JP2003328155A - Lubrication treatment method of sliding member made of aluminum or aluminum alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming a composite lubricating film having high wear resistance and a low friction coefficient on the surface of a sliding member made of aluminum or an aluminum alloy at a low cost in a low environmental contamination load. <P>SOLUTION: An anodic oxidation coating with a thickness of 3 to 30 μm is formed on the surface of a cleaned sliding member made of Al or an Al alloy. A lubricating film with a thickness of 2 to 20 μm containing, by mass, a 30 to 70 pts. polyester resin, 30 to 70 pts. polytetrafluoroethylene and 0.5 to 5 pts. ceramic particles is formed thereon. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubrication method for imparting excellent sliding lubricity to a sliding member made of aluminum or aluminum alloy. More specifically, the present invention provides a composite film comprising an anodized film layer having excellent wear resistance and a lubricating film layer containing PTFE, ceramic particles and polyester resin on the surface of a sliding member made of aluminum or an aluminum alloy. The present invention relates to a lubrication treatment method for forming a film. INDUSTRIAL APPLICABILITY The method of the present invention is effectively used, for example, in pistons and scrolls used in compressors for air conditioners and the like.

[0002]

2. Description of the Related Art Generally, a sliding member is required to have a low friction property so as not to lose energy transmission. In addition, load resistance that does not cause seizure when a load is applied, that is, even under high surface pressure, is an important property. Then, industrially, high durability of these characteristics, high durability of the member (high abrasion resistance), and low treatment cost are strongly demanded. As a method for forming a sliding film made of aluminum or an aluminum alloy (hereinafter referred to as an aluminum material) for a sliding member, a hard anodic oxidation treatment method has been used for a long time. The anodized film does not reduce the friction coefficient on the surface of the sliding member by itself, but it improves the wear resistance, and the many holes formed in the anodized film improve the oil retention. This improves the lubricity of the surface. Since seizure is caused by the same metal contact, many methods of plating different metals are used to prevent this. For example, tin plating, iron plating, and nickel-based plating are disclosed in Japanese Patent Publication No. Sho 56-1808.
No. 0, Japanese Patent Publication No. 58-9160, etc. have been disclosed and put to practical use. In the case of tin plating, tin itself acts as a solid lubricant and has the effect of reducing the coefficient of friction, but it is soft and therefore has a problem of low durability. Further, in general, in the case of plating, there is a problem that it is difficult to uniformly form a plating film on an article having a complicated shape and surface, and the cost is generally high.

As an industrially inexpensive surface treatment, there is a chemical conversion coating treatment. As a method of forming a lubricating film for a sliding member made of an aluminum material by chemical conversion treatment, there is disclosed in Japanese Patent Application Laid-Open No. 11-19.
The method disclosed in Japanese Patent No. 3478 can be mentioned. In this method, an aluminum material is immersed in a treatment liquid containing a fluorine compound and ammonium silicofluoride and treated in a temperature range of 70 to 100 ° C. As a result, Al-OH-F compound or NH ₄ is formed on the surface.
It is said that a film containing the MgAlF ₆ compound or both of them is formed. However, this coating alone does not reduce the coefficient of friction of the material surface. Further, since a large amount of fluorine compound is used in the treatment liquid, the wastewater treatment load is large, which is a problem from the viewpoint of global environment conservation.

A method of overcoating the anodized film with a lubricant is disclosed, for example, in Japanese Patent Publication No. 52-39059. In the method disclosed in this publication,
An anodized film is formed on an aluminum material, and this is immersed in a solution of polytetrafluoroethylene to impregnate it. Further, in the method disclosed in JP-A-5-51794, fine particles of polytetrafluoroethylene are electrochemically or chemically adsorbed on the surface of a hard anodic oxide film made of an aluminum material, and after this is dried, A lubricating coating is formed by sliding the mating material with the mating material. All of these methods use PT in the pores of the anodized film.
The FE is filled and held. However, PTFE
Has basically low adhesion to an anodized film of an aluminum material, and therefore, the methods disclosed in these publications do not always provide sufficient adhesion (binding property). Although the overcoated PTFE has a function of reducing the coefficient of friction, it has a problem in that it is soft and easily worn, and its durability is insufficient.

