JPH04120293A - Method for coating titanium or titanium alloy - Google Patents

Abstract

PURPOSE:To form a coating film on a Ti surface excellent in adhesion property, heat resistance and wear resistance by providing a flash plating film of Cu or Ni on the surface of Ti by substitution method, forming a Ni or Ni-P alloy plating film thereon and heating in vacuum to form an alloy layer of Ti and Ni plating, and further activating and providing a finish composite plating. CONSTITUTION:A flash plating film of Cu or Ni is provided on the surface of Ti or Ti alloy by substitution method to form an extremely thin film of 0.1-2mum thickness. Then, a Ni or Ni-P alloy plating layer or Ni or P composite plating layer containing fine ceramics is formed thereon and heated in vacuum of 10<-2>-10<-5>Torr at >=450 deg.C for one hour or longer to make an alloy between the Ti and Ni-base plating layer. Then, for example, the surface is treated for activation with a nitric acid-hydrofluoric acid soln. and coated with a composite plating film comprising Ni, P or Co as the matrix and containing various kinds of fine hard ceramic powders.

Description

[Detailed Description of the Invention] [Field of Industrial Application] Titanium and titanium alloys are increasingly being used in functional parts that aim to reduce weight, such as engine valves, valve retainers, connecting rods, and rocker arms for automobiles and motorcycles. It is also used in pump parts such as impellers and shafts that require chemical resistance and wear resistance.

The present invention relates to a method for forming a film with excellent adhesion, heat resistance, and wear resistance on titanium and titanium alloys.

[Conventional Technique II] Conventional methods for forming wear-resistant films on the surfaces of titanium and titanium alloys include gas nitriding, salt bath nitriding, ion nitriding, and dry methods such as ion blating, CVD, and PVD. Marshall as a plating method or pretreatment
There are various wet plating methods using the method, Thomas method, ASTM method, etc.

First, the case of the nitriding method will be explained. This method has drawbacks such as high processing temperature, which causes large deformation due to thermal strain, and furthermore, a long time required to obtain a hardened layer, resulting in a lack of productivity.

Also, the dry plating method and wet plating method mentioned above.

In either case, the adhesion of the plating film to titanium or titanium alloy is poor, and the film tends to peel off during use. In other words, in order to sufficiently withstand friction of 1 strength, it is essential that the coating has excellent abrasion resistance and excellent adhesion to the base metal. It cannot withstand wear and tear.

Recently, the Martin-Thoma method has been published (Japanese Patent Laid-Open No. 1-79397) as a method for forming a wear-resistant film on titanium or titanium alloy. The present invention relates to a method for forming an anti-wear layer on the surface of a component made of titanium or a titanium alloy. However, in this method (1) heat treatment is performed in an oxidizing atmosphere, so the nickel film formed by the chemical precipitation method is considerably oxidized, and when the chromium film is formed by electroplating in the next step, the oxide film is removed. It has the disadvantage that it requires a relatively long film removal process. Furthermore, (2) the chromium film formed on the outermost surface as the wear-resistant layer has a problem in that it has insufficient seizure resistance and heat and wear resistance.

[Problems to be Solved by the Invention] Problems with the prior art include the problem that it takes a relatively long time to remove the oxide film, which is a burden on process control, as explained in (1) above, and ( 2
) There are quality problems such as insufficient seizure resistance and wear resistance of the chromium film, and the present inventors aim to solve these problems.

[Means for Solving the Problems] As a method for solving the above-mentioned problems, the present inventors have invented a method of forming a film with excellent heat resistance and wear resistance on titanium or a titanium alloy, and have developed this method as a special method. Ganpei 2-30494
No. (hereinafter referred to as the earlier invention) has been applied for a patent.

However, as a result of further research related to the earlier invention, the inventors of the present invention found that by improving a part of the treatment process of the earlier invention, titanium or titanium alloy can be coated with a heat-resistant and wear-resistant film with even better film adhesion. They discovered a method to form a sexual film.

