JP2728313B2 - Surface treatment method of aluminum or its alloy - Google Patents
Surface treatment method of aluminum or its alloyInfo
- Publication number
- JP2728313B2 JP2728313B2 JP2325480A JP32548090A JP2728313B2 JP 2728313 B2 JP2728313 B2 JP 2728313B2 JP 2325480 A JP2325480 A JP 2325480A JP 32548090 A JP32548090 A JP 32548090A JP 2728313 B2 JP2728313 B2 JP 2728313B2
- Authority
- JP
- Japan
- Prior art keywords
- alumite
- current
- current density
- bath voltage
- aluminum
- 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 - Lifetime
Links
- 238000000034 method Methods 0.000 title claims description 32
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims description 15
- 229910052782 aluminium Inorganic materials 0.000 title claims description 15
- 238000004381 surface treatment Methods 0.000 title claims description 13
- 229910045601 alloy Inorganic materials 0.000 title claims description 6
- 239000000956 alloy Substances 0.000 title claims description 6
- 239000008151 electrolyte solution Substances 0.000 claims description 18
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 14
- 238000012545 processing Methods 0.000 claims description 11
- 239000010407 anodic oxide Substances 0.000 claims description 2
- 238000005868 electrolysis reaction Methods 0.000 description 26
- 239000003792 electrolyte Substances 0.000 description 21
- 239000007788 liquid Substances 0.000 description 11
- 230000003647 oxidation Effects 0.000 description 8
- 238000007254 oxidation reaction Methods 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 7
- 230000007423 decrease Effects 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 229910000838 Al alloy Inorganic materials 0.000 description 6
- 230000006872 improvement Effects 0.000 description 5
- 238000007743 anodising Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- 230000035882 stress Effects 0.000 description 4
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000009499 grossing Methods 0.000 description 3
- 238000003672 processing method Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000004227 thermal cracking Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 230000000873 masking effect Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 238000002048 anodisation reaction Methods 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010410 dusting Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009661 fatigue test Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000002040 relaxant effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Landscapes
- Insulated Metal Substrates For Printed Circuits (AREA)
- Pistons, Piston Rings, And Cylinders (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、主にアルミニウム又はアルミニウム合金製
のピストン頂部等の表面被覆に利用される硬質アルマイ
ト処理方法の改良に関し、より具体的には、特開昭56-1
58893号で開示されたアルミニウム又はアルミニウム合
金の高速陽極酸化方法の改良に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in a hard anodizing treatment method mainly used for surface coating of a piston or the like made of aluminum or an aluminum alloy, and more specifically, JP-A-56-1
No. 58893 relates to an improvement in a method for high-speed anodic oxidation of aluminum or aluminum alloy.
近年、エンジンの高出力化に対応して、ピストンが受
ける熱的応力、機械的応力は増大してきており、このた
めアルミニウム合金製ピストンではピストン頂部燃焼室
回りの亀裂発生が問題となっている。In recent years, thermal stress and mechanical stress applied to a piston have been increasing in response to an increase in the output of an engine. For this reason, cracking around the combustion chamber at the top of the piston has become a problem in an aluminum alloy piston.
この亀裂対策として、重力鋳造から高圧鋳造や鍛造へ
の変更等製造法により改善、硬質アルマイト表面処理に
よる改善、セラミックファイバやセラミックウィスカに
よるFRM化等材料による改善等、要求仕様に応じて各種
対策が採用されており、本発明は、そのうちの一つであ
る高速硬質アルマイト処理方法に関するものである。Various countermeasures according to the required specifications, such as improvement by manufacturing methods such as changing from gravity casting to high pressure casting or forging, improvement by hard anodizing surface treatment, improvement by material such as ceramic fiber or ceramic whisker FRM, etc. The present invention relates to a high-speed hard anodizing method, which is one of the methods.
アルマイトがピストン頂部、特に直噴機関用ピストン
燃焼室口元部の熱亀裂に効果があるのは、燃焼によりピ
ストン温度が上昇した時に、燃焼室口元部のアルミ母材
部には通常圧縮応力が発生するのに対し、若しアルマイ
ト層が存在する場合にはアルマイト層近傍母材部には引
張応力が発生し、母材のアルミニウム部に生じる圧縮応
力を緩和する作用があるためと考えられている。Alumite is effective for thermal cracking at the top of the piston, especially at the mouth of the piston combustion chamber for direct injection engines. Normally, compressive stress is generated in the aluminum base material at the mouth of the combustion chamber when the piston temperature rises due to combustion. On the other hand, if an alumite layer is present, a tensile stress is generated in the base material near the alumite layer, which is considered to have an effect of relaxing compressive stress generated in the aluminum part of the base material. .
而して、アルマイトは、電解液中でアルミニウムを陽
極とし、通電、電解することにより生成する酸化アルミ
の皮膜であるが、皮膜の厚みとして約20μｍ以上ものが
硬質アルマイトとして一般的に定義されている。Thus, anodized aluminum is a film of aluminum oxide which is formed by using aluminum as an anode in an electrolytic solution, energizing and electrolyzing, and a film having a thickness of about 20 μm or more is generally defined as hard anodized aluminum. I have.
