで、マグネシウム又はマグネシウム合金の腐食を抑制する効果を有する。 Magnesium material of the present invention, the presence of the film mainly composed of apatite has the effect of suppressing the corrosion of magnesium or magnesium alloy.
さらに、本発明の皮膜を有するマグネシウム材は、環境に安全な元素からのみ構成されるため、マグネシウム材のリサイクル時の環境負荷を軽減する効果も有する。 Further, the magnesium material having the coating of the present invention, since it is constituted only from a secure element in the environment, also has the effect of reducing the environmental impact of recycling the magnesium material.
また、皮膜作製の溶液を環境に安全な元素のみを含む水溶液とすることで、工場周辺の環境保全や廃液コストの削減に効果を発する。 Further, by the solution of the coating produced with an aqueous solution containing only secure element to the environment, it emits effect to reduce environmental and waste costs around the factory.
一般にリン酸を含む皮膜は塗料の付着性が高いため、本発明のアパタイト結晶を主成分とする皮膜には塗料との高い密着性が期待できる。 Coating generally containing phosphoric acid has high adhesion of the coating, the coating consisting mainly of apatite crystals of the present invention can be expected high adhesion to the paint. さらに、アパタイト結晶は透明又は白色の結晶であるため、上塗りする塗料の発色を妨げないという利点も期待できる。 Furthermore, since the apatite crystals are transparent or white crystals, it can also be expected advantage does not interfere with the color development of the paint to be overcoating.

試料A〜DのXRDパターンを示すグラフ。 Graph showing an XRD pattern of the sample to D. 試料Bの表面の電子顕微鏡写真。 Electron micrograph of the surface of the sample B. 試料Bの断面の電子顕微鏡写真。 Electron micrograph of a cross section of Sample B. 試料Cの表面の電子顕微鏡写真。 Electron micrograph of the surface of the sample C. 試料Cの断面の電子顕微鏡写真。 Electron micrograph of a cross section of the sample C. 試料H、IのXRDパターンを示すグラフ。 Sample H, a graph showing an XRD pattern of I. 試料K〜MのXRDパターンを示すグラフ。 Graph showing an XRD pattern of the sample K~M. 試料Hの表面の電子顕微鏡写真。 Electron micrograph of the surface of the sample H. 試料N〜PのXRDパターンを示すグラフ。 Graph showing an XRD pattern of the sample N~P. 試料Q〜TのXRDパターンを示すグラフ。 Graph showing an XRD pattern of the sample Q-T. 試料U〜WのXRDパターンを示すグラフ。 Graph showing an XRD pattern of the sample U to W. 試料Cの96時間乾湿繰り返し試験後に、表面処理層および腐食生成物を除去した表面の写真。 After 96 hours dry-wet cycle test sample C, the surface photograph of the removal of the surface treatment layer and the corrosion products. 試料Jの24時間乾湿繰り返し試験後に、表面処理層および腐食生成物を除去した表面の写真。 After 24 hours dry-wet cycle test of the sample J, the surface photograph of the removal of the surface treatment layer and the corrosion products. 試料Kの24時間乾湿繰り返し試験後に、表面処理層および腐食生成物を除去した表面の写真。 After 24 hours dry-wet cycle test sample K, surface photograph of the removal of the surface treatment layer and the corrosion products. 研磨まま試料の24時間乾湿繰り返し試験後に、表面処理層および腐食生成物を除去した表面の写真。 After 24 hours dry-wet cycle test of polishing while sample surface photograph of the removal of the surface treatment layer and the corrosion products. 試料C、J、Kおよび研磨まま試料の3.5wt% NaCl溶液中でのアノード分極曲線。 Sample C, J, K and anode polarization curve in the polishing remains 3.5 wt% of the sample NaCl solution. −1.45V(SCE)におけるアノード電流密度を示すグラフ。 Graph showing an anode current density at -1.45V (SCE).