That is, in the present invention, an extremely thin flash plating of copper or nickel is first applied to the surface of titanium or a titanium alloy by a displacement method, and then this plated surface is further plated with nickel, nickel-phosphorous alloy plating, or nickel-phosphorous alloy plating.
A phosphorus composite plating film is formed, and then an alloy layer with these films is formed on the surface of titanium or titanium alloy by vacuum heat treatment under specific conditions, and the surface is then subjected to an extremely short activation treatment. Finally, the gist is to apply final composite plating as the top layer coating. That is, in the present invention, the surface of titanium or titanium alloy is flash-plated with copper or nickel by a substitution method, and then nickel plating, nickel-phosphorus alloy plating, or nickel-phosphorus composite plating is applied, and then vacuum pressure 10-1~ 1
0″″’ Torr, furnace temperature at least 1 at 450°C
adhesion to titanium or titanium alloy, characterized by subjecting titanium or titanium alloy to a vacuum heat treatment for more than an hour to form an alloy layer of titanium or titanium alloy and the plated metal, then activating the surface and finally applying final composite plating; The present invention relates to a method for forming a film with excellent heat resistance and abrasion resistance.

[Function] When performing flash plating of copper or nickel on the surface of titanium or titanium alloy by a substitution method, the plating thickness is not specified, but is preferably 0.1 to 2 μm thick. 0
．． If it is less than 1μI, it is difficult to deposit a film uniformly;
If it is larger than μm, Ti, Ni can be removed by the subsequent vacuum heat treatment.
, T1Ni, T1Ni, or T1Cu.

This is not preferred because it tends to gradually hinder the formation of an alloy layer of titanium and nickel or copper such as T1Cu2. A film with the best adhesion can be formed especially when the film thickness of flash plating is within the range of 0.1 to 1 μm.

Next, to give an example of a plating solution bath that can be applied to the flash plating of the present invention, in the case of copper flash plating, copper sulfate Log/Q, sodium hydroxide 10gIQ, E)
Lt? 'J'/ (37%) 20mff1/a
, using a solution of EDTA 20g/Q at 450°C.

Next, in the case of flash plating of nickel, a solution of nickel chloride 30g/Q, sodium hypophosphite 10g/Q, and sodium citrate 10g/fi at 60°C can be used, all of which can be used to obtain flash plating by a chemical substitution method. be able to.

Nickel plating applied on flash plating is, for example, nickel sulfamate 800/Q, nickel chloride 1
Using a plating solution containing 5g/Q, 30g/Q of phosphoric acid, and nickel-phosphorus alloy plating, for example, nickel sulfamate 800g/11, nickel chloride 1
5g/Q, oxalic acid 30g/Q, sodium hypophosphite 3
Using a plating solution containing g/Q, nickel and
For phosphorus composite plating, SiC with an average particle size of, for example, 1 μm is placed in a nickel-phosphorus alloy plating solution bath.

Si3N*t BNt^Q, Oa, VC, ZrB,
, CrB, and one or two selected from diamond
It is obtained by electroplating using a plating solution to which 200 g/2 of fine powder of 50% or more is added. The film thickness of these platings applied after flash plating is not specified, but is preferably 5 to 30 μm, and by setting the thickness within this range, the main plating film will remain stable during vacuum heating performed after main plating. Flash plating and titanium or titanium alloy are used as a base metal to achieve excellent mutual adhesion. If the film thickness is less than 5 μm, it is difficult to obtain excellent results due to the insufficient film thickness, and if the film thickness exceeds 30 μm, no improvement in the effect can be expected and it is also unfavorable in terms of cost.

Nickel plating films have sufficient hardness up to about 200°C, and nickel-phosphorus alloy plating and nickel-phosphorus composite plating films have sufficient hardness up to about 350°C. In the present invention, considering the heat-resistant and wear-resistant coating described later, nickel plating, nickel-phosphorus alloy plating, or nickel-phosphorus alloy plating,
Select one of phosphorus composite plating.

