JP2004149910A

JP2004149910A - Color-developed film, and production method therefor

Info

Publication number: JP2004149910A
Application number: JP2002319681A
Authority: JP
Inventors: Norio Kikukawa; 範夫菊川; Norio Nakada; 紀夫中田; Hironobu Wakasa; 裕信若狭; Shinsaku Matsuki; 晋策松木
Original assignee: YKK Corp
Current assignee: YKK Corp
Priority date: 2002-11-01
Filing date: 2002-11-01
Publication date: 2004-05-27

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating film which has a noble feeling because of the mixing of a uniformly developed interference color with a vivid and strong hue and a material color of noble metal, and also has excellent durability and corrosion resistance, and to provide a production method therefor. <P>SOLUTION: The surface of a plating film (1) of noble metal is provided with a metal oxide film (4) by metal other than noble metal contained in the plating film (1), and the surface color combining an interference color owing to the metal oxide film (4) and a material color with a noble metal feeling characteristic of the noble metal plating film (1) is given. The metal oxide film consists of one or more metals I selected from Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W and Y. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は貴金属メッキ等を施す高級品に適用される新規の金属表面処理に関し、更に詳しくは例えばエントランスやドアノブなどの建材関連部品、スライダー、上下止めその他のファスナー部品、スナップボタンなどのファスニング分野、ブローチ、イヤリング、指輪、ペンダントなどの装飾品、或いは靴やバッグ類の装飾用部品等、多様な分野に適用できる高級感があり且つ耐用性と耐蝕性に優れた新規な表面処理技術に関する。
【０００２】
【従来の技術】
従来のメッキ色は、多くのものは淡灰色や銅色の金属色であり、或いは真鍮メッキ、金メッキによる黄金色に限定されている。また着色メッキとしては、Ｓｎ−Ｎｉ系メッキ等よる黒色メッキの他、有彩色を得る方法としてメッキの上に着色クリアー塗装を行う方法や、メッキ膜を硫化物により染色する方法がある。
【０００３】
メッキを化学的に着色する方法としては、銅メッキを硫化物で処理する方法（特公昭６１−１５１５３号公報）、ニッケルメッキを硝酸で処理する方法（特公昭６２−３０２６３号公報）、またクロメート処理を施し、干渉色を得る方法も（特公昭６０−２０４６７号公報）などが提案されている。更に、熱処理により色を得る方法としては、クロムメッキの熱処理（特開昭６０−８２６７７号公報）の他に、銅やニッケル等の金属において酸化膜を形成することが知られている。
【０００４】
上記特公昭６１−１５１５３号公報による着色方法は、銅製又は銅メッキ処理の施された素材の銅表面を、硫化アンモン水溶液に硫化カリ及び塩化アンモンを添加した混合水溶液に浸漬して黒褐色に着色するものであり、着色液の寿命が延び、着色力及び均一着色性を損なわず、干渉色が出にくくなるというものである。これに対して、特公昭６０−２０４６７号公報は２０重量％以下のニッケルを含有する亜鉛−ニッケル合金メッキ製品をクロメート処理するにあたり、Ｃｒ^６＋濃度が０．５〜１００ｇ／ｌ、ＳＯ_４ ^２−濃度とＣｒ^６＋濃度との比の値を０．０２５〜１．５、ｐＨ１．３〜２．７の処理液を用いて処理し、耐塩水性及び耐蝕性に優れた美しい虹色の干渉色を得ている。また、特開昭６０−８２６７７号公報では、金属ベース板にニッケルメッキを施し、しかる後に強制的にニッケルの酸化皮膜を形成して、その干渉色で発色させている。このとき、その酸化皮膜の膜厚を制御して赤色、黒色、茶色、緑色等のカラーを得ることができる。
【０００５】
【特許文献１】
特公昭６１−１５１５３号公報
【特許文献２】
特公昭６０−２０４６７号公報
【特許文献３】
特公昭６２−３０２６３号公報
【特許文献４】
特開昭６０−８２６７７号公報
【０００６】
【発明が解決しようとする課題】
しかしながら、上述の単なるメッキ法で得られるメッキ色は、既述したとおり限られたものとなる。更に黒色メッキや染色法では、メッキ表面の摩擦により色が脱落しやすく、また塗装法はキズに弱いという欠点もあり、いずれの方法も耐久性に乏しく、また硫化物による染色法では、有彩色は得られるものの、高級感に乏しく、貴金属感と有彩色を兼ね備えた発色を得ることができない。
【０００７】
一方、上述のような化学処理方法では、ほとんどが黒色、黒褐色を得る方法であるに過ぎず、鮮やかで様々な有彩色は得られない。クロメート処理は、鮮やかな干渉色は得られるものの、濃い色を得にくく、また環境の面からも、近年クロムの使用が規制される方向にあり、大量に使用することは好ましくない。
【０００８】
上記特許文献４によるニッケルメッキの酸化皮膜の形成により干渉色を得る方法は、単一成分からなるメッキを熱処理し、その表面に酸化皮膜を形成する方法である。しかしながら、この方法では酸化膜厚が薄い場合は、酸化膜表面近傍では均一な酸化膜が形成され、薄い色の干渉膜が得られるが、更に熱酸化を続けた場合、酸化膜が厚くなり、メッキ膜が単一成分であるがゆえにムラのある酸化膜が形成される。これにより干渉色もムラのある色あいとなり、装飾などの実用には耐え得ない。
【０００９】
本発明は、こうした従来のメッキでは期待できない、均一に着色された有彩色を兼ね備えた高級感を持つメッキ膜とその製造方法を提供することを第１の目的としている。また第２の目的は、色の脱落がしにくく且つキズに強く耐食性、耐久性に優れたメッキ膜とその製造方法を提供することにある。更には、第３の目的として熱処理条件によって、酸化膜の厚さを変えることにより、貴金属感をもち殆ど全ての有彩色を発色する高級感に溢れたメッキ膜とその製造方法を提供することにある。
【００１０】
【課題を解決するための手段及び作用効果】
本発明の発色メッキ膜とその製造方法には、大別して３態様がある。その１は、貴金属のメッキ膜の表面に同メッキ膜に含有される貴金属以外の金属による金属酸化膜を有し、同金属酸化膜による干渉色と、前記貴金属メッキ膜に特有な貴金属感の物質色とを兼ね備えた表面色を発現してなることを特徴とする発色メッキ膜と、その製造方法である。このときの貴金属のメッキ膜の母材Ｂは、金属母材であるか、プラスチック母材であるか、その材質は問わない。そして、前記金属酸化膜への入射光と同酸化膜の表面の反射光とが干渉するとともに、その干渉光には貴金属メッキ膜の表面の反射光が複合化されて、金属酸化膜による干渉色と、前記貴金属メッキ膜に特有な貴金属感の物質色とを兼ね備えた表面色を発色する。金属酸化膜は、硬度が増加するとともに、耐蝕性にも優れ、キズにも強く、耐久性が向上する。
【００１１】
前記貴金属のメッキ膜は、貴金属を主成分として、Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｔｉ，Ｖ，Ｃｒ，Ｚｎ，Ｎｂ，Ｍｏ，Ｗ，Ｙから選ばれる１以上の金属Ｉを含んだ合金からなり、前記金属酸化膜が貴金属に含まれる金属Ｉの酸化膜からなる。すなわち、本発明による貴金属メッキ膜に含まれる金属は、外部エネルギーが与えられると、表層へと移動しやすく、且つ外部の酸素と結合しやすい上記金属Ｉから選ばれる一種以上の金属であることが好ましい。また、貴金属の表面に金属酸化膜を形成する金属を直接メッキする場合と比較すると、その膜厚にムラがなく極めて均一に形成されるようになる。そのため、いわゆる玉虫色ではなく、その金属酸化膜の膜厚を制御することにより、膜厚と入射する光の波長に基づく干渉色、すなわち７色に連続して変化する多様な色を独立して発色させることができるようになる。
【００１２】
前記貴金属のメッキ膜は、次の一般式（ｉ）にて示される合金からなることが好ましい。
ＡａＸｂ ……（ｉ）
但し、Ａは貴金属の内の一種の元素、Ｘは金属Ｉから選ばれる少なくとも一種の元素、ａ，ｂはそれぞれ重量％で、ａはメッキ膜の全重量に対するｂとの差分、ｂは金属Ｉとそれ以外の不可避的元素を含み、０≦ｂ≦５の範囲である。ここで、金属Ｉから選ばれる少なくとも一種の元素Ｘと不可避的元素の量が５％を越えると、貴金属特有の物質色が薄くなり、得られるメッキ膜の発色から貴金属特有の色が失われ、貴金属感も失われる。
