Interface Elements Diffusion Effects On Wear Behaviors Of High-aluminum Bronze Coating Sprayed By Plasma Welding

Our group developed a high-strength wear-resistant novel aluminum bronze for die material designated as Cul4A14.5FeNiRe, and it has shown a great progress on the hardness and uncorrosion. The friction coefficient can be reduced to0.08under the boundary conditions. But it is brittle in nature and too hard to machine for a mould. In order to use this excellent antifriction material in industry, Li’s group attempts using thermal spraying to fabricating high aluminum bronze coating to solve the problem as mention earlier.In this work, we study the influences morphologies, phase structure and phase element distribution changed by the element diffusion exert on its wear behavior were respectively analyzed. The complex aluminum bronze coating wear annealed under different temperature to improved it’s performance. The main conclusion are given in the following.1.High frictional coefficient was caused by the abrasive and adhesive wear occurred in the high Al bronze coating on45#middle carbon steel substrate due to the enrich k phases which were increased by the Fe element diffusion from the substrate.2.Coatings on ZQA19-4substrate contains a lot of (α+γ2) net-like eutectic phases, which is brittle and results in a decrease to the coatings compact toughness, fatigue and abrasive wear occurs and results in a low wear resistance.3.In the coatings on T3copper substrate, k phases are uniformly distributed in the β’ phase and thus coatings were hardened by the refined coatings micro structure due to high thermal conductivity of T3copper, which causes a low friction coefficient and wear rate.4.Fe element coming from substrate has diffused into coating. With the distance from the interface increased, the Fe element diffusion decreased. The rich content of Fe on the surface of2mm layer precipitates Fe-rich k phase, whose volume fraction is greatest. This increases the compatibility of structure between coating and Fe-based counterpart. The k phase of coating resembles gathered spots or globules. Such k phase tends to stick the counterpart during friction process, which even causes some particles. Therefore, despite of the high hardness of coating, its wear behavior is the worst. On the contrast, the content of Fe on the surface of4mm layer is relatively lower and coating is covered with twig and particle-shaped k phase. In this case, the coating possesses high hardness and excellent toughness and meanwhile the wear resistance is improved.5.The aluminum bronze coating annealed at480℃has excellent abrasion resistance. After the heat treatment, the structure of coating became uniformity, while the residual stress reduced, the fatigue failure caused by residual stresses has improved. Most of those impacts have been positive. The hard phase distribution became uniformly. It is benefit to inprove the resistance to micro cutting and squeezing. All this mentioned above causes wear properties improved.