JPS583039B2 - Fukugoumetsukihou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite plating method for forming electrical contacts.

Conventionally, a method of dispersing various metal or non-metal particles in a plating bath in the electrodeposition process and eutectoiding these particles into the plating layer to improve various properties of the plated product is described, for example, in Japanese Patent Publication No. 1973- It is known from the publication No. 3806.

However, a composite plating method that has favorable characteristics for electrical contacts used in relays and the like has not yet been proposed.

This is probably because the characteristic factors required of electrical contacts are complex and diverse, and cannot necessarily be classified into simple characteristics such as surface hardness and lubricity.

This means that in order to improve composite plating for electrical contacts, it is necessary to actually make contacts, put them to practical tests, and conduct hundreds of thousands of on-off tests, leading to improvement research in this area. This made it difficult.

The present invention was developed based on the above-mentioned circumstances, and is characterized in that composite plating is completed using a noble metal or an alloy containing a noble metal as a matrix and specific metal particles as a composite agent.

The present invention will be explained in detail below.

What is used as the matrix in the present invention is:
Precious metals or alloys of precious metals such as gold, silver, palladium, etc.
or alloys of noble metals and other metals, such as, for example, palladium-nickel.

In order to be used as an electrical contact, a noble metal is used as the matrix because it must not be oxidized even when exposed to high temperatures in the air.

Further, in the composite agent of the present invention, metal particles of rhenium are used.

Although the particle size of these metal particles is not intended to be limited, it is preferably 10 μm or less.

To perform composite plating in the present invention, metal particles as a composite agent are dispersed in a plating bath containing ions of the noble metal, and composite plating is performed under conditions used in practical use.

Examples of noble metal plating baths include, but are not limited to, gold potassium cyanide-phosphate baths, gold chloride-hydrochloric acid baths, silver cyanide baths, silver nitrate baths, palladium chloride baths, diaminodinitropalladium baths, and the like. .

Further, as the plating bath, an acid bath, an alkaline bath, a neutral bath, etc. are selected in conjunction with the selection of the matrix and composite agent.

When performing plating by dispersing a composite agent in the above plating bath, it is also permissible to stir the bath or use an active surfactant in order to uniformly disperse the composite agent.

For stirring the bath, methods such as mechanical stirring, air stirring, liquid circulation method, ultrasonic stirring, etc. are appropriately adopted.

Examples of surfactants include, but are not limited to, ester types such as alkyl phosphate esters and polyoxyethylene sorbitan fatty acid esters, ether types such as polypropylene glycol, polyethylene glycol esters, and polyoxyethylene higher alcohol ethers, and cationic surfactants. type is used.

Although the amount of the composite agent added is not intended to be limited, it is preferably 5 to 100 g/l relative to the plating bath, and the amount of the surfactant is also not limited, but it is 0.1 to 0.5% by weight. is preferred.

The conditions for plating using the above composite plating bath are not limited, but the bath temperature is 15 to 30°C.
, the current density is preferably 0.1 to 2.0 A/dm2.

The amount of the composite agent co-folded into the matrix is also not limited, but is preferably 0.2 to 10% by weight.

The thickness of plating for forming electrical contacts is also not limited, but is preferably 1 to 15 .mu.m.

The electrical contact having a composite plated surface formed as described above has a longer lifespan than conventional noble metal plated contacts.

Example 1 A composite plated contact was obtained using gold as a matrix and rhenium powder (particle size of 5 μm or less) as a composite agent.

The plating solution used was Autoronex N (trademark, Japan Electroplating Engineers Co., Ltd., acidic type), and 20 g/l of rhenium powder was used.

The bath temperature was 25°C, and the current density was 0. Stirring was performed at 5 A/dm2 using air, plating thickness was 10 μm, and rhenium eutectoid amount was 4% by weight.

When a relay assembled using the contacts obtained by the above plating was subjected to an on-off test at 20 V and 1 A, a relay with a lifespan of 1 million openings and closings was obtained.

Comparative Example 1 In Example 1, a contact plated with the same thickness without eutectoid rhenium was obtained, and when a relay on-off test was performed, it had a life of 120,000 opening/closing operations.

Claims (1)

[Claims] 1. A composite plating method for electrical contacts characterized by dispersing rhenium metal particles in a precious metal or precious metal alloy plating bath and performing composite plating.