Influences of Sintering Temperature on Chemical Reaction and Microstructure in Al2O3-Ti(C0.7N0.3)-cBN Composite

摘要

A system of Al2O3-Ti(C0.7N0.3)-cubic BN (cBN) composite was prepared by hot pressing in the temperature range from 1200 degrees C to 1700 degrees C for 20 min under the pressure of 35 MPa. The influences of sintering temperature on chemical reaction and microstructure in Al2O3-Ti(C0.7N0.3)-cBN composite were studied. Results show that Ti(C0.7N0.3) solid solution totally forms until the sintering temperature is higher than 1400 degrees C, and then decomposes to Ti(CxN1-x) (0.7< x < 1) as the sintering temperature exceeds 1500 degrees C. In addition, cBN particles keep their sharp edges until 1500 degrees C, while hexagonal BN and TiB2 are found at 1600 degrees C. As for the matrix, the grain size of Al2O3 is around 200 nm even when the sintering temperature reaches as hot as 1400 degrees C. Consequently, the appropriate sintering temperature for Al2O3-Ti(C0.7N0.3)-cBN is 1400 to 1500 degrees C and our work has laid a foundation for controlling the phases in Al2O3-Ti(C0.7N0.3)-cBN composite.