【００１３】
前記貴金属のメッキ膜の膜厚が１μｍ〜５μｍ、金属酸化膜の膜厚が３５ｎｍ〜２４０ｎｍであることが好ましい。貴金属メッキ膜の膜厚が１μｍより薄いとメッキが施されるベース部材の色の影響が出て、貴金属感に乏しくなり、５μｍを越えるとコスト高になる。金属酸化膜（４）が上記膜厚の範囲にあるとき、太陽光の７色とそれらに連続する色を独立して発現させることができる。
【００１４】
更に本発明の製造方法にあっては、前述のようにして母材の表面に前記貴金属メッキ膜を形成した後に、２３０℃以上の酸素雰囲気中で１０分以上の熱処理条件下で熱処理を行うことを特徴としている。この熱処理条件のうち適正な条件を選択して熱処理を行うことにより、所望の膜厚が得られ、任意の色を発色するメッキ膜が得られる。熱処理温度が２３０°より低いと、貴金属中に含まれる金属元素Ｘの移動が遅く、所望の金属酸化膜の膜厚を得るために長時間を要する。より好ましくは、前記熱処理条件を２５０℃〜３３０℃、３０分〜６時間の酸素雰囲気とする。このとき、前記熱処理条件を制御することにより、金属酸化膜の膜厚を３５ｎｍ〜２４０ｎｍに形成する。
【００１５】
本発明の第２の態様による発色メッキ膜は、Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｔｉ，Ｖ，Ｃｒ，Ｚｎ，Ｎｂ，Ｍｏ，Ｗ，Ｙから選ばれる１以上の金属Ｉの表面又は同金属Ｉを含む金属メッキ膜の表面に形成される貴金属メッキ膜を有する層状金属メッキ膜と、前記貴金属メッキ膜の表面に形成され同メッキ膜に含有する前記金属Ｉから生成された金属酸化膜とを有しており、同金属酸化膜による干渉色と、前記貴金属メッキ膜に特有の貴金属感の物質色とを兼ね備えた表面色を発色することを特徴とする発色メッキ膜を基本構成としている。
【００１６】
本発明では、金属Ｉの表面又は同金属Ｉを含む金属メッキ膜の表面に貴金属のメッキ膜を形成し、更にその表面に金属酸化膜を形成している。この金属酸化膜は、熱処理条件が２００℃以上の酸素雰囲気中で、１０分以上の熱処理を行うことにより、金属Ｉの元素が貴金属メッキ中を表面に向けて移動し、同貴金属メッキの表面にて雰囲気酸素と結合して形成される。より好ましくは、２３０℃〜２９０℃の酸素雰囲気中、０．５〜５時間にて熱処理を行う。前記金属酸化膜の膜厚は、処理条件である温度と時間とを調整することにより任意の厚みに形成することができる。本発明にあっても、金属酸化膜の膜厚に基づく多彩な干渉色と貴金属メッキ膜の物質色とが混合した貴金属感に優れ高級感のある独立した色を発色する。勿論、表面の酸化膜による耐久性及び耐蝕性にも優れたものが得られる。
【００１７】
この発明にあっても、前記金属メッキ膜を以下の一般式（ｉ）で示される金属からなり、同金属メッキ膜（２）の表面に形成される貴金属メッキ膜（３）を以下の一般式（ｉｉ）で示される金属からなる構成することが好ましい。
ＡａＸｃ……… （ｉ）
ＡａＸｄ……… （ｉｉ）
但し、Ａは貴金属のうちから選ばれる一種の元素、Ｘは金属Ｉから選ばれる少なくとも一種の元素、ａ，ｃ，ｄは重量％で、ａは各メッキ膜ごとの全重量に対するｃ及びｄとのそれぞれの差分、ｃ，ｄは各メッキ膜ごとの金属Ｉとそれ以外の不可避的元素を含み、０＜ｃ＜１００及び０≦ｄ≦５の範囲にある。
【００１８】
金属メッキ膜の膜厚を０．１μｍ以上、貴金属メッキ膜の膜厚を３μｍ以下、金属酸化膜（４）の膜厚を３５ｎｍ〜２４０ｎｍとすることが好ましい。金属メッキ膜の膜厚が０．１μｍよりも薄いと、金属Ｉから選ばれる１以上の元素が貴金属メッキ膜の表面に十分に析出されず、所望の膜厚の金属酸化膜が形成されない。
【００１９】
本発明の発色メッキ膜の第３の態様は、Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｔｉ，Ｖ，Ｃｒ，Ｚｎ，Ｎｂ，Ｍｏ，Ｗ，Ｙから選ばれる１以上の金属Ｉを含みかつ金属Ｉの濃度がメッキ膜下面から表面に向かって濃度が低くなる傾斜貴金属メッキ膜であって、その傾斜貴金属メッキ膜の表面に、同メッキ膜に含まれる前記金属Ｉから生成される金属酸化膜を有しており、金属酸化膜による干渉色と、傾斜貴金属メッキ膜の特有の貴金属感の物質色を兼ね備えた表面色を発色してなることを特徴とする基本構成を備えている。
【００２０】
かかる構成により、上述と同様の熱処理を行うと、傾斜貴金属メッキ膜中において金属Ｉから選ばれた１以上の元素が表面に向けて活発に移動するようになり、短時間で傾斜貴金属メッキ膜の表面に所望の膜厚をもつ金属酸化膜が得られる。
【００２１】
本発明にあっては、前記傾斜貴金属メッキ膜の下面に、更に下部メッキ膜を形成しておいてもよい。前記下部メッキ膜は次の一般式（ｉｉｉ）で示される金属からなり、前記傾斜貴金属メッキ膜は、次の一般式（ｉｖ）で示される金属からなることが好ましい。
ＡａＸｅ……… （ｉｉｉ）
ＡａＸｆ……… （ｉｖ）
但し、Ａは貴金属のうちから選ばれる一種の元素、Ｘは金属Ｉから選ばれる少なくとも一種の元素、ａ，ｅ，ｆは重量％を示し、ａは各メッキ膜ごとの全重量に対するｅ及びｆとのそれぞれの差分、ｅ，ｆは各メッキ膜ごとの金属Ｉとそれ以外の不可避的元素を含み、１０≦ｅ≦１００、０≦ｆ≦１０の範囲にある。
【００２２】
本発明にあっても、上述の理由と同様の理由により、下部メッキ膜の膜厚を０．５μｍ以下、上部傾斜貴金属メッキ膜の膜厚を０．５μｍ以下、金属酸化膜の膜厚を３５ｎｍ〜２４０ｎｍとすることが好ましい。
【００２３】
こうした発色メッキ膜は、貴金属のうちの一種とＦｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｔｉ，Ｖ，Ｃｒ，Ｚｎ，Ｎｂ，Ｍｏ，Ｗ，Ｙから選ばれる１以上の金属Ｉとを含み、次の一般式（ｉｉｉ）で示される金属からなる下部メッキ膜（８）を形成し、その表面に次の一般式（ｉｖ）で示され、金属Ｉの濃度がメッキ膜下面から表面に向かうにつれ濃度が低くなる傾斜貴金属メッキ膜（９）を形成したのち、これらの下部メッキ膜（８）及び上部の傾斜貴金属メッキ膜（９）を２００℃〜２９０℃の酸素雰囲気中にて３０分〜５時間で熱処理を行うことにより得ることができる。
ＡａＸｅ……… （ｉｉｉ）
ＡａＸｆ……… （ｉｖ）
但し、Ａは貴金属のうちから選ばれる一種の元素、Ｘは金属Ｉから選ばれる少なくとも一種の元素、ａ，ｅ，ｆは重量％を示し、ａは各メッキ膜ごとの全重量に対するｅ及びｆとのそれぞれの差分、ｅ，ｆは各メッキ膜ごとの金属Ｉとそれ以外の不可避的元素を含み、１０≦ｅ≦１００、０≦ｆ≦１０の範囲にある。
【００２４】
前記傾斜貴金属メッキ膜は、メッキ初期に低電流密度とし、連続又は不連続に電流密度を高くし、同じメッキ浴内にて行うことにより形成する。貴金属との合金メッキにあって、上記貴金属元素Ａの成分濃度はメッキ浴中の電流密度の変化に応じて変化する。すなわち、貴金属元素の濃度は電流密度が高いと高濃度となり、電流密度を低くするとその濃度も低くなる。従って、メッキ浴中の電流密度を制御することにより、任意の傾斜濃度をもつ傾斜貴金属メッキを効率的に形成することができる。
上記製造方法にあって、その酸素雰囲気中の酸素分圧は１ＭＰａ〜１０ＭＰａとすることが好ましいが、通常は大気圧の下で行われることが多い。
【００２５】
【発明の実施形態】
以下、本発明の代表的な実施形態に基づく発色メッキ膜の組成及び製造条件をを図面に基づいて具体的に説明する。なお、以下の実施形態では、貴金属として代表的な金属である金（Ａｕ）を例に挙げて説明するが、他の白金族（Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ）や銀を金に置き換えても同様であるため、それらの説明は省略する。
【００２６】
図１は本発明の第１実施形態による発色メッキ膜の構成を示している。
この実施形態によれば、母材Ｂの表面に金メッキ膜１が形成され、その表面に金属酸化膜４が形成されている。この金属酸化膜４は干渉膜として機能し、金メッキ膜１のもつ金色と金属酸化膜４から発する干渉色とが混じって、貴金属感と鮮やかな有彩色を同時に感じる従来にない新しい色を発色する。
【００２７】
前記母材Ｂには通常金属の他にも各種のプラスチックや木質材などであって、その材質は限定されない。また、前記金属酸化膜４は、金メッキに含まれる合金成分の金属酸化物からなり、Ｆｅ，Ｃｏ，Ｎｉ，ＣｕＴｉ，Ｖ，Ｃｒ，Ｚｎ，Ｎｂ，Ｍｏ，Ｗ，Ｙで表される金属Ｉの一種又は二種以上からなる。金メッキ膜１には種々の金属が添加されるが、本発明では酸素に比較的活性で熱処理により容易に酸化物を生成できる金属Ｉを用いる。金属酸化膜４は金メッキ膜１に対し熱処理を行うことにより形成される。また、この金属酸化膜４は下地の金メッキ膜１に含まれる金属Ｉから生成された酸化物であるため、この金属酸化膜４は金メッキ膜１との密着性が非常に高く、また酸化皮膜であることから耐久性、耐食性にも優れている。
【００２８】
前記熱処理時の処理条件は、処理温度を２３０℃以上、好ましくは２５０℃〜３３０℃に設定し、熱処理時間は１０分以上、好ましくは３０分〜６時間をかけて酸素雰囲気中にて、熱処理するものである。金属酸化膜４は比較的低い温度でも形成されるが、均一で鮮やかな干渉色を安定して得るには、金属酸化膜４を形成する金メッキ膜１中の合金成分が、十分金メッキ膜１の表面に供給される必要がある。すなわち、本発明では、干渉色を発する金属酸化膜４の形成と熱拡散による金メッキ膜１中の合金成分の移動が同時に行われる条件が必要である。そのため、この熱処理温度は２３０℃以上必要であり、２５０℃〜３３０℃では安定して金属酸化膜４が形成される。処理時間は目的の色合いに応じて変化させるが、発色には１０分以上が必要であり、０．５時間〜６時間の処理にて干渉作用による一連の発色が可能である。これ以上の処理も可能ではあるが、干渉色の性質上、同様の発色が繰り返されるにすぎない。