On the other hand, a lubricating paint is often used for the purpose of reducing the friction coefficient. As a lubricating coating, a polyamide-imide-based coating containing a solid lubricant such as molybdenum disulfide, graphite or polytetrafluoroethylene (PTFE) as a pigment has been put into practical use. In this method, the polyamide-imide resin functions as a binder, and therefore the adhesion to the anodized film on the aluminum material is good. However, it is general to use a method of spraying-baking a lubricant coating diluted with a solvent for this treatment. This method has the problem that harmful solvent vapors are released into the atmosphere. In order to avoid this problem, it is desired to develop a lubrication means that does not use a solvent for the purpose of protecting the global environment.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art, namely, the surface of a sliding member made of aluminum or an aluminum alloy is excellent in wear resistance and has a friction coefficient. An object of the present invention is to provide a method for lubricating a sliding member made of aluminum or an aluminum alloy, which can form a film having reduced and extremely excellent sliding characteristics at low cost and with low environmental pollution load. It is a thing.

In the present specification, "aluminum or aluminum alloy sliding member" is abbreviated as "aluminum material".

[0008]

A method for lubricating a sliding member made of aluminum or an aluminum alloy according to the present invention comprises: cleaning the surface of a sliding member made of aluminum or an aluminum alloy; and subjecting this surface to anodizing treatment. 3-30μ
An anodic oxide coating having a thickness of m is formed, and a lubricating coating containing polyester resin, polytetrafluoroethylene, and ceramic particles and having a thickness of 2 to 20 μm is formed on the coating. To do. In the method of lubricating a sliding member made of aluminum or an aluminum alloy of the present invention, a sulfuric acid bath or an oxalic acid bath is used in the anodizing treatment, the treatment temperature is 0 to 30 ° C., and the current density is 0.5 to It is preferably 4 A / dm ² . In the method for lubricating a sliding member made of aluminum or an aluminum alloy according to the present invention, an aqueous treatment liquid containing a polyester resin, polytetrafluoroethylene, and ceramic particles is formed on the anodized film to form the lubricating film. And apply 100 to 2 to the treatment liquid layer.
The baking is preferably performed at a temperature of 50 ° C. for 1 to 20 minutes. In the method for lubricating a sliding member made of aluminum or an aluminum alloy according to the present invention, the ratio of the mass content of the polyester resin (A), polytetrafluoroethylene (B), and ceramic particles (C) in the lubricating coating is ( A): 30 to 70 parts, (B): 30 to 7
0 part, (C): It is preferably in the range of 0.5 to 5 parts. In the method for lubricating an aluminum or aluminum alloy sliding member of the present invention, it is preferable that the ceramic particles are alumina particles having an average particle size of 0.01 to 0.2 μm.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The contents of the present invention will be described in more detail below. The metals to which the method of the present invention is applied are aluminum and aluminum alloys. In the method of the present invention, first, the surface of the aluminum material is cleaned. The purpose of this cleaning is to remove the oil agent (cutting oil or the like) and dirt used when forming the sliding member. The cleaning method is not particularly limited, but it is not preferable to use a solvent-based cleaning agent from the viewpoint of global environmental protection, and it is preferable to use an alkaline aqueous degreasing agent. The cleaned aluminum material sliding member is subjected to the anodized film forming step.

The thickness of the anodic oxide coating of the present invention is 3 to 30 μm.
m, preferably 10 to 20 μm. The anodized film has abrasion resistance, seizure resistance, and a function of retaining the lubricating film. A considerable pressure may be applied locally when sliding, but the anodized film
This heat-resisting body prevents direct metal contact with the aluminum material, and also functions to prevent seizure. If the thickness of the anodized film is less than 3 μm, the abrasion resistance is insufficient. Further, even if it exceeds 30 μm, the performance is not particularly changed, but there is a disadvantage that the cost becomes high. A conventional sulfuric acid bath or oxalic acid bath may be used to form the anodized film. In the case of a sulfuric acid bath, the sulfuric acid concentration is 10 to 20%, the treatment temperature is 10 to 20 ° C., and the current density is 0.5 to 1 It is preferable to use a treatment condition of 0.5 A / dm ² , and in the case of an oxalic acid bath, a treatment condition of an oxalic acid concentration of 2 to 5%, a treatment temperature of 25 to 30 ° C. and a current density of ^{2 to} 3 A / dm ^2. It is preferable.

In the method of the present invention, the lubricating film is formed on the surface side of the sliding member made of an aluminum material. The main purpose of the lubricating film is to reduce the friction with the mating metal material that comes into contact during sliding. In the method of the present invention,
When the thickness of the lubricating coating is less than 2 μm, which is controlled to a thickness of 2 to 20 μm, preferably 6 to 14 μm, the slipperiness is insufficient and the effect of low friction becomes insufficient. Further, even if it exceeds 20 μm, there is no particular problem in performance, but there is a disadvantage that the cost becomes high.

