JPH0359151B2 - - Google Patents
Info
- Publication number
- JPH0359151B2 JPH0359151B2 JP25647487A JP25647487A JPH0359151B2 JP H0359151 B2 JPH0359151 B2 JP H0359151B2 JP 25647487 A JP25647487 A JP 25647487A JP 25647487 A JP25647487 A JP 25647487A JP H0359151 B2 JPH0359151 B2 JP H0359151B2
- Authority
- JP
- Japan
- Prior art keywords
- electrolysis
- cathode
- stainless steel
- current electrolysis
- alternating current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000005868 electrolysis reaction Methods 0.000 claims description 116
- 239000000463 material Substances 0.000 claims description 29
- 229910001220 stainless steel Inorganic materials 0.000 claims description 28
- 239000010935 stainless steel Substances 0.000 claims description 28
- 238000004040 coloring Methods 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 12
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 10
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 claims description 4
- 239000011259 mixed solution Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 description 32
- 239000011651 chromium Substances 0.000 description 10
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 5
- 238000012733 comparative method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 238000005498 polishing Methods 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 3
- 239000004566 building material Substances 0.000 description 3
- 235000019646 color tone Nutrition 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000010348 incorporation Methods 0.000 description 2
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- JHWIEAWILPSRMU-UHFFFAOYSA-N 2-methyl-3-pyrimidin-4-ylpropanoic acid Chemical compound OC(=O)C(C)CC1=CC=NC=N1 JHWIEAWILPSRMU-UHFFFAOYSA-N 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000002932 luster Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
Landscapes
- Electroplating Methods And Accessories (AREA)
Description
＜産業上の利用分野＞
本発明は、建材用の主要な用途とする耐摩耗性
に優れた、化学発色方法による着色ステンレス鋼
材の製造方法に関する。
＜従来技術とその問題点＞
近年、ステンレス鋼材の建築材としての需要が
高まつており、特に意匠性の面から、着色ステン
レス鋼材の開発が進んでいる。
着色ステンレス鋼材は、その表面に極薄のスピ
ネル型酸化皮膜が存在し、この皮膜の外表面と素
地金属との間で行われる光の干渉作用により色が
ついて見えるというもので、色調は膜厚が厚くな
るに従つて、黒、青、金、紫、緑色と変化する。
この着色ステンレス鋼材は、特に外装用として
用いる場合、表面が他物に接触する機会が多いこ
とから、耐摩耗性が不可欠である。
着色ステンレス鋼材を交番電流電解によつて製
造する方法については、本出願人により従前に出
願され、特開昭61−127899号公報にて開示されて
いる。
かかる方法においては、着色ステンレス鋼材の
耐摩耗性を向上させ、かつ１液１工程で製造する
ことができるが、着色酸化皮膜厚が厚くなると耐
摩耗性が劣り、美観上からも、また耐食性の点か
らも不十分であるという問題がある。
そこで、上記方法を改良して、さらに耐摩耗性
が向上した着色ステンレス鋼材が得られれば、外
装向建材用として着色ステンレス鋼材をより広く
利用することができる。
＜発明の目的＞
本発明は、上述した従来技術の問題点を解決し
ようとしてなされたものであり、その目的とする
ところは、着色ステンレス鋼材の耐摩耗性を著し
く向上させるとともに、このような多彩な色調を
もつ着色ステンレス鋼材を１液１工程で製造する
ことができる着色ステンレス鋼材の製造方法を提
供しようとするにある。
＜問題点を解決するための手段＞
化学着色法による酸化皮膜は、電気化学的には
着色電解液中で陽極電解を行うことにより得られ
る。また、硬膜処理は、着色とは逆に陰極電解を
施すことにより、多孔質な酸化皮膜を強固にして
いる。本発明は、「着色」；陽極電解、「硬膜」；陰
極電解という基本的認識を基にして、鋭意研究を
重ねた結果、陰極パルス電流電解の採用により、
陰極電流を一定条件で断続的に流すことで水素発
