RESEARCH ON METHODS OF IMPROVING THE QUALITY OF THE COATING OF LOW-MELTING ALLOY B83 FORMED BY ELECTROSPARK PROCESSING METHODS

Abstract

The electro-spark deposition (ESD) process uses electric spark discharge to coat and melt conductive materials onto the surface of the substrate to form an alloyed coating. It can realize the function of strengthening or repairing the surface of parts. Because of the low cost and simple processing, this process is often used to generate anti-wear coatings and anti-friction coatings on the surface of parts to extend its service life. The improvement of surface quality of electro-spark deposition has always been the focus of research in the scientific and industrial circles. Soft metals can be used as antifriction materials to reduce metal surface friction and improve service life. Low-temperature soft metals are prone to melting and bending when electrodes are working, and with which the improvement of surface quality has become a processing difficulty. The Babbitt B83 is one of the characteristic materials of low-temperature soft metals. It has good ability to reduce surface friction and improve corrosion resistance. As the outermost layer of the composite coating, it can meet the special requirements of parts surface remanufacturing. In this article, the use of vibration, control energy, reasonable control of the discharge gap can be obtained better surface quality of low temperature soft metal by new vibration method. In the case of the same discharge energy, the surface roughness of the new ESD process was 43 % less than the surface roughness of the traditional vibration deposition process, and the standard deviation was 73 % less. With the discharge gap was controlled at 0.377~0.6mm, continuous ESD sputtering can be achieved. The major vibration frequency was 337 Hz, the vibration impact was small, which can achieve the continuous deposition of low-temperature soft metal. And 3mm electrode did not appear bending. Reasonable selection of argon protection process can reduce the generation of oxide film and improve the surface quality of B83 material. The process can reduce the coating thickness of soft metals and the cost of ESD coatings, thus it will make some precious friction-reducing metal materials widely available. It provided a new solution for continuous processing of ESD on robots and multi-axis machine.