The material forming the lubricating film contains polyester resin, polytetrafluoroethylene, and ceramic particles as its components. The polyester resin acts as a binder that holds other components and forms a strong film. In order for the lubricating coating to exhibit high mechanical strength during sliding, it is preferable to use a polyester resin having high mechanical strength. Further, in the lubrication environment, the lubricating film comes into contact with the lubricating oil. Further, in the case of a sliding member of a compressor of an air conditioner, a refrigerant (CFC) is also present in addition to the lubricating oil. Therefore, the lubricating coating must be stable to these. Therefore, when a binder resin having high resistance to lubricating oil and refrigerant was examined, the polyester resin was the most suitable. Polytetrafluoroethylene is added to reduce friction. Further, the ceramic particles are for improving the seizure resistance of the lubricating film. In the present invention, the case where seizure occurs is when the mating metal destroys the lubricating coating and further the anodic oxide coating to cause direct metal contact with the aluminum material. Therefore, by improving the seizure resistance of the lubricating film,
The seizure resistance of the sliding member as a whole can be improved, and the durability of the sliding member can be improved.

As a method of forming the lubricating film of the present invention, a method of forming the lubricating film using a water-based treating agent is preferable in consideration of environmental protection. Specifically, after forming an anodized film, an aqueous treatment liquid obtained by dispersing a polyester resin, polytetrafluoroethylene, and ceramic particles in an aqueous medium liquid is applied thereon, and this aqueous system is applied. It is preferable to bake the treatment liquid layer at a temperature of 100 to 250 ° C., preferably 160 to 200 ° C. for 1 to 20 minutes, preferably 5 to 15 minutes. The film thickness of the lubricating film can be controlled by controlling the coating amount of the aqueous treatment liquid. If the baking temperature is less than 100 ° C, it takes too much time to complete the baking, which is not preferable. If it exceeds 250 ° C, the polyester resin may deteriorate. Further, if the baking time is less than 1 minute, it may not be possible to perform sufficient baking, and if it exceeds 20 minutes, there is no particular problem, but productivity may be deteriorated. The member to be coated is preheated (80
It is also effective to adjust the temperature to 120 ° C.

The content ratio of each component in the lubricating coating can be controlled by controlling the concentration of each component contained in the dispersion treatment agent. In the method of the present invention, the content ratio of the polyester resin (A), polytetrafluoroethylene (B), and ceramic particles (C) in the lubricating coating is (A): 30 to 70 parts, preferably 40 to 60. Parts, (B): 30 to 70 parts, preferably 40 to 60 parts, and (C): 0.5 to 5 parts, preferably 1 to 3 parts. If the content of the polyester resin is less than 30 parts, the binder effect may be insufficient to form a strong film, and if it exceeds 70 parts, the weight of the polytetrafluoroethylene may be relatively large. May decrease, and sufficient slipperiness may not be obtained. When the content mass ratio of polytetrafluoroethylene is less than 30 parts, sufficient slipperiness may not be obtained in the same manner as described above.
If it exceeds the amount, the content of the polyester resin is relatively insufficient, the binder effect becomes insufficient, and a strong film may not be formed. If the content of the ceramic particles is less than 0.5 part, the effect of improving the seizure resistance may be insufficient, and if it exceeds 5 parts, the continuity of the formed film may be impaired and the strength may be increased. The film may not be obtained.

The ceramic particles have an average particle size of 0.01 to
Alumina particles of 0.2 μm are preferable, and the average particle diameter thereof is more preferably 0.05 to 0.1 μm. In this case, if the average particle size is less than 0.01 μm, the particles may be too fine to obtain sufficient seizure resistance. Further, when the average particle diameter exceeds 0.2 μm, the particles are likely to aggregate, and as a result, the continuity of the film may be hindered or local adhesion may occur. As the ceramic particles, in addition to the above alumina powder, silicon oxide,
Zirconium oxide and / or titanium oxide may be used, or these may be used in combination with alumina particles.

[0016]

The present invention will be further described by the following examples.
In addition, a comparative example will be shown to compare and explain the effect of the method of the present invention. The aluminum materials, treatment methods, film thickness measurements and evaluation methods used in the following Examples and Comparative Examples were as follows.

(1) Aluminum Material The following aluminum materials were lubricated. Aluminum plate (40 × 40mm thickness: 1.5
mm) Material: ADC10 (2) Treatment method An aluminum material is immersed in a 2% aqueous solution of a cleaning agent (trademark Fine Cleaner 315: manufactured by Nippon Parkerizing Co., Ltd.) at 60 ° C. for 3 minutes, pulled out, and tapped with tap water for 30 minutes.
It was cleaned by washing with water for 2 seconds. This cleaned aluminum material is subjected to anodizing treatment shown in each of Examples and Comparative Examples,
It was washed with tap water for 30 seconds and dried at 100 ° C. for 5 minutes.
Immediately thereafter, a water-based lubricating liquid having a compounding ratio shown in each of the examples and comparative examples was spray-coated on the anodized film by air spray, and baked under the conditions shown in each of the examples and comparative examples.