生を防ぎ、Cr還元を促進させ、酸化皮膜を強化
できることを見出した。
そこで、着色ステンレス鋼材の製造に際し、交
番電流電解パターンの陰極電解部分に陰極パルス
電流電解を採用すなわち組込むことにより、耐摩
耗性に優れた着色ステンレス鋼材を製造すること
ができることを知見し、本発明に至つた。
＜発明の構成＞
本発明者らは、耐摩耗性向上には最終面にCr
量を富化することが必要であるという知見に基づ
き、最表面Cr量を富化する方法を調べ、ここに
著しくCr量を富化する方法をみつけた。その方
法とは、特開昭61−127899号公報に開示した本発
明者らによる着色ステンレス鋼材の製造方法にお
いて、交番電流電解を行う際に、全工程の後半部
分の陰極電流電解部分に、以下の条件で陰極パル
ス電流電解を採用する方法である。
その条件とは、
陰極電解電流密度；4A／ｄm2〜10A／ｄm2、
１パルス通電時間；0.01ｍsec〜0.1sec、
陰極パルス電流電解時間を、全陰極電解時間
の20％〜50％採用する、
というものである。
このように陰極パルス電流電解を従来の交番電
流電解の陰極電流電解部分に採用することによ
り、特別に硬膜処理を施すことなく、１液１工程
で、発色されるすべての色調において効率良く、
耐摩耗性の著しい向上を図ることができる。
すなわち本発明によれば、２モル以上の６価ク
ロムと2.5モル以上の硫酸を含む混合液中におい
て、陽極電解電流密度0.01〜3.0A／ｄm2、陰極電
解電流密度0.03〜5.0A／ｄm2、繰返し数100Hz以
下の交番電流電解を行なつてステンレス鋼材に着
色する際に、該交番電流電解工程の後半部分の陰
極電解部分に、１パルスの通電時間0.01ｍsec〜
0.1sec、陰極電解電流密度４〜10A／ｄm2で行わ
れる陰極パルス電流電解を、全陰極電解時間の20
〜50％の時間で採用すなわち組込み、電解を行な
うことを特徴とする着色ステンレス鋼材の製造方
法が提供される。
以下に、本発明の着色ステンレス鋼材の製造方
法を詳細に説明する。
ここでいうステンレス鋼材とは、線材、管材、
板材、塊、異形断面材、粉粒体など任意の形状で
よいが、以下の説明は代表的に鋼板について行
う。
化学着色法による酸化皮膜は、Cr2O3主体のも
ので、電気化学的には陽極電解を行うことにより
得られる。また、硬膜処理は、着色とは逆に陰極
電解を施すことにより、多孔質なCr2O3皮膜を強
固にしている。本発明は、前述したように、「着
色」；陽極電解、「硬膜」；陰極電解という基本的
認識を基にして、交互に電流方向を変えて、電解
を行う交番電流電解において、陰極パルス電流電
解を組込ませて陰極電流を一定条件で断続的に流
すことにより、１液１工程で耐摩耗性に著しく優
れた着色ステンレス鋼板が製造できることを見出
した。
ここで用いる溶液は、硫酸濃度が高く、従来は
着色用にのみ用いられてきたものであり、硬膜処
理ができるとは知られていなかつた。
このような着色用溶液でも、硬膜処理が上述の
方法によれば可能であるということは、全く新し
い発見である。
本発明においてなされる交番電流電解は、第１
ａ〜第１ｄ図に示すように、陽・陰極電解の電流
密度と電解時間を適宜に組合せ、所定の回数、
〔６価クロム（２モル以上）＋H2SO4（2.5モル以
上）〕溶液中で、交番電流を印加するものである。
交番電流電解とは、通電時間が例えば秒オーダ
ーで、＋、−交互に繰返される。第１ａ〜１ｄ図に
おいて、縦軸は電解電流密度、横軸は電解時間を
示し、１は陽極電解時間、２は陽極電解電流密
度、３は陰極電解時間、４は陰極電解電流密度で
ある。
この交番電流電解の条件は、陽極電解電流密度
0.01〜3.0A／ｄm2、陰極電解電流密度0.03〜
5.0A／ｄm2、電解繰返し数100Hz以下である。以
下にその理由を記す。
交番電流電解の陽極電解電流密度が0.01A／ｄ
m2未満では全く着色しない。また、3.0A／ｄm2
超では干渉色を有する均一な皮膜が得られないの
で、陽極電解電流密度は0.01〜3.0A／ｄm2の範囲
とする。
交番電流電解の陰極電解電流密度が0.03A／ｄ
m2未満では皮膜は後述の耐摩耗性試験で容易に剥
離する。また、5.0A／ｄm2以上では鋼板表面は、
全面金属光沢になり着色した鋼板とは言い難いの
で、陰極電解電流密度は0.03〜5.0A／ｄm2の範囲
とする。
交番電流電解の電解繰返し数が100Hzを越える
と着色しないので、100Hz以下が適する。
以上に述べた電解条件で、無水クロム酸、重ク
ロム酸ナトリウム、重クロム酸カリウム等の形で
添加した２モル以上の６価クロムと2.5モル以上
の硫酸を含む混合溶液中において交番電流電解を
行う。
本発明は、上記条件下においてなされる交番電
流電解の全工程の後半部分の陰極電解部分に、１
パルスの通電時間0.01ｍsec〜0.1sec、陰極電解電
流密度４〜10A／ｄm2で行われる陰極パルス電流
電解を、全陰極電解時間の20〜50％の時間で採用
し、電解を行なうことに特徴がある。
ここで、陰極パルス電流電解とは、第１ａ〜１
ｄ図に示すように、符号７で示される通電時間が
例えばミリ秒オーダーで、交番電流電解の通電時
間に比して短く、負のパルス電流６のみが通電さ
れ、通電の次に必ず非通電区間があり、この通電
−非通電が２以上繰返される。
この陰極パルス電流電解を上記条件に限定した
理由を以下に述べる。
陰極パルス電流電解の陰極電流密度は、4A／
ｄm2未満では耐摩耗性試験で容易に着色皮膜が剥
離し硬膜の効果がなく、10A／ｄm2を超えるとガ
ス発生が起こり、着色表面が荒れる。
陰極パルス電流電解１パルス通電時間は、0.01
ｍsec未満では耐摩耗性向上に効果がなく、
0.1secを越えるとガス発生が起こり、着色表面が
荒れる。
陰極パルス電流電解の陰極パルス電流電解時間
は、交番電流電解の全陰極電流電解時間の20％未
満では硬膜効果がなく、50％を超えるとガス発生
により着色表面が荒れる。
かかる条件下で行われる陰極パルス電流電解
は、第１ａ〜１ｄ図に示すように、交番電流電解
工程の後半部分の陰極電解部分に採用される。
ここで、交番電流電解の全工程の後半部分と
は、本発明に係る陰極パルス電流電解を採用しな
いと想定した場合における全交番電流電解工程を
二等分した場合における後工程部分をいう。
該後半部分の陰極電解部分への採用すなわち組
込みとは、交番電流電解の陰極電流電解における
秒オーダーの１通電部分において、それに代わ
り、ミリ秒オーダーの陰極パルス電解電流を上記
相当時間流すことをいう。
陰極パルス電流電解の採用を、交番電流電解の
