JPS6041156B2 - Surface treatment method for aluminum or aluminum alloy parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a non-electrified pipe box slippery hard coating on the surface of an aluminum or aluminum alloy member.

In general, aluminum or aluminum alloys are lightweight, and can be expected to improve surface hardness and corrosion resistance through anodizing treatment, as well as impart a variety of colors through dyeing and secondary electrolytic coloring, so they are widely used in a variety of fields. It is well known that it has many uses.

By the way, it is also known that the oxide film surface layer of aluminum or aluminum alloy that has been anodized is generally non-conductive and therefore has some chargeability.

In other words, aluminum or aluminum alloy materials themselves exhibit only a radiation charge or no charge at all when exposed to a corona discharge of 4 to 10 KV, whereas anodized aluminum or aluminum alloys show no charge at all. , for example, the oxide film is 20 to 3
If the voltage is about 0m, apply 100 to 200V under similar conditions.
It has been measured that a certain amount of charge is exhibited. of course,
The material to be measured in this case was under a grounded condition. However, as a recent trend, anodized aluminum or aluminum alloy is often used as a lightweight functional material in cameras, VTRs, copiers, and other electronic devices to reduce weight. In many cases, the anodized coating surface of such aluminum or aluminum alloy parts is required to be non-static, that is, to be conductive and have good lubricity. The request will be
With the rapid progress and development of the electronics industry, the situation is expected to become even more active.

Conventionally, in order to impart conductivity to the oxide film surface of anodized aluminum or aluminum alloy and prevent charging, colloidal carbon, Ag and other metal powders, and conductive oxide fine powders were mixed. It is known to apply conductive paste paint, but with this method, the surface color is limited depending on the paste paint used, and it is difficult to obtain sufficient surface hardness and surface strength. Moreover, there have been various problems such as relatively high processing costs due to the use of a relatively expensive conductive paste.

In addition, improving the self-lubricating performance of anodized aluminum by impregnating it with a fluororesin is known as a surface treatment method commonly known as Toughflame treatment using a fluororesin dispersion solution. In case,
It was not possible to avoid the above-mentioned problem caused by the treated product having electrostatic properties.

From the above-mentioned viewpoints, the present inventors have developed an aluminum or aluminum alloy that has a non-static surface, good self-lubricating properties, and can be manufactured at a low manufacturing cost and with highly accurate dimensions. As a result of conducting research to obtain a surface-coated member, the findings shown in a to d above were obtained.

That is, [a] The present inventors first published Hakamabuta No. 55-159617 (
The conductive fine powder proposed as Tokkoku Sho 56-156603) contains 0.1 to 20% by weight of antimony, with the remainder consisting essentially of tin oxide, and has a composition of 0.2% by weight of antimony. Fine powder having an average particle size of less than 1.5 m is very small depending on the manufacturing method, so if an anodic oxide film of aluminum or aluminum alloy is immersed in a dispersion of this fine powder, Conductive fine powder is impregnated into the fine pores of the oxide film and is also adsorbed and fixed on the surface of the oxide film, so that the oxide film itself exhibits non-static properties to the same degree as the aluminum or aluminum alloy base; 'b} A fine fluororesin powder having an average particle size similar to that of the conductive fine powder is allowed to coexist in the conductive fine powder dispersion to impregnate the anodic oxide film of aluminum or aluminum alloy. Alternatively, a fluororesin fine powder dispersion is prepared separately from the conductive fine powder dispersion, and an anodic oxide film of aluminum or aluminum alloy is applied to both the conductive fine powder dispersion and the fluororesin fine powder dispersion. By doing so, the conductive fine powder and the fluororesin fine powder are both impregnated or adsorbed and fixed in the fine pores and on the surface of the oxide film, ensuring the non-static property of the oxide film and providing an excellent coating for the film. Provided with sliding performance (
c' As mentioned above, conductive fine powders and fluororesin powders with fine dimensions are extremely fine particles, so when dispersed in dispersed soot, it is possible to easily create an extremely high-quality dispersion liquid, and this dispersion The liquid is extremely stable, with almost no powder settling even after a long period of time.
Therefore, the dipping work of the anodic oxide film can be carried out easily; {d) Since the torme-conducting fine powder and the fluororesin fine powder have a particle size smaller than the wavelength of visible light,
Even when impregnated or adsorbed into the fine pores or on the surface of the anodic oxide film, the color tone of the anodic oxide film does not change, and the anodic oxide film can be impregnated after dyeing or secondary electrolytic coloring.

