Tribological Properties of Ti_3SiC_2,Stainless Steel and NiCr Alloy in Artificial Seawater

The tribological properties of Ti3SiC2,stainless steel and NiCr alloy under dry sliding,in distilled and sea water were investigated on an SRV-1 tribometer.The worn surfaces were analyzed by using scanning electron microscopy and X-ray photoelectron spectrometer.The results show that the friction coefficient of Ti3SiC2/Al2O3 tribo-pair was insensitive to sliding condition.The wear rate of Ti3SiC2 in liquids(distilled water and sea water) was one order of magnitude lower than that under dry sliding.In the competition between the two wear mechanisms of mechanical wear and tribo-oxidation wear,mechanical wear was the dominant mechanism,which was independent on the sliding condition.So the friction coefficient and wear were high for Ti3SiC2/Al2O3 tribo-pair under the three sliding conditions.Tribological properties of stainless steel/Al2O3 and NiCr alloy/Al2O3 were sensitive to sliding condition.The friction coefficient and wear rate of stainless steel and NiCr alloy successively decreased in the order of dry sliding,distilled water,and sea water.The degree of decrease was the largest for NiCr alloy/Al2O3 tribo-pair.Under dry sliding mechanical wear was the dominant wear mechanism for both the tribo-pairs.In distilled water both mechanical wear and tribo-oxidation wear worked.In the sea water corrosion wear was the main wear mechanism.The tribo-corrosive products(FeCl2,CrCl3 or CrO22- and CrO42-) were lubricants to decrease the friction and wear.