JP3131324B2 - Pretreatment method for coating stainless steel - Google Patents
Pretreatment method for coating stainless steelInfo
- Publication number
- JP3131324B2 JP3131324B2 JP04361360A JP36136092A JP3131324B2 JP 3131324 B2 JP3131324 B2 JP 3131324B2 JP 04361360 A JP04361360 A JP 04361360A JP 36136092 A JP36136092 A JP 36136092A JP 3131324 B2 JP3131324 B2 JP 3131324B2
- Authority
- JP
- Japan
- Prior art keywords
- potential
- stainless steel
- film
- coating
- noble
- 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 - Fee Related
Links
Landscapes
- Chemical Treatment Of Metals (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、有機質被覆層との密着
性が優れた皮膜をステンレス鋼の表面に形成する被覆前
処理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating pretreatment method for forming a film having excellent adhesion to an organic coating layer on the surface of stainless steel.
【０００２】[0002]
【従来の技術】ステンレス鋼は、耐食性が優れているこ
とを生かして、建材、各種プラント用構造部材、厨房用
品等の広範な分野で使用されている。この使用分野の多
用化に伴って、ステンレス鋼に対して意匠性を高め、商
品価値をあげるべく、各種着色法、有機質被覆法等が開
発されている。ステンレス鋼の有機質被覆に先立って、
脱脂，粗面化，化成処理等の前処理が施されている。ま
た、脱脂、粗面化、化成処理等を適宜組み合わせて、ス
テンレス鋼を有機質被覆に適した表面状態に調整してい
る。2. Description of the Related Art Stainless steel has been used in a wide range of fields such as building materials, structural members for various plants, kitchenware, etc., taking advantage of its excellent corrosion resistance. With the diversification of fields of use, various coloring methods, organic coating methods and the like have been developed in order to enhance the design of stainless steel and increase its commercial value. Prior to the organic coating of stainless steel,
Pretreatments such as degreasing, surface roughening, and chemical conversion are performed. In addition, stainless steel is adjusted to a surface state suitable for organic coating by appropriately combining degreasing, surface roughening, and chemical conversion treatment.
【０００３】[0003]
【発明が解決しようとする課題】塗布型クロメート処理
は、これらの前処理の中で最も普及しており、且つ生成
した皮膜は有機質被覆層との密着性に優れている。塗布
型クロメート処理液に含まれる６価及び３価のＣｒは、
有機質被覆層との架橋及び自己重合による強固な皮膜を
形成する作用を有しているため、有機質被覆層に対して
高い接着力を発現する。しかし、ステンレス鋼の表面は
極めて安定で反応性に乏しいため、クロメート皮膜をス
テンレス鋼の上に密着性良く形成させるためには適切な
下地処理が必要である。The coating type chromate treatment is the most widespread of these pretreatments, and the resulting film has excellent adhesion to the organic coating layer. Hexavalent and trivalent Cr contained in the coating type chromate treatment liquid are as follows:
Since it has a function of forming a strong film by crosslinking with the organic coating layer and self-polymerization, it exhibits high adhesive strength to the organic coating layer. However, since the surface of stainless steel is extremely stable and poor in reactivity, an appropriate base treatment is required to form a chromate film on stainless steel with good adhesion.
【０００４】下地処理として実用的な方法に、アルカリ
による表面の清浄化、フッ硝酸浸漬，硫酸浸漬，リン酸
浸漬等による活性化が行われている。しかし、有機質皮
膜形成後に加工を施した場合，高温に加熱した場合等で
は、塗布型クロメート皮膜との十分な密着性を保持でき
ない。亜鉛系めっき鋼鈑では、予めＺｎ，Ｆｅ，Ｎｉ，
Ｃｏ等のイオンを含有する処理液で処理し、これらの金
属を表面に置換析出させた後、塗布型クロメート処理を
施すことによりクロメート皮膜の吸着固定を促す方法が
行なわれている（特開平４−１９８４８８号公報参
照）。しかし、表面が不活性なステンレス鋼において
は、同様の置換析出は起こらないので、金属イオン含有
溶液による処理で十分な性能が得られない。[0004] Practical methods for undercoating include cleaning of the surface with an alkali, immersion in hydrofluoric / nitric acid, immersion in sulfuric acid, immersion in phosphoric acid, and the like. However, when processing is performed after the formation of the organic film, or when the film is heated to a high temperature, sufficient adhesion with the coating type chromate film cannot be maintained. In the case of galvanized steel sheet, Zn, Fe, Ni,
A method is known in which a treatment solution containing ions such as Co is used to displace and precipitate these metals on the surface, and then a coating-type chromate treatment is performed to promote the adsorption and fixation of the chromate film (Japanese Patent Laid-Open No. Hei 4 (1994)). -198488). However, in stainless steel having an inert surface, the same substitutional precipitation does not occur, so that sufficient performance cannot be obtained by treatment with a metal ion-containing solution.