電解液としては硫酸系やシュウ酸系が大部分を占める
が、クロム酸やアルカリ液を電解液とする例もある。電
解液の種類や操作電流密度、処理温度等により数多くの
処理方法が知られている。アルマイト皮膜の生成速度は
電流密度と処理温度によって決まり、通常硬質法として
採用されている条件は、電流密度１〜5A/dm2、電解液温
度０〜５℃で、皮膜生成速度は0.5〜２μm/minの例が多
い。As the electrolytic solution, a sulfuric acid type or an oxalic acid type occupies most, but there is also an example in which chromic acid or an alkaline solution is used as the electrolytic solution. Numerous processing methods are known depending on the type of electrolyte, operating current density, processing temperature, and the like. The formation rate of the alumite film is determined by the current density and the processing temperature. The conditions usually adopted as the hard method are a current density of 1 to 5 A / dm 2 , an electrolyte temperature of 0 to 5 ° C., and a film formation rate of 0.5 to 2 μm. Many examples are / min.
而して、アルマイト処理の特徴の一つとして、電解中
に生成した皮膜が溶解するという現象が生じる。生成し
た皮膜とアルマイト（酸化アルミ）に変化したアルミニ
ウム重量との比を一般に皮膜生成率（Coating Ratio、
以下C.R.）と呼んでおり、皮膜が全く溶解しないものと
すれば、C.R.は1.89となる。Thus, as one of the features of the alumite treatment, a phenomenon occurs in which the film generated during the electrolysis is dissolved. The ratio of the formed film to the aluminum weight changed to alumite (aluminum oxide) is generally calculated as the film formation ratio (Coating Ratio,
Hereafter referred to as CR), if the film does not dissolve at all, CR will be 1.89.
皮膜溶解の原因は主に電解液による化学溶解であり、
従ってC.R.を上げるためには通常次の方法のいずれか一
つ、或いはそれらの組合せが用いられる。The cause of film dissolution is mainly chemical dissolution by the electrolyte,
Therefore, one of the following methods or a combination thereof is generally used to increase the CR.
（１）液温を低温度とする。(1) The liquid temperature is set to a low temperature.
（２）電解液濃度を低温度とする。(2) The concentration of the electrolyte is lowered.
（３）高電流密度による短時間処理。(3) Short-time processing with high current density.
（４）電解液に有機酸などの添加物を入れる（溶解抑制
作用）。(4) Additives such as organic acids are added to the electrolytic solution (dissolution suppressing action).
而して、アルマイト皮膜厚さは電解電流量に比例する
ので、短時間で必要膜厚を得るためには、皮膜生成率の
大きい高電流密度、低温等で処理すれば良いことになる
が、電流密度を上げ過ぎるとアルマイト厚さが増してく
る電解後半時の異常な発生熱のために皮膜が侵された
り、いわゆる「焼け」と呼ばれる皮膜の脆化が生じる。
従って焼け等の不具合を避け、健全なアルマイト層を生
成させるためには適用できる電流密度は限界があり、定
電流電解法では４〜5A/dm2で行われるのが一般的であ
る。Thus, since the thickness of the alumite film is proportional to the amount of electrolytic current, in order to obtain the required film thickness in a short time, it is sufficient to process at a high current density with a high film formation rate, at a low temperature, etc. If the current density is too high, the film is attacked by abnormal heat generated in the latter half of the electrolysis when the alumite thickness increases, or the film becomes so-called "burn" and becomes brittle.
Therefore, there is a limit to the current density that can be applied in order to avoid problems such as burning and to generate a sound alumite layer, and the current density is generally 4 to 5 A / dm 2 in the constant current electrolysis method.
而して、特開昭56-158893号公報（特許出願人：星野
重夫）には、前記「焼け」に着目し、5A/dm2以上数10A/
dm2にも及ぶ超高電流密度で電解した時の焼けの発生時
間から焼け曲線を求め、第５図に示すように焼け曲線に
沿って電解電流を漸次減少させて電解し、焼けを回避
し、且つ極めて短時間で必要膜厚を得ることが可能なア
ルミニウム又はアルミニウム合金の高速陽極酸化方法が
開示されている。And Thus, JP 56-158893 JP: (Patent Applicant Shigeo Hoshino) focuses on the "burnt", 5A / dm 2 or more number 10A /
calculated curves burn from the time of occurrence of burning when the electrolyte in ultra-high current density extend to dm 2, the electrolysis current electrolysis gradually decreased along the burnt curve as shown in FIG. 5, to avoid scorching A high-speed anodic oxidation method of aluminum or aluminum alloy capable of obtaining a required film thickness in a very short time is disclosed.