本発明のアパタイト結晶を主成分とする皮膜は、処理溶液に含まれるリン酸イオンおよびカルシウムイオンがアパタイト結晶として基材表面に析出したものであるため、基材の組成に依らず作製することができる。 Film composed mainly of apatite crystals of the present invention, since phosphate ions and calcium ions contained in the process solution is obtained by precipitation on the surface of the substrate as the apatite crystals, be made regardless of the composition of the base material it can. したがって、基材の組成は特に限定されず、純マグネシウムであってもよくマグネシウム合金であってもよい。 Therefore, the composition of the substrate is not particularly limited, and may be also good magnesium alloy be pure magnesium.
本発明の皮膜は、水溶液中への浸漬処理により作製されるため、基材の表面形状が複雑であってもその影響を受けない。 Coating of the present invention, because it is produced by the immersion treatment in an aqueous solution, is not affected even complicated surface shape of the substrate.
本発明の皮膜はアパタイト結晶を主成分としている。 Coating of the present invention is mainly composed of apatite crystals. 浸漬処理条件によっては、基材との境界に結晶性Mg(OH) を主成分とする層を有している。 The immersion treatment conditions, has a layer mainly composed of crystalline Mg (OH) 2 at the boundary between the base material. 熱力学的に安定な結晶構造であるアパタイト結晶の塩類溶液中での溶解度は非常に低い。 Solubility in saline solution of thermodynamically stable crystal structure apatite crystals is very low. さらに、結晶性Mg(OH) の溶解度は、マグネシウム材表面に大気中で形成されるアモルファスMg(OH) よりも非常に低い。 Furthermore, the solubility of the crystalline Mg (OH) 2 is much lower than the amorphous Mg (OH) 2 which is formed in the atmosphere to the magnesium material surface. このために、本発明の皮膜を有するマグネシウム材は、大気酸化皮膜を有するマグネシウム材に比べて高い耐食性を示すことができる。 Therefore, the magnesium material having the coating of the present invention can exhibit high corrosion resistance as compared with the magnesium material having the atmospheric oxide film.
本発明の皮膜を有するマグネシウム材を製造するための表面処理溶液は、カルシウムキレート化合物およびリン酸イオンを含むpH5〜pH13の水溶液である。 Surface treatment solution for producing a magnesium material having the coating of the present invention is an aqueous solution of pH5~pH13 containing calcium chelate compound and phosphate ion.

広いpH範囲で高濃度のカルシウムイオンを溶解させることができるカルシウム化合物としては、EDTA, NTA, HEDTE, アミノポリカルボン酸等のキレートのカルシウム化合物などが挙げられる。 The calcium compound capable of dissolving a high concentration of calcium ions in a wide pH range, EDTA, NTA, HEDTE, like calcium compound chelates such as aminopolycarboxylic acid. 中性付近から酸性の処理溶液であれば、水酸化カルシウム、硝酸カルシウム、炭酸カルシウム、酢酸カルシウム、リン酸2水素カルシウム、チオ硫酸カルシウムなどの無機塩を用いることもできる。 If treatment solution acidic near neutral to be calcium hydroxide, calcium nitrate, calcium carbonate, calcium acetate, dihydrogen phosphate calcium, also be an inorganic salt such as calcium thiosulfate. また、無機塩とともにキレート剤を加えることで、カルシウムイオン濃度を増加させることもできる。 Further, by adding a chelating agent with inorganic salts, it is also possible to increase the calcium ion concentration. このように、カルシウム源をキレート化合物にすることで、酸性水溶液中はもとより、アルカリ性水溶液中においても比較的高濃度のカルシウムイオンを溶解することができる。 In this way, by a calcium source to a chelating compound, an acidic aqueous solution as well, it is possible to dissolve a relatively high concentration of calcium ions in an alkaline aqueous solution.
EDTAなどのキレート剤を含むアルカリ性水溶液は、酸洗したマグネシウム材表面からのスマット除去に用いられることもある(特許文献6)。 Alkaline aqueous solution containing a chelating agent such as EDTA may also be used in the desmutting from pickled magnesium material surface (Patent Document 6). このため、キレート剤濃度が高いと、基材マグネシウム表面が荒れる傾向がある。 Therefore, when the chelating agent concentration is high, the substrate magnesium surface is rough trend. 例えば、純マグネシウムにおいてEDTA濃度が2.5×10 -1 Mより高いと、マグネシウム基材表面の荒れが大きくなり、リン酸カルシウムを主成分とする皮膜が均質に表面を覆えなかった。 For example, when the EDTA concentration is 2.5 × 10 -1 higher than M in pure magnesium, roughening of the magnesium-based material surface is increased, the film mainly composed of calcium phosphate was uniformly Ooe surface.
一方、キレート剤の存在により、皮膜形成と併行して基材表面の脱脂および離型剤、酸化皮膜やスマットの除去を進めるため、形成される皮膜中の不純物が軽減できることが期待される。 On the other hand, the presence of a chelating agent, degreasing and release agent on the substrate surface in parallel with the film formation, to advance the removal of oxide film or smut, impurities in the film formed is expected to be reduced.

