Basic introduction to electroless nickel plating

Since prehistoric times metals have been prized and worked by man. Such metals as copper, iron, lead, tin, gold and silver have all been in use for as far as historians and archeologists can trace. Nickel, however, is one of the newer ones; it was discovered only in 1751 in an ore that was reddish like copper but contained none, hence the name (Kupfernickel means false copper). Since then it has found numerous uses besides the American and Canadian five-cent piece owing to its hard and durable quality, such as plating for softer metals.

Electroless plating

The electroless nickel plating is the most valuable technique in this field; it is done by depositing a layer of an alloy of nickel with either phosphorus or boron on a metal or plastic work piece. The material thus plated must first be treated with chemicals to remove soils that would otherwise make plating difficult. After each treatment, the material must be washed two or three times. It must also be cleansed of grease and scales, the latter by means of an acid solution.

Even after the plating has been put on, the process is not yet finished. Trisodium phosphate or chromate, or some other chemical that protects the finished product against oxidation or tarnish, must be used, after which the plating is to be washed and dried so that it will not be stained.

Electroless nickel plating is the preferred method of coating metals for several reasons. It does not require the use of electricity or any complex racks, the volume and thickness can easily be adjusted, it is possible to plate only part of a surface and “blind holes” (those that reach only part of the way through) can be filled in with a stable thickness. There are only two basic disadvantages, viz. the limited lifetimes of the chemicals used and the high cost of waste treatment.

Two similar processes

You can use several metals to prepare electroless nickel plating, such as plated nickel, copper, steel, pewter, zinc castings, zincated aluminum and more, without the danger of cyanides or other such toxic chemicals. The plating can be bought pre-mixed and all ready to be used. A good color may be achieved in two to three minutes, though if the bronze plate is to be buffed the time should be increased to a half hour or even forty minutes. Ferritic nitrocarburizing is the process of carbon and nitrogen into ferrous alloys at temperatures below the critical temperature, which is usually 1049 degrees. It helps the material thus treated to resist fatigue, corrosion and scuffing, without distorting its shape.

In this article, the author provides his idea about the inception of metal plating and its rapid use in today’s modern world.