Study on surface roughness change of modified silicon carbide in ion beam polishing

The change of surface roughness of modified silicon carbide during ion beam polishing is introduced in this paper. Silicon carbide has been gradually applied to laxer mirrors due to its excellent physical properties. Ion beam polishing is a high precision and high certainty processing method, but it is not suitable to directly process silicon carbide body due to material reasons. First, the silicon carbide substrate material was modified by ion beam assisted deposition of silicon, and then the relationship between the depth of ion beam removal and the surface roughness evolution experiment was carried out. The experiment was divided into two stages. The first stage was to verify the quality of the modified layer, after a large number of processing and removal, to detect the change of the modified layer; the second stage was to find the change rule of the roughness, by adjusting the ion beam addition. In order to control the trend of roughness the basis of experiments, a Ф600mm modified silicon carbide plane mirror was fabricated by ion beam polishing. After two iterations, the processing results show that the surface roughness of the sample can be controlled within 2 nanometers(Sq value)by adjusting the processing strength and removal depth.