全工程の後半部分に限定した理由は、本発明の陰
極パルス電流電解を着色皮膜が充分に成長してい
ない前半部分に採用すると、陰極電流密度が高す
ぎて着色反応が進みにくい。そこで、後半部分に
限定して採用すると、着色皮膜が充分に成長して
いるので着色皮膜の封孔反応として充分に反応が
進むためである。
この陰極パルス電流電解は交番電流電解工程の
後半部分の初期、中期、後期のいずれかの部分に
集中させても、また全体の分散させても良く、具
体的には第１ａ図（初期に組込んだ場合）、第１
ｂ図（中期に組込んだ場合）、第１ｃ図（後期に
組込んだ場合）および第１ｄ図（全体に分散させ
た場合）のように図示される。
なお、一般的にはパルス電流電解は通電時間と
非通電時間との比は１：１であり、後述する本発
明の実施例についても１：１で行つた。
このように、交番電流電解の後半部分の陰極電
解部分において、陰極パルス電流電解を採用する
ことによりステンレス鋼材に着色・硬膜がなされ
る原理は、交番電流電解の陽極電流電解により酸
化皮膜の着色が促され、陰極電流電解により、多
孔質な酸化皮膜の硬膜化がなされ、特に後半部分
における陰極電流電解部分において陰極パルス電
流電解を行うことにより、陰極電流を一定条件で
断続的に流すことで水素発生を防ぎ、Cr還元が
促進され、前述の酸化皮膜のスピネル結晶の封孔
作用がより強固になされ、硬膜化が促進されるも
のと考えられる。
＜実施例＞
本発明に係る着色ステレス鋼材の製造方法を実
施例につき具体的に説明する。
本発明法、比較法および従来交番電流電解法と
もに、SUS 304 HL（ヘヤーライン仕上げ）材
（大きさ70×72mm）を、（硫酸450g／＋無水ク
ロム酸300g／）溶液中に浸漬し、表１に示す
各条件により、発色させた。
発色後、荷重500ｇｆで摩耗試験機を用いて酸
化クロム0.5μｍ研摩紙で100往復研摩し、研摩後
の皮膜の変化の度合から耐摩耗性を評価した。
本発明法、比較法ともに、陽極電流、陰極電
流、繰返し数を同条件とし、パルス電流電解法を
条件を変えて交番電解電流法に組み込んだ。
また、パルス電解を含まない従来の交番電流電
解を従来交番法として示した。詳しい電解条件と
耐摩耗性の評価を表１にまとめて示す。
評価の基準としては研摩後ほとんど色の変化の
ないものを○、研摩により表面が変色したものを
△、研摩により下地のステンレスが見えたものを
×として目視により判定した。また、イオンマイ
クロアナライザーにより、最表面Cr量を測定し
た結果を示す。さらに、表面状態についても表面
荒れの発生を目視にて観察し、有無として評価し
た。また、陰極パルス電流電解のパターンは第１
ａ〜第１ｄ図で示した通りであり、本発明法およ
び比較法で採用したパターンは表１に示した。
表１から明らかなように、本発明法において
は、最表面Cr量が富化され、比較法、従来交番
電流電解法に比べ、耐摩耗性に優れていることが
わかる。また、表面荒れも全くみられない。これ
らの結果から、本発明により製造された着色ステ
ンレス鋼材の耐摩耗性は、従来法および比較法に
よるものより著しく優れていることは明白であ
る。
<Industrial Field of Application> The present invention relates to a method for producing colored stainless steel materials, which are mainly used as building materials and have excellent wear resistance, by a chemical coloring method. <Prior art and its problems> In recent years, the demand for stainless steel materials as building materials has increased, and the development of colored stainless steel materials is progressing, especially from the standpoint of design. Colored stainless steel materials have an extremely thin spinel-type oxide film on their surface, and appear colored due to the interference of light between the outer surface of this film and the base metal, and the color tone depends on the film thickness. As the color becomes thicker, the color changes to black, blue, gold, purple, and green. Especially when used for exterior purposes, this colored stainless steel material must have wear resistance because its surface often comes into contact with other objects. A method for manufacturing colored stainless steel materials by alternating current electrolysis has been previously filed by the present applicant and disclosed in Japanese Patent Laid-Open No. 127899/1983. In this method, the wear resistance of colored stainless steel materials can be improved and it can be manufactured in one liquid and one process, but as the thickness of the colored oxide film becomes thicker, the wear resistance deteriorates, and from the aesthetic point of view as well as corrosion resistance. There