【０００５】本発明は、このような問題を解決すべく案
出されたものであり、塗布型クロメート処理を行なう前
の下地調整として、特定波形のパルス電位をステンレス
鋼に印加することにより、鋼中に含有されている各金属
を利用した溶解−析出反応を行なわせ、密着性の優れた
塗布型クロメート皮膜を有する有機質被覆用ステンレス
鋼を得ることを目的とする。The present invention has been devised to solve such a problem. As a base adjustment before performing a coating-type chromate treatment, a pulse potential of a specific waveform is applied to stainless steel to adjust the base. An object of the present invention is to perform a dissolution-precipitation reaction using each metal contained therein to obtain an organic coating stainless steel having a coating type chromate film having excellent adhesion.
【０００６】[0006]
【課題を解決するための手段】本発明の被覆前処理方法
は、その目的を達成するため、Ｎｉを含むステンレス鋼
を酸性電解浴に浸漬し、Ｃｒの不働態化電位Ｅ1 より卑
の電位範囲ＥL と、Ｆｅの自然電位Ｅ2 からＦｅの不働
態化完了電位Ｅ3 までの貴の電位範囲ＥH との間で振幅
する方形波電位を、前記ステンレス鋼に印加し、Ｆｅ，
Ｎｉの酸化物及び水酸化物を含む皮膜を前記ステンレス
鋼の表面に形成した後、塗布型クロメート処理を施すこ
とを特徴とする。Coating pretreatment method of the present invention, in order to solve the problems] In order to achieve the object, immersing the stainless steel containing Ni in an acidic electrolytic bath, baser potential than passivation potential E 1 of Cr a range E L, a square wave voltage swinging between the potential range E H noble from spontaneous potential E 2 of Fe to passivation complete potential E 3 of Fe, was applied to the stainless steel, Fe,
After forming a film containing an oxide and a hydroxide of Ni on the surface of the stainless steel, a coating type chromate treatment is performed.
【０００７】ステンレス鋼としては、オーステナイト系
ステンレス鋼，フェライト系ステンレス鋼，二相ステン
レス鋼等があり、Ｃｒ含有量が１０％以下のステンレス
鋼も使用することができる。本発明に従った電解処理で
は、Ｃｒの他にＮｉを含有するステンレス鋼が使用され
る。含有されるＮｉは、ステンレス鋼中に不可避的に混
入するもの、或いは耐食性，加工性等を改善するための
合金元素として積極的に添加されるもの、何れであって
も良い。同様に、Ｃｕを含むステンレス鋼も使用可能で
ある。酸性電解浴としては、硫酸浴を始めとして、硝酸
溶液，リン酸溶液等を混合した酸性溶液を使用すること
ができる。この酸性電解液には、貴の電位範囲における
電解でステンレス鋼から金属イオンが溶出するため、皮
膜形成素材となる金属イオンを別途添加する必要がな
い。As the stainless steel, there are austenitic stainless steel, ferritic stainless steel, duplex stainless steel and the like, and stainless steel having a Cr content of 10% or less can also be used. In the electrolytic treatment according to the present invention, stainless steel containing Ni in addition to Cr is used. The contained Ni may be either inevitably mixed into stainless steel or actively added as an alloy element for improving corrosion resistance, workability, and the like. Similarly, stainless steel containing Cu can be used. As the acidic electrolytic bath, an acidic solution obtained by mixing a nitric acid solution, a phosphoric acid solution, and the like, such as a sulfuric acid bath, can be used. Since metal ions are eluted from stainless steel by electrolysis in a noble potential range to the acidic electrolyte, it is not necessary to separately add metal ions to be a film forming material.
