Tribological properties of Ni-Cr/hBN self-lubricating composite

The Ni-Cr/hBN self-lubricating composites are prepared by the powder metallurgy technology. The influences of the hBN contents and working load on the properties and tribological performance of the Ni-Cr/ hBN composite are investigated. The results show that the density, bending strength and friction coefficient of the Ni-Cr/hBN composites decrease with the increasing of the hBN contents. Under the working load of 20 N, the wear rate of the Ni-Cr/hBN composite decreases with the increasing of hBN contents. However, under the loading of 60 N and 100 N, the wear rate declines first, and then increases with the increasing of hBN contents. The wear rate increases with the increasing of working load, when the hBN content remains constant. According to the lubrication and wear mechanism of the Ni-Cr/hBN self -lubricating composite, the friction coefficient depends on the hBN content, and the wear rate is related with the mechanical properties. The best tribological properties are obtained when the hBN content is 9 % ( mass fraction) and working load is 60 N.