is also the problem that it is insufficient. Therefore, if the above method is improved to obtain a colored stainless steel material with further improved wear resistance, the colored stainless steel material can be used more widely as an exterior building material. <Object of the Invention> The present invention has been made in an attempt to solve the problems of the prior art described above, and its purpose is to significantly improve the wear resistance of colored stainless steel materials, and to An object of the present invention is to provide a method for producing a colored stainless steel material that can produce a colored stainless steel material having a unique color tone using one liquid and one step. <Means for Solving the Problems> An oxide film formed by a chemical coloring method can be obtained electrochemically by performing anodic electrolysis in a colored electrolyte. Also, in hardening treatment, the porous oxide film is strengthened by applying cathode electrolysis, which is the opposite of coloring. The present invention was developed based on the basic understanding of "coloring"; anodic electrolysis; "during"; cathodic electrolysis, and as a result of extensive research, by adopting cathodic pulsed current electrolysis,
It has been discovered that by intermittently passing cathode current under certain conditions, hydrogen generation can be prevented, Cr reduction can be promoted, and the oxide film can be strengthened. Therefore, when manufacturing colored stainless steel materials, it was discovered that it was possible to manufacture colored stainless steel materials with excellent wear resistance by adopting or incorporating cathode pulsed current electrolysis in the cathode electrolysis portion of the alternating current electrolysis pattern, and the present invention. It came to this. <Structure of the invention> The present inventors have discovered that Cr is added to the final surface to improve wear resistance.
Based on the knowledge that it is necessary to enrich the amount of Cr, we investigated ways to enrich the amount of Cr on the outermost surface and found a method to significantly enrich the amount of Cr. The method is that in the manufacturing method of colored stainless steel materials disclosed by the present inventors in JP-A No. 61-127899, when performing alternating current electrolysis, the following is applied to the cathodic current electrolysis portion in the latter half of the entire process. This method employs cathode pulsed current electrolysis under the following conditions. The conditions are: cathode electrolysis current density: 4A/ dm2 to 10A/ dm2 , one pulse current duration: 0.01msec to 0.1sec, cathode pulse current electrolysis time to be 20% to 50% of the total cathode electrolysis time. , . In this way, by adopting cathode pulsed current electrolysis in the cathode current electrolysis part of conventional alternating current electrolysis, all color tones can be developed efficiently with one solution and one process without special hardening treatment.
