베어링용 Silver 박막의 제작과 고체윤활 특성

Preparation of Silver Thin Film for Bearing Applications and Their Solid Lubricating

As many industrial fields are rapidly advancing, material requirements for propulsion engines are becoming ever more sever. Particularly in machine and shipping industries, high durable engines are much desired. In these sectors, the development of high performance materials is a very important subject in order to enhance the properties of bearings whose role is to transfer energy harmoniously by reducing the problem of friction and wear down, etc. between the interacting solid surfaces in relative motion under high loads in comply with mechanical operating mechanism of engines. Silver is known to have such characteristics as low shear strength, good transfer-film forming tendency, and good corrosion resistance. Silver thin films have been prepared by ion plating of physical vapour deposition (PVD) using both argon gas pressure and bias voltage of processing condition. After the silver films were prepared, the properties in them were examined by gas pressure and bias voltage of substrate. Their morphology and crystal orientation were investigated by scanning electron microscopy(SEM) and X-ray diffractor. The properties of film were, also, studied to relate with morphology, X-ray diffraction pattern, and friction coefficient at vacuum ambient. The friction coefficient was stabilized remarkably on deposited films with increasing argon pressure for deposition. Also, the effect of increasing of the bias voltage for deposition resulted in lower friction coefficient and stability in 1.7x10-4torr. On the contrary, behavior of friction coefficient was stabilized on deposited films with decreasing the bias voltage in 1.7x10-5torr for deposition.