Hard Nickel Plating

Nickel plating usually do before chromium planting as the preliminary coating in order the surface more smooth and easier to plated by chrome. Nickel plating also usual as the self coating on the metals surface for many purposes.

A Nickel bath recommended for producing hard nickel deposit has been used for applying nickel on the surface of rolls, the salvaging of worn on mismachined, and current density is necessary in this bath to maintain the desired hardness value. The tensile strength increase and the ductility decreases with an increase of pH and a decrease in temperature. The deposit has a rather low annealing temperature and will not retain full harness above 232 ^oC. Disadvantages of this hard nickel bath are a greater tendency to form nodules and trees than the chloride or Watt bath and a high internal stress in the deposits which can cause sporadic cracking.

In almost all cases, it is much better and much simpler to use class I addition agents, the stress reducers, in Watts or sulfamate baths to obtain the desired harness reducers, in Watts or sulamate baths to obtain the desired hardness without tensile stress. The stess reducers such as saccharin, p-toluena sulfonamide, sodium m-benzene disulfonate, sodium 1,3,5-naphtalene trisulfonamide, o-slfobenzaldehyde, can introduce about 0.03% sulfur as sulfide in the plate, are most generally used.

Black Color Chromium Plating

Electroplating can result in several color such as black color chromium plate, and such deposits color have used commercially. The result of this electroplating actually not real black but rather grey, all dull or mat chromium deposits seem to turn bright metallic rather readily if exposed to much abrasion or wear. With further treatment such as oiling can give more black appearance. To produce black color on electroplating is use of high current density in a cold bath containing chromic and acetic acids.

Success was very limited in effort to utilize such bath for electroplating. A chromium ammonium chloride solution was used for brush plating. Better result in brush plating were obtained with Gregory's salt, ammonium chromium oxalate.

Anodizing Process in Decoration

In decative industry anodizing process often use to make more interesting product. Aluminum will not interested if just like the original color, but using anodizing process aluminum plate can convert their performance more interesting and look more beautiful. Other benefit value of this anodizing process is not just the beauty look but also make the steel more durable to the environmental, because they make a layer on the surface that have a stable character, not affected by the hard environment.

Many product use this benefit of process as decorative product, like car wheel, door handle and windows frame. Many accessories product also use anodizing process as finished process to make them more interesting, like on key chains, and on doll parts. Anodizing process on many part and on building structure is used as final protection on aluminum metal in order this metal will pretent from corrosion.

Naturally aluminum sheet will protected by them self by make an oxide film on the surface but this layer is not strong enough to the environment attack. This is different with the anodized layer that created by industry, the thick of the layer can make more than naturally and stronger to the environment exposure.