It is possible to significantly improve wear resistance. That is, according to the present invention, in a mixed solution containing 2 moles or more of hexavalent chromium and 2.5 moles or more of sulfuric acid, an anodic electrolytic current density of 0.01 to 3.0 A/ dm2 and a cathodic electrolytic current density of 0.03 to 5.0 A/ dm2. When coloring stainless steel materials by performing alternating current electrolysis at a repetition rate of 100 Hz or less, one pulse of current is applied for a duration of 0.01 msec to 0.01 msec to the cathode electrolysis portion in the latter half of the alternating current electrolysis process.
Cathodic pulsed current electrolysis performed at 0.1 sec, cathodic electrolysis current density of 4 to 10 A/ dm2 was performed for 20 minutes of the total cathodic electrolysis time.
A method for producing colored stainless steel material is provided, characterized in that the adoption or incorporation and electrolysis occur ~50% of the time. Below, the method for manufacturing colored stainless steel material of the present invention will be explained in detail. Stainless steel materials here include wire rods, pipe materials,
Although any shape may be used, such as a plate, a lump, a modified cross-section material, or a powder, the following description will be made with reference to a steel plate as a representative example. The oxide film formed by the chemical coloring method is mainly composed of Cr 2 O 3 and can be obtained electrochemically by performing anodic electrolysis. Also, in hardening treatment, the porous Cr 2 O 3 coating is strengthened by applying cathode electrolysis, which is the opposite of coloring. As mentioned above, the present invention is based on the basic recognition that "coloring"; anodic electrolysis; "hardening"; cathodic electrolysis. It has been discovered that by incorporating current electrolysis and passing cathode current intermittently under certain conditions, it is possible to produce a colored stainless steel sheet with extremely excellent wear resistance in one process using one liquid. The solution used here has a high sulfuric acid concentration and has conventionally been used only for coloring, and was not known to be capable of hardening. It is a completely new discovery that even with such a coloring solution, film hardening is possible according to the above-mentioned method. The alternating current electrolysis performed in the present invention is the first
As shown in Figures a to 1d, the current density and electrolysis time of anode/cathode electrolysis are appropriately combined, and the electrolysis is carried out a predetermined number of times.
