High-temperature tribological properties of Mo-Si-B intermetallic alloy/Si3N4 tribopairs

In our present study, Mo-Si-B intermetallic alloy plate specimens of different compositions were prepared by spark plasma sintering, and their friction and wear properties were investigated by sliding against Si3N4 ball specimens in a temperature range of 298 K-1273 K in air. After the friction and wear tests, the worn surfaces of the plate specimens were investigated using a SEM with an EDS attachment and an XPS. The MoB-based alloy plate specimens exhibited steady friction coefficients as low as 0.1 at 1073 K due to the formation of low friction hexagonal BN and MoO3 films. The MoB-based alloy plate specimens exhibited similar low friction coefficients for 600 s from the start of the friction tests at 1273 K. The Mo5Si3- and MoSi2-based alloy plate specimens exhibited the highest steady friction coefficients (approximately 0.6) of all the plate specimens at 1073 K and 1273 K, respectively.