In the method of the present invention, in order to form an alloy layer with titanium or a titanium alloy and a plated metal, and to obtain excellent film adhesion, the heat treatment conditions include a vacuum degree of 10-1 to 10
−' Torr vacuum heat treatment is performed. If the degree of vacuum is less than 10'''' Torr, there is a risk that the plating film will be oxidized, and conversely, obtaining a degree of vacuum greater than 10-' Torr is extremely costly, and the method of the present invention Regarding the zero-order processing temperature and processing time conditions that do not require a high degree of vacuum, it is necessary to hold the film in the vacuum atmosphere described above at 450° C. or higher for one hour or more in consideration of metal diffusion.

By performing vacuum heat treatment under these specified conditions, the already formed film will not be oxidized, and when forming a composite plating film in the next step, the surface of the treated titanium or titanium alloy will be coated in advance. They discovered that a final composite plating film with excellent adhesion could be formed thereon by chemically activating it. Although the method of the activation treatment is not specified, for example, 3 to 10
A short time treatment of 2 to 5 seconds at room temperature is preferred with a nitric-hydrofluoric acid aqueous solution containing % of hydrofluoric acid.

Next is the final composite plating as the top layer coating.

Although not specified in the present invention, preferably 5iCt 5isN4. BN, AQ, 0. , VC
Fine ceramics selected from diamonds such as , ZrB, and CrBt were dispersed and co-deposited. Composite plating with nickel-phosphorous or cobalt as a matrix can be mentioned. By forming these final composite plating films, it is possible to form a heat-resistant and abrasion-resistant film with extremely excellent adhesion.

Preferred examples of the water droplet process are outlined below.

First, the surface of titanium or titanium alloy is coated with, for example, AQ, O
After stainplast with the powder of a, the surface is subjected to processes such as organic solvent cleaning, alkaline degreasing, water washing, pickling, and water washing, followed by copper flash plating or nickel flash plating using the substitution method.Next, the surface is nickel plated, Nickel-phosphorus alloy plating or nickel-phosphorus composite plating is applied, first vacuum heat treatment is performed, and after the heat treatment, activation treatment is performed.

Finally, a final composite plating film is formed as the top layer film.