This invention was made based on the above knowledge, and includes:
An aluminum or aluminum alloy member whose surface has been anodized has a composition containing antimony in a cloud content of 0.1 to 2%, the remainder being substantially tin oxide, and 0.1% to 2% in cloud content, with the remainder being substantially tin oxide.
Obtain an aluminum or aluminum alloy member having a non-static lubricating anodic oxide film on its surface by immersing it in a dispersion of conductive fine powder having an average particle size of 24 m or less and fluororesin fine powder. It is characterized by the fact that it is made as follows.

In addition, in the method of this invention, the fluororesin fine powder is
It may be used as a treatment liquid by dispersing the conductive fine powder together in the dispersion, or it may be a dispersion of only the fluororesin fine powder, which is separate from the conductive fine powder dispersion. The anodic oxide film can be immersed in each dispersion liquid in sequence.

If a coexisting dispersion of conductive fine powder and fluororesin fine powder is used, the work can be completed with just one immersion treatment, but the adjustment of the dispersion liquid and the final treatment of the treatment liquid become troublesome.
On the other hand, if separate dispersions are used, the opposite problem will occur, so one can be selected depending on the need. Furthermore, the reason why the antimony content of the conductive fine powder used in the method of the present invention is limited to 0.1 to 2% by weight is that if the content is less than 0.1% by weight, the desired good conductivity cannot be achieved. On the other hand, if the content exceeds 20% by weight, the powder becomes bluish, and when it is impregnated and adsorbed into the fine pores or the surface of the anodic oxide film, the color tone and This is because transparency will be compromised.
In addition, the reason why the average particle size was limited to 0.2 mm or less was 0.2 mm.
If the average particle size exceeds 2 m, it becomes difficult to impregnate and adsorb into the fine pores and surface of the anodic oxide film, resulting in weak adhesion of the fine powder and the risk of peeling. This is because it becomes impossible to maintain a uniformly dispersed state in the medium.

This also applies to fluororesin fine powder, where fine powder refers to one with an average particle size of 0.2 mm or less. Furthermore, the conductive fine powder used in the method of this invention is
A solution consisting of tin chloride (hereinafter referred to as SnC14) and antimony chloride (hereinafter referred to as S ratio 13) dissolved in a mixture of one or more of alcohol, hydrochloric acid aqueous solution, and acetone is heated. It can be produced by a method in which Sb-containing Sn02 is precipitated in water, but it can also be produced by a method in which Sn02 powder and an Sb compound are calcined,
Sb-containing 6n02 manufactured by a known method such as a method of mixing a Sn compound and an Sb compound and then firing.
All of the powders have an average particle size exceeding 0.2 mm. Therefore, in these known methods, the S-containing Sn powder of the present invention having an average particle size of 0.2 mm or less cannot be used.
02 powder cannot be manufactured.

On the other hand, a fluororesin fine powder dispersion can be easily obtained by simply diluting a commercially available fluororesin concentrate with a common dispersion medium. Furthermore, the conductive fine powder concentration in the dispersion is preferably in the range of 1 to 30 m/s, particularly preferably 10 to 20 m/s.

This is because if the concentration is less than 1 night/night, a sufficient antistatic property imparting effect cannot be obtained, and on the other hand, if the concentration exceeds 30 nights/night, no further improvement in the effect is observed. The appropriate concentration of the fluororesin fine powder, which is prepared together with the conductive fine powder or prepared independently, is 1 to 20 m/m.
Particularly preferably, it is used at a concentration of 5 to 10.