【００２９】
金メッキ膜１中の合金成分は酸化膜形成に必要な十分な濃度がなければならない。しかしながら、濃度が大きいと電解メッキにおいて金メッキ膜厚の成長を阻害し、また耐食性も悪くなる恐れがあるので濃度は０．５〜５％が好適である。
【００３０】
メッキ膜厚は、合金成分が安定して供給されるために必要な厚さが要求される。すなわち、あまり薄い膜厚では、合金成分を多くしても、金属酸化膜の形成は起こらない。逆に厚すぎると熱拡散による合金成分の供給が安定せず色ムラが発生しやすいため、好適な金メッキ膜厚は１μｍ〜５μｍである。また、酸化膜厚は３５ｎｍ〜２４０ｎｍが好適である。酸化膜厚が３５ｎｍより少ないと干渉色が発色しない。また２４０ｎｍより多いと酸化膜自体の色が発現し始め、鮮やかな干渉色が得られなくなる。
【００３１】
単一成分のメッキ膜、例えばＣｒやＮｉからなるメッキ膜を熱処理して発色させ、干渉色を得る場合、均一な色を得るために、酸素分圧を低くして行うが、本発明では金メッキ膜を介して合金金属の酸化による干渉膜を形成するため、酸素分圧が如何ようであっても発色は安定して行われるが、その好適条件は１ＭＰａ〜１０ＭＰａある。しかして、通常の発色は大気下にて行うのが好ましい。
【００３２】
次に、図２を参照して本発明の第２の実施形態について説明する。
この第２実施形態は、金属Ｉが含有している金属メッキ膜２の表面に金メッキ膜３を施した層状金属メッキ膜６からなり、その金メッキ膜３の表面に層状メッキ膜６に含まれる金属Ｉから生成される金属酸化膜４をもち、金属Ｉの酸化膜による干渉色と、金メッキ膜３に特有な物質色を兼ね備えもつことを特徴としている。この実施形態による金メッキ膜３は、金属酸化膜４の金属供給源となる金属メッキ膜２を金メッキ膜３の下層に有することにより、図１に示した第１実施形態の発色メッキ合金膜より鮮やかな強い色合いとなる。
【００３３】
金属酸化膜４は、層状金属メッキ膜６に含まれる合金成分の酸化物であり、上述の金属Ｉの一種又は二種以上の酸化物からなる。これは金メッキ膜３と金属メッキ膜２に含有されている金属であり、第１実施形態と同様に、酸素に対して比較的活性で熱処理により酸化物を生成できる金属Ｉを用いる。また、この金属酸化膜４は下地の層状金属メッキ膜６から形成された酸化膜であるため、下地のメッキとの密着性が非常に強く、また酸化皮膜であることから耐久性、耐食性にも優れている。
【００３４】
この実施形態にあって、その熱処理の好適条件は、２００℃以上好ましくは２３０℃〜２９０℃にて１０分以上、好ましくは０．５時間〜５時間である。この実施形態では、金属酸化膜４を形成するための金属Ｉが、金メッキ膜３と金属メッキ膜２から供給される。なお、金属メッキ膜２から多量の金属が供給可能であり、このため上記第１実施形態と比較しても、より低い温度又は短い時間で酸化膜の形成が可能である。また熱処理温度が低いことから、本実施形態の母材Ｂに、特に樹脂製品をも好適に適用できる。
【００３５】
金メッキ膜３の下層に形成される金属メッキ膜２は酸化物を形成するための金属の供給源となるため、金メッキ膜３には合金成分に関する規定はなく、純金メッキであってもよい、しかしながら、金メッキ膜２中の合金成分が多くなりすぎると腐食、変色の可能性が出てくるため、金メッキ膜２中の合金成分の好適条件は約５％以下であることが好ましい。また金属メッキ膜２は金属の供給源であるため、効率よく供給するためには１０重量％以上あることが必要である。しかし、添加金属が増加すると、上層にある金メッキ膜３との密着性が悪くなり、更に耐食性も悪くなるので、好適条件は１０重量％〜５０重量％が好適である。
【００３６】
また、金属メッキ膜２の膜厚についても格別の制限はないが、金属酸化膜４を形成することによる干渉色の発色を効率よく行うには薄いほうがよく、好適条件は３μｍ以下である。３μｍより厚くなると金メッキ膜３そのものが不均一となり剥離しやすい。また、金メッキ膜３の膜厚に関しては、金メッキの貴金属感の色が発色するくらいのメッキ膜厚があればよいため、０．１μｍ以上としている。０．１μｍより少ないと、金メッキの色が均一に発色しない。金属酸化膜４の膜厚に関しては、第１実施形態と同様の理由により、その膜厚を３５ｎｍ〜２４０ｎｍとする。
【００３７】
金属酸化膜４の形成時における酸素分圧は、上記第１実施形態と同様に、好適には１ＭＰａ〜１０ＭＰａであるが、通常の発色は大気下にて行うのが好ましい。
【００３８】
図３は本発明の発色メッキ膜の第３実施形態を示している。
この実施形態にあっては、同図に示すように、母材Ｂの表面に形成されるメッキ膜が、上述の金属Ｉが含有し、メッキ膜下面から表面に向かい金属Ｉの濃度が小さくなっている傾斜金メッキ膜９からなり、この傾斜金メッキ膜９の表面に、傾斜メッキ膜９に含まれる金属Ｉから金属酸化膜４が形成されており、金属Ｉの金属酸化膜４による干渉色と、傾斜金メッキ膜９の物質色を兼ね備えもつことを基本の構成としている。
【００３９】
この第３実施形態にあっても、傾斜金メッキ膜９の表面に、傾斜メッキ膜９に含まれる金属Ｉから選ばれる一種又は二種以上からなる金属酸化膜４が形成されており、この金属酸化膜４による干渉色と、傾斜金メッキ膜９の物質色を兼ね備えもつ色合いを発色する。
【００４０】
一方、図４に示す発色メッキ膜は、本発明の第４の実施形態を示している。
この実施形態による発色メッキ膜は、同図に示すように、母材Ｂの表面に形成される傾斜メッキ膜１０が上述の金属Ｉを含有する上下二層のメッキ膜７，８から構成され、その上部メッキ膜７の表面に金属酸化膜４が形成されている。前記上部メッキ膜７中に含まれる金属Ｉの濃度は下部メッキ膜８の金属Ｉの濃度よりも低く設定されている。前記金属酸化膜４は、上述した金属Ｉの一種又は二種以上の酸化物から構成される。
【００４１】
この金属酸化膜４も、下部メッキ膜８と上部メッキ膜７に含有され、そこから析出した金属の酸化物であり、第１及び第２実施例と同様に、酸素に比較的活性で熱処理により酸化物を精製できる金属Ｉを用いている。このように前記金属酸化膜４は、下地の傾斜メッキ膜９，１０に含まれる金属Ｉから形成された酸化物であるため、下地のメッキとの密着性が非常に強く、また酸化皮膜であることから耐久性、耐食性にも極めて優れている。
【００４２】
上記第３及び第４実施形態による発色メッキ膜を製造するときの熱処理条件は、上記第２実施形態と同様の理由により２００℃〜２９０℃の酸素雰囲気中にて、０．５時間〜５時間行うのがよい。
【００４３】
傾斜金メッキ膜９や傾斜メッキ膜１０中の金属Ｉの濃度傾斜は連続的であっても不連続でもよく、表面に向かって濃度を小さくする。本実施形態による発色メッキ膜は、金属酸化膜４の供給源となるべき金属Ｉの高濃度部分をメッキ膜の底部に有することにより、図１に示した第１の実施形態の発色メッキ合金膜よりも鮮やかで強い色合いとなる。この第３及び第４の実施形態による熱処理を行う前の傾斜金メッキ膜９又は傾斜メッキ膜１０は、底部における金属Ｉの濃度を１０％以上とする。このメッキ底部における金属Ｉの濃度が小さいと金属酸化膜４の金属供給源とはならず、逆にメッキ表面部における金属Ｉの濃度が大きいと色むらが発生しやすいため、このメッキ表面部の金属Ｉの濃度は１０％以下、好ましくは５％以下とするのがよい。
【００４４】
また、一般に金メッキ膜を厚くする程、金メッキ膜中の金属Ｉの濃度は徐々に小さくなる。従って、特に上記第４の実施形態にあっては、金属Ｉの高濃度領域である下部メッキ膜８の厚さを０．５μｍ以下とし、また上部メッキ膜８は熱処理による酸化膜形成の干渉色の発色を容易に行うには、メッキ膜は薄いほうがよく、好適な条件は０．１μｍ〜０．５μｍ以下である。金属酸化膜厚４の膜厚に関しては、上記第１実施形態と同様に理由により、酸化膜厚を３５ｎｍ〜２４０ｎｍとする。
【００４５】
上記第３及び第４の実施形態のような金属Ｉの濃度が傾斜する傾斜メッキ膜９，１０を形成するには、メッキ時の初期に低電流密度とし、連続（傾斜金メッキ膜９）又は不連続（傾斜メッキ膜１０）に電流密度を高くすることにより行われる。図２に示した第２実施形態では、２層のメッキを個別に行わなければならなかったが、これらの実施形態では１浴で形成されるメッキ膜を、例えば断続的に２段で電流密度を操作すれば、連続する２層のメッキ膜７，８を形成することができ、上記第２の実施形態と同様の効果を生み出すことができる。
酸素分圧は第一実施形態による発色メッキ合金膜と同様の理由により、好適条件は１ＭＰａ〜１０ＭＰａであるが、通常の発色は大気下で行われる。
【００４６】
次に、本発明のより具体的な実施例を上記第１〜第４の実施形態に対応させて説明することにする。
【００４７】
（実施例１）
メッキ実験用ハルセル板（真鍮板）に、２μｍのニッケルメッキを施し基盤とした。次いで、クエン酸５０ｇ／ｌ、クエン酸カリウム５０ｇ／ｌ、シアン化金カリウム４．５ｇ／ｌの液にコバルト塩、ニッケル塩を加えてメッキ浴とし、メッキ条件を、ｐＨ３．２、電流密度１．２Ａ／ｄｍ^２、浴温度３５℃で電気メッキを施し、基盤に２μｍの金メッキを施して試料を作成した。このときのメッキ膜には、合金成分として２重量％のコバルト、２重量％のニッケルが含有されていた。この試料を、大気下にて３４０℃で１〜６時間の範囲で焼き付け、１時間ごとの試料の色合いと、コバルト及びニッケルの混合酸化膜の膜厚を計測した。その結果を、表１にまとめた。
【００４８】
【表１】