[Example] Example 1 (1) Test piece - JIS Ti type 2 Cw 50mmX
11100mm
4 Water washing 5 Pickling with hydrochloric acid (17% room temperature) (30 seconds) 6 Water washing 7 Copper flash plating (replacement method) Bath composition Sulfuric acid steel log/Q Sodium hydroxide 10 g IQ Formalin (37%) 20飄Q/QEDTA 20g/Q treatment temperature
45℃ Film thickness 0.7μ Garden 8 Water washing 9 Nickel/phosphorous plating treatment bath composition Nickel sulfamate 800g/Q Nickel chloride 15g/Q Boric acid 30g/Q Sodium hypophosphite 3g/Q Processing temperature 57℃ Current density 20A/dm ” Film thickness 20 μm 10 Water washing 11 Hot air drying (approx. 80°C) 12 Vacuum heat treatment Vacuum degree 10-'Torr Furnace temperature 600°C Treatment time 2 hours 13 Activation treatment Treatment aqueous solution...HF5%, HNo, 60% Room temperature, 3 seconds immersion 14 Water washing 15 Final composite plating Nickel/phosphorus/SiC double gold plating bath composition Nickel sulfamate 800g/Q Nickel chloride
15g/Q Boric acid 30g/fi Sodium hypophosphite 3g/Q SiC200g/Q Processing temperature 57°C Current density 15A/dll” Film thickness 20μ 16 Water washing 17 Hot air drying (approx. 80°C) Example 2 (1) Test Piece...Ti-6AΩ-4V (shape is the same as Example 1) (2) Surface treatment of test piece 1 Shot blasting treatment with alumina 2 Triclean steam cleaning Alkaline degreasing (same as Example 1) Water washing Hydrochloric acid Pickling (same as in Example 1) Washing with water Copper flash plating (replacement method) (Same as in Example 1 except that the film thickness was 0.2 μ-) 8 Washing with water 9 Nickel-phosphorous-SiC double gold plating treatment Bath composition Nickel sulfamate 800g/AI nickel chloride 15gIQ boric acid 30g/Q Sodium hypophosphite 3g/Q SiC20Gg/Q Processing temperature 57℃ Current density 15A/dwm'' Film thickness 20μ 10Washing 11Hot air drying (approx. 80℃) ) 12 Vacuum heat treatment Vacuum degree 10-” Torr Furnace temperature 450°C Treatment time 1.5 hours 13 Activation treatment (same as in Example 1) 14 Water washing 15 Final composite plating treatment Nickel/phosphorus/SiC double gold plating treatment (Same as Example 1) 16 Water washing 17 Hot air drying (approximately 80°C) Example 3 (1) Test piece...JIS Ti type 2 (shape is the same as Example 1) Test piece surface treatment alumina Shot blasting treatment with triclene steam cleaning Alkaline degreasing (same as in Example 1) Washing with water Pickling with hydrochloric acid (same as in Example 1) Washing with water Copper flash plating (W exchange method) (film thickness 1.2 μ- Other than that, the same as in Example 1) Water-washed nickel/phosphorus plating treatment (same as in Example 1, except that the film thickness was 10 μ-) Water-washed hot air drying (approximately 80°C) Vacuum heat treatment Vacuum degree: 10-' Torr furnace Internal temperature
850°C Treatment time 1 hour activation treatment (same as in Example 1 except for 2 seconds of immersion) Washing composite plating treatment Nickel/phosphorus/BN composite plating treatment Bath composition Nickel sulfamate 800g/Q Nickel chloride 15g/Q Hou Acid 30g/Q Sodium hypophosphite 3g/Q B N 200g/Q Treatment temperature 5
7℃ Current density 15A/dm” Film thickness 20μ Oil 16 Water washing 17 Hot air drying (about 80℃) Example 4 (1) Test piece... JIS Ti type 2 (shape is the same as Example 1) (2) Surface treatment of test piece 1 Shot blasting with alumina 2 Triclean steam cleaning 3 Alkaline degreasing (same as in Example 1) 4 Washing with water 5 Pickling with hydrochloric acid (same as in Example 1) 6 Washing with water 7 Nickel flash plating ( Replacement method) Bath composition Nickel chloride 30g/Q Sodium hypophosphite LOg/Q Sodium citrate 10gIQ Processing temperature 60℃ Film thickness 0.5μ Water-washed nickel/phosphorus/WCC alloy plating treatment Bath composition Nickel sulfamate 800g/Q Chloride Nickel 15g/Q Boric acid 30g/Q Sodium hypophosphite 3g/Q W C200g/Q Processing temperature 57℃ Current density 15A/da" Film thickness 20μ Grease washing Hot air drying (approx. 80℃) Vacuum heat treatment Vacuum degree 10- Torr furnace temperature: 550°C Treatment time: 3 hours activation treatment (same as Example 1 except for 5 seconds of immersion) Water washing Final composite plating treatment (same as Example 1) 16 Water washes 17 Hot air drying ( (about 80°C) Example 5 (1) Test piece...Ti-6A Q-4V (shape is the same as Example 1) (2) Surface treatment of test piece 1 Shot blasting treatment with alumina 2 Triclean steam cleaning 3 Alkaline degreasing (same as in Example 1) 4 Washing with water 5 Pickling with hydrochloric acid (same as in Example 1) 6 Washing with water 7 Nickel flash plating (replacement method) (film thickness 0.
(Same as in Example 4 except that 2μ was used) 8 Water washing 9 Nickel/phosphorous plating treatment (same as in Example 1) 1O water washing 11 Hot air drying (approximately 80°C) 12 Vacuum heat treatment Vacuum degree 10-' Torr Furnace temperature 800°C Treatment time 1 hour 13 Activation treatment (same as in Example 4) 14 Washing with water 15 Double gold plating treatment (same as in Example 3) 16 Washing with water 17 Hot air drying (approximately 80°C) Example 6 (1) Test piece...Ti-6AΩ-4V (shape is the same as Example 1) (2) Surface treatment of test piece 1 Shot blasting with alumina 2 Triclean steam cleaning 3 Alkaline degreasing (for Example 1) ) 4 Washing with water 5 Pickling with hydrochloric acid (same as in Example 1) 6 Washing with water 7 Nickel flash plating (substitution method) (film thickness 1.