処理溶液を構成する無機リン酸塩としては、リン酸2水素カリウム、リン酸水素2ナトリウム、リン酸2水素アンモニウム、リン酸水素2アンモニウム、リン酸1水素カルシウムなどの種々のアルカリ塩、アンモニウム塩、アルカリ土類オルト2水素塩などが挙げられる。 The inorganic phosphate constituting the processing solution, potassium dihydrogen phosphate, sodium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium hydrogen phosphate, various alkali salts of phosphoric acid monohydrogen calcium, ammonium salt , and the like alkaline earth ortho dihydrogen salt.
カルシウム塩およびリン酸塩濃度が5×10 -4 M未満であると、アパタイト結晶の析出速度が非常に小さくなる傾向がみられた。 When the calcium salt and phosphate concentration is less than 5 × 10 -4 M, the deposition rate of the apatite crystals were seen very small tendency. この場合は、浸漬時間を長くする必要が生じてしまう。 In this case, necessary to increase the soaking time occurs.
上記のカルシウム化合物および無機リン酸塩より調整した処理溶液のpHを調整するために、水酸化ナトリウム、水酸化カリウム、アンモニアなどのアルカリ性溶液を用いる。 To adjust the pH of the treatment solution prepared from the above calcium compound and inorganic phosphate, sodium hydroxide, potassium hydroxide, an alkaline solution such as ammonia is used. 調整するpHの範囲はpH5〜pH13が望ましい。 Range of pH to be adjusted pH5~pH13 is desirable. これは、処理溶液に浸漬したマグネシウム基材の溶解が起こり、溶解反応によるpH上昇により、マグネシウム基材表面近傍のpHが、アパタイト結晶相が安定なpH7以上になりうるpHだからである。 This occurs dissolving of the magnesium substrate was immersed in the processing solution, the pH increase caused by the dissolution reaction, pH of the neighborhood magnesium substrate surface, a pH So apatite crystal phase can be a stable pH7 or more. pH11以上の水酸化マグネシウムが不溶になるpH範囲においてもアパタイト結晶相が安定なため、マグネシウム基材表面にアパタイトを析出させることができる。 Magnesium hydroxide or pH11 because even apatite crystalline phase is stable in the pH range of the insoluble, can be precipitated apatite magnesium substrate surface.

本発明のアパタイト結晶を主成分とする皮膜の厚さは、1×10 -2 μm〜5×10 μmが好ましい。 The thickness of the film composed mainly of apatite crystals of the present invention, 1 × 10 -2 μm~5 × 10 1 μm is preferred. より好適には1×10 -1 μm以上、好適には5×10 -1 μm以上、さらに好適には1μm以上である。 More preferably 1 × 10 -1 μm or more, preferably 5 × 10 -1 μm or more, and more preferably 1μm or more. また、より好適には2.5×10 μm以下、1×10 μm以下、さらには5μm以下である。 Further, more preferably 2.5 × 10 1 μm or less, 1 × 10 1 [mu] m or less, more is 5μm or less. 皮膜の厚さが薄すぎると表面を均一に覆うことができずに耐食性が悪くなるおそれがあり、厚すぎると基材表面から剥離しやすくなる。 There is a possibility that the corrosion resistance is deteriorated not able to the thickness of the coating is too thin to cover the surface uniformly, easily peeled off from the too thick substrate surface.
本発明のアパタイト結晶を主成分とする皮膜を有するマグネシウム材は、各種の用途に使用することができる。 The apatite crystals of the present invention the magnesium material having film whose main component can be used in various applications. 自動車や2輪車用部品や、携帯電話、パソコン、ビデオカメラなどの筺体などに使用することができる。 Automobiles and parts and for two-wheeled vehicles, mobile phones, personal computers, can be used, such as in a housing such as a video camera.
本発明のアパタイト結晶を主成分とする皮膜を有するマグネシウム材は、処理ままでも高い耐食性を示すが、さらに耐食性を向上させるために、あるいはマグネシウム材の美観性を向上させるために、必要に応じて塗装がなされる。 Magnesium material having film composed mainly of apatite crystals of the present invention exhibits a high corrosion resistance even while processing, in order to further improve the corrosion resistance, or to improve the aesthetics of the magnesium material, if necessary painting is made. 塗装に用いる塗料は特に限定されず、水系、溶剤系のいずれでもよい。 Paint used in painting is not particularly limited, water-based, it may be any of solvent-based. また、塗装方法も特に限定されず、浸漬塗装、スプレー塗装、電着塗装など公知のいずれの方法であってもよい。 Further, the coating method is not particularly limited, dip coating, spray coating, or may be any known method such as electrodeposition coating.