An alternating current is applied in a solution of [hexavalent chromium (2 moles or more) + H 2 SO 4 (2.5 moles or more)]. In alternating current electrolysis, the current application time is, for example, on the order of seconds, and is repeated alternately. In FIGS. 1a to 1d, the vertical axis shows the electrolysis current density, and the horizontal axis shows the electrolysis time, where 1 is the anodic electrolysis time, 2 is the anodic electrolysis current density, 3 is the cathodic electrolysis time, and 4 is the cathodic electrolysis current density. The conditions for this alternating current electrolysis are the anodic electrolysis current density
0.01~3.0A/ dm2 , cathode electrolysis current density 0.03~
5.0A/dm 2 and electrolysis repetition rate of 100Hz or less. The reason is described below. The anodic electrolysis current density of alternating current electrolysis is 0.01A/d
If it is less than m2 , it will not be colored at all. Also, 3.0A/ dm2
Since a uniform film with interference color cannot be obtained at a temperature exceeding 0.05 m, the anodic electrolytic current density is set in the range of 0.01 to 3.0 A/dm 2 . The cathode electrolysis current density of alternating current electrolysis is 0.03A/d
If it is less than m 2 , the film will easily peel off in the abrasion resistance test described below. In addition, at 5.0A/dm 2 or more, the steel plate surface becomes
Since it is hard to say that the steel sheet has a metallic luster on the entire surface and is colored, the cathode electrolytic current density is set in the range of 0.03 to 5.0 A/dm 2 . If the electrolysis repetition rate of alternating current electrolysis exceeds 100Hz, coloring will not occur, so a frequency of 100Hz or less is suitable. Under the electrolysis conditions described above, alternating current electrolysis was carried out in a mixed solution containing 2 moles or more of hexavalent chromium added in the form of chromic anhydride, sodium dichromate, potassium dichromate, etc. and 2.5 moles or more of sulfuric acid. conduct. The present invention provides that the cathode electrolysis portion of the latter half of the entire process of alternating current electrolysis performed under the above conditions is
It is characterized by the use of cathode pulse current electrolysis, which is performed at a pulse current density of 4 to 10 A/ dm2 , with a pulse current duration of 0.01 msec to 0.1 sec, for 20 to 50% of the total cathode electrolysis time. There is. Here, cathode pulsed current electrolysis refers to 1a to 1
As shown in Figure d, the energization time indicated by the symbol 7 is, for example, on the order of milliseconds, which is shorter than the energization time in alternating current electrolysis, and only a negative pulse current 6 is energized, and there is always a de-energization period after energization. There is a section, and this energization/de-energization is repeated two or more times. The reason why this cathode pulsed current electrolysis was limited to the above conditions will be described below. The cathode current density of cathode pulsed current electrolysis is 4A/
If it is less than dm 2 , the colored film will easily peel off in the abrasion resistance test and there will be no hardening effect, and if it exceeds 10 A/dm 2 , gas will be generated and the colored surface will become rough. Cathode pulse current electrolysis 1 pulse energization time is 0.01
If it is less than msec, it will not be effective in improving wear resistance.