【００４９】
（実施例２）
実施例と同じ基盤に、硫酸コバルト１２０ｇ／ｌ、硼酸４０ｇ／ｌの浴にて、メッキ条件ｐＨ５．５で電気メッキを施し、１．５μｍのコバルトメッキ膜を形成した。次いで、その上に、実施例１と同様のメッキ条件にてメッキ処理を行い、金メッキ膜の膜厚を０．１、０．５、１．０、２．０μｍ形成して試料を作成した。これらの試料を大気下において２３０℃で４時間焼き付けた。その結果を表２に示す。
【００５０】
【表２】

【００５１】
（実施例３）
実施例２のコバルトメッキに代えて、コバルト含有量の多い金メッキ膜を形成した。このときのメッキ浴は、クエン酸５０ｇ／ｌ、クエン酸カリウム５０ｇ／ｌ、シアン化金カリウム５ｇ／ｌ、コバルトイオン５０ｇ／ｌとし、ｐＨ６．０、電流密度０．８Ａ／ｄｍ^２、浴温度４０℃として、実施例１と同じ基盤に金メッキを施した。このときのメッキ膜中のコバルト含有量は５０重量％であった。次いで、クエン酸５０ｇ／ｌ、クエン酸カリウム５０ｇ／ｌ、シアン化金カリウム４．５ｇ／ｌのメッキ浴中で、メッキ条件をｐＨ３．２、電流密度１．２Ａ／ｄｍ^２、浴温度を３５℃で、０．１μｍ、０．５μｍ、１．０μｍ及び２．０μｍの純金メッキ膜を形成し、実施例２と同様の熱処理条件で熱処理を行ったところ、実施例２と同じ結果が得られた。
【００５２】
（実施例４）
メッキ浴を、クエン酸５０ｇ／ｌ、クエン酸カリウム５０ｇ／ｌ、シアン化金カリウム５ｇ／ｌ、コバルト濃度１５ｇ／ｌ、ｐＨ６．０、浴温度４０℃で、実施例１と同じ基盤にメッキを施した。メッキ初期には電流密度０．４Ａ／ｄｍ^２で２分行い、次いで同じ浴中で電流密度１．２Ａ／ｄｍ^２で１分メッキを施し、試料を作成した。このときのメッキ膜中のコバルト含有量は、メッキ底部で１０％、表面部ではほぼ純金メッキであった。また、トータルの膜厚は０．１５μｍであった。これらの試料を、大気中で２１０℃、１時間、３時間及び５時間ずつ焼き付けて、それぞれの色合いと酸化膜の膜厚とを計測した。その結果を表３に示す。
【００５３】
【表３】

