1. Corrosion resistance: Cadmium plating ( sun-glo.com/cadmium-plating ) is done on an object to make it resistant to corrosion. This is the reason why cadmium plated bolts can be suitable for machinery which is installed in harsh environmental conditions. It is also the main reason why aviation, military defense and aerospace industries opt for fasteners with this coating.
2. Adhesion: Whenever cadmium coating is done on an object, the adhesive properties of the object improve. Hence, with cadmium plating, the surface of the object becomes more bondable to adhesives which are commonly used in various applications.
3. Lubricity: The form of coating can improve the lubricity of an object and is an ideal choice for moving parts of machines. It is also very important for the functioning of machinery where metal surfaces touch each other.
Additional advantages of the plating include outstanding conductivity, low electrical resistance, favorable galvanic coupling with aluminum, higher solderability and prevention of galling. It is also important to note that the corrosion products of cadmium are less significant than other plated coatings like zinc. These characteristics of cadmium plating are useful in applications where the components will be repeatedly reassembled and disassembled, for example, in an aircraft. The plating is crucial in aerospace industry and resists the growth of bacteria. It is not suitable for spaceflight applications due to the propensity to outgas, sublimate and spontaneously form whiskers in a vacuum. It is highly preferred and recommended for use in aerospace industry only.
Cadmium is very similar to zinc plating and there are many ways of application of the same. The usual chromates that are applied include black, olive, yellow and clear. However, it is important to keep in mind that cadmium is highly toxic; it cannot be utilized on surfaces that are intended for direct contact with food and is mostly used in harsh environment and in aerospace. It is considered superior protection when it comes to aquatic and brackish applications. There are several ways of application but the most common is through electroplating. In the process, cadmium goes through electrodeposition on to the metal from a solution that is rich in electrolytes. This solution is based on a cyanine alkaline system and other solutions may also be used but they produce results that lack the covering power ( http://www.sun-glo.com/blog/ ), brightness and throwing power. There are two other methods of application like mechanical cadmium plating and application through vacuum deposition. Depending on the end use and the base, the application method is determined.