Tribological Behaviors of B6O/Si3N4 and B6O/Al2O3 Sliding Pairs in Water

In this study, B6O powder compacts were fabricated by spark plasma sintering b(6)O powder at 1800 degrees C for 600 seconds. We then investigated the microstructures and mechanical properties of the powder compacts and assessed the tribological behaviors of the powder compacts by sliding them against commercially available Si3N4 and Al2O3 bearing balls in water at room temperature. The average friction coefficients of the B6O/Si3N4 sliding pairs were as low as 0.17, while the average friction coefficients of the B60/A1203 sliding pairs :dually increased from 0.10 to 0.18. Also, the B6O/Si3N4 sliding pairs showed slightly more stable friction coefficients with smaller error bars than the B60/A1203 sliding pairs 1200 seconds after starting the friction tests. The specific wear rates of the B60 powder compacts ranged from approximately 2 x 10(-6) to 5 x 10(6) mm(3)/Nm when the Si3N4 and Al2O3 balls were used as the paired materials. We conjectured that the low friction coefficients and low specific wear rates stemmed from the formation of extremely thin H3B03 films on the wear tracks of the powder compacts.