【０００８】[0008]
【作 用】以下、ステンレス鋼の代表的な材料ＳＵＳ３
０４を例にとって説明する。本発明者等は、パルス電位
の印加によってステンレス鋼を電解するとき、ステンレ
ス鋼の表面に形成される皮膜の構造に与えるパルス電位
の波形の影響を調査・研究した。そして、Ｃｒの不動態
化電位Ｅ1 より卑な電位範囲ＥL と、Ｆｅの自然電位Ｅ
２からＦｅの不働態化完了電位Ｅ3 までを貴の電位範囲
ＥH として、これら卑の電位範囲ＥL と貴の電位範囲Ｅ
H との間で振幅する方形波電位をステンレス鋼板に印加
するとき、たとえば、電解浴温度２５℃の場合に合計印
加時間が３０秒を越えると、クロメート皮膜との密着性
の良好な皮膜がステンレス鋼表面に形成されることを見
い出した。[Operation] The following is a typical stainless steel material, SUS3.
04 will be described as an example. The present inventors have investigated and studied the effect of the pulse potential waveform on the structure of a film formed on the surface of stainless steel when electrolyzing stainless steel by applying a pulse potential. Then, a potential range E L of less noble than passivation potential E 1 of Cr, self-potential of the Fe E
From No. 2 to the passivation completion potential E 3 of Fe is defined as the noble potential range E H , these low potential range E L and the noble potential range E H
When a square wave potential that swings between H and H is applied to a stainless steel plate, for example, when the total application time exceeds 30 seconds at an electrolytic bath temperature of 25 ° C., a film having good adhesion to a chromate film is formed. It was found to form on the steel surface.
【０００９】ＳＵＳ３Ｏ４系のステンレス鋼は、図ｌの
分極曲線を示す電位一電流密度の関係にある。なお、図
１には、Ｆｅ，Ｃｒ及びＮｉの分極曲線を併せ示してい
る。図ｌから明らかなように、ＳＵＳ３Ｏ４系ステンレ
ス鋼の分極曲線は、Ｆｅ，Ｃｒ及びＮｉの分極曲線を重
ね合わせたものである。そして、Ｏ．５ｋｍｏ１／ｍ 3
硫酸水溶液においては、卑の電位範囲ＥL は−０．４
２Ｖ（ｖｓ ＳＨＥ）以下の電位であり、貴の電位範囲
ＥH は−０．２８〜Ｏ．７８Ｖ（ｖｓ ＳＨＥ）であ
る。SUS3O4 series stainless steel is shown in FIG.
There is a relationship between potential and current density showing a polarization curve. The figure
1, the polarization curves of Fe, Cr and Ni are also shown.
You. As is clear from FIG. 1, SUS3O4 stainless steel
The polarization curve of stainless steel overlaps the polarization curves of Fe, Cr and Ni.
It is a combination. And O. 5 kmo1 / m Three
In the aqueous sulfuric acid solution, the base potential range EL Is -0.4
2V (vs SHE) or less potential, noble potential range
EH Is -0.28-O. 78V (vs SHE)
You.
【００１０】卑の電位範囲ＥL 及び貴の電位範囲ＥH そ
れぞれから適当な電解電位ＥL'及びＥH'を選び、電位Ｅ
L'及びＥH'をステンレス鋼に交互に印加して電解を行な
うとき、鋼表面から不働態皮膜が除去され、清浄化及び
活性度の均質化が図られる。また、鋼に含まれている金
属の溶解−析出反応が進行し、有機質被覆層に対して親
和性の強い表面状態になる。貴の電位範囲ＥH における
電解では、ステンレス鋼に含まれている金属元素Ｆｅ，
Ｃｒ，Ｎｉ等が溶出する。主としてＦｅ，Ｎｉイオン
は、卑の電位範囲ＥLにおける電解によって形成される
皮膜形成材料の補給源となる。このとき、ステンレス鋼
にＣｕが含まれている場合には、ＣｕもＦｅ，Ｎｉ等と
同様に貴の電位範囲ＥH で溶解する。An appropriate electrolytic potential E L ′ and E H ′ is selected from each of the base potential range E L and the noble potential range E H , and the potential E
L 'and E H' when the performing electrolysis by applying alternately a stainless steel, are passive film removed from the steel surface, homogenization of cleaning and activity can be achieved. Further, the dissolution-precipitation reaction of the metal contained in the steel proceeds, and a surface state having a strong affinity for the organic coating layer is obtained. In the electrolysis in the noble potential range E H , the metal elements Fe,
Cr, Ni, etc. elute. Mainly Fe, Ni ions, a supply source of the film-forming material formed by electroless the potential range E L of less noble. At this time, if it contains Cu in a stainless steel, Cu also Fe, dissolved in the potential range E H noble as with Ni or the like.
