Iron-base alloys are widely used in various industrial equipment and parts due to their moderate strength, good plasticity and toughness, and low price. However, in some harsh friction environment, the workpiece of iron-based alloy often suffers severe wear and failure. There are two ways to improve the workpiece wear resistance. One is alloying. Alloying, however, usually adds significantly to the cost of materials. The other is surface engineering. That is to prepare a layer of wear-resistant coating on the surface of the workpiece to improve the workpiece wear resistance, thus extending the service life of the workpiece and enhancing production efficiency.
Common surface engineering techniques include thermal spraying, magnetron sputtering, laser surface cladding, and plasma spray welding. Among various surface engineering technologies, plasma arc spray welding technology has the following advantages: high deposition efficiency, high arc energy density, low cost, thick coating and metallurgical combination between coating and substrate. Therefore, plasma arc spray welding technology is widely used in the production of wear – resistant coating.
It is found that Mo alloy can form MoO3 with low friction coefficient on the worn surface due to oxidation during the friction and wear process. Anti-friction effect significantly improved the wear resistance of the alloy. Therefore, the purpose of this study is to prepare a layer of Mo coating on the surface of the Fe-based alloy by plasma arc spray welding technology. On the one hand, the wear resistance of the matrix alloy is improved. On the other side, the excellent mechanical properties of the matrix alloy are retained.
- The uniform and dense Mo coating were prepared on the 45 steel substrate by plasma arc spray welding technology, and the metallurgical combination between the coating and the substrate was achieved.
- The micro-hardness of Mo coating is evenly distributed along the longitudinal section of the coating. Compared with the hardness of 45 steel matrix, the hardness of the coating is four times higher. The relative wear resistance of Mo coating is 15 times that of 45 steel matrix, and the friction coefficient is reduced by 19%.