当該高速陽極酸化法における電解電流密度と生成する
アルマイト厚さは、第５図の電解時間０≦ｔ≦t1の定電
流区間と、t1≦ｔ≦tEの電流逓減区間について次のよう
に示される。The electrolytic current density and the generated alumite thickness in the high-speed anodic oxidation method are as follows for the constant current section of electrolysis time 0 ≦ t ≦ t 1 and the current step-down section of t 1 ≦ t ≦ t E in FIG. Is shown in
定電流区間（０≦ｔ≦t1）において； 電流密度 ｉ＝i0 アルマイト厚さ d1＝ｋ・i0・t1 定電流電解時間 t1＝SB/ki3/2 電流逓減区間（t1≦ｔ≦tE）において； 電流密度 i2＝i0／〔１＋β（ｔ−t1）〕2/3 アルマイト厚さ d2＝SB〔１＋β（ｔ−t1）〕1/3／i0 1/2 生成アルマイト厚さ ｄ＝d1＋d2 （但し、上記各式において、 i0：初期電流密度 B:焼け定数 k:皮膜生成定数 S:安全係数 β＝3ki0 3/2/SBである。） k,B,Sの各定数値は、高電流密度による定電流電解時
間の長さ、電流密度逓減区間における逓減度合の大小を
決定するものである。k,B,S値は被処理材の組成、電解
液の組成、温度及び処理装置の構造に応じて最適値を求
める必要があるが、AC8A材で硫酸を電解液とした場合、
通常ｋ＝0.4〜0.7、Ｂ＝400〜550、Ｓ＝0.5〜0.8の範囲
にあり、ｋ、Ｓ値を大きくとることで電解時間は短くな
る。In the constant current section (0 ≦ t ≦ t 1 ); current density i = i 0 alumite thickness d 1 = ki 0 i t 1 constant current electrolysis time t 1 = SB / ki 3/2 current decreasing section (t 1 ≦ t ≦ t E ); current density i 2 = i 0 / [1 + β (t−t 1 )] 2/3 alumite thickness d 2 = SB [1 + β (t−t 1 )] 1/3 / i 0 1/2 thickness of formed alumite d = d 1 + d 2 (However, in the above formulas, i 0 : initial current density B: burn constant k: film formation constant S: safety coefficient β = 3ki 0 3/2 / SB The constant values of k, B, and S determine the length of the constant current electrolysis time due to the high current density, and the magnitude of the step-down degree in the current density step-down section. k, B, S value, the composition of the material to be treated, the composition of the electrolytic solution, it is necessary to determine the optimum value according to the temperature and the structure of the processing apparatus, but when using sulfuric acid as the electrolytic solution with AC8A material,
Usually, k = 0.4 to 0.7, B = 400 to 550, and S = 0.5 to 0.8. The electrolysis time is shortened by increasing the k and S values.
然しながら、この方法においては、アルマイト層の設
定厚さを90μｍとして処理を行った場合、アルマイト厚
さは設定通りに生成するが、電解時の浴電圧が第６図に
示すように100Vを超える高電圧となるため、アルマイト
組織中に低硬度（HMV200以下）の不均質層が発生し、ア
ルマイト組織がアルミ生地側から皮膜の表面側に向かっ
て縦縞状の様相を呈することが判明した。However, in this method, when the treatment is performed with the set thickness of the alumite layer being 90 μm, the alumite thickness is generated as set, but the bath voltage during electrolysis has a high voltage exceeding 100 V as shown in FIG. Due to the voltage, a heterogeneous layer of low hardness (HMV200 or less) was generated in the alumite structure, and it was found that the alumite structure exhibited vertical stripes from the aluminum fabric side to the surface side of the film.
その原因は、この高速アルマイト法が電流制御法であ
るので、電解中の浴電圧は電解の進行（アルマイト厚さ
の増加）に伴って上昇し、この浴電圧の過上昇が不均一
組織の生成原因になっているものと考えられる。The reason is that, because the high-speed alumite method is a current control method, the bath voltage during electrolysis increases with the progress of electrolysis (increase in alumite thickness). It is thought to be the cause.
また、特開昭63-38599号公報には、アルミニウム合金
の陽極酸化処理方法において、一定電流密度にて電解
し、浴電圧が50V以上となる前に電解を50V以下の一定電
圧に切り換えて陽極酸化処理を行うようにしたものが開
示されている。しかしながら、その浴電圧の設定値が50
V以下に制限され、電流密度も10A/dm2であったり、1.5A
/dm2であるなど任意的であるため、得られる被膜の厚さ
は、16分間で53μｍとか、10分間で4.5μｍというよう
に必ずしも効率のよいものではなく、耐熱亀裂性も充分
ではなかった。そのため、ピストン頂面のように過酷な
熱及び衝撃にさらされる部分の表面処理としては、採用
できる段階に達していなかった。Japanese Patent Application Laid-Open No. 63-38599 discloses that in an anodizing method of an aluminum alloy, electrolysis is performed at a constant current density, and the electrolysis is switched to a constant voltage of 50 V or less before the bath voltage becomes 50 V or more. An apparatus that performs an oxidation treatment is disclosed. However, if the set value of the bath voltage is 50
V is limited to, or a current density at 10A / dm 2, 1.5A
because it is optional, such as a / dm 2, the thickness of the resulting coating, Toka 53μm in 16 minutes, not necessarily efficient as that 4.5μm in 10 minutes, there was no thermal cracking resistance is also sufficient . Therefore, it has not reached a stage where it can be adopted as a surface treatment for a portion exposed to severe heat and impact such as a piston top surface.
本発明は叙上の観点に立ってなされたものであり、そ
の目的とするところは、均質で厚い耐熱亀裂性に優れた
高硬度のアルマイト層を高速短時間で形成し得るアルミ
ニウム又はその合金の表面処理方法を提供することにあ
る。The present invention has been made in view of the above description, and an object of the present invention is to provide a high-hardness anodized aluminum layer or an alloy capable of forming a high-hardness anodized layer having a uniform and thick heat-resistant crack in a short time. An object of the present invention is to provide a surface treatment method.