表1に示す、50mMのCa−EDTA/50mMのKH PO 水溶液に対して、0、1/40、1/20もしくは3/40の1N NaOH溶液を添加してpHを調整した溶液に、表面を0.1μmアルミナラッピングフィルムで仕上げた純マグネシウムを基材として浸漬し、95℃にて8時間静置し、試料A〜Dを作製した。 Shown in Table 1, with respect to aqueous KH 2 PO 4 of Ca-EDTA / 50 mM of 50 mM, the solution was adjusted to pH by addition of 1N NaOH solution 0,1 / 40,1 / 20 or 3/40, the pure magnesium finished with 0.1μm alumina lapping film surface was immersed as a substrate, and allowed to stand for 8 hours at 95 ° C., to prepare a sample to D.
図1に処理した試料A〜DのXRDパターンを示す。 It shows the XRD pattern of the sample A~D treated in FIG. いずれの試料においても、ヒドロキシアパタイト(HAp)およびMg(OH) (Brucite型)のピークが観察された。 In any of the samples, a peak of hydroxyapatite (HAp) and Mg (OH) 2 (Brucite-type) were observed. 処理溶液のpHの上昇にともないHApピーク強度は増加し、Mg(OH) (Brucite)ピーク強度は減少した。 HAp peak intensity with increasing pH of the treatment solution is increased, Mg (OH) 2 (Brucite ) peak intensity was decreased.
試料BおよびCの表面および断面の電子顕微鏡写真を図2〜5に示す。 The electron micrograph of the surface and cross section of Sample B and C shown in Figures 2-5. いずれの試料も表面をアパタイト結晶が均一に覆っていることが確認された。 It was confirmed that all samples surface apatite crystals are uniformly covered. アパタイトは径1μmから10μm程度の板状もしくは針状結晶であった。 Apatite was 10μm approximately plate-like or needle-like crystals from the diameter 1 [mu] m. 断面観察、EDS分析およびXRD測定より、処理皮膜はCa、PとO濃度が高いアパタイト結晶を主成分とする層と、OとMg濃度が高いMg(OH) が主成分の境界層で構成されていた。 Observation of the cross section from the EDS analysis and XRD measurement, treatment film Ca, composed of a layer mainly containing P and O concentration is high apatite crystals, O and Mg concentration is higher Mg (OH) 2 is the boundary layer of the main components It had been. 試料BのようにMg(OH) 境界層がSEM観察レベルでは明瞭に観察されないほど薄いか、もしくは存在しない試料もあった。 In Mg (OH) or second boundary layer is thin enough not clearly observed in the SEM observation level as in Sample B, or there does not exist the sample well. 形成された皮膜の厚さを表1に示す。 The thickness of the formed film shown in Table 1. 処理溶液のpHの上昇にともない、厚さが増加する傾向がみられた。 With increasing pH of the treatment solution, it tended to thickness increases.
これらの結果より、処理溶液のpH制御により、アパタイト結晶のサイズや皮膜の厚さを制御できることが示された。 From these results, pH control of the processing solution was shown to be capable of controlling the thickness of the size or coating of apatite crystals.

