In situ growth of TiCxN1−x whiskers in Al2O3 matrix for ceramic cutting tools

For resolving the dispersing problem of whiskers and fabricating cutting tool materials with excellent properties, an in situ growth technology is used to directly synthesize TiCxN1−x whiskers in α-Al2O3 matrix by a carbothermal reduction process at a temperature range of 1250–1550 °C. The raw materials are consisted of TiO2, carbon, nickel, and NaCl. Various molar ratios from 1:3, 1:4, 1:5 to 1:7 of TiO2:C are experimentally used. For the molar ratio 1:3, a few whiskers can be found only at the synthesis temperature of 1550 °C. For the other molar ratios, large amount of whiskers can be observed at the whole synthesis temperature range. The highest yield of whisker is observed when the synthesis temperature is 1250 °C and the molar ratio of TiO2:C is 1:4. The compound AlO appears at 1250 °C and AlN instead at 1550 °C. The majority of the synthesized whiskers display an ideal aspect ratio of 10–30 with a diameter of 1–3 μm. No obviously influence on the whiskers growth by the present of α-Al2O3 matrix powder can be noted.