【００１１】卑の電位範囲ＥL における電解では、貴の
電位範囲ＥH における電解で溶解した金属イオンが析出
し、ステンレス鋼表面に皮膜を形成する。皮膜中にはＦ
ｅ，Ｎｉ，Ｃｕ等が電解前よりも高濃度に存在し、クロ
メート皮膜との密着性が向上する。密着性の向上には、
皮膜との相互作用が最も有効に寄与するものと推察され
る。卑の電位範囲ＥL 及び貴の電位範囲ＥH のそれぞれ
から適当な電位を選び、その電位をステンレス鋼板に交
互に印加して電解することにより、析出したＦｅ，Ｎｉ
及びＣｕの酸化物，水酸化物及び硫化物が混在して、ク
ロメート皮膜と相互作用する皮膜を形成される。この皮
膜の上に塗布型クロメート皮膜を形成することにより、
有機被覆層との密着性の高い表面を作ることができる。In electrolysis in the lower potential range E L , dissolved metal ions precipitate in the electrolysis in the noble potential range E H and form a film on the surface of stainless steel. F in the film
e, Ni, Cu, etc. are present at a higher concentration than before electrolysis, and the adhesion to the chromate film is improved. To improve adhesion,
It is presumed that the interaction with the film contributes most effectively. An appropriate potential is selected from each of the base potential range E L and the noble potential range E H , and the potential is alternately applied to the stainless steel plate to perform electrolysis, thereby depositing Fe and Ni.
And oxides, hydroxides and sulfides of Cu and Cu are mixed to form a film that interacts with the chromate film. By forming a coating type chromate film on this film,
A surface having high adhesion to the organic coating layer can be produced.
【００１２】塗布型クロメート皮膜は、先ず電解皮膜の
析出金属化合物に吸着し、次にクロメート皮膜を加熱造
膜する際にこれらの析出金属化合物と脱水一次結合を形
成することにより、ステンレス鋼表面に強固に密着する
と考えられる。したがって、Ｆｅ，Ｎｉ，Ｃｕの酸化
物，水酸化物及び硫化物を含む緻密な皮膜をステンレス
鋼表面に生成させることにより、クロメート皮膜の密着
性が向上する。卑の電位範囲ＥL における電解と貴の電
位範囲ＥH における電解とを交互に繰り返すことによ
り、換言すれば方形波電位を繰り返し印加することによ
り、金属の溶解量は増大し、皮膜も厚く成長する。形成
される皮膜は、貴の電位範囲ＥHにおける電解で電解浴
中にステンレス鋼から溶出した金属イオンを補給源とす
るため、電解浴中に皮膜素材となる金属イオンを必要と
しない。The coating type chromate film is first adsorbed on the deposited metal compound of the electrolytic film, and then forms a dehydration linear bond with the deposited metal compound when the chromate film is heated to form a film. It is thought that it adheres firmly. Therefore, the adhesion of the chromate film is improved by forming a dense film containing oxides, hydroxides and sulfides of Fe, Ni and Cu on the stainless steel surface. By repeating noble of an electrolyte in a potential range E H of electrolyte and noble in potential range E L alternately, by repetitively applying a square wave voltage in other words, the amount of dissolved metal is increased, the film also thicker growth I do. Film formed is, for the metal ions eluted from the stainless steel in an electrolytic bath in the electrolysis in the potential range E H noble and supply source, does not require the metal ions of coating material in the electrolytic bath.
