Process for lubrication-treating aluminum or aluminum alloy material

Abstract

A lubrication-treating process for an Al or Al alloy material is carried out by cleaning the material; applying an anodic oxidation to the cleaned material surface to form a 3 to 30 mum thick anode oxidation coating; and forming a lubrication coating including a polyester resin (30 to 70 mass parts), a particulate PTFE (30 to 70 mass parts) and ceramic (alumina) particles (0.5 to 5 mass parts), and 2 to 20 mum thick, to thereby impart excellent resistances to adhesion and seizure, and a low friction, to the Al or Al alloy material at a low cost and with no or a very low pollution of the environment.

Description

BACKGROUND OF INVENTION[0001] (1) Field of the Invention[0002] The present invention relates to a process for lubrication-treating an aluminum or aluminum alloy material. More particularly, the present invention relates to a process for lubrication-treating aluminum or an aluminum alloy material such as, for example, an aluminum or aluminum alloy sliding material to form a wear-resistant composite coating on the surface of the material. The process of the present invention is applied to productions of high wear-resistant sliding materials, for example, pistons and scrolls for compressors of air conditioners.[0003] (2) Description of the Related Art[0004] Generally, sliding materials are required to have a low friction property to prevent an energy transfer loss. Also, when a load is applied to the sliding material, an important property of the sliding material is high load-resistance to prevent a seizure of the sliding material under a high face pressure. Also, from an industrial vi...

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Problems solved by technology

However, a plated tin layer is soft and thus exhibits a poor durability (a poor wear resistance).

Also, in general, there are problems that materials having a complicated form and surface are difficult to uniformly plate and the plating cost is generally high.

Also, this treatment is disadvantageous in that since the treatment liquid contains a large amount of a fluorine compound, a load for purifying the waste water from the treatment is high and thus a problem of the preservation of the global environment occurs.

In these methods, however, the close adhesive property of PTFE to the anodic oxidation coating layer formed on the aluminum or an aluminum material is low, and thus the PTFE layers formed by the above-mentioned methods are unsatisfactorily close-bonded to the anodic oxidation layer on the aluminum or aluminum alloy material.

However, the PTFE layer per se is soft and easily worn and thus a problem that the PTFE layer is unsatisfactory in durability occurs.

This method causes a problem that a harmful vapor of the organic solvent is diffused into the air atmosphere.

If the thickness of the anodic oxidation coating is less than 3 .mu.m, the resultant lubrication treated material exhibits an insufficient wear resistance.

Also, if the thickness of the anodic oxidation coating is more than 30 .mu.m, while the performance of the resultant material is saturated, the treatment cost is too high, and thus an economical disadvantage occurs.

If the thickness of the lubrication coating is more than 20 .mu.m the friction-reducing effect is saturated and the coating cost becomes high, and thus an economical disadvantage occurs.

If the baking temperature is lower than 100.degree. C., an undesirable long time may be necessary to complete the baking procedure.

Also, if the baking temperature is higher than 250.degree. C., the polyester resin may be undesirably deteriorated.

If the baking time is less than one minute, the baking procedu