上記の目的は、電解液として100±10g/lの希硫酸を用
い、処理温度を10±３℃に保ちつつ、浴電圧が一定の限
界値80±5Vに達するまでの初期の期間中は、電流密度が
30±5A/dm2の範囲に保たれるよう電流を制御し、浴電圧
が上記一定の限界値80±5Vに達した後は、浴電圧がその
限界値の範囲に保たれるよう電流を制御しつゝ減少さ
せ、陽極酸化被膜を形成することを特徴とするアルミニ
ウム又はその合金の表面処理方法によって達成し得る。
その場合、電解液を被処理体の処理すべき面にのみ供給
するようにすることが推奨される。The above objective is to use 100 ± 10 g / l of dilute sulfuric acid as the electrolytic solution, while maintaining the processing temperature at 10 ± 3 ° C., and during the initial period until the bath voltage reaches a certain limit value of 80 ± 5 V, Current density
Controlling the current to be kept in the range of 30 ± 5A / dm 2, after the bath voltage reaches the predetermined limit value 80 ± 5V, the current to the bath voltage is maintained at the range of the limit value It can be achieved by a method for surface-treating aluminum or an alloy thereof, characterized in that it is controlled and reduced to form an anodized film.
In that case, it is recommended to supply the electrolyte only to the surface of the object to be treated.
上記の如き構成であると、浴電圧が過度に上昇するこ
となく略一定に保たれた状態で陽極酸化が行なわれるの
で、均質で厚い硬質陽極酸化被膜が短時間で形成される
ものである。With the above configuration, the anodization is performed in a state where the bath voltage is kept substantially constant without excessively increasing, so that a uniform and thick hard anodic oxide film is formed in a short time.
以下、図面を参照しつゝ本発明を具体的に説明する。 Hereinafter, the present invention will be specifically described with reference to the drawings.
第１図は本発明に係る表面処理方法を実施するために
使用する装置の一例を示しており、図中、であり、１は
エアシリンダ、２は絶縁板、３は給電板、４は被処理体
としてのピストン、５は治具本体、６はシールゴム、７
はカソード電極、８は電解液噴出ノズル、９は電解液供
給管、10は電解槽であり、これら１ないし10で示す構成
要素により電解装置が構成され、更に、11はポンプ、12
は電解液タンク、13は液温調節装置、14は液温検知器、
15は交流電源、16は整流器、17はスイッチング素子、18
はパルスジェネレータ、19は平滑回路、20は電解電流検
出用の挿入抵抗、21は電解電流検知器、22は浴電圧検知
器、23はマイクロコンピュータである。FIG. 1 shows an example of an apparatus used for carrying out the surface treatment method according to the present invention, in which 1 is an air cylinder, 2 is an insulating plate, 3 is a power supply plate, and 4 is a cover. Piston as a processing body, 5 is a jig body, 6 is seal rubber, 7
Is a cathode electrode, 8 is an electrolytic solution jet nozzle, 9 is an electrolytic solution supply pipe, 10 is an electrolytic cell, and an electrolytic device is constituted by the components indicated by 1 to 10. Further, 11 is a pump, 12
Is an electrolyte tank, 13 is a liquid temperature controller, 14 is a liquid temperature detector,
15 is an AC power supply, 16 is a rectifier, 17 is a switching element, 18
Is a pulse generator, 19 is a smoothing circuit, 20 is an insertion resistor for detecting an electrolytic current, 21 is an electrolytic current detector, 22 is a bath voltage detector, and 23 is a microcomputer.
被処理体としてのピストン４は、電解槽10内に設けた
治具本体５内に逆さまにして取り付けられ、ピストン４
の頂部のみが電解槽内の電解液と接触するようになって
いる。The piston 4 as an object to be processed is mounted upside down in a jig body 5 provided in the electrolytic cell 10.
Is in contact with the electrolyte in the electrolytic cell.
電解槽10内への電解液の供給は、電解液噴出ノズル８
の上面に明けた複数の孔8aを通じて行なわれ、カソード
電極７にもこれに対応する孔が明けられ、電解液はこれ
らの孔からピストン４の頂部へ向けて噴出、供給される
ようになっている。The supply of the electrolytic solution into the electrolytic cell 10 is performed by the electrolytic solution ejection nozzle 8.
Are performed through a plurality of holes 8a formed in the upper surface of the electrode 4. Corresponding holes are also formed in the cathode electrode 7, and the electrolyte is ejected and supplied from these holes toward the top of the piston 4. I have.
電解処理時には電解槽10の上縁まで一杯に電解液が満
たされ、電解槽10の上縁から溢れた電解液は、捕集槽1
0′により集められ電解液タンク12に還流するようにな
っている。During the electrolytic treatment, the electrolytic solution is completely filled up to the upper edge of the electrolytic cell 10, and the electrolytic solution overflowing from the upper edge of the electrolytic cell 10 is collected in the collecting tank 1.
The liquid is collected by O 'and returned to the electrolyte tank 12.
このように、ピストン４全体を電解液中に浸漬するこ
となく、ピストンの頂部のみが電解液と接触するように
槽外方式によりピストンを取り付けるようにしてあるた
め、面倒なマスキング工程が省略でき、生産性の向上と
低コスト化を図ることが可能となる。As described above, since the piston 4 is attached by an out-of-tank method so that only the top of the piston comes into contact with the electrolyte without immersing the entire piston 4 in the electrolyte, a troublesome masking step can be omitted, It is possible to improve productivity and reduce costs.
