Metal matrix nano h-BN self-lubricating composite coating synthesized by Nd:YAG laser cladding

Abstract

Ni-based alloy matrix nano h-BN self-lubricant composite coatings were synthesized by Nd:YAG laser cladding in the present study. A novel high-energy ball milling method was adopted to clad nano-Ni onto nano h-BN with an aim to enhance the compatibility between the h-BN and the metal matrix during laser cladding process. Microstructure and phases of the laser-clad coatings were investigated to understand laser cladding behaviors of two kinds of coating materials, i.e., Ni45-BN and Ni60-BN(nano Ni-clad). The unclad nano h-BN was hardly composed into Ni45 matrix coating even if increasing the weight percentage of BN from 5% to 15%. For laser cladding of the Ni60-BN coating, the high-energy ball milling of nano-Ni onto nano h-BN significantly improved the interfacial compatibility between h-BN and Ni60 matrix, and Ni-based alloy matrix nano h-BN self-lubricant composite coatings were successfully synthesized. Friction coefficient and wear resistance of the laser-clad Ni60-BN coating was reduced to about 0.36 (about 0.5-0.6 for the laser-clad Ni60 coating) and was three times higher than that of the laser-clad Ni60 coating respectively.Ni-based alloy matrix nano h-BN self-lubricant composite coatings were synthesized by Nd:YAG laser cladding in the present study. A novel high-energy ball milling method was adopted to clad nano-Ni onto nano h-BN with an aim to enhance the compatibility between the h-BN and the metal matrix during laser cladding process. Microstructure and phases of the laser-clad coatings were investigated to understand laser cladding behaviors of two kinds of coating materials, i.e., Ni45-BN and Ni60-BN(nano Ni-clad). The unclad nano h-BN was hardly composed into Ni45 matrix coating even if increasing the weight percentage of BN from 5% to 15%. For laser cladding of the Ni60-BN coating, the high-energy ball milling of nano-Ni onto nano h-BN significantly improved the interfacial compatibility between h-BN and Ni60 matrix, and Ni-based alloy matrix nano h-BN self-lubricant composite coatings were successfully synthesized. Friction coefficient and wear resistance of the laser-clad Ni60-BN coating was reduced to about 0.36...