Wear behaviour of Al2O3–Mo and Al2O3–Nb composites

The wear behaviour of two Al2O3–Mo and two Al2O3–Nb particulate composites with different Mo particle size and Nb contents, respectively, obtained by hot-pressing, was evaluated. The inverted pin-on-disc tests were performed by making ceramic pins slide against WC discs at different loads with a constant sliding speed and sliding distance. When the load increased the specific wear of alumina–molybdenum composites increased dramatically while the wear of alumina–niobium material remained almost constant inspite of the increase of the applied load. On the other hand, the wear of the WC discs was very low against Al2O3–Mo but extremely high against Al2O3–Nb composites. It was also found that the friction coefficient strongly depends on the applied load but weakly on the pin material. The lower the load the higher the friction. A possible explanation of the wear mechanisms is proposed.