Fabrication and test of reaction bond silicon carbide for optical applications

A reaction bonding fabrication process using various grain size of SiC powder was investigated. The properties such as mechanical, thermal and physic property were tested and analyzed. RBSiC produced using this process is a polycrystalline material and has high specific stiffness (density of 3.09 g/cm3 with elastic modulus of 362.39 GPa), strength (269.64 MPa) and hardness (19.43 GPa). At room temperature its low CTE (3.47 × 10−6/K), combined with relatively high thermal conductivity (161.14 W/mK) and specific heat capacity (593.86 J/kg·K) can minimize the bothersome thermal distortion. This advantage is outstanding even at higher temperature of test range. Two d 250 mm RBSiC mirror were polished. Surface roughness value less than 5 nm was obtained. Results prove that this reaction bonding process is a feasible method to produced high quality RBSiC optical mirror.