This is because even if the concentration is less than 19%, the fluororesin impregnation effect can be obtained, but in order to obtain a sufficient impregnation concentration, a dispersion concentration of 10% or more is required. If the amount is exceeded, post-treatment after impregnation (drying, etc.)
This is because phenomena such as surface stains and cloudiness that lack uniformity of appearance are likely to occur. The suitable temperature for impregnation treatment with the dispersion is room temperature to about 60 qo, but 35 to 45 °C
Particularly good results can be obtained depending on the degree of

As described above, this invention treats an anodized film with a conductive fine powder and a fluororesin fine powder dispersion, but this treatment can also be carried out after the dyeing process or secondary electrolytic coloring process. In addition, a series of processing methods such as anodizing, washing with water, dyeing, secondary electrolytic coloring, and sealing can be carried out under the same manufacturing conditions as conventional aluminum or aluminum alloy anodized materials. It is available.

Next, the present invention will be specifically explained using examples.

First, a 1050 aluminum plate was subjected to a predetermined pretreatment that is commonly performed, and then subjected to anodization treatment to form a hard oxide film with a thickness of 30 cm.

The anodizing conditions at this time were: Sun 2S04:300pm/evening, oxalic acid: 39/day, AIH 1:5pm/day in the bath, temperature: 0°C, current density: 2. For me/d, the processing time was 40 minutes.

Next, after washing this with running water, (Sn/Sb)02 fine powder (fine powder containing Sb: 1% by weight and the remainder essentially consisting of Sn02) with an average grain size of 0.07 French m was added. 15
(Sn/Sb
), 02 and Teflon ■ (trade name), washed with water, and then dried with hot air. Used here (Sn・S
b).02 and Teflon ■ (trade name) dispersions were prepared as follows.

That is, 3,000 cc of water was heated and maintained at a temperature of 90 oo, and 3000 cc of methanol was added to it while vigorously adding Takaazusa.
00cc to SnC14:173 evening and SbC13:20.
A solution consisting of a mixture of 9 and 10% was slowly injected over a period of 4 hours to precipitate (Sb/Sn)/02 powder, and then the (Sb/Sn)/02 powder was diced.
After washing, the fine powder obtained by heat treatment in the air at a temperature of 50,000 for 2 hours was poured into a predetermined amount of weak alkaline solution together with Teflon ■ (trade name), and placed in a pole mill. After adjusting the stock solution by kneading for 1 hour, add a dispersant (Triton: 5
The solution was diluted with ion-exchanged water containing 100% water and 50% water. We measured the surface charge potential of the 1050 aluminum plate treated in this way, and also measured the friction coefficient in order to know the surface lubrication characteristics.
It was revealed that rostatic Paper (using a female lyzer) exhibited a charge amount of 3 to 5 V, and that it had a surface charge potential close to 0 to 2 V, which is the charge potential of 1050 aluminum material. The coefficient of friction (French) showed a value of 0.15.

By the way, a comparative material in which a hard oxide film of 30 fm thick was formed on 1050 aluminum showed a charge amount of 120 to 180 V and a high coefficient of friction of 0.5 to 0.7. In this example, (Sb/Sn)/
A coexisting dispersion of 02 powder and Teflon ■ (trade name) was used. Separate dispersions with the same concentrations as above were prepared for each, and each was subjected to bond immersion treatment in the above order. However, we were able to obtain good results that were almost the same as the above results.

As described above, according to the present invention, it is possible to extremely easily manufacture non-static, highly lubricating surface-coated aluminum members with high productivity, and the finished dimensions of the anodized material are the same as the product dimensions. As a result, products with high dimensional accuracy can be obtained, and products with enhanced anti-static properties and lubricity can be obtained without deteriorating the strength of the anodic oxide film, providing industrially useful effects. .

Claims (1)

[Scope of Claims] 1. An aluminum or aluminum alloy member whose surface has been anodized, containing 0.1 to 20% by weight of antimony, with the remainder substantially consisting of tin oxide, and having a thickness of 0.2 μm. Aluminum or aluminum characterized by forming a non-static lubricating hard film on the surface of the member by immersing it in a dispersion of a conductive fine powder having the following average particle size and a fluororesin fine powder. Surface treatment method for alloy parts. 2. The method according to claim 1, wherein the dispersion liquid is a dispersion liquid in which the conductive fine powder and the fluororesin fine powder coexist. Surface treatment method. 3. The method according to claim 1, wherein the dispersion liquid is composed of two types: a dispersion liquid of the conductive fine powder and a dispersion liquid of the fluororesin fine powder. Or surface treatment method for aluminum alloy parts.