【００１３】塗布型クロメート皮膜の有機質被覆層との
優れた親和性は、通常の有機質材料を積層する場合や塗
料を焼き付け塗装する場合は勿論、カチオン電着塗装の
場合も同様に効果的であり、密着性に優れた有機質被覆
層が形成される。すなわち、被塗着物を陰極とするカチ
オン電着塗装においては、皮膜の特性を保ったままで塗
料が電着され、その後の塗装焼き付けにより三次元架橋
が行なわれる。この塗装焼き付け時に、通常の焼き付け
塗装と同様に塗布型クロメート皮膜と塗膜との脱水縮合
反応が生じ、密着性に優れた強固な塗膜が形成されると
推察される。卑の電位範囲ＥL における電解は、Ｃｒの
不働態化電位Ｅ1 よりも低い電位で行なうことが必要で
ある。電解電位がＣｒの不働態化電位Ｅ1 よりも高い
と、十分な還元反応を起こらず、貴の電位範囲ＥH で溶
出させた金属イオンを析出させることができない。ただ
し、卑の電位範囲ＥL は、低すぎると水素発生反応が優
先的に起こり、皮膜形成反応の効率が低下することか
ら、−ｌ．５ＯＶ（ｖｓＳＨＥ）以上が好ましい。The excellent affinity of the coating type chromate film with the organic coating layer is effective not only in the case of laminating ordinary organic materials and baking paint, but also in the case of cationic electrodeposition coating. Thus, an organic coating layer having excellent adhesion is formed. That is, in the cation electrodeposition coating using an object to be coated as a cathode, the coating is electrodeposited while maintaining the properties of the film, and three-dimensional crosslinking is performed by subsequent baking of the coating. It is presumed that a dehydration-condensation reaction between the coating type chromate film and the coating film occurs during the coating baking in the same manner as in normal baking coating, and a strong coating film having excellent adhesion is formed. Electrolyte in a potential range E L of less noble, it is necessary to perform at a lower potential than the passivation potential E 1 of Cr. When electrolysis potential is higher than the passivation potential E 1 of Cr, not occur a sufficient reduction reaction, it is impossible to deposit a metal ion eluted with potential range E H noble. However, the potential range E L of less noble is too low occurs hydrogen generation reaction is preferentially, since the efficiency is decreased film forming reaction, -l. 50 OV (vs SHE) or more is preferable.
【００１４】貴の電位範囲ＥH における電解は、Ｆｅの
自然電位Ｅ2 よりも高く、Ｆｅの不働態化完了電位Ｅ3
よりも低い電位で行なうことが必要である。自然電位Ｅ
2 よりも低い電位での電解では、Ｆｅの活性溶解が起こ
らず、Ｃｒの溶解のみが優先的に進行する。そのため、
卑の電位ＥL で保持したとき、金属の析出がなく、密着
性に優れた皮膜が形成されない。貴の電位ＥH がＦｅの
自然電位Ｅ2 より高いとき、Ｎｉ，Ｃｕの自然電位以下
の電位で電解しても、Ｆｅ及びＣｒは勿論、Ｎｉ及びＣ
ｕも溶解する。その結果、卑の電位ＥL に保持したと
き、Ｆｅ，Ｃｒ，Ｎｉ，及びＣｕが複合した析出皮膜が
形成される。The electrolysis in the noble potential range E H is higher than the natural potential E 2 of Fe and the passivation completion potential E 3 of Fe
It is necessary to perform at a lower potential. Natural potential E
In electrolysis at a potential lower than 2 , active dissolution of Fe does not occur, and only dissolution of Cr proceeds preferentially. for that reason,
When kept at less noble potential E L, no metal deposition, a film excellent in adhesion can not be formed. When the noble potential E H is higher than the natural potential E 2 of Fe, even if electrolysis is performed at a potential lower than the natural potential of Ni or Cu, Ni and C
u also dissolves. As a result, when held at a potential more negative E L, Fe, Cr, Ni, and Cu deposited film is combined is formed.
