Metals & Chemicals

Decorative chrome plating is also called as nickel chrome plating because it always involves electroplating nickel onto the object before plating the chrome. Nickel plating has smoothness, corrosion resistance and is reflective. But chrome plating is exceptionally thin, measured in millionths of an inch rather than in thousandths. When you look at decorative chromium plated surface, like chrome plated wheel or truck bumper, what you actually see is the effect of nickel plating. The chrome adds a bluish cast, and it protects against tarnish, and minimizes scratching. Some metals like zinc die castings, cannot be directly nickel plated but must be copper plated first. Other materials, like aluminum, cannot be copper plated until they have been zincated. Decorative chromium plating is applied in many consumer items, including appliances and plumbing fixtures. This finish is also used in many industrial parts, including medical, motorcycle, automotive, and marine items.

Chromate conversion on Chicago coatings are a type of conversion coating which is applied to passivate zinc, aluminum, cadmium, silver, copper, magnesium, tin and their alloys to slow corrosion. The process involves the use of various toxic chromium compounds which might include hexavalent chromium. The industry is now developing less toxic alternatives so as to comply with substance restriction legislation. One option is trivalent chromate conversion which is less environmentally damaging. Chromating is normally used on zinc-plated parts to defend the zinc from white corrosion, which is mainly a cosmetic issue. It can't be applied directly to steel or iron, and it does not enhance zinc's anodic protection of the underlying steel from brown corrosion. It is also most commonly used on aluminum alloy parts in the aircraft industry where it is often called as chemical film. It also has an additional value as a primer for subsequent organic coatings, as any untreated metal, esp...

Chrome is a metal, but it is not useful for solid or pure substance. Chrome really means that it has a thin layer and a plating of chrome on the object (the bulk of the object has steel, but sometimes brass, aluminium, copper, plastic or stainless steel). People generally think that any shiny finish is chrome even when it has nothing to do with chromium. For example, electro polished stainless steel boat rigging, shiny painted wheels, vacuum metallized balloons and helmets, brightly polished aluminum motorcycle parts, are sometimes called 'chrome' by the common person. Chrome plating is bluer, reflective and more specular than other finishes. If we put one end of the yardstick in a bright finish then the clouds reflection can be seen in the chrome plating.

There are two types of chromium plating; one is industrial and the other being decorative. Industrial chromium plating is divided into two such as hexavalent and the other being trivalent plating. The decorative plating is a mixture of chrome and nickel. It has a mirror finish. Its thickness range from 0.002 to 0.020 miles. In jewelry, plastic knobs, hardware and hard tools the decorative chrome is used. The process for hexavalent chromium is first the activation bath is done, and then chromium bath then it is rinsed twice. While using activation bath a separate tank of chromic acid is used. Occasionally the activation step takes place in the chromium bath itself. Other than bath the other important things that matter are temperature and current density. These two affects the brightness and coverage. Trivalent chromium plating process is divided into three such as the single electrolyte bath is done then sulfate based bath using shielded anodes and at last sulfate ba...