Tribological behavior of Ni-Cr-based composite at high temperatures

The wear behavior of Ni-Cr-based alloys was investigated at ambient and elevated temperatures. The wear samples were prepared by metallurgical hot pressing. Wear tests were carried out on a general purpose wear testing machine having a heating unit and pin-disc sample configuration. The counterface material was prepared from Al2O3 ceramics. The tests were carried out at room temperature(RT),200 ℃ and 600 ℃. The effects of temperatures on the tribological properties were determined by using optical microscopy,and X-ray diffractometry. The results show that at room temperature the worn surfaces of the alloys are characterized by mild scuffing and micro cracks,the action of nano-crystal structural wear debris on the worn surfaces is responsible for the reduction of friction. At 200 ℃,the friction coefficient is the highest. The worn surfaces of the alloys are adhesive and oxidative. At 600 ℃,the friction coefficient is reduced due to the effect of the oxides,tungstates and sulfides residue on the worn surface.

The wear behavior of Ni-Cr-based alloys was investigated at ambient and elevated temperatures. The wear samples were prepared by metallurgical hot pressing. Wear tests were carded out on a general purpose wear testing machine having a heating unit and pin-disc sample configuration. The counterface material was prepared from Al2O3 ceramics. The tests were carded out at room temperature （RT）, 200 ℃ and 600℃. The effects of temperatures on the tribological properties were determined by using optical microscopy, and X-ray diffractometry. The results show that at room temperature the worn surfaces of the alloys are characterized by mild scuffing and micro cracks, the action of nano-crystal structural wear debris on the worn surfaces is responsible for the reduction of friction. At 200℃, the friction coefficient is the highest. The worn surfaces of the alloys are adhesive and oxidative. At 600℃, the friction coefficient is reduced due to the effect of the oxides, tungstates and sulfides residue on the worn surface.