【００５４】
以上の説明からも明らかなように、本発明の発色メッキ膜は貴金属類と特定の金属Ｉとの合金メッキ膜、又はそれらの層状メッキ膜を、所定の加熱条件下で加熱処理することにより、前記メッキ膜の表面に同メッキ膜に含まれる前記金属Ｉから生成される酸化膜を形成しているため、従来のごとく単一の金属メッキを使った酸化膜と異なり、酸化膜が均一に生成され、その膜厚により鮮やかで強い色合いをもつ様々な干渉色をそれぞれ独立して発色させると同時に、貴金属特有の物質色が交わり、貴金属感に優れ高級感のある優れた発色が維持される。また、前記金属酸化膜は極めて耐久性と耐蝕性に優れているため、発色メッキ膜自体の耐久性及び耐蝕性も著しく増加する。
【図面の簡単な説明】
【図１】本発明の発色メッキ膜に係る第１実施形態を模式的に示す断面図である。
【図２】本発明の発色メッキ膜に係る第２実施形態を模式的に示す断面図である。
【図３】本発明の発色メッキ膜に係る第３実施形態を模式的に示す断面図である。
【図４】本発明の発色メッキ膜に係る第４実施形態を模式的に示す断面図である。
【符号の説明】
１，３金メッキ膜（貴金属メッキ膜）
２金属メッキ膜
４金属酸化膜
６層状金属メッキ膜
７上部メッキ膜
８下部メッキ膜
９傾斜金（貴金属）メッキ膜
１０傾斜（貴金属）メッキ膜
Ｂ母材（基盤）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a novel metal surface treatment applied to high-grade products subjected to precious metal plating and the like, and more particularly, for example, building material related parts such as entrances and door knobs, sliders, upper and lower stoppers and other fastener parts, fastening fields such as snap buttons, The present invention relates to a novel surface treatment technology which has a high-grade feel and is excellent in durability and corrosion resistance which can be applied to various fields such as decorative articles such as brooches, earrings, rings, and pendants, or decorative parts for shoes and bags.
[0002]
[Prior art]
Conventional plating colors are mostly metallic colors such as light gray or copper, or are limited to golden by brass plating or gold plating. As the color plating, there are a method of obtaining a chromatic color, a method of applying a colored clear coating on the plating, and a method of dyeing a plating film with a sulfide, in addition to black plating by Sn-Ni-based plating or the like.
[0003]
As a method of chemically coloring the plating, a method of treating copper plating with sulfide (Japanese Patent Publication No. 61-15153), a method of treating nickel plating with nitric acid (Japanese Patent Publication No. 62-30263), and a method of chromate A method of obtaining an interference color by performing a process (Japanese Patent Publication No. 60-20467) has been proposed. Further, as a method of obtaining a color by heat treatment, it is known to form an oxide film on a metal such as copper or nickel, in addition to the heat treatment of chromium plating (Japanese Patent Application Laid-Open No. 60-82677).
[0004]
The coloring method according to the above-mentioned Japanese Patent Publication No. 61-15153 discloses that a copper surface of a copper or copper-plated material is immersed in a mixed aqueous solution obtained by adding potassium sulfide and ammonium chloride to an aqueous ammonium sulfide solution and colored blackish brown. In this case, the life of the coloring liquid is prolonged, the coloring power and the uniform coloring property are not impaired, and interference colors are hardly produced. On the other hand, Japanese Patent Publication No. 60-20467 discloses that when a zinc-nickel alloy plated product containing 20% by weight or less of nickel is subjected to chromate treatment, Cr⁶⁺Concentration of 0.5-100 g / l, SO₄ ^2-Concentration and Cr⁶⁺A beautiful rainbow-colored interference color excellent in salt water resistance and corrosion resistance is obtained by processing using a processing solution having a ratio of the concentration to a value of 0.025 to 1.5 and a pH of 1.3 to 2.7. Further, in Japanese Patent Application Laid-Open No. 60-82677, a metal base plate is plated with nickel, and then a nickel oxide film is forcibly formed, and the color is generated by the interference color. At this time, colors such as red, black, brown, and green can be obtained by controlling the thickness of the oxide film.
[0005]
[Patent Document 1]
JP-B-61-15153
[Patent Document 2]
Japanese Patent Publication No. 60-20467
[Patent Document 3]
JP-B-62-30263
[Patent Document 4]
JP-A-60-82677
[0006]
[Problems to be solved by the invention]
However, the plating color obtained by the simple plating method described above is limited as described above. Furthermore, the black plating and dyeing methods have the disadvantage that the color tends to fall off due to the friction of the plating surface, and the coating method has the disadvantage of being weak to scratches.Each method has poor durability, and the sulfide dyeing method has a chromatic color. Can be obtained, but the quality is poor, and it is not possible to obtain a color development having both a noble metal feeling and a chromatic color.
[0007]
On the other hand, most of the above-mentioned chemical treatment methods are only methods for obtaining black and black-brown, and do not provide bright and various chromatic colors. In the chromate treatment, although a vivid interference color can be obtained, it is difficult to obtain a dark color, and in view of the environment, the use of chromium has recently been regulated, and it is not preferable to use a large amount of chromium.
[0008]
The method of obtaining an interference color by forming an oxide film of nickel plating according to Patent Document 4 is a method of heat-treating a single-component plating to form an oxide film on the surface thereof. However, in this method, when the oxide film thickness is small, a uniform oxide film is formed near the oxide film surface, and a light-colored interference film is obtained. However, when the thermal oxidation is further continued, the oxide film becomes thick, An uneven oxide film is formed because the plating film is a single component. As a result, the interference color becomes uneven in color, and cannot be put to practical use such as decoration.
[0009]
It is a first object of the present invention to provide a plating film having a high-grade appearance and having a chromatic color uniformly colored, which cannot be expected by such conventional plating, and a method for manufacturing the same. Another object of the present invention is to provide a plating film which is resistant to color dropout, is resistant to scratches, has excellent corrosion resistance and durability, and a method for producing the plating film. A third object of the present invention is to provide a high-grade plating film which has a noble metal feeling and develops almost all chromatic colors by changing the thickness of the oxide film depending on heat treatment conditions, and a method of manufacturing the same. is there.
[0010]
Means for Solving the Problems and Functions and Effects
The colored plating film of the present invention and the method for producing the same can be roughly classified into three modes. No. 1 has a metal oxide film made of a metal other than the noble metal contained in the noble metal plating film on the surface of the noble metal plating film. A color plating film characterized by exhibiting a surface color having a color and a method of manufacturing the same. At this time, the base material B of the plating film of the noble metal is a metal base material or a plastic base material, and the material thereof does not matter. The light incident on the metal oxide film and the reflected light on the surface of the oxide film interfere with each other, and the interference light is combined with the reflected light on the surface of the noble metal plating film to form an interference color due to the metal oxide film. And a surface color having a material color of a noble metal feeling unique to the noble metal plating film. The metal oxide film has increased hardness, excellent corrosion resistance, strong scratches, and improved durability.
[0011]
The noble metal plating film is made of an alloy containing a noble metal as a main component and one or more metals I selected from Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W, and Y. The metal oxide film comprises an oxide film of metal I contained in the noble metal. That is, the metal contained in the noble metal plating film according to the present invention may be one or more metals selected from the above-mentioned metals I which are easily transferred to the surface layer when external energy is applied, and are easily bonded to external oxygen. preferable. Further, as compared with the case where the metal forming the metal oxide film is directly plated on the surface of the noble metal, the thickness of the noble metal is extremely uniform without unevenness. Therefore, by controlling the film thickness of the metal oxide film instead of the so-called iridescent color, interference colors based on the film thickness and the wavelength of incident light, that is, various colors continuously changing to seven colors are independently formed. Will be able to do that.
[0012]
The noble metal plating film is preferably made of an alloy represented by the following general formula (i).
AaXb (i)
Here, A is one kind of noble metal, X is at least one kind of element selected from metal I, a and b are each weight%, a is a difference from b with respect to the total weight of the plating film, and b is metal I And other unavoidable elements, and is in the range of 0 ≦ b ≦ 5. Here, if the amount of at least one element X selected from the metal I and the unavoidable element exceeds 5%, the material color peculiar to the noble metal becomes thin, and the color peculiar to the noble metal is lost from the color development of the obtained plating film. The precious metal feeling is also lost.
[0013]
The thickness of the noble metal plating film is preferably 1 μm to 5 μm, and the thickness of the metal oxide film is preferably 35 nm to 240 nm. If the thickness of the noble metal plating film is less than 1 μm, the color of the base member to be plated is affected, and the feeling of noble metal is poor. If it exceeds 5 μm, the cost increases. When the metal oxide film (4) is in the above-mentioned thickness range, seven colors of sunlight and colors continuous with them can be independently expressed.
[0014]
Furthermore, in the manufacturing method of the present invention, after the noble metal plating film is formed on the surface of the base material as described above, heat treatment is performed in an oxygen atmosphere at 230 ° C. or more for 10 minutes or more. It is characterized by. By performing a heat treatment by selecting an appropriate condition from the heat treatment conditions, a desired film thickness can be obtained, and a plating film that develops an arbitrary color can be obtained. If the heat treatment temperature is lower than 230 °, the movement of the metal element X contained in the noble metal is slow, and it takes a long time to obtain a desired thickness of the metal oxide film. More preferably, the heat treatment conditions are an oxygen atmosphere at 250 ° C. to 330 ° C. for 30 minutes to 6 hours. At this time, the metal oxide film is formed to have a thickness of 35 nm to 240 nm by controlling the heat treatment conditions.
[0015]
The color plating film according to the second embodiment of the present invention is formed on the surface of one or more metals I selected from Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W and Y, or the same metal I A layered metal plating film having a noble metal plating film formed on the surface of the metal plating film containing: a metal oxide film formed on the surface of the noble metal plating film and formed from the metal I contained in the plating film. The basic structure of the color plating film is to develop a surface color having both the interference color of the metal oxide film and the material color of the noble metal feeling unique to the noble metal plating film.
[0016]
In the present invention, a noble metal plating film is formed on the surface of the metal I or the surface of the metal plating film containing the metal I, and a metal oxide film is further formed on the surface. This metal oxide film is subjected to heat treatment for 10 minutes or more in an oxygen atmosphere at a heat treatment condition of 200 ° C. or more, whereby the metal I element moves toward the surface of the noble metal plating, and Formed in combination with atmospheric oxygen. More preferably, the heat treatment is performed in an oxygen atmosphere at 230 ° C. to 290 ° C. for 0.5 to 5 hours. The thickness of the metal oxide film can be formed to an arbitrary thickness by adjusting the processing conditions of temperature and time. According to the present invention as well, a variety of interference colors based on the thickness of the metal oxide film and the material color of the noble metal plating film are mixed to produce a high-grade independent color with an excellent noble metal feeling. Of course, a material having excellent durability and corrosion resistance due to the oxide film on the surface can be obtained.
[0017]
Also in the present invention, the metal plating film is made of a metal represented by the following general formula (i), and the noble metal plating film (3) formed on the surface of the metal plating film (2) is represented by the following general formula: It is preferable to constitute the metal represented by (ii).
AaXc (i)
AaXd ... (ii)
Here, A is one kind of element selected from noble metals, X is at least one kind of element selected from metal I, a, c and d are% by weight, and a is c and d with respect to the total weight of each plating film. The differences c and d include the metal I for each plating film and other unavoidable elements, and are in the range of 0 <c <100 and 0 ≦ d ≦ 5.
[0018]
It is preferable that the thickness of the metal plating film is 0.1 μm or more, the thickness of the noble metal plating film is 3 μm or less, and the thickness of the metal oxide film (4) is 35 nm to 240 nm. When the thickness of the metal plating film is smaller than 0.1 μm, one or more elements selected from the metal I are not sufficiently deposited on the surface of the noble metal plating film, and a metal oxide film having a desired thickness cannot be formed.
[0019]
A third embodiment of the color plating film according to the present invention includes one or more metals I selected from the group consisting of Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W, and Y. A gradient noble metal plating film in which the concentration decreases from the lower surface of the plating film toward the surface, wherein the surface of the gradient noble metal plating film has a metal oxide film generated from the metal I contained in the plating film. In addition, a basic structure is provided in which a surface color having both the interference color due to the metal oxide film and the material color of the characteristic noble metal feeling of the inclined noble metal plating film is generated.
[0020]
With this configuration, when the same heat treatment as described above is performed, one or more elements selected from the metal I in the inclined noble metal plating film actively move toward the surface, and the inclined noble metal plating film can be formed in a short time. A metal oxide film having a desired film thickness on the surface is obtained.
[0021]
In the present invention, a lower plating film may be further formed on the lower surface of the inclined noble metal plating film. Preferably, the lower plating film is made of a metal represented by the following general formula (iii), and the inclined noble metal plating film is made of a metal represented by the following general formula (iv).
AaXe ...... (iii)
AaXf ... (iv)
Here, A is one kind of element selected from noble metals, X is at least one kind of element selected from metal I, a, e, and f indicate weight%, and a is e and f with respect to the total weight of each plating film. And e and f include the metal I for each plating film and other unavoidable elements, and are in the range of 10 ≦ e ≦ 100 and 0 ≦ f ≦ 10.
[0022]
Even in the present invention, for the same reason as described above, the thickness of the lower plating film is 0.5 μm or less, the thickness of the upper inclined noble metal plating film is 0.5 μm or less, and the thickness of the metal oxide film is 35 nm. It is preferable to set it to 240 nm.
[0023]
Such a color plating film contains one of noble metals and one or more metals I selected from Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W, and Y. A lower plating film (8) made of a metal represented by the formula (iii) is formed, and on the surface thereof, represented by the following general formula (iv), the concentration of the metal I decreases from the lower surface of the plating film toward the surface. After forming the inclined noble metal plating film (9), the lower plating film (8) and the upper inclined noble metal plating film (9) are heat-treated in an oxygen atmosphere at 200 ° C. to 290 ° C. for 30 minutes to 5 hours. Can be obtained.
