Tribological property of in situ directly nitrided and sintered Al/AlN composite

An in situ directly nitrided and sintered Al/AlN composite was developed using a chemical reaction between aluminium and nitrogen gas at temperatures below 823 K. It is clear from SEM and TEM observation that the composite has good bonding of the in situ formed AlN to the aluminium matrix. The composite shows an unusually low friction coefficient (0.004-0.008) under oil lubrication, and also has excellent wear resistance and antiseizure properties when compared with hard anodised aluminium alloys. AlN particles protruding from the matrix create oil microgrooves and which work as oil pits to enhance the formability of oil films. Therefore, it is easy to form hydrodynamic lubrication with continuous oil films on a sliding surface.