Effect of Gradient TiC-Ti5Si3-TiSi2 barrier layer on SiC in SiC-borosilicate glass composites

The oxidation of SiC in SiC-borosilicate glass composites releases gases which cause a high volume expansion ratio and low bending strength and limits the application of the composites as packaging materials. To solve this problem, we deposited a Ti compound coating on SiC by heating a mixture of TiH2 and SiC particles at 750 °C for 1 h under vacuum. The thickness of the coating was about 200 nm, and the coating was a gradient TiC-Ti5Si3-TiSi2 barrier layer according to the result of the X-ray diffraction. The coated SiC had a better anti-oxidation ability than uncoated ones in borosilicate glass, and as a result, the volume expansion ratio of the composites with 25 vol.% coated SiC was reduced by 287%, and the bending strength was increased by 117%. The composites with 55 vol.% SiC had the maximum thermal conductivity (14.2 Wm− 1 K− 1) and rather low thermal expansion coefficient (4.98 × 10− 6).