電解液は、液管理が容易な硫酸単独浴とすることが推
奨される。It is recommended that the electrolyte be a sulfuric acid single bath that is easy to manage.
電解電流は、交流電源15からの電流を整流器16により
整流し、この直流を、パルスジェネレータ18により開閉
せしめられるスイッチング素子17によって断続せしめて
パルス電流とし、更にこれを平滑回路19により平滑な直
流として給電板３とカソード電極７とに供給するもので
あるが、この電解電流の増減制御は、パルスジェネレー
タ18の発振するパルスのデューテイファクタをマイクロ
コンピュータ23からの指令によって変更することにより
行なう。The electrolytic current is obtained by rectifying a current from an AC power supply 15 by a rectifier 16 and intermittently turning this direct current by a switching element 17 opened and closed by a pulse generator 18 into a pulse current, which is further converted into a smooth direct current by a smoothing circuit 19. The increase and decrease of the electrolytic current is controlled by changing the duty factor of the pulse oscillated by the pulse generator 18 according to a command from the microcomputer 23.
即ち、電解電流検知器21及び浴電圧検知器22の検知信
号をマイクロコンピュータ23にもたらし、電解初期に
は、浴電圧が一定の限界値に達するまで、電流密度が一
定〔前記定電流区間（０≦ｔ≦t1）における電流密度
ｉ＝i0〕となるように電解電流を制御し、浴電圧が一定
の限界値に達した後は、浴電圧がその限界値に保たれる
よう電解電流を減少〔前記電流逓減区間（t1≦ｔ≦
tE）における電流密度i2＝i0／〔１＋β（ｔ−t1）〕
2/3〕させながら電解処理を行なうものである。That is, the detection signals of the electrolytic current detector 21 and the bath voltage detector 22 are sent to the microcomputer 23, and the current density is constant until the bath voltage reaches a certain limit value at the initial stage of the electrolysis. ≦ t ≦ t 1 ), the electrolytic current is controlled so that the current density i = i 0 ], and after the bath voltage reaches a certain limit value, the electrolytic current is controlled so that the bath voltage is maintained at the limit value. [The current step-down section (t 1 ≦ t ≦
current density at t E ) i 2 = i 0 / [1 + β (t−t 1 )]
2/3 ] while performing the electrolytic treatment.
その場合、液温検知器14により電解液の温度を検知
し、その検知信号をマイクロコンピュータ23にもたら
し、これから液温調節装置13に指令信号を送って、電解
液温度を一定に保つものである。In this case, the temperature of the electrolytic solution is detected by the liquid temperature detector 14, and a detection signal is sent to the microcomputer 23, and a command signal is sent to the liquid temperature control device 13 to keep the temperature of the electrolytic solution constant. .
上記装置を用いて、ピストン頂部の硬質アルマイト処
理として、本発明方法を適用するためAC8A合金ピストン
を用いた処理実験を行ない、ピストンの熱亀裂に効果の
高い厚さ90μｍ、硬度400（HMV）以上のアルマイトが最
短時間で得られる条件（前記k,B,S値、初期電流密度、
電解液濃度、電解液温度、浴電圧等）を検討した。Using the above apparatus, as a hard alumite treatment for the piston top, a treatment experiment using an AC8A alloy piston was performed to apply the method of the present invention, and a thickness of 90 μm, a hardness of 400 (HMV) or more, which is highly effective in thermal cracking of the piston. Alumite is obtained in the shortest time (k, B, S value, initial current density,
Electrolyte concentration, electrolyte temperature, bath voltage, etc.) were studied.
まず、前記特開昭56-158893号に開示された高速陽極
酸化方法に従い、設定アルマイト厚さを90μｍとすると
共に、電解液として希硫酸（濃度100g/l）を使用し、下
記表−１に示す２種類の電解条件で実験を行ない、実際
に生成したアルマイト層の厚さを測定した。First, according to the high-speed anodic oxidation method disclosed in the above-mentioned JP-A-56-158893, the set alumite thickness was set to 90 μm, and dilute sulfuric acid (concentration: 100 g / l) was used as an electrolyte. An experiment was performed under the two types of electrolysis conditions shown below, and the thickness of the actually formed alumite layer was measured.
このときの電解時間の経過に伴う電流密度と浴電圧の
関係が第６図に示してあり、グラフ中、条件の場合の
電流密度と浴電圧はそれぞれ実線及び点線で示し、
条件の場合の電流密度と浴電圧はそれぞれ実線及び
点線で示してある。 The relationship between the current density and the bath voltage with the passage of the electrolysis time at this time is shown in FIG. 6, and in the graph, the current density and the bath voltage in the case of the condition are shown by a solid line and a dotted line, respectively.
The current density and bath voltage under the conditions are shown by a solid line and a dotted line, respectively.
初期のアルマイト厚さが得られるまでの最短電解時間
は、条件における初期電流密度50A/dm2としたときの
３分35秒であった。The shortest electrolysis time until the initial alumite thickness was obtained was 3 minutes and 35 seconds when the initial current density was 50 A / dm 2 under the conditions.