(3) Measurement of film thickness The film thickness (μm) was measured using the prepared sample. (4) Evaluation method (a) Adhesion test Lubrication tester (trademark: Tribogear HEIDON-14
DR, manufactured by Shinto Kagaku) was used. A lubricated sliding member test piece and an untreated steel ball (SUJ2 diameter 5 mm) were brought into contact with each other, and a load of 10 N, a vibration speed of 0.1 m / s, and an amplitude of 10
Both were slid under the condition of mm. At this time, lubricating oil (trademark: ND OIL 8, manufactured by DENSO CORPORATION) was applied to the sliding surface. Two conditions were evaluated, with and without oil applied. The sliding distance until sliding and adhesion and the friction coefficient between them were measured and evaluated. The longer the sliding distance,
Excellent lubrication performance was evaluated as 20 m or more in the absence of oil and 400 m or more in the presence of oil. Further, the lower the coefficient of friction is, the better, and 0.15 or less is evaluated as good.

(B) Seizure test A friction and wear tester (MODEL EFM-III-E, manufactured by Toyo Baldwin) was used. Treated specimen and untreated aluminum collar (ADC10, inner diameter: 23 mm:
Outer diameter 25 mm) and apply lubricating oil to the sliding surface,
Both were slid under the condition of a load of 50 N and a vibration speed of 2 m / s. The load was stepped up by 50 N every 2 minutes and the load at which seizure occurred was measured. The higher the withstand load is, the better, and 800 N or more is evaluated as good. The results of the above tests are shown in Table 1.

Example 1 A lubricated aluminum material for a sliding member was manufactured under the following conditions. ・ Anodic oxide film treatment conditions Treatment bath: Sulfuric acid 18% Treatment temperature: 15 ° C Current density: 1 A / dm ² Treatment time: 60 minutes Coating thickness: 20 μm ・ Lubrication film formation conditions Polyester resin: 50% (mass) PTFE: 48% (Mass) Ceramic particles: Alumina (average particle size 0.1 μm) 2%
(Mass) Baking temperature: 180 ° C. Baking time: 10 minutes Coating thickness: 10 μm

Example 2 A lubricated aluminum material for sliding members was manufactured under the following conditions. ・ Anodic oxide film treatment conditions Treatment bath: Sulfuric acid 18% Treatment temperature: 15 ° C Current density: 1 A / dm ² Treatment time: 75 minutes Film thickness: 25 μm ・ Lubrication film formation conditions Polyester resin: 30% (mass) PTFE: 66% (Mass) Ceramic particles: Alumina (average particle size 0.04 μm) 4
% (Mass) Baking temperature: 220 ° C. Baking time: 5 minutes Coating thickness: 6 μm

Example 3 A lubricated aluminum material for sliding members was produced under the following conditions. ・ Anodic oxide film treatment conditions Treatment bath: Oxalic acid 4% Treatment temperature: 28 ° C Current density: 2.5 A / dm ² Treatment time: 40 minutes Film thickness: 5 μm ・ Lubrication film formation conditions Polyester resin: 68% (mass) PTFE : 30% (mass) Ceramic particles: Alumina (average particle size 0.05 μm) 2
% (Mass) Baking temperature: 240 ° C. Baking time: 3 minutes Coating thickness: 20 μm

Example 4 A lubricated aluminum material for a sliding member was manufactured under the following conditions. ・ Anodic oxide film treatment conditions Treatment bath: Oxalic acid 4% Treatment temperature: 28 ° C Current density: 2.5 A / dm ² Treatment time: 80 minutes Film thickness: 10 μm ・ Lubrication film formation conditions Polyester resin: 35% (mass) PTFE : 63% (mass) Ceramic particles: Alumina (average particle size 0.05 μm) 2
% (Mass) Baking temperature: 150 ° C. Baking time: 15 minutes Coating thickness: 15 μm

Example 5 A lubricated aluminum material for a sliding member was produced under the following conditions. ・ Anodic oxide film treatment conditions Treatment bath: Sulfuric acid 18% Treatment temperature: 15 ° C Current density: 1 A / dm ² Treatment time: 60 minutes Coating thickness: 20 μm ・ Lubrication film formation conditions Polyester resin: 40% (mass) PTFE: 59% (Mass) Ceramic particles: Alumina (average particle size 0.15 μm) 1
% (Mass) Baking temperature: 200 ° C. Baking time: 5 minutes Film thickness: 10 μm

Comparative Example 1 Only cleaning was performed, and no anodizing treatment or lubricating film forming treatment was performed.