(Same as Example 4 except for 5 μm binding) 8 Water-washed nickel-phosphorus-BNN alloy plating treatment bath composition Nickel sulfamate 800g/Q Nickel chloride 15t/Q Boric acid -30g/Q Sodium hypophosphite 3g/Q BN 200g/Q treatment temperature
57℃ Current density 15A/d■2 Film thickness 10μm Washing with water and drying with hot air (approximately 80℃) Vacuum heat treatment Degree of vacuum 10-'Torr Furnace temperature 700℃ Treatment time 1.5 hours Activation treatment (other than 2-second immersion) is the same as in Example 1) Washing composite plating treated nickel/phosphorus/AQ20. Composite plating bath composition Nickel sulfamate 800g/Q Nickel chloride
15g/Q Boric acid 30g/Q Sodium hypophosphite 3g/Q A Qz O-200g/Ω Treatment temperature 57℃ Current density 15A/d■2 Film thickness 20μm 16 Water washing 17 Hot air drying (approx. 80℃) Comparative example 1 (1) Test piece... JIS Ti type 2 (same shape as in Example 1) (2) Surface treatment of test piece 1 Shot blasting with alumina 2 Triclean steam cleaning 3 Alkaline degreasing (same as in Example 1) 4 Washing with water 5 Pickling with hydrochloric acid (same as in Example 1) 6 Washing with water 7 Copper flash plating (II substitution method (same as in Example 1) 8 Washing with water 9 Nickel/phosphorous plating treatment (Same as in Example 1) ) 10 Water washing 11 Hot air drying (approximately 80°C) 12 Vacuum heat treatment Vacuum degree 10-'Torr Furnace temperature 400°C Treatment time 40 minutes 13 Activation treatment (same as in Example 1) 14 Water washing 15 Double gold plating treatment (same as in Example 1) 16 Washing with water 17 Hot air drying (approximately 80°C) Comparative example 2 (1) Test piece... JIS Ti type 2 (shape is the same as Example 1) (2) Surface treatment of test piece 1 Shot blasting treatment with alumina 2 Triclean steam cleaning Alkaline degreasing (same as in Example 1) Washing with water Pickling with hydrochloric acid (same as in Example 1) Washing with water Copper strike plating bath Composition Sulfuric acid steel 60g/ Q Rossel salt
160g/Q Caustic soda 50g/Q Processing temperature Room temperature current density 0.5A/d irises 2 Film thickness 1μm Water-washed electroless nickel/phosphorus plating 160g/Q Processing conditions for using Nyco ME bath are 50g/Q Film thickness according to specifications 20μm Water-washing hot air drying (approx. 80℃) Heat treatment in an oxidizing atmosphere at 450℃ for 20 hours (using a manful furnace) Film removal HNO, aqueous solution immersion (approximately 33%, immersion for 15 minutes) Room temperature water washing Electrochromium plating treatment Bath composition Cry, 265g/QH, So,
1% by weight (based on Cry) Temperature: 45°C Current density: 40A/da” Film thickness: 20μm Washing with water and drying with hot air (approximately 80°C) Reference example 1 (1) Test piece: JIS Ti type 2 (the shape is Same as Example 1) Surface treatment of test piece (Patent Application No. 2-30494, Example 1)
Shot blasting with alumina Triclean steam cleaning Alkaline degreasing (same as in Example 1) Washing with water 5 Pickling with hydrochloric acid (same as in Example 1) 6 Washing with water 7 Copper strike plating (same as in Comparative Example 2) 8
Water washing 9 Nickel/phosphorous plating treatment (same as in Example 1) 10 Water washing 11 Hot air drying (approximately 80°C) 12 Vacuum heat treatment Vacuum degree 10-'Torr Treatment temperature 450°C Treatment time 3 hours 13 Activation treatment (Example (Same as in Example 1) 14 Washing with water 15 Final composite plating treatment (Same as in Example 1) 16
Washing with water 17 Hot air drying (approximately 80°C) Reference example 2 (1) Test piece...JIS Ti type 2 (shape is the same as Example 1) (2) Surface treatment of test piece (Japanese Patent Application No. 2-30494, Example 2) Shot blasting with alumina Triclean steam cleaning Alkaline degreasing (same as in Example 1) Washing with water Pickling with hydrochloric acid (same as in Example 1) Washing with water Nickel strike plating bath composition Nickel chloride 100g/Q hydrochloric acid
30g/Q Processing temperature 40°C Current density 3A/da” Film thickness 3μ (same as water-washed nickel-phosphorus-WCC alloy plating treatment Example 4) Water-washed hot air drying (approximately 80°C) Vacuum heat treatment (reference example 1) (same as in Example 1) Activation treatment (same as in Example 1) Washing with water 15 Final composite plating treatment Nickel/phosphorous/SiC composite plating treatment (same as in Example 1) 16 Washing with water 17 Hot air drying (approximately 80°C) The adhesion of the films formed on test pieces by the methods of Examples, Comparative Examples, and Reference Examples was evaluated by bending using a universal testing machine.