表2に示す、1N NaOHを1/40添加してpHを調整した50mMのCa−EDTA/50mMのKH PO 水溶液中に、実施例1と同様の表面仕上げをした純マグネシウムを基材として浸漬し、95℃にて24、96および168時間静置し、試料E〜Gを作製した。 Shown in Table 2, a 1N NaOH 1/40 added in aqueous KH 2 PO 4 of Ca-EDTA / 50mM of 50mM adjusted for pH, pure magnesium has a similar surface finish as in Example 1 as a substrate immersion, and allowed to stand 24, 96 and 168 hours at 95 ° C., to prepare a sample E to G. また、表2に示す、1N NaOHを1/20添加してpHを調整した50mMのCa−EDTA/50mMのKH PO 水溶液中に、実施例1と同様の表面仕上げをした純マグネシウムを基材として浸漬し、95℃にて2、4、16、24、96および168時間静置し、試料H〜Mを作製した。 Also, shown in Table 2, a 1N NaOH 1/20 added in aqueous KH 2 PO 4 of Ca-EDTA / 50mM of 50mM adjusted for pH, pure magnesium has a similar surface finish as Example 1 group immersed as wood, standing 2,4,16,24,96 and 168 hours at 95 ° C., to form sample h to M. 図6にpH7.1〜7.4溶液で処理した試料HおよびIのXRDパターンを、図7にpH7.1〜7.4溶液で処理した試料K〜Mの表面のXRDパターンを示す。 Samples H and I of the XRD patterns treated with pH7.1~7.4 solution 6 shows the XRD pattern of the surface of the sample K~M treated with pH7.1~7.4 solution in FIG. いずれの処理時間でもHApのピークが観察され、処理時間が長い試料ではMg(OH) (Brucite)のピークも観察された。 The peak of HAp any processing time observation, the processing time is long samples were observed peaks of Mg (OH) 2 (Brucite) . 一方、処理時間が2時間の試料HではMg(OH) (Brucite)のピークは観察されなかった。 On the other hand, the peak of the sample H in processing time 2 hours Mg (OH) 2 (Brucite) was observed.
処理時間の増加に伴いHApピークは先鋭になり、強度が大きく増加した。 HAp peaks with increasing processing time becomes sharp, the strength is greatly increased. Mg(OH) ピーク強度も処理時間の増加にともない増加した。 Mg (OH) 2 peak intensity also increased with the increase of the processing time. 一方、基材のマグネシウムピーク強度は、処理時間の増加にともない大きく減少した。 On the other hand, magnesium peak strength of the substrate is greatly decreased with the increase in processing time. pH6.1〜6.5溶液で処理した試料E〜Gにおいてもほぼ同様の結果が得られた。 pH6.1~6.5 substantially the same results also in the solution treated samples E~G was obtained.
試料の断面観察などにより求めた形成された皮膜の厚さを表2に示す。 The thickness of the film formed was determined by including samples of cross-sectional observation shown in Table 2. 1μmより薄い皮膜の厚さは処理時間と皮膜厚さの関係より求めた推測値である。 The thickness of the thin film than 1μm are estimated value determined from the relationship of the processing time and the film thickness. 処理時間が2時間と短い場合でも、図8 に示すようにアパタイト結晶は表面を均一に覆っており、処理時間が長くなるのにともない、アパタイト結晶層の厚さが増加する傾向がみられた。 Even if the processing time is 2 hours and short apatite crystals as shown in FIG. 8 is uniformly covers the surface, nor a for a longer processing time, the thickness of the apatite crystal layer tends to have seen increased . また、処理時間が96時間以上と長い場合では、アパタイト結晶の析出量は増加したが、基材表面から皮膜の一部又は全部が剥離する場合が多かった。 Further, in the case where the processing time is long and more than 96 hours, although the amount of precipitated apatite crystals increased, some or all of the coating from the substrate surface in many cases of peeling.
これらの結果は、処理時間が短くてもアパタイト結晶層を作製できること、および処理時間を変化することによりアパタイトの結晶の析出量を変化させて膜厚を調整できることを示している。 These results show that it is possible to adjust the processing time can be manufactured shorter in apatite crystal layer, and processing the film thickness by changing the amount of precipitation of crystals of apatite by varying the time. しかし、処理時間が長すぎて皮膜厚さが50μmを超えると皮膜の剥離の原因になることがわかった。 However, the film thickness of the processing time is too long it has been found that cause peeling of the film exceeds 50 [mu] m.

表3に示す、250mMのCa−EDTA/250mMのKH PO 水溶液に1/40、1/20もしくは3/40の1N NaOH溶液を添加してpHを調整した溶液中に、実施例1と同様の表面仕上げをした純マグネシウムを基材として浸漬し、95℃にて8時間静置し、試料N〜Pを作製した。 Shown in Table 3, the solution was adjusted to pH by addition of 1N NaOH solution 1/40, 1/20 or 3/40 in aqueous KH 2 PO 4 of 250mM of Ca-EDTA / 250mM, Example 1 pure magnesium has a similar surface finish was immersed as a substrate, and allowed to stand for 8 hours at 95 ° C., to prepare a sample N~P. 本処理溶液中のリン酸イオンおよびカルシウムイオン濃度は、実施例1および実施例2で使用した溶液の5倍である。 Phosphate ion and calcium ion concentration of the processing solution is 5 times the solution used in Example 1 and Example 2.
図9に処理した試料N〜PのXRDパターンを示す。 It shows the XRD pattern of the sample N~P treated in FIG. いずれの試料においても、HApのピークが観察された。 In any of the samples, a peak of HAp was observed. 処理溶液のpHの上昇にともない、HApピーク強度が増加した。 With increasing pH of the treatment solution, HAp peak intensity was increased. Mg(OH) (Brucite)のピークは試料OおよびPでは観察されたが、処理溶液のpHが比較的低い試料Nでは明瞭に観察されなかった。 Peaks of Mg (OH) 2 (Brucite) has been observed in Sample O and P, pH of the treatment solution was observed relatively low sample N in clearly. また、試料OおよびPのMg(OH) のピークは試料A〜Dに比較して非常に小さかった。 Moreover, Mg (OH) 2 peak samples O and P were very small compared to the sample to D. これより、カルシウムイオンおよびリン酸イオン濃度が高い溶液中では、水酸化マグネシウム層は形成されにくいことが示された。 Than this, the calcium ion and phosphate ion concentration higher solution showed that the magnesium hydroxide layer is formed difficult. 形成された皮膜の厚さを表3に示す。 The thickness of the formed film shown in Table 3.
実施例1で50mMのCa−EDTA/50mMのKH PO 溶液で処理した表面と比較すると、HApピーク強度は250mMの溶液中における方が高い傾向がみられた。 Compared with KH 2 PO 4 solution treated surfaces of Ca-EDTA / 50mM in 50mM in Example 1, HAp peak intensity is high tendency towards the 250mM solution in was observed. 一方、Mg(OH) ピーク強度は、250mMの溶液中における方が小さい傾向がみられた。 On the other hand, Mg (OH) 2 peak intensity, a tendency toward the 250mM solution in small was observed.
これらの結果は、処理溶液中のリン酸イオンおよびカルシウムイオン濃度の増加により、アパタイト結晶の析出量を増加できること、および境界層のMg(OH) 層の成長を抑制できることを示している。 These results are processed by an increase of phosphate ions and calcium ions concentration in the solution, indicating that can increase the amount of precipitated apatite crystals, and the boundary layer of the Mg (OH) can suppress the growth of two layers.