Comparative Example 2 Under the following conditions, only the anodizing treatment was performed, and the lubricating film forming treatment was not performed. ・ Anodic oxide film treatment conditions Treatment bath: Sulfuric acid 18% Treatment temperature: 15 ° C Current density: 1 A / dm ² Treatment time: 30 minutes Coating thickness: 10 μm ・ Lubricating film formation treatment None

Comparative Example 3 A lubricating film forming treatment was performed under the following conditions without performing anodizing treatment. ・ No anodic oxide film treatment ・ Lubrication film formation treatment Polyester resin: 50% (mass) PTFE: 48% (mass) Ceramic particles: Alumina (average particle diameter 0.05 μm) 2
% (Mass) Baking temperature: 180 ° C. Baking time: 5 minutes Film thickness: 10 μm

Comparative Example 4 An aluminum material for sliding members was tin-plated under the following conditions. ・ Tin plating conditions Treatment bath: Alkali-substituted tin plating bath Treatment temperature: 60 ° C Treatment time: 4 minutes Film thickness: 1 μm

[0029]

[Table 1]

As is clear from Table 1, in Examples 1 to 5 according to the treatment method of the present invention, it was confirmed that a lubricating aluminum material exhibiting excellent adhesion resistance and seizure resistance can be obtained by a simple process. Was done. However, the product of Comparative Example 1 having only the cleaning treatment had extremely poor performance. In Comparative Example 2 having no lubricating film and Comparative Example 3 having no anodic oxide film, both adhesion resistance and seizure resistance could not be satisfied. Also, in Comparative Example 4 where tin plating was performed, sufficient performance was not obtained.

[0031]

By using the method for lubricating a sliding member made of aluminum or aluminum alloy of the present invention, a composite having extremely excellent adhesion resistance and seizure resistance on a sliding member made of aluminum or aluminum alloy is obtained. The film can be formed by a simple process in a short time, at low cost, and with low environmental pollution load.

Front page continuation (51) Int.Cl. ⁷ identification code FI theme code (reference) B05D 7/24 303 B05D 7/24 303B C25D 11/08 C25D 11/08 11/10 11/10 11/18 312 11 / 18 312 313 313 (72) Inventor Masayuki Yoshida 1-1-15-1 Nihonbashi, Chuo-ku, Tokyo Within Nippon Parkerizing Co., Ltd. (72) Inventor Hiroshi Sumiya 1-1, Showa-cho, Kariya City, Aichi Prefecture DENSO CORPORATION F term (reference) 4D075 AE03 BB67X CA02 CA09 CA47 DA06 DB07 DC15 EA10 EA37 EB16 EB35 EB56 EC05 EC53 EC54 4K044 AA06 AB10 BA13 BA21 BB03 BB11 BC01 CA17 CA53 CA62

Claims (5)

[Claims] 1. A surface of a sliding member made of aluminum or an aluminum alloy is cleaned and anodized on the surface to form an anodized film having a thickness of 3 to 30 μm. Containing tetrafluoroethylene and ceramic particles, and 2 to 20 μm
A method for lubricating a sliding member made of aluminum or an aluminum alloy, which comprises forming a lubricating film having a thickness of 1. 2. In the anodizing treatment, a sulfuric acid bath or an oxalic acid bath is used, and the treatment temperature is 0 to 30 ° C.
The method for lubricating a sliding member made of aluminum or aluminum alloy according to claim 1, wherein the current density is 0.5 to 4 A / dm ² . 3. An aqueous treatment liquid containing a polyester resin, polytetrafluoroethylene, and ceramic particles is applied onto the anodized film to form the lubricating film, and the treatment liquid layer is provided with 100 to 250. Baking for 1 to 20 minutes at a temperature of [deg.] C is performed.
The method for lubricating a sliding member made of aluminum or an aluminum alloy according to item 4. 4. The content ratio of the polyester resin (A), polytetrafluoroethylene (B), and ceramic particles (C) in the lubricating coating is (A): 30.
~ 70 parts, (B): 30-70 parts, (C): 0.5-5
The method for lubricating a sliding member made of aluminum or an aluminum alloy according to any one of claims 1 to 3, which is within a range of a part. 5. The ceramic particles have an average particle size of 0.
The alumina particles having a diameter of 01 to 0.2 μm.
A method for lubricating a sliding member made of aluminum or an aluminum alloy according to any one of 1.