AaXe ...... (iii)
AaXf ... (iv)
Here, A is one kind of element selected from noble metals, X is at least one kind of element selected from metal I, a, e, and f indicate weight%, and a is e and f with respect to the total weight of each plating film. And e and f include the metal I for each plating film and other unavoidable elements, and are in the range of 10 ≦ e ≦ 100 and 0 ≦ f ≦ 10.
[0024]
The gradient noble metal plating film is formed by setting the current density to a low current density at the initial stage of plating, continuously or discontinuously increasing the current density, and performing the plating in the same plating bath. In alloy plating with a noble metal, the component concentration of the noble metal element A changes according to a change in current density in the plating bath. That is, the concentration of the noble metal element becomes high when the current density is high, and the concentration becomes low when the current density is low. Therefore, by controlling the current density in the plating bath, a gradient noble metal plating having an arbitrary gradient concentration can be efficiently formed.
In the above-mentioned production method, the oxygen partial pressure in the oxygen atmosphere is preferably set to 1 MPa to 10 MPa, but usually it is often carried out under atmospheric pressure.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the composition and manufacturing conditions of a color plating film according to a typical embodiment of the present invention will be specifically described with reference to the drawings. In the following embodiments, gold (Au), which is a typical metal as a noble metal, will be described as an example. However, another platinum group (Ru, Rh, Pd, Os, Ir, Pt) or silver is replaced with gold. The description is omitted because the same applies to the case of the above.
[0026]
FIG. 1 shows a configuration of a color plating film according to the first embodiment of the present invention.
According to this embodiment, the gold plating film 1 is formed on the surface of the base material B, and the metal oxide film 4 is formed on the surface. This metal oxide film 4 functions as an interference film, and the gold color of the gold plating film 1 and the interference color emitted from the metal oxide film 4 are mixed to produce a new color that is unprecedented in that a precious metal feeling and a vivid chromatic color are simultaneously felt. .
[0027]
The base material B is usually various kinds of plastics or wood materials in addition to metals, and the material is not limited. The metal oxide film 4 is made of a metal oxide of an alloy component contained in the gold plating, and is formed of a metal I represented by Fe, Co, Ni, CuTi, V, Cr, Zn, Nb, Mo, W, and Y. Consists of one or more. Various metals are added to the gold plating film 1. In the present invention, a metal I which is relatively active in oxygen and can easily form an oxide by heat treatment is used. The metal oxide film 4 is formed by performing a heat treatment on the gold plating film 1. Further, since the metal oxide film 4 is an oxide generated from the metal I contained in the underlying gold plating film 1, the metal oxide film 4 has very high adhesion to the gold plating film 1. Because of this, it has excellent durability and corrosion resistance.
[0028]
The conditions of the heat treatment are as follows: the treatment temperature is set to 230 ° C. or more, preferably 250 ° C. to 330 ° C., and the heat treatment time is 10 minutes or more, preferably 30 minutes to 6 hours in an oxygen atmosphere. Is what you do. Although the metal oxide film 4 is formed even at a relatively low temperature, in order to stably obtain a uniform and vivid interference color, the alloy component in the gold plating film 1 forming the metal oxide film 4 is sufficient for the gold plating film 1. Need to be supplied to the surface. That is, in the present invention, a condition is required in which the formation of the metal oxide film 4 that emits an interference color and the movement of the alloy component in the gold plating film 1 by thermal diffusion are simultaneously performed. Therefore, the heat treatment temperature needs to be 230 ° C. or higher, and the metal oxide film 4 is formed stably at 250 ° C. to 330 ° C. Although the processing time is changed according to the target color, it takes at least 10 minutes for the color development, and a series of color developments due to the interference effect can be performed by the processing for 0.5 to 6 hours. Although further processing is possible, similar colors are merely repeated due to the nature of the interference color.
[0029]
The alloy component in the gold plating film 1 must have a sufficient concentration necessary for forming an oxide film. However, when the concentration is high, the growth of the gold plating film thickness is inhibited in electrolytic plating, and the corrosion resistance may be deteriorated. Therefore, the concentration is preferably 0.5 to 5%.
[0030]
The plating film thickness is required to be a thickness necessary for the alloy component to be stably supplied. That is, if the film thickness is too small, the formation of the metal oxide film does not occur even if the alloy component is increased. Conversely, if the thickness is too large, the supply of alloy components due to thermal diffusion is not stable, and color unevenness is likely to occur. Therefore, a preferable gold plating film thickness is 1 μm to 5 μm. The oxide film thickness is preferably 35 nm to 240 nm. When the oxide film thickness is less than 35 nm, no interference color is generated. On the other hand, if it is more than 240 nm, the color of the oxide film itself starts to appear, and a vivid interference color cannot be obtained.
[0031]
When a plating film of a single component, for example, a plating film made of Cr or Ni is heat-treated to form a color and an interference color is obtained, in order to obtain a uniform color, the oxygen partial pressure is lowered. Since the interference film is formed by oxidizing the alloy metal through the film, the color development is stably performed regardless of the oxygen partial pressure, but the preferable condition is 1 MPa to 10 MPa. Thus, it is preferable that normal coloring be performed in the atmosphere.
[0032]
Next, a second embodiment of the present invention will be described with reference to FIG.
The second embodiment comprises a layered metal plating film 6 in which a gold plating film 3 is provided on the surface of a metal plating film 2 containing metal I, and the metal contained in the layered plating film 6 is formed on the surface of the gold plating film 3. It has a metal oxide film 4 formed from I, and is characterized by having both an interference color of the metal I oxide film and a material color unique to the gold plating film 3. The gold plating film 3 according to this embodiment is more vivid than the color plating alloy film of the first embodiment shown in FIG. 1 by having the metal plating film 2 serving as a metal supply source of the metal oxide film 4 below the gold plating film 3. It becomes a strong color.
[0033]
The metal oxide film 4 is an oxide of an alloy component contained in the layered metal plating film 6, and is composed of one or more oxides of the above-mentioned metal I. This is a metal contained in the gold plating film 3 and the metal plating film 2, and as in the first embodiment, a metal I that is relatively active against oxygen and can generate an oxide by heat treatment is used. Further, since the metal oxide film 4 is an oxide film formed from the underlying layered metal plating film 6, the metal oxide film 4 has an extremely strong adhesion to the underlying plating, and since it is an oxide film, the durability and the corrosion resistance are also reduced. Are better.
[0034]
In this embodiment, suitable conditions for the heat treatment are 200 ° C. or more, preferably 230 ° C. to 290 ° C., for 10 minutes or more, preferably 0.5 hour to 5 hours. In this embodiment, the metal I for forming the metal oxide film 4 is supplied from the gold plating film 3 and the metal plating film 2. Note that a large amount of metal can be supplied from the metal plating film 2, and therefore, an oxide film can be formed at a lower temperature or in a shorter time than in the first embodiment. Further, since the heat treatment temperature is low, a resin product can be suitably applied to the base material B of the present embodiment.
[0035]
Since the metal plating film 2 formed below the gold plating film 3 is a supply source of a metal for forming an oxide, the gold plating film 3 does not have any rules regarding alloy components, and may be pure gold plating. If the amount of the alloy component in the gold plating film 2 is too large, corrosion and discoloration may occur. Therefore, the preferable condition of the alloy component in the gold plating film 2 is preferably about 5% or less. Further, since the metal plating film 2 is a metal supply source, it needs to be 10% by weight or more in order to efficiently supply the metal. However, when the amount of the added metal increases, the adhesion to the gold plating film 3 as the upper layer deteriorates, and the corrosion resistance also deteriorates. Therefore, the preferable condition is 10 to 50% by weight.
[0036]
There is no particular limitation on the film thickness of the metal plating film 2, but the thinner the better, the more efficient the interference color formation by forming the metal oxide film 4 is, and the preferable condition is 3 μm or less. When the thickness is more than 3 μm, the gold plating film 3 itself becomes non-uniform and easily peels. The thickness of the gold plating film 3 is set to 0.1 μm or more because it is sufficient that the plating thickness is such that the color of the noble metal feeling of the gold plating develops. If it is less than 0.1 μm, the color of the gold plating will not be uniform. The thickness of the metal oxide film 4 is set to 35 nm to 240 nm for the same reason as in the first embodiment.
[0037]
The oxygen partial pressure at the time of forming the metal oxide film 4 is preferably 1 MPa to 10 MPa as in the first embodiment, but it is preferable that ordinary coloring be performed in the atmosphere.
[0038]
FIG. 3 shows a third embodiment of the color plating film of the present invention.
In this embodiment, as shown in the figure, the plating film formed on the surface of the base material B contains the above-mentioned metal I, and the concentration of the metal I decreases from the lower surface of the plating film to the surface. The metal oxide film 4 is formed from the metal I included in the metal gradient film 9 on the surface of the metal gradient film 9, and the interference color of the metal I by the metal oxide film 4 and The basic configuration is to also have the material color of the inclined gold plating film 9.
[0039]
Also in the third embodiment, on the surface of the inclined gold plating film 9, the metal oxide film 4 composed of one or more metals selected from the metals I contained in the inclined plating film 9 is formed. A color having both the interference color of the film 4 and the material color of the inclined gold plating film 9 is developed.
[0040]
On the other hand, the color plating film shown in FIG. 4 shows a fourth embodiment of the present invention.
As shown in the figure, the color plating film according to this embodiment is such that the inclined plating film 10 formed on the surface of the base material B is composed of upper and lower two-layer plating films 7 and 8 containing the above-mentioned metal I, The metal oxide film 4 is formed on the surface of the upper plating film 7. The concentration of metal I contained in the upper plating film 7 is set lower than the concentration of metal I in the lower plating film 8. The metal oxide film 4 is composed of one or more oxides of the metal I described above.
[0041]
The metal oxide film 4 is also contained in the lower plating film 8 and the upper plating film 7 and is an oxide of a metal deposited therefrom. As in the first and second embodiments, the metal oxide film 4 is relatively active in oxygen and is heat-treated. Metal I that can purify the oxide is used. As described above, since the metal oxide film 4 is an oxide formed from the metal I contained in the underlying inclined plating films 9 and 10, the metal oxide film 4 has very strong adhesion to the underlying plating and is an oxide film. Therefore, it is extremely excellent in durability and corrosion resistance.
[0042]
The heat treatment conditions for manufacturing the color plating films according to the third and fourth embodiments are, for the same reason as in the second embodiment, in an oxygen atmosphere at 200 to 290 ° C. for 0.5 to 5 hours. Good to do.
[0043]
The concentration gradient of the metal I in the gradient gold plating film 9 or the gradient plating film 10 may be continuous or discontinuous, and the concentration decreases toward the surface. The coloring plating film according to the present embodiment has a high concentration portion of metal I to be a supply source of the metal oxide film 4 at the bottom of the plating film, so that the coloring plating alloy film of the first embodiment shown in FIG. More vivid and intense color. Before the heat treatment according to the third and fourth embodiments, the gradient gold plating film 9 or the gradient plating film 10 has a metal I concentration at the bottom of 10% or more. If the concentration of metal I at the bottom of the plating is low, it will not be a metal supply source for the metal oxide film 4. Conversely, if the concentration of metal I at the plating surface is high, color unevenness is likely to occur. The concentration of metal I is 10% or less, preferably 5% or less.
[0044]
In general, the thicker the gold plating film, the lower the concentration of the metal I in the gold plating film. Therefore, particularly in the fourth embodiment, the thickness of the lower plating film 8, which is a high concentration region of the metal I, is set to 0.5 μm or less, and the upper plating film 8 is an interference color of an oxide film formed by heat treatment. In order to easily perform the color development, it is preferable that the plating film is thin, and the preferable condition is 0.1 μm to 0.5 μm or less. The thickness of the metal oxide film 4 is set to 35 nm to 240 nm for the same reason as in the first embodiment.
[0045]
In order to form the inclined plating films 9 and 10 in which the concentration of the metal I is inclined as in the third and fourth embodiments, the current density is set to be low at the initial stage of the plating, and the continuous (graded gold plating film 9) or non-continuous This is performed by increasing the current density continuously (graded plating film 10). In the second embodiment shown in FIG. 2, the plating of two layers had to be performed individually. However, in these embodiments, the plating film formed in one bath is intermittently provided with two layers of current density. By operating, the continuous two layers of plating films 7 and 8 can be formed, and the same effect as in the second embodiment can be produced.
The oxygen partial pressure is preferably 1 MPa to 10 MPa for the same reason as the color plating alloy film according to the first embodiment, but normal color development is performed in the atmosphere.
[0046]
Next, more specific examples of the present invention will be described in association with the first to fourth embodiments.
[0047]
(Example 1)
A 2 μm nickel plating was applied to a hull cell plate (brass plate) for plating experiment to be used as a base. Next, a cobalt salt and a nickel salt were added to a liquid of 50 g / l of citric acid, 50 g / l of potassium citrate, and 4.5 g / l of potassium potassium cyanide to form a plating bath. The plating conditions were pH 3.2 and a current density of 1. .2A / dm²Then, electroplating was performed at a bath temperature of 35 ° C., and 2 μm gold plating was performed on the base to prepare a sample. At this time, the plating film contained 2% by weight of cobalt and 2% by weight of nickel as alloy components. This sample was baked at 340 ° C. for 1 to 6 hours in the atmosphere, and the color of the sample and the thickness of the mixed oxide film of cobalt and nickel were measured every hour. The results are summarized in Table 1.
[0048]
[Table 1]