どちらの条件でも、アルマイト厚さは設定通り90μｍ
のものが得られたが、電解時の浴電圧が第６図に示すよ
うにいずれも100Vを超え、前記の如く、アルマイト組織
中に低硬度（HMV 200以下）の不均質層が形成され、ア
ルマイト組織がアルミ生地側から皮膜の表面側に向かっ
て縦縞上の様相を呈していた。Under both conditions, the anodized thickness is 90μm as set
However, as shown in FIG. 6, the bath voltage during electrolysis exceeded 100 V, and as described above, a low-hardness (HMV 200 or less) heterogeneous layer was formed in the alumite structure, The alumite structure had the appearance of vertical stripes from the aluminum fabric side to the surface side of the film.
このようにアルマイト層中に低硬度の不均一組織が生
成する原因は、上記特開昭56-158893号に開示された高
速陽極酸化方法が電流制御法であるため、電解の進行
（アルマイト厚さの増加）に伴い浴電圧が過度に上昇す
ることにあると考えられる。The cause of the formation of a low-hardness heterogeneous structure in the alumite layer is that the high-speed anodic oxidation method disclosed in the above-mentioned JP-A-56-158893 is a current control method. It is considered that the bath voltage is excessively increased with the increase in the bath voltage.
而して、浴電圧に最も影響するのは電解液温度であ
り、第３図に示すように温度を上げた場合浴電圧は低下
する。液温を10℃以上とした場合、更に浴電圧は下がる
が、15℃以上では処理面の冷却不足となり、アルマイト
被膜表面に粉ふき現象が生じてくる。Thus, the bath temperature is most affected by the temperature of the electrolytic solution. As shown in FIG. 3, when the temperature is increased, the bath voltage decreases. When the liquid temperature is set to 10 ° C. or higher, the bath voltage further decreases, but at 15 ° C. or higher, the treated surface becomes insufficiently cooled, and a dusting phenomenon occurs on the alumite coating surface.
液温10℃の条件で、初期電流密度30A/dm2、k,B,S値に
ついてはｋ＝0.6、Ｂ＝450、Ｓ＝0.6の設定で浴電圧の
上昇を抑えられる結果が得られた。この電解条件による
電流密度と浴電圧の関係を第２図に示す。電解時間は7.
4分で、浴電圧は約80Vに上昇後は90μｍのアルマイト厚
さ生成終了まで平行状態である。この条件で処理したア
ルマイト組織は、均質で硬さもHMV 400以上であること
が確認された。Under the condition of the liquid temperature of 10 ° C., the result that the rise of the bath voltage was suppressed by setting the initial current density at 30 A / dm 2 , k, B, and S values at k = 0.6, B = 450, and S = 0.6 was obtained. . FIG. 2 shows the relationship between the current density and the bath voltage under these electrolysis conditions. Electrolysis time is 7.
After 4 minutes, the bath voltage rises to about 80 V and remains in a parallel state until the formation of a 90 μm alumite thickness is completed. It was confirmed that the alumite structure treated under these conditions was homogeneous and had a hardness of HMV 400 or more.
以上の実験結果から、厚さ90μｍ、硬さHMV 400以上
の高速アルマイト処理条件として下記表−２に示す条件
値を決定した。From the above experimental results, the condition values shown in Table 2 below were determined as high-speed alumite treatment conditions with a thickness of 90 μm and a hardness of HMV 400 or more.
こゝで、初期電流密度が25A/dm2以下であると電解時
間が増加して処理効率が低下し、35A/dm2以上であると
アルマイト層の硬度が低下する。 Here, when the initial current density is 25 A / dm 2 or less, the electrolysis time increases and the treatment efficiency decreases, and when the initial current density is 35 A / dm 2 or more, the hardness of the alumite layer decreases.
また、浴電圧が75V以下であると処理効率が低下し、8
5V以上になるとアルマイト層が不均質で脆くなる。If the bath voltage is 75 V or less, the processing efficiency decreases,
Above 5V, the alumite layer becomes heterogeneous and brittle.
電解液濃度が90g/l以下であると抵抗が低くなり過ぎ
て不都合を生じ、110g/l以上であるとアルマイト層の厚
み精度が低下する。If the concentration of the electrolyte is 90 g / l or less, the resistance becomes too low, causing inconvenience. If the concentration is 110 g / l or more, the thickness accuracy of the alumite layer decreases.
電解液温度が７℃以下であると浴電圧が上がりアルマ
イト層が不均質で脆くなり、13℃以上になると処理面の
冷却不足によりアルマイト被膜表面に白い粉ふき現象が
生じ、脆くなる。When the electrolyte temperature is 7 ° C. or lower, the bath voltage increases and the alumite layer becomes inhomogeneous and brittle. When the temperature is 13 ° C. or higher, the surface of the alumite film is whitened due to insufficient cooling of the treated surface and becomes brittle.
上記の如くして本発明の表面処理を行なったアルマイ
ト被膜品の耐熱亀裂性を、熱疲労試験装置を用いて評価
し、一般的な定電流（4A/dm2）によるアルマイト被覆品
と比較した。テストピースは両者ともAC8A-T5材に90μ
ｍのアルマイト層を形成したものである。The heat-resistant crack resistance of the alumite-coated article subjected to the surface treatment of the present invention as described above was evaluated using a thermal fatigue tester, and compared with a general anodized article using a constant current (4 A / dm 2 ). . Both test pieces are 90μ on AC8A-T5 material
m having an alumite layer.