表4に示す、pHを調整した50mMのCa−EDTA/50mMのKH PO 水溶液中に、表面を0.1μmアルミナラッピングフィルムで仕上げたAZ31合金、AZ61合金、AZ91合金およびMg−1.0Al合金を基材として浸漬し、95℃にて8時間静置し、試料Q〜Tを作製した。 Table 4 shows, pH in KH 2 PO 4 in an aqueous solution of Ca-EDTA / 50mM the adjusted 50mM the, AZ31 alloy finished surface at 0.1μm alumina lapping films, AZ61 alloy, AZ91 alloy and Mg-1.0Al alloy was immersed as a substrate, and allowed to stand for 8 hours at 95 ° C., to prepare a sample Q-T. 図10に試料Q〜TのXRDパターンを示す。 It shows the XRD pattern of the sample Q~T Figure 10. いずれの試料でもHApのピークが観察された。 Peak of HAp was observed in any of the samples. AZ系合金の場合、合金中のAl濃度が増加するにともない、HApの基材合金に対する相対ピーク強度が増加した。 For AZ-based alloy, with the increase of Al concentration in the alloy, the relative peak intensity to the substrate alloy HAp increased. 一方、Mg(OH) (Brucite)の明瞭なピークは観察されなかった。 On the other hand, clear peaks of Mg (OH) 2 (Brucite) was observed. これより、基材の種類によって水酸化マグネシウム層の形成されやすさが異なることが示された。 From this, forming the easiness of the magnesium hydroxide layer on the type of substrate is shown to be different. 皮膜の厚さを表4に示す。 The thickness of the film are shown in Table 4. 基材合金の種類により皮膜の厚さが変化した。 The thickness of the coating is changed by the type of substrate alloy.
これより、基材であるマグネシウム合金の組成にかかわらず、本発明の処理により表面にアパタイト結晶を主成分とする皮膜を形成できることが明らかになった。 From this, regardless of the composition of the magnesium alloy as the substrate, it was clarified that can form a film composed mainly of apatite crystals on the surface by treatment of the present invention.