[0049]
(Example 2)
Electroplating was performed on the same substrate as in the example under a plating condition of pH 5.5 in a bath of cobalt sulfate 120 g / l and boric acid 40 g / l to form a 1.5-μm cobalt plating film. Next, a plating process was performed thereon under the same plating conditions as in Example 1, and the thickness of the gold plating film was formed to 0.1, 0.5, 1.0, and 2.0 μm to prepare a sample. These samples were baked at 230 ° C. in air for 4 hours. Table 2 shows the results.
[0050]
[Table 2]

[0051]
(Example 3)
Instead of the cobalt plating of Example 2, a gold plating film having a high cobalt content was formed. The plating bath used at this time was citric acid 50 g / l, potassium citrate 50 g / l, potassium potassium cyanide 5 g / l, and cobalt ion 50 g / l, pH 6.0, and current density 0.8 A / dm.²With the bath temperature set to 40 ° C., the same base as in Example 1 was plated with gold. At this time, the cobalt content in the plating film was 50% by weight. Next, in a plating bath of 50 g / l of citric acid, 50 g / l of potassium citrate, and 4.5 g / l of potassium potassium cyanide, the plating conditions were adjusted to pH 3.2 and the current density was set to 1.2 A / dm.²A 0.1 μm, 0.5 μm, 1.0 μm, and 2.0 μm pure gold plating film was formed at a bath temperature of 35 ° C., and heat treatment was performed under the same heat treatment conditions as in Example 2. The same result was obtained.
[0052]
(Example 4)
The plating bath was plated on the same substrate as in Example 1 at 50 g / l of citric acid, 50 g / l of potassium citrate, 5 g / l of potassium potassium cyanide, 15 g / l of cobalt concentration, pH 6.0, and a bath temperature of 40 ° C. gave. Current density 0.4A / dm at the beginning of plating²At a current density of 1.2 A / dm in the same bath.²For 1 minute to prepare a sample. At this time, the cobalt content in the plating film was 10% at the bottom of the plating and almost pure gold plating at the surface. The total film thickness was 0.15 μm. These samples were baked in the air at 210 ° C. for 1 hour, 3 hours, and 5 hours, respectively, and each color and the thickness of the oxide film were measured. Table 3 shows the results.
[0053]
[Table 3]