【００１５】塗布型クロメート処理としては、通常用い
られる塗布型クロメート処理剤が使用できる。具体的に
は、処理剤の主成分が、全Ｃｒ量５〜８Ｏｇ／ｌのうち
３価の比率が０．ｌ〜Ｏ．７であり、ＳｉＯ2 ，有機高
分子，リン酸，シランカップリング剤等を含む溶液であ
る。方形波電位電解した表面にＣｒ付着量で１０〜１５
Ｏｍｇ／ｍ2 となるように処理剤を塗布した後、乾燥し
て造膜させる。このように、本発明においては、電解電
流を制御することなく、卑の電位範囲ＥL 及び貴の電位
範囲ＥH それぞれにおける電解電位を設定することによ
り、電気化学反応を任意に制御し、塗布型クロメート皮
膜を強固にステンレス鋼表面に形成させ、有機質被覆層
の下地として好適なステンレス鋼表面に形成する。方形
波電位電解で形成した皮膜に塗布型クロメート処理下地
としての機能を発現させるためには、卑の電位範囲ＥL
及び貴の電位範囲ＥH それぞれにおける電解電位の印加
時間を一回当り０．０１〜１０秒，パルス電位の繰返し
回数を４回以上に設定することが好ましい。As the coating type chromate treatment, a commonly used coating type chromate treatment agent can be used. Specifically, the main component of the treatment agent has a trivalent ratio of 0. l-O. 7, a solution containing SiO 2 , an organic polymer, phosphoric acid, a silane coupling agent, and the like. 10 to 15 Cr adhesion amount on square wave potential electrolyzed surface
After applying the treating agent to Omg / m 2 , it is dried to form a film. Thus, in the present invention, without controlling the electrolysis current, by setting the electrolyte potential in the potential range E L and the potential range E H respective noble more negative, and arbitrarily controlled electrochemical reactions, coating A mold chromate film is firmly formed on the surface of the stainless steel, and is formed on the surface of the stainless steel suitable as a base for the organic coating layer. To express the function as a coating-type chromate treatment underlying the formed film by square wave potential electrolysis, potential more negative range E L
And 0.01 to 10 seconds per once the application time of the electrolysis potential in the potential range E H respective noble, it is preferable to set the number of repetitions of the pulse potential than 4 times.
【００１６】[0016]
【実施例】板厚０．６ｍｍのＳＵＳ３Ｏ４ステンレス鋼
板（Ｎｉ含有量８．０２重量％）をｌ００ｍｍ角の大き
さに切断して、試験片とした。試験片の表面を、ジクロ
ルメタンの液及び蒸気で脱脂した後、方形波電位を印加
する電解を行つた。電解浴としては、２５℃に保った
０．５ｋｍｏｌ／ｍ3 の硫酸溶液を使用した。電解に用
いた電位波形を図２に示す。貴の電解電位ＥH における
電解時間ｔH 及び卑の電解電位ＥL における電解時間ｔ
L は、何れも０．１秒に設定した。塗布型クロメート処
理は、Ｃｒ3+比率０．５に還元したクロム酸３５ｇ／ｌ
及びＳｉＯ2 ２Ｏｇ／ｌを含む溶液を処理液として用
い、卜ータルＣｒ付着量が３０ｍｇ／ｍ2 となるように
塗布し、１５０℃で乾燥した。EXAMPLE A 0.6 mm thick SUS3O4 stainless steel sheet (Ni content: 8.02% by weight) was cut into a 100 mm square size to obtain a test piece. After the surface of the test piece was degreased with dichloromethane and liquid, steam was applied to apply a square wave potential. As the electrolytic bath, a 0.5 kmol / m 3 sulfuric acid solution kept at 25 ° C. was used. FIG. 2 shows a potential waveform used for electrolysis. Electrolysis time t in the electrolytic potential E L of electrolysis time t H, and baser in the electrolytic potential E H noble
L was set to 0.1 second in each case. The coating type chromate treatment is performed using a chromic acid reduced to a Cr 3+ ratio of 0.5 at 35 g / l.
And using a solution containing SiO 2 2Og / l as the processing liquid, Bok Taru Cr deposition amount is coated to a 30 mg / m 2, and dried at 0.99 ° C..
