New-technology silicon carbide (NT-SiC): demonstration of new material for large lightweight optical mirror

Newly developed high-strength reaction-sintered silicon carbide, called New-Technology Silicon Carbide (NT-SiC) is an attractive material for lightweight optical mirror with two times higher bending strength than other SiC materials. The material has advantages in its fabrication process. The sintering temperature is significantly lower than that of pure silicon carbide ceramics and its sintering shrinkage is smaller than one percent. These advantages will provide rapid progress to fabricate large structures. The characteristics of the material are also investigated. The polish of the test piece demonstrated that the polished surface has no pore and is suited to visible region as well as infrared without CVD SiC coating. It is concluded that NT-SiC has potential to provide large lightweight optical mirror.