熱疲労試験装置としては、直噴機関用ピストン頂部を
模したテストピースに、高周波誘導加熱方式による加熱
（400℃）と、圧縮空気吹きつけによる冷却（150℃）を
約20秒周期で繰り返し、熱疲労による亀裂を生じさせる
ものである。As a thermal fatigue test device, a test piece simulating the top of a piston for a direct injection engine is heated at a high frequency induction heating method (400 ° C) and cooled by blowing compressed air (150 ° C) at a cycle of about 20 seconds. This causes cracks due to thermal fatigue.
第４図にその試験結果を示しており、図中◎が本発明
による処理品、○が従来の定電流による処理品、△が非
処理品である。これから、本発明による表面処理方法が
アルミニウム合金製のピストン頂部の耐熱亀裂性を大幅
に向上させ得ることが理解される。FIG. 4 shows the test results, in which ◎ indicates a processed product according to the present invention, ○ indicates a conventional processed product with a constant current, and Δ indicates a non-processed product. From this, it is understood that the surface treatment method according to the present invention can greatly improve the thermal crack resistance of the aluminum alloy piston top.
本発明は上記の如く構成されるから、本発明によると
きは、均質で厚い耐熱亀裂性に優れた高硬度のアルマイ
ト層を高速短時間で形成し得るアルミニウム又はその合
金の表面処理方法を提供し得るものである。Since the present invention is constituted as described above, according to the present invention, there is provided a surface treatment method for aluminum or an alloy thereof capable of forming a high-hardness alumite layer having high uniformity and excellent heat crack resistance in a short time at a high speed. What you get.
従ってまた、本発明は下記の如き利点をもたらすもの
である。Accordingly, the present invention also provides the following advantages.
（１）処理時間が短いので、１個流しができ、加工ライ
ンとの同期化を図ることも可能である。(1) Since the processing time is short, one piece can be flown, and synchronization with the processing line can be achieved.
（２）電解液は硫酸単液で良いので、液管理が容易であ
る。(2) Since the electrolyte solution may be a single solution of sulfuric acid, solution management is easy.
（３）単に処理時間が短いだけでなく、処理方式として
槽外方式を併用することでマスキング工程が不要であ
り、ピストン頂部のアルマイト処理法として非常に適し
ている。(3) Not only the processing time is short, but also the masking step is unnecessary by using the outside-tank method as the processing method, which is very suitable as an alumite processing method for the top of the piston.
なお、本発明は叙上の実施例に限定されるものでな
く、本発明の目的の範囲内において上記の説明から当業
者が容易に想到し得るすべての変更実施例を包摂するも
のである。It should be noted that the present invention is not limited to the embodiments described above, but encompasses all modified embodiments that can be easily conceived by those skilled in the art from the above description within the scope of the present invention.
第１図は本発明に係る表面処理方法を実施するために使
用する装置の一例を示す説明図、 第２図は本発明に係る表面処理方法を実施する際の電解
時間の経過に伴う電流密度と浴電圧の関係を示すグラ
フ、 第３図は電解液温度と浴電圧の関係を示すグラフ、 第４図は本発明に係る表面処理方法により得られたアル
マイト層の耐熱亀裂効果を、従来法によるものと比較し
たグラフ、 第５図は前記特開昭56-158893号公報に開示された高速
陽極酸化方法を実施する場合における電解時間の経過に
伴う電流密度の変化を示すグラフ、 第６図は特開昭56-158893号公報に開示された高速陽極
酸化方法を実施する場合における電解時間の経過に伴う
電流密度と浴電圧の関係を示すグラフである。 １……エアシリンダ ２……絶縁板 ３……給電板 ４……被処理体（ピストン） ５……治具本体 ６……シールゴム ７……カソード電極 ８……電解液噴出ノズル ９……電解液供給管 10……電解槽 11……ポンプ 12……電解液タンク 13……液温調節装置 14……液温検知器 15……交流電源 16……整流器 17……スイッチング素子 18……パルスジェネレータ 19……平滑回路 20……挿入抵抗 21……電解電流検知器 22……浴電圧検知器 23……マイクロコンピュータFIG. 1 is an explanatory view showing an example of an apparatus used for carrying out the surface treatment method according to the present invention, and FIG. 2 is a current density accompanying the passage of electrolysis time when carrying out the surface treatment method according to the present invention. FIG. 3 is a graph showing the relationship between electrolyte temperature and bath voltage, and FIG. 4 is a graph showing the heat cracking effect of the alumite layer obtained by the surface treatment method according to the present invention. FIG. 5 is a graph showing a change in current density with the passage of electrolysis time when the high-speed anodic oxidation method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 56-158893 is carried out. Is a graph showing the relationship between the current density and the bath voltage with the passage of electrolysis time when the high-speed anodic oxidation method disclosed in JP-A-56-158893 is carried out. DESCRIPTION OF SYMBOLS 1 ... Air cylinder 2 ... Insulating plate 3 ... Power supply plate 4 ... Workpiece (piston) 5 ... Jig body 6 ... Seal rubber 7 ... Cathode electrode 8 ... Electrolyte ejection nozzle 9 ... Electrolysis Liquid supply tube 10 Electrolyzer 11 Pump 12 Electrolyte tank 13 Liquid temperature controller 14 Liquid temperature detector 15 AC power supply 16 Rectifier 17 Switching element 18 Pulse Generator 19 Smoothing circuit 20 Insertion resistance 21 Electrolytic current detector 22 Bath voltage detector 23 Microcomputer
Claims (1)
処理温度を10±３℃に保ちつつ、浴電圧が一定の限界値
80±5Vに達するまでの初期の期間中は、電流密度が30±
5A/dm2の範囲に保たれるよう電流を制御し、浴電圧が上
記一定の限界値80±5Vに達した後は、浴電圧がその限界
値の範囲に保たれるよう電流を制御しつゝ減少させ、陽
極酸化被膜を形成することを特徴とするアルミニウム又
はその合金の表面処理方法。(1) 100 ± 10 g / l of dilute sulfuric acid is used as an electrolytic solution,
The bath voltage is a certain limit value while keeping the processing temperature at 10 ± 3 ℃
During the initial period until reaching 80 ± 5V, the current density is 30 ±