表5に示すCa/P比をHApと同様の1.67になるようにCa−EDTAおよびKH PO 濃度を決めた水溶液中に、表面を0.1μmアルミナラッピングフィルムで仕上げた純マグネシウムを基材として浸漬し、95℃にて8時間静置し、試料U〜Wを作製した。 The Ca / P ratio shown in Table 5 in an aqueous solution decided Ca-EDTA and KH 2 PO 4 concentration so that the same 1.67 and HAp, pure magnesium finished with 0.1μm alumina lapping film surface It soaked as a substrate, and allowed to stand for 8 hours at 95 ° C., to form sample U to W. 図11に試料U〜WのXRDパターンを示す。 It shows the XRD pattern of the sample U~W Figure 11. カルシウムイオン濃度が1mMの時にはHAp(002)面に由来するピーク以外は痕跡程度のHApピークしか現れなかったが、カルシウムイオン濃度の増加にともないHApピークは増加した。 Although calcium ion concentration at the time of 1mM except peak derived from the HAp (002) plane did not appear only HAp peaks of a trace, HAp peaks with increasing calcium ion concentration increased. これより、HAp結晶化を阻害するマグネシウムが主成分である材料表面にアパタイト結晶を主成分とする皮膜を形成するには、処理溶液中のカルシウムイオンおよびリン酸イオン濃度が高い方がよりよいことが示された。 From this, in order to form a film of magnesium to inhibit HAp crystallization mainly of apatite crystals on the surface of the material being the main component, the higher is the calcium ion and phosphate ion concentration in the processing solution to be better It has been shown. また、カルシウムイオンおよびリン酸イオン濃度が低い試料UおよびVでは、Mg(OH) の明瞭なピークは得られなかった。 Further, the calcium ion and phosphate ion concentration is lower samples U and V, clear peaks of Mg (OH) 2 was obtained. これより、水酸化マグネシウム層の存在は処理溶液中のカルシウムイオンおよびリン酸イオン濃度に依存することが示された。 From this, the presence of magnesium hydroxide layer was shown to be dependent on calcium ion and phosphate ion concentration in the processing solution.

表1および表2に示す、試料C、J、Kおよび研磨まま試料の表面に1g/m のNaClを付着させ、室温下で、相対湿度を55%から95%、再び55%に8時間周期にて制御し、合計96時間の乾湿繰り返し試験を行った。 Shown in Table 1 and Table 2, sample C, J, depositing the K and polishing remain on the surface of the sample of 1 g / m 2 NaCl, at room temperature, 8 hours and 95% relative humidity from 55%, again 55% and controlled by the cycle, it was dry-wet cycle test of a total of 96 hours. 比較材の研磨試料は、0.1μmアルミナラッピング仕上げの試料である。 Polishing the sample of Comparative material is a sample of 0.1μm alumina lapping. ここで、1g/m というNaCl付着量は海浜地域でのNaCl付着量に近く、腐食環境としては非常に過酷である。 Here, NaCl coating weight of 1 g / m 2 is close to NaCl deposition amount in coastal areas, is a very severe as corrosive environment. 本試験で腐食がみられても、必ずしも実環境で腐食がおこるとは限らない。 Even if corrosion was observed in this study, does not necessarily corrosion occurs in the real environment.
図12〜図15に96時間の乾湿繰り返し試験後の試料C、J、Kおよび研磨まま試料表面から、表面処理層と腐食生成物を除去した表面の写真を示す。 Sample C after dry-wet cycle test of 96 hours in FIGS. 12 to 15, J, K and polished while the surface of the sample, showing a photograph of the surface to remove the surface treatment layer corrosion product. 96時間試験後の試料CおよびKでは端の方に小さな糸状腐食が発生していたが、試料Jでは顕著な腐食はみられなかった。 Small filiform corrosion had occurred towards the end the samples C and K after 96 hours the test, but the sample J significant corrosion was observed. 一方、研磨まま試料はほぼ全面が糸状腐食に覆われていた。 On the other hand, the polishing while the samples had almost the entire surface covered by the filiform corrosion. これより、本発明における表面処理により、大気腐食に対する耐食性が十分に得られることが明らかになった。 Than this, the surface treatment in the present invention, it was found that corrosion resistance against atmospheric corrosion can be sufficiently obtained. また、5μmよりも薄い皮膜でも、十分な耐食性を示すことがわかった。 Also, a thin film than 5 [mu] m, was found to exhibit a sufficient corrosion resistance.

表1および表2に示す、試料C、J、Kおよび研磨まま試料を、室温の3.5wt% NaCl溶液中でアノード分極した。 Shown in Table 1 and Table 2, sample C, J, K and polishing while samples were anodically polarized in 3.5 wt% NaCl solution at room temperature. NaCl濃度3.5wt%は、海水と同等の塩類濃度である。 NaCl concentration of 3.5wt% is the equivalent of the salt concentration and seawater. 試料C、J,Kおよび研磨まま試料の分極曲線を図16に示す。 Sample C, J, polarization curves K and polishing while samples are shown in Figure 16. 電位−1.45V(SCE)におけるアノード電流密度を図17および表6にまとめる。 Summarized anode current density at a potential -1.45V (SCE) in FIG. 17 and Table 6. 研磨まま試料は分極開始直後から急激に電流密度が増加し、10mA/cm より大きなアノード電流密度を示したのに対し、本発明の皮膜を有するマグネシウム材は腐食電位付近に数十mVの電位幅の疑似不働態域が存在し、皮膜破壊による電流密度の急激な増加が起こった後も、1mA/cm よりも低い電流密度を示した。 Polishing while samples rapidly current density increases immediately after the start of the polarization, 10 mA / contrast showed a large anode current density than cm 2, magnesium material having the coating of the present invention is several tens mV potential in the vicinity of the corrosion potential there is pseudo passive zone width, even after the occurred a sudden increase in current density by coating fracture showed lower current density than 1 mA / cm 2.
これらの結果より、海水と同等の濃度のNaClを含む水溶液中であっても、本発明の皮膜を有するマグネシウム材は高い耐食性を示すことが明らかになった。 From these results, even in an aqueous solution containing NaCl of seawater equivalent concentrations, the magnesium material having the coating of the present invention it was found to exhibit high corrosion resistance. また、水溶液中での腐食に対しては、皮膜が厚い方が高い耐食性を示すことがわかった。 Further, with respect to corrosion in an aqueous solution, it was found that better coating thicker exhibit high corrosion resistance.

