JPS6196096A - Method for plating ternary nickel-tungsten-phosphorus alloy - Google Patents

Abstract

PURPOSE:To obtain a plated layer having superior hardness at high temp., superior wear resistance and magnetic characteristics in spite of the low W content by plating a ternary Ni-W-P alloy contg. a specified amount of P on the surface of a metal. CONSTITUTION:A plating bath contg. 60-100g/l nickel sulfate, 10-30g/l sodium tungstate, 10-50g/l sodium hypophosphite and 100-200g/l sodium citrate is adjusted to 7-8pH with an aqueous ammonia soln. and heated to 70-90 deg.C. An insoluble anode such as a stainless steel plate or a Pt plated Ti plate and a metallic member of Fe, Cu or the like as a cathode are placed in the plating bath, and a ternary alloy consisting of 10-20% W, 5-15% P and the balance Ni is electroplated on the cathode at 10-20A/dm<2> cathode current density. A plated alloy layer having superior hardness at high temp., superior wear resistance and magnetic characteristics can be formed with an amount of expen sive W in the alloy layer of only 10-20%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relies on a plating method for a ternary nickel-tungsten alloy containing 10-20% tungsten and 5-15% phosphorus, and its purpose is to improve hardness at high temperatures. ,
The object of the present invention is to obtain an alloy plating having high wear resistance and excellent magnetic properties.

It is known that nickel-tungsten alloy plating containing 40X or more of tungsten has high hardness at high temperatures and is effective as a plating for glass molds. However, since tungsten is an extremely expensive metal, it contains a high percentage of tungsten.

High heat-resistant hardness can be obtained with a low tungsten content, which is extremely advantageous industrially.

The present inventor discovered that by alloying nickel-tungsten with phosphorus to form a ternary alloy plating, a plating with heat resistance hardness equivalent to that of high tungsten alloy plating can be obtained with a lower tungsten content. completed this invention. Furthermore, it has been found that this nickel-tungsten ternary alloy plating has excellent magnetic properties and can be used as a magnetic material.

The plating bath of the present invention includes nickel sulfate 60 to toogA,
Sodium tungstate 10-3o g/l, sodium hypophosphite 10-50g/l, sodium citrate 100-200g/l, adjusted to pH 7-8 with aqueous ammonia, bath temperature 70-90℃. Cathode current density 1
It is characterized by electrolysis at 0 to 20 A//'drr+.

Under the conditions within the above range, a nickel-tungsten-terminal ternary alloy plating containing 10 to 20 weight percent tungsten, 5 to 15 weight percent phosphorus, and the balance nickel can be obtained. The hardness of this plating film is HV550-650, and it was confirmed through experiments that a hardness of HV1100-1200 can be obtained by heating at 600°C for 1 hour. Further, when the magnetic properties of this electrodeposited film were tested, it was found that the coercive force Ha was 500 to 6000e, and the saturation magnetic flux density Bm was 5000 to 10.000G, indicating that it had excellent properties as a magnetic material.

Next, the present invention will be explained with reference to examples. Example 1 Nickel sulfate 8o g/l Sodium tungstate 20g/13 Sodium citrate
Using a plating bath containing 160 gA and adjusted to pH 7.5 with ammonia at a bath temperature of 80°C, using a mild steel plate as the cathode and a 18-8 stainless steel plate as the anode, the cathode current density was 20 A/d.
Electrolysis was performed for 20 minutes at rr+2 to obtain a shiny nickel-tungsten ternary alloy plating.The plating film thickness was approximately 4.
It was 0μ. Quantitative analysis of this plating with EPMA revealed that it contained 65% nickel, 20% tungsten, and 1% phosphorus.
It was found to be a ternary alloy containing 5%. The hardness of this plated layer was HV590, and when heat treated at 600°C for 1 hour, the hardness increased to HV1180.

Example 2 Nickel sulfate 70 g/l Sodium tungstate 20 g/1 Sodium hypophosphite
sog/l sodium citrate 1oog/l
A plating bath adjusted to pH 7.0 with aqueous ammonia was electrolyzed for 80 minutes at a cathode current density of 2oA/drn2 using a copper plate as a cathode and a platinum-menki titanium anode at a bath temperature of 90°C to produce a glossy finish. A 90μ nickel-tungsten ternary alloy plating was obtained.

Quantitative analysis of this plating film using EPMA revealed that it was a ternary alloy containing 70% nickel, 18% tungsten, and 12% phosphorus. This item\The result of testing the magnetic properties was coercive force Hc 5800e, saturation magnetic flux density B
It turned out to be 9000G.

As is clear from the above explanation, the present invention provides a metal alloy with a low tungsten content and high temperature hardness comparable to high tungsten alloys, and also has a nickel coating that can be used as a magnetic material as a plating with excellent magnetic properties. Ru tungsten
This invention provides ternary alloy plating and is an industrially significant invention.

Claims (1)

[Claims] Nickel sulfate 60-100g/l Sodium tungstate 10-30g/l Sodium hypophosphite 10-50g/l Sodium citrate 100-200g/l pH adjusted to 7-8 with aqueous ammonia Using a plating bath, at a bath temperature of 70 to 90°C, a cathode current density of 10 to 20 A/
A method of plating a nickel-tungsten-phosphorus ternary alloy, which is characterized by electrolyzing at dm^2.