If the time exceeds 0.1 sec, gas generation will occur and the colored surface will become rough. If the cathode pulse current electrolysis time of cathode pulse current electrolysis is less than 20% of the total cathode current electrolysis time of alternating current electrolysis, there will be no hardening effect, and if it exceeds 50%, the colored surface will become rough due to gas generation. Cathodic pulsed current electrolysis carried out under such conditions is employed in the cathodic electrolysis portion of the latter half of the alternating current electrolysis process, as shown in Figures 1a-1d. Here, the latter part of the entire alternating current electrolysis process refers to the latter part when the entire alternating current electrolysis process is divided into two, assuming that the cathode pulsed current electrolysis according to the present invention is not adopted. The adoption or incorporation of the latter half into the cathode electrolysis section means that in one energization section on the order of seconds in cathode current electrolysis of alternating current electrolysis, instead of it, a cathode pulse electrolysis current on the order of milliseconds is passed for the corresponding period of time. . The reason why we limited the use of cathode pulsed current electrolysis to the latter half of the entire process of alternating current electrolysis is that if the cathode pulsed current electrolysis of the present invention is employed in the first half where the colored film has not grown sufficiently, the cathode current density will increase. It is too high and the coloring reaction is difficult to proceed. Therefore, if the reaction is limited to the latter half, the reaction proceeds sufficiently as a pore-sealing reaction of the colored film since the colored film has grown sufficiently. This cathode pulsed current electrolysis may be concentrated in any of the early, middle, and late stages of the latter half of the alternating current electrolysis process, or it may be dispersed throughout the entire process. ), 1st
They are illustrated in Figure b (when incorporated in the middle stage), Figure 1c (when incorporated in the late stage), and Figure 1d (when dispersed throughout). Generally, pulse current electrolysis has a ratio of energizing time to non-energizing time of 1:1, and the ratio of energizing time to non-energizing time is 1:1 in the examples of the present invention to be described later. In this way, the principle behind coloring and hardening of stainless steel materials by adopting cathode pulsed current electrolysis in the cathodic electrolysis part of the second half of alternating current electrolysis is that the oxide film is colored and hardened by the anodic current electrolysis of alternating current electrolysis. is promoted, and the porous oxide film is hardened by cathodic current electrolysis. By performing cathodic pulsed current electrolysis especially in the cathodic current electrolysis part in the latter half, cathodic current is passed intermittently under certain conditions. It is thought that this prevents hydrogen generation, promotes Cr reduction, strengthens the pore-sealing effect of the spinel crystals in the oxide film, and promotes hardening. <Example> The method for manufacturing a colored stainless steel material according to the present invention will be specifically described with reference to an example. In both the inventive method, the comparative method, and the conventional alternating current electrolysis method, SUS 304 HL (hairline finish) material (size 70 x 72 mm) was immersed in a solution (450 g of sulfuric acid/+300 g of chromic anhydride/). Color was developed under each condition shown in 1. After color development, the film was polished 100 times with a chromium oxide 0.5 μm abrasive paper using an abrasion tester under a load of 500 gf, and the wear resistance was evaluated from the degree of change in the film after polishing. In both the present invention method and the comparative method, the anodic current, cathodic current, and repetition rate were set to the same conditions, and the pulse current electrolysis method was incorporated into the alternating current electrolysis method under different conditions. In addition, conventional alternating current electrolysis that does not include pulsed electrolysis is shown as a conventional alternating method. Detailed electrolytic conditions and wear resistance evaluation are summarized in Table 1. The evaluation criteria were as follows: ◯ if there was almost no color change after polishing, △ if the surface changed color due to polishing, and × if the underlying stainless steel was visible after polishing. Also shown are the results of measuring the amount of Cr on the outermost surface using an ion microanalyzer. Furthermore, regarding the surface condition, occurrence of surface roughness was visually observed and evaluated as presence or absence. In addition, the pattern of cathode pulsed current electrolysis is
The patterns adopted in the method of the present invention and the comparative method are shown in Table 1. As is clear from Table 1, in the method of the present invention, the amount of Cr on the outermost surface is enriched, and the wear resistance is superior to that of the comparative method and the conventional alternating current electrolysis method. Moreover, no surface roughness is observed at all. From these results, it is clear that the wear resistance of the colored stainless steel materials produced by the present invention is significantly superior to those produced by conventional and comparative methods.