表1および表2に示す、試料H、I、Cおよび研磨まま試料表面に水性エポキシ塗料を塗布し、クロスカット試験(JIS K 5600―5―6)を行った。 Shown in Table 1 and Table 2, samples H, I, a water-based epoxy paint C and polished while the surface of the sample was applied was subjected to a cross cut test (JIS K 5600-5-6). JIS規格の分類法にのっとって、塗装の剥離の割合を評価した。 And Ho' the classification method of JIS standard, was to evaluate the proportion of peeling of paint. 試験結果を表7にまとめる。 The test results are summarized in Table 7. 研磨まま表面の結果が分類3であったのに対し、試料Iの結果は分類2であった。 While the results of the polishing while the surface was classified 3, the results of sample I was classified 2. 本発明の皮膜の存在により、塗料との付着性が向上することが明らかとなった。 The presence of the film of the present invention, adhesion to the paint was found to improve. また、水性エポキシ塗料との付着性は皮膜の厚さに依存し、1から2μmが望ましいことが示された。 Further, adhesion between the water-based epoxy coating depends on the thickness of the coating was shown to be 2μm from 1 desirable.

WO2003/080897 WO2003 / 080897 特開平11―131225 JP-A-11-131225 特開2003―286582 Patent 2003-286582 特開2003―3237 JP 2003-3237 特開2005―281717 Patent 2005-281717 特開平6−220663 JP-A-6-220663

Claims (4)

  1. マグネシウム又はマグネシウム合金を基材とし、所望の構造形状に成形されてなるMg基構造部材であって、 Magnesium or magnesium alloy as a base material, an Mg-based structural member formed is molded into the desired structural configuration,
    前記基材の表面がアパタイト結晶を主成分とする皮膜により覆われており、 Surface of the substrate is covered by film composed mainly of apatite crystals,
    前記皮膜と基材とが水酸化マグネシウム層を介して一体化されてなり、 The coating and the substrate is being integrated via a magnesium hydroxide layer,
    前記皮膜の厚さが1〜5μmであることを特徴とするMg基構造部材。 Mg-based structural member the thickness of the coating, characterized in 1~5μm der Rukoto.
  2. 請求項1に記載のMg基構造部材において、前記皮膜の表面が、樹脂塗料により塗装されてなることを特徴とするMg基構造部材。 In Mg-based structure according to claim 1, the surface of the coating, Mg group structural member, characterized in that formed by coating a resin coating material.
  3. 請求項1 又は2に記載のMg基構造部材の製造方法であって、 A method of manufacturing a Mg based structure according to claim 1 or 2,
    所望の形状に成形された前記基材を、リン酸イオンおよび過飽和状態で溶解している非塩化物系カルシウムイオンを含む水溶液中に浸漬して、前記基材の表面にアパタイト結晶を主成分とする皮膜を析出させることを特徴とするMg基構造部材の製造方法。 It said base material molded into the desired shape, is immersed in an aqueous solution containing a non-chloride-based calcium ions dissolved in the phosphate ion and supersaturated, and composed mainly of apatite crystals on the surface of the substrate method for producing a Mg-based structural member, characterized in that to deposit a coating that.
  4. 請求項に記載のMg基構造部材の製造方法において、 The method of manufacturing a Mg based structure according to claim 3,
    前記水溶液のカルシウムイオンはカルシウムキレート化合物の溶解により得られたものであることを特徴とするMg基構造部材の製造方法。 Method for producing a Mg-based structural member, wherein the calcium ions of the aqueous solution is obtained by dissolving calcium chelate compound.
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