The results are shown in Table 1 together with the evaluation results of heat resistance and abrasion resistance.

Film adhesion evaluation method: Method by bending using a universal testing machine Testing machine YONEKURA CATY-20025 (2
'Ton)Cross Head 5peed
10mm/winCross Head drop amount 1
0waw+O No film peeling until test piece fracture, no other film abnormalities 0 No film peeling, no other film abnormalities up to test piece deformation of 10 m △ Partial film peeling occurred up to test piece deformation of 110 l1× Wide range Table 1 Adhesion, heat resistance, and abrasion resistance evaluation test results Heat resistance evaluation method 0 Sufficient hardness up to approximately 350°C × Approximately 200°C
Wear resistance evaluation method: Falex wear test Wear speed: 0.39 m/s Lubrication: 8-stone gear oil EP90 (immersion 100cc)
Load step up by 50kg every minute 080
Seizure occurs at 0 kg Seizure occurs at 200 kg As shown in Table 1, the film formed by the method of the present invention shows no problems such as film cracking and film peeling even when the amount of deformation (falling distance of the cross head) is 10 - Oboro. No abnormalities were observed, and a heat-resistant and wear-resistant film with excellent adhesion could be formed on titanium or titanium alloy.

[Effects of the Invention] As explained above, by the method of the present invention, a heat-resistant and wear-resistant film with excellent adhesion can be formed on titanium or titanium alloy, and can be used, for example, in engine valves and valve retainers for automobiles and two-axle motor vehicles. It is particularly advantageous when applied to parts that require both heat resistance and wear resistance, such as connecting rods and rocker arms. Furthermore, by replacing a wide variety of sliding parts for which iron-based materials have traditionally been used with titanium or titanium alloy parts treated by the method of the present invention, durability and weight reduction can be achieved. This contributes to greater durability and energy savings due to lighter weight.

Claims (4)

[Claims] (1) After flash plating copper or nickel by substitution method on the surface of titanium or titanium alloy, nickel plating, nickel-phosphorus alloy plating or nickel-plating
Apply phosphorus composite plating, then vacuum pressure 10^-^1~1
Vacuum heat treatment is performed at 0^-^5 Torr and a furnace temperature of 450°C or more for 1 hour or more to form an alloy layer of titanium or titanium alloy and the plated metal, followed by surface activation treatment and final composite plating. A method for forming a film on titanium or a titanium alloy, characterized by: (2) Thickness of copper or nickel flash plating is 0
．． A method for forming a film on titanium or a titanium alloy according to claim 1, wherein the film has a thickness of 1 to 2 μm. (3) The method for forming a film on titanium or a titanium alloy according to claim (1), wherein the activation treatment is performed with an acidic aqueous solution containing fluoride or hydrofluoric acid. (4) The method for forming a film on titanium or a titanium alloy according to claim (1), wherein the final composite plating is obtained by dispersing and co-depositing fine ceramics in a nickel-phosphorus or cobalt matrix.