【表】【table】
【表】
＜発明の効果＞
以上詳述したように本発明によれば、従来の交
番電流電解工程の後半部分の陰極電流電解部分に
陰極パルス電流電解を採用することにより、着色
皮膜の硬膜化が促進され、連続的に、１液１工程
で耐摩耗性に著しく優れた着色ステンレス鋼材の
製造方法を提供することができるという効果があ
る。[Table] <Effects of the Invention> As detailed above, according to the present invention, by employing cathode pulsed current electrolysis in the cathode current electrolysis portion in the latter half of the conventional alternating current electrolysis process, the hardening of the colored film can be improved. The present invention has the effect that it is possible to provide a method for producing a colored stainless steel material with extremely excellent wear resistance in a continuous, one-liquid, one-step process.
第１ａ図、第１ｂ図、第１ｃ図および第１ｄ図
は、それぞれ、本発明に用いられる交番電流電解
と、それに組込まれるパルス電流電解による着色
ステンレス鋼材の製造方法の電解条件を模式的に
示した図である。
符号の説明、１……交番電流電解の陽極電解時
間、２……交番電流電解の陽極電解電流密度、３
……交番電流電解の陰極電解時間、４……交番電
流電解の陰極電解電流密度、６……パルス電流電
解の負のパルス電流、７……パルス電流電解の１
パルスの通電時間。
Figures 1a, 1b, 1c, and 1d schematically show the electrolytic conditions of the alternating current electrolysis used in the present invention and the method for manufacturing colored stainless steel materials by pulsed current electrolysis incorporated therein, respectively. This is a diagram. Explanation of symbols, 1... Anodic electrolysis time of alternating current electrolysis, 2... Anodic electrolysis current density of alternating current electrolysis, 3
...Cathode electrolysis time of alternating current electrolysis, 4...Cathode electrolysis current density of alternating current electrolysis, 6...Negative pulse current of pulsed current electrolysis, 7...1 of pulsed current electrolysis
Pulse energization time.
Claims (1)
酸を含む混合液中において、陽極電解電流密度
0.01〜3.0A／ｄm2、陰極電解電流密度0.03〜
5.0A／ｄm2、繰返し数100Hz以下の交番電流電解
を行なつてステンレス鋼材に着色する際に、該交
番電流電解工程の後半部分の陰極電解部分に、１
パルスの通電時間0.01ｍsec〜0.1sec、陰極電解電
流密度４〜10A／ｄm2で行われる陰極パルス電流
電解を、全陰極電解時間の20〜50％の時間で採用
し、電解を行なうことを特徴とする着色ステンレ
ス鋼材の製造方法。1 In a mixed solution containing 2 moles or more of hexavalent chromium and 2.5 moles or more of sulfuric acid, the anodic electrolytic current density
0.01~3.0A/ dm2 , cathode electrolysis current density 0.03~
When coloring stainless steel materials by performing alternating current electrolysis at 5.0 A/dm 2 and a repetition rate of 100 Hz or less, 1
It is characterized by the use of cathode pulsed current electrolysis, which is performed at a pulse current density of 4 to 10 A/ dm2 , with a pulse current density of 0.01 msec to 0.1 sec, for 20 to 50% of the total cathode electrolysis time. A method for producing colored stainless steel material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25647487A JPH01100299A (en) | 1987-10-12 | 1987-10-12 | Production of colored stainless steel material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25647487A JPH01100299A (en) | 1987-10-12 | 1987-10-12 | Production of colored stainless steel material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01100299A JPH01100299A (en) | 1989-04-18 |
| JPH0359151B2 true JPH0359151B2 (en) | 1991-09-09 |
Family
ID=17293137
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25647487A Granted JPH01100299A (en) | 1987-10-12 | 1987-10-12 | Production of colored stainless steel material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01100299A (en) |
-
1987
- 1987-10-12 JP JP25647487A patent/JPH01100299A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01100299A (en) | 1989-04-18 |
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