【００１７】前処理を施した試験片に、焼付け後の塗膜
厚さが２０μｍとなるようにアクリル樹脂を含有したフ
ッ素樹脂塗料を塗装し、焼き付けた。形成された塗膜の
密着性を、次の試験方法で調べた。ｌｍｍ間隔の枡目が
１００個になるように、塗膜表面から下地鋼に達する切
込みをカッターで試験片に入れた。次いで、試験片を沸
騰水中に２４時間浸漬した。試験片を沸騰水から取り出
した後、水分を拭き取り、直ちに切込みを入れた試験片
表面に粘着テープを密着させて引き剥した。粘着テープ
の引き剥がしによって塗膜が剥離した試験片表面の枡目
をカウントした。この枡目の数で塗膜密着性を評価し
た。The pretreated test piece was coated with a fluororesin paint containing an acrylic resin so that the film thickness after baking became 20 μm, and baked. The adhesion of the formed coating film was examined by the following test method. A notch reaching the base steel from the coating film surface was cut into the test piece with a cutter such that 100 meshes at 1 mm intervals were formed. Next, the test piece was immersed in boiling water for 24 hours. After removing the test piece from the boiling water, the water was wiped off, and the adhesive tape was immediately adhered to the surface of the cut test piece and peeled off. The meshes on the surface of the test piece from which the coating film was peeled off by peeling off the adhesive tape were counted. The coating film adhesion was evaluated by the number of the squares.
【００１８】評価結果を、貴の電位範囲ＥH にある電解
電位ＥH'及び卑の電位範囲ＥL にある電解電位ＥL' と
共に表ｌに示す。なお、印加時間は、電解電位ＥH'及び
電解電位ＥL'による電解を交互に繰り返し、両者を含む
合計の通電時間で表した。The evaluation results are shown in Table l with 'electrolysis potential E L in and less noble potential range E L' electrolysis potential E H in the potential range E H noble. The application time was represented by the total energization time including the electrolysis potential E H ′ and the electrolysis potential E L ′ alternately and alternately.
【表１】 [Table 1]
【００１９】表ｌから明らかなように、貴の電解電位Ｅ
H'及び卑の電解電位ＥL'の間で繰り返し変化する方形波
電位により電解を行なった後、塗布型クロメート処理を
行なった本発明例の試験片表面に形成された塗膜は、何
れも優れた塗膜密着性を示し、粘着テープ剥取り後に試
験片の下地鋼が露出することがなかった。しかも、優れ
た塗膜密着性は、比較的短時間の電解で発現した。これ
に対し、卑の電解電位ＥL'或いは貴の電解電位ＥH'の何
れか一方が本発明で規定する範囲を外れる方形波電位に
より電解を行なった後、塗布型クロメート処理を行なっ
た比較例の試験片表面には、十分な密着性をもつ塗膜が
形成されなかった。As is clear from Table 1, the noble electrolytic potential E
After performing electrolysis with a square wave potential that repeatedly changes between H ′ and the base electrolysis potential E L ′, the coating film formed on the surface of the test piece of the present invention example subjected to the coating type chromate treatment, It showed excellent coating film adhesion, and the base steel of the test piece was not exposed after the adhesive tape was peeled off. In addition, excellent coating film adhesion was exhibited by electrolysis for a relatively short time. On the other hand, after performing electrolysis with a square wave potential in which either the base electrolytic potential E L ′ or the noble electrolytic potential E H ′ is out of the range specified in the present invention, a comparison was performed in which the coating type chromate treatment was performed. No coating film having sufficient adhesion was formed on the surface of the test piece of the example.