[0054]
As is clear from the above description, the color plating film of the present invention is obtained by subjecting an alloy plating film of a noble metal and a specific metal I or a layered plating film thereof to a heat treatment under a predetermined heating condition. Since an oxide film generated from the metal I included in the plating film is formed on the surface of the plating film, the oxide film is uniformly formed unlike the oxide film using a single metal plating as in the related art. Depending on the film thickness, various interference colors having a vivid and strong color are formed independently of each other, and at the same time, a material color peculiar to the noble metal is intersected to maintain an excellent color with an excellent noble metal feeling and high quality. Further, since the metal oxide film is extremely excellent in durability and corrosion resistance, the durability and corrosion resistance of the color plating film itself are significantly increased.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a first embodiment according to a color plating film of the present invention.
FIG. 2 is a cross-sectional view schematically showing a second embodiment according to the color plating film of the present invention.
FIG. 3 is a cross-sectional view schematically showing a third embodiment of the color plating film of the present invention.
FIG. 4 is a cross-sectional view schematically showing a fourth embodiment according to the color plating film of the present invention.
[Explanation of symbols]
1,3 Gold plating film (noble metal plating film)
2 Metal plating film
4 Metal oxide film
6 Layered metal plating film
7 Upper plating film
8 Lower plating film
9 Inclined gold (precious metal) plating film
10 Inclined (precious metal) plating film
B Base material (base)

Claims

A metal oxide film (4) of a metal other than the noble metal contained in the plating film (1) is provided on the surface of the noble metal plating film (1), and the interference color due to the metal oxide film (4) and the noble metal plating film (1) A color-plated film characterized by exhibiting a surface color having a noble metal-like material color unique to (1).

The noble metal plating film (1) includes one or more metals I selected from Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W, and Y, and the metal oxide film (4) 3. The color-forming plating film according to claim 1, wherein (a) comprises an oxide film of the metal I.

The colored plating film according to claim 1, wherein the noble metal plating film (1) is made of an alloy represented by the following general formula (i).
AaXb (i)
Here, A is one kind of noble metal, X is at least one kind of element selected from metal I, a and b are each weight%, a is the difference from b to the total weight, b is metal I and other And in the range of 0 ≦ b ≦ 5.

The color-forming plating film according to any one of claims 1 to 3, wherein the thickness of the noble metal plating film (1) is 1 m to 5 m, and the thickness of the metal oxide film (4) is 35 nm to 240 nm.

After forming the noble metal plating film (1) represented by the general formula (i) according to claim 3, heat treatment is performed in an oxygen atmosphere at 230 ° C. or more for 10 minutes or more. A method for producing a color plating film.

The method according to claim 4, wherein the heat treatment is performed in an oxygen atmosphere at 250C to 330C for 30 minutes to 6 hours.

The method for producing a color plating film according to any one of claims 1 to 6, wherein the thickness of the noble metal plating film (1) is 1 μm to 5 μm, and the thickness of the metal oxide film (4) is 35 nm to 240 nm.

Formed on the surface of one or more metals I selected from the group consisting of Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W and Y, or on the surface of a metal plating film (2) containing the same. A metal oxide film made of the metal I contained in the layered metal plating film (6) having the noble metal plating film (3) and the layered metal plating film (6) formed on the surface of the noble metal plating film (3). 4) having
A color plating film characterized by a surface color having both the interference color of the metal oxide film (4) and the material color of a noble metal feeling unique to the noble metal plating film (3).

The metal plating film (2) is made of a metal represented by the following general formula (ii), and the noble metal plating film (3) formed on the surface of the metal plating film (2) is represented by the following general formula (iii). 9. The color-forming plating film according to claim 7, comprising a metal represented by the following formula.
AaXc (ii)
AaXd ... (iii)
Here, A is one kind of element selected from noble metals, X is at least one kind of element selected from metal I, a, c and d are% by weight, and a is c and d with respect to the total weight of each plating film. The differences c and d include the metal I for each plating film and other unavoidable elements, and are in the range of 0 <c <100 and 0 ≦ d ≦ 5.

The metal plating film (2) has a thickness of 0.1 μm or more, the noble metal plating film (3) has a thickness of 3 μm or less, and the metal oxide film (4) has a thickness of 35 nm to 240 nm. A color-developing plating film as described in Crab.

After forming the noble metal plating film (3) of the alloy represented by the general formula (iii) on the surface of the metal plating film (2) of the alloy represented by the general formula (ii) according to claim 9, the heat treatment condition is 200 ° C. A method for producing a colored plating film, comprising performing heat treatment for 10 minutes or more in the above oxygen atmosphere.

The method according to claim 11, wherein the heat treatment is performed in an oxygen atmosphere at 230C to 290C for 0.5 to 5 hours.

13. The color plating film according to claim 11, wherein the metal plating film (2) has a thickness of 0.1 μm or more, the noble metal plating film (3) has a thickness of 3 μm or less, and the metal oxide film (4) has a thickness of 35 nm to 240 nm. Method.

It contains one or more metals I selected from Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W, and Y, and the concentration of the metal I decreases from the lower surface of the plating film toward the surface. A metal oxide film (9, 10) formed from the metal I contained in the inclined noble metal plating film (9, 10) on the surface of the inclined noble metal plating film (9, 10). 4) having
A color plating film characterized by a surface color having both an interference color due to the metal oxide film (4) and a material color of a characteristic noble metal feeling of the inclined noble metal plating films (9, 10).

The noble metal plating film (10) further has a lower plating film (8) on the lower surface of the upper plating film (7);
The color plating according to claim 14, wherein the lower plating film (8) is made of a metal represented by the following general formula (iv), and the upper plating film (7) is made of a metal represented by the following general formula (v). film.
AaXe ... (iv)
AaXf ... (v)
Here, A is one kind of element selected from noble metals, X is at least one kind of element selected from metal I, a, e, and f indicate weight%, and a is e and f with respect to the total weight of each plating film. And e and f include the metal I for each plating film and other unavoidable elements, and are in the range of 10 ≦ e ≦ 100 and 0 ≦ f ≦ 10.

The thickness of the lower plating film (8) is 0.5 μm or less, the thickness of the upper inclined noble metal plating film (7) is 0.5 μm or less, and the thickness of the metal oxide film (4) is 35 nm to 240 nm. The colored plating film as described.

It contains one kind of noble metals and one or more metals I selected from Fe, Co, Ni, Cu, Ti, V, Cr, Zn, Nb, Mo, W and Y, and is represented by the following general formula (iv) A lower plating film (8) made of a metal to be formed is formed, an upper plating film (7) represented by the following general formula (v) is formed on the surface, and the concentration of metal I is increased from the lower surface of the plating film to the surface. After forming the inclined plating film (10) to be lowered, the plating film (10) is subjected to a heat treatment in an oxygen atmosphere at 200 ° C. to 290 ° C. for 30 minutes to 5 hours to form the inclined plating film (10). A method for producing a color plating film, wherein an oxide film of the metal contained in the plating film (10) is formed on the surface.
AaXe ... (iv)
AaXf ... (v)
Here, A is one kind of element selected from noble metals, X is at least one kind of element selected from metal I, a, e, and f indicate weight%, and a is e and f with respect to the total weight of each plating film. And e and f include the metal I for each plating film and other unavoidable elements, and are in the range of 10 ≦ e ≦ 100 and 0 ≦ f ≦ 10.

The method according to claim 17, wherein the step of forming the inclined noble metal plating film (9) is carried out in the same plating bath with a low current density at an early stage of plating and a continuous or discontinuous increase in current density.

The thickness of the lower plating film (8) is 0.5 μm or less, the thickness of the upper inclined noble metal plating film (7) is 0.5 μm or less, and the thickness of the metal oxide film (4) is 35 nm to 240 nm. 19. The method for producing a color plating film according to item 18.

18. The method for producing a color plating film according to claim 5, wherein the oxygen partial pressure in the oxygen atmosphere is 1 MPa to 10 MPa.