Description:
MoSi2‐particulate‐reinforced α‐SiAlON ceramic composites containing 10, 20, 25, and 30 vol% were prepared by hot pressing at 1750°‐1800°C. The α‐SiAlON matrix was of the composition (Y0.48Si10.00A12.30O1.17N15.29). The hardness for the fully dense samples changed from HV10 = 22.5 to 15.3 GPa and the toughness from 3.2 to around 5.2 MPa.m1/2 when up to 30 vol% MoSi2 was present. Two interesting microstructural features have been found. First, with an increasing amount of MoSi2 a pronounced coalescence of MoSi2 particles formed a “dual phase” material. The second effect was the growth of elongated α‐SiAlON grains in the matrix with 10 vol% MoSi2 added. The oxidation resistance has been determined to be unaffected by the addition of 2hd vol % MoSi2 at 1250°C in oxygen gas of l atm pressure.