【００２０】[0020]
【発明の効果】以上に説明したように、本発明において
は、卑の電位範囲ＥL と貴の電位範囲ＥH との間で振幅
する方形波電位をステンレス鋼に印加することにより、
塗布型クロメート皮膜と強固に密着するＦｅ，Ｃｒ，Ｎ
ｉの酸化物，水酸化物及び硫化物に富む皮膜をステンレ
ス鋼表面に再現性良く形成している。そして、ステンレ
ス鋼表面に緻密に形成した電解皮膜に塗布型クロメート
皮膜を吸着・結合させることにより、有機質被覆に好適
な表面が形成される。この皮膜形成は、ステンレス鋼の
表面層が溶解し析出する反応を利用し、皮膜素材となる
電解質を含む電解浴を使用する必要がない。このように
本発明によると、有機質被覆層に対する密着性に優れた
表面処理鋼板を再現性良く製造することができ、意匠
性，耐久性，耐食性に優れた外装建材，水回り等の苛酷
な環境にも使用可能な材料が得られる。As described above, according to the present invention, in the present invention, by applying a square wave voltage swinging between the potential range E L and noble potential range E H of less noble stainless steel,
Fe, Cr, N adheres firmly to the coating type chromate film
A film rich in oxides, hydroxides and sulfides of i is formed on the stainless steel surface with good reproducibility. Then, a surface suitable for organic coating is formed by adsorbing and bonding the coating type chromate film to the electrolytic film densely formed on the stainless steel surface. This film formation utilizes a reaction in which the surface layer of stainless steel is dissolved and precipitated, and there is no need to use an electrolytic bath containing an electrolyte serving as a film material. As described above, according to the present invention, a surface-treated steel sheet having excellent adhesion to an organic coating layer can be manufactured with good reproducibility, and exterior building materials excellent in design, durability, and corrosion resistance, and harsh environments such as around water. A material that can also be used is obtained.
【図１】 ＳＵＳ３Ｏ４ステンレス鋼，Ｆｅ，Ｃｒ，Ｎ
ｉの分極曲線FIG. 1 SUS3O4 stainless steel, Fe, Cr, N
Polarization curve of i
【図２】 本発明実施例において試験片に印加した方形
波電位の波形FIG. 2 shows a waveform of a square wave potential applied to a test piece in an embodiment of the present invention.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平５−230693（ＪＰ，Ａ) 特開 平４−83899（ＪＰ，Ａ) 特開 平２−107798（ＪＰ，Ａ) 特開 平２−4999（ＪＰ，Ａ) 特開 平１−100299（ＪＰ，Ａ) 特開 昭62−158898（ＪＰ，Ａ) 特開 昭61−270396（ＪＰ，Ａ) 特開 平４−13895（ＪＰ，Ａ) 特開 平２−305993（ＪＰ，Ａ) 特開 昭62−267494（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C25D 11/00 - 11/38 C23C 28/04 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-230693 (JP, A) JP-A-4-83899 (JP, A) JP-A-2-107798 (JP, A) JP-A-2- 4999 (JP, A) JP-A-1-100299 (JP, A) JP-A-62-158898 (JP, A) JP-A-61-270396 (JP, A) JP-A-4-13895 (JP, A) JP-A-2-305993 (JP, A) JP-A-62-267494 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C25D 11/00-11/38 C23C 28/04
Claims (1)
浸漬し、Ｃｒの不働態化電位Ｅ1 より卑の電位範囲ＥL
と、Ｆｅの自然電位Ｅ2 からＦｅの不働態化完了電位Ｅ
3 までの貴の電位範囲ＥH との間で振幅する方形波電位
を、前記ステンレス鋼に印加し、Ｆｅ，Ｎｉの酸化物及
び水酸化物を含む皮膜を前記ステンレス鋼の表面に形成
した後、塗布型クロメート処理を施すことを特徴とする
ステンレス鋼の被覆前処理方法。1. A dipping the stainless steel containing Ni in an acidic electrolytic bath, the potential range of less noble than passivation potential E 1 of Cr E L
And the passivation completion potential E of Fe from the natural potential E 2 of Fe
After applying a square wave potential oscillating between the noble potential range E H up to 3 to the stainless steel and forming a film containing oxides and hydroxides of Fe and Ni on the surface of the stainless steel A coating pretreatment method for stainless steel, characterized by applying a coating type chromate treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04361360A JP3131324B2 (en) | 1992-12-28 | 1992-12-28 | Pretreatment method for coating stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04361360A JP3131324B2 (en) | 1992-12-28 | 1992-12-28 | Pretreatment method for coating stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07173685A JPH07173685A (en) | 1995-07-11 |
| JP3131324B2 true JP3131324B2 (en) | 2001-01-31 |
Family
ID=18473266
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04361360A Expired - Fee Related JP3131324B2 (en) | 1992-12-28 | 1992-12-28 | Pretreatment method for coating stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3131324B2 (en) |
-
1992
- 1992-12-28 JP JP04361360A patent/JP3131324B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07173685A (en) | 1995-07-11 |
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