With the rapid development of China electrical equipment industry, the electrical contact components widely used in electric equipment such as power and communications systems. If a contact of electrical system failure, will directly affect the reliable operation of the whole system, the loss caused by far more than the value of the contact itself, so as to improve the system reliability requirements contact, contact as key components in the system is more and more attention.Contact is to measure contact performance of contact resistance is a basic and important parameters, directly affect the contact electrical contact behavior is good or bad. Contact the contact resistance is too high, will produce larger temperature rise, even welding phenomena occur, both affect contact work reliability, and reduce the service life of the contact. And contact resistance research has become the key problem in the contact reliability testing, and often to contact resistance to measure the reliability level of contact system ", in order to contact resistance exceeds a certain specified value as the main criterion of contact component failure.
Cattle contact resistance refers to a pair of contact resistance of contact area when I touch each other. It consists of shrinkage on the surface of the touch point contact resistance and the resistance of surface film.Two contact contact with each other, due to the contact surface can't be done very ideal, contact the actual contact area is composed of many conductive spots, current, flows through these several conductive spots scattered, shrinkage occurs, contact resistance of the resulting called shrinkage resistance.Contact surface by reason of pollution, chemical corrosion, poor can form a layer of conductive material (including dust particles, residual abrasives or polishing agent, organic and inorganic membranes, etc.), contact resistance that is called the membrane resistance.