Controlling the current to be kept in the range of 5A / dm 2, after the bath voltage reaches the predetermined limit value 80 ± 5V, and controls the current so that the bath voltage is maintained at the range of the limit value A surface treatment method for aluminum or an alloy thereof, wherein the surface treatment is performed by reducing the amount of the anodic oxide film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2325480A JP2728313B2 (en) | 1990-11-29 | 1990-11-29 | Surface treatment method of aluminum or its alloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2325480A JP2728313B2 (en) | 1990-11-29 | 1990-11-29 | Surface treatment method of aluminum or its alloy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04198497A JPH04198497A (en) | 1992-07-17 |
| JP2728313B2 true JP2728313B2 (en) | 1998-03-18 |
Family
ID=18177351
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2325480A Expired - Lifetime JP2728313B2 (en) | 1990-11-29 | 1990-11-29 | Surface treatment method of aluminum or its alloy |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2728313B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2657888B2 (en) * | 1993-05-31 | 1997-09-30 | シグマメルテック株式会社 | Anodizing method and apparatus |
| US6126808A (en) * | 1998-03-23 | 2000-10-03 | Pioneer Metal Finishing | Method and apparatus for anodizing objects |
| TWI356857B (en) * | 2005-06-17 | 2012-01-21 | Univ Tohoku | Metal oxide film, laminate, metallic member and me |
| JP5207124B2 (en) | 2008-03-24 | 2013-06-12 | スズキ株式会社 | Anodizing method |
| JP5274097B2 (en) * | 2008-04-28 | 2013-08-28 | 富士フイルム株式会社 | Fine structure and manufacturing method thereof |
| JP5141968B2 (en) * | 2008-06-06 | 2013-02-13 | 株式会社ジェイテクト | Manufacturing method of metal parts |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6338599A (en) * | 1986-07-31 | 1988-02-19 | Aisin Seiki Co Ltd | Method for anodizing aluminum alloy |
-
1990
- 1990-11-29 JP JP2325480A patent/JP2728313B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04198497A (en) | 1992-07-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8691403B2 (en) | Method for anodizing aluminum and anodized aluminum | |
| JP5152574B2 (en) | Method for anodizing aluminum member | |
| CN106399762B (en) | A kind of high-strength corrosion-resisting aluminium alloy extrusions and preparation method thereof | |
| CN106435302B (en) | A kind of corrosion-resistant and high-temperature resistant aluminium alloy extrusions and preparation method thereof | |
| JP2767711B2 (en) | Method for producing a lithographic printing plate support | |
| TWI424096B (en) | Method for forming anodic oxide film | |
| JP2728313B2 (en) | Surface treatment method of aluminum or its alloy | |
| JP2837397B2 (en) | Anodizing equipment for aluminum or aluminum alloy | |
| JP5700235B2 (en) | Method of forming alumite film | |
| US20080087551A1 (en) | Method for anodizing aluminum alloy and power supply for anodizing aluminum alloy | |
| JPH0394099A (en) | Apparatus for anodic oxidation of aluminum alloy piston for use in internal engine | |
| CN109355693B (en) | Surface passivation chromatic aberration repair process for automobile bright decorative strip | |
| JP2018527516A (en) | Improved method for forming a coating on a duct of a cylinder head and the resulting cylinder head | |
| JPH04224695A (en) | Method and apparatus for executing anodic oxide coating treatment to piston | |
| JP2003328187A (en) | Surface treatment method of aluminum material | |
| KR101207708B1 (en) | Method for anodizing aluminum and anodized aluminum | |
| JPH0577737B2 (en) | ||
| Ponomarev et al. | Features of the influence of electric modes on micro-arc oxidation process | |
| JPH01205091A (en) | Surface treatment of al alloy frame member of bicycle for welded structure | |
| RU2718820C1 (en) | Method of electrochemical oxidation of coatings on valve metals or alloys | |
| RU2775013C1 (en) | Method for plasma-electrochemical formation of nanostructured chromium coating and device for implementing the method | |
| RU2771409C1 (en) | Method for plasma-electrochemical formation of nanostructured chromium coating and device for implementing the method | |
| RU2821036C1 (en) | Method for electrolytic-plasma polishing of part in alternating magnetic field | |
| KR102230872B1 (en) | Manufacturing method of titanium ring for electro-deposition drum and titanium ring manufactured thereof | |
| JPS63235500A (en) | Pretreatment for electrolytic surface roughening treatment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20071212 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081212 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081212 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091212 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091212 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101212 Year of fee payment: 13 |
|
| EXPY | Cancellation because of completion of term |