Microstructures and properties of nickel-aluminum-bronze coating by laser wire additive manufacturing

Abstract

This study aims to investigate the microstructure, mechanical properties and corrosion resistance of nickel-aluminum bronze (NAB) coatings fabricated on Q235 steel using laser fused wire additive manufacturing. The coatings were characterized using X-ray diffraction, electron backscatter diffraction and electrochemical analysis. The main phases identified in the NAB coating are α-phase-Cu, κI-phase AlFe3, and κII-phase AlNi. The microstructure is fine, dense and uniform, with an average microhardness of 259 HV0.2. The average coefficient of friction and wear rate are 0.317 and 1.694 × 10–6g/(N·m), respectively. Corrosion tests show a corrosion potential of −0.21V and a corrosion current density of 6.201 × 10–7A/cm². The solid solution of Al and Ni in the coating enhances strength through solid solution strengthening. Grain refinement from Al and the formation of a dense oxide layer, along with the presence of the Ni-rich κII-phase, significantly improve the coating’s strength, wear resistance and corrosion resistance, contributing to its excellent overall performance. A systematic investigation was conducted on the microstructural characteristics and mechanical behavior of the resulting coatings, and the corresponding strengthening mechanisms were further clarified.