A Study Of Microstructure And Wear Behaviors Of High Al Bronze Coating/Cladding After Different Thermal Diffusion

The phase structure and interface diffusion of Ferrum and Aluminum in the High A1 bronze coatings and claddings which prepared by flame spraying and plasma welding with different temperatures of thermal diffusion were investigated by means of optical microscope, X-ray diffraction, scanning electron microscope and energy dispersion spectroscope. The interface bonding strength was measured by tensile test. The tribological properties were studied by Pine-on-disk wear machine. The phase structure, interface bonding strength, mechanical and tribological properties were investigated by interface diffusion of Ferrum and Aluminum in the High A1 bronze coatings and claddings, the best matching relations will be found which can promote and expand the application of High A1 bronze in the field of mold’s preparation and repair.Results indicated that the claddings are composed of characteristic phases in β’+α+γ2+k phases after thermal diffusion process, the microstructure segregation and the hardness of High Al bronze plasma welding claddings were improved by thermal diffusion process. Thermal diffusion widened the metallurgical layer, and significant element diffusion was observed, the bonding strength reached 448.93 MPa after 650 ℃ thermal diffusion. The best tribological properties were obtained after 480℃ thermal diffusion, which caused by the species distribution of the hard and soft phases and the Fe content. The wear mechanisms are abrasive wear, which is the dominating wear mechanism, fatigue wear and adhesive wear.The existence of amorphous and microcrystalline in High A1 bronze alloy powder changed into polycrystalline coatings after flame spraying. The coatings were thicker, denser and with smaller grain size after flame spraying with compressed air. The coatings were mechanical bond to the substrate, the hardness of High A1 bronze flame spraying coatings were improved by thermal diffusion process, and slight element diffusion was observed. The best tribological properties were obtained after flame spraying with compressed air by thermal diffusion, which caused by the species distribution of the hard and soft phases and the Fe content. The wear mechanisms which mainly was delamination wear changed into coexistence of delamination wear, adhesive wear and abrasive wear after thermal diffusion.