Wear resistance requirements of wear-resistant coatings

       In addition to ensuring that the coating has a strong enough bond with the substrate, an excellent wear-resistant coating must also have the following requirements for the wear resistance of the coating.



1) Coating hardness. Increasing the hardness of the coating is beneficial to increase the yield strength of the coating and prevent deformation; the higher the hardness of the coating, the stronger the anti-abrasive wear performance, and the abrasive wear rate of the coating is inversely proportional to the hardness of the coating. If the hardness of the coating exceeds the hardness of the abrasive particles, the abrasive wear rate drops sharply. Therefore, in the case of abrasive wear, the hardness of the coating should be increased as much as possible. In the case of sliding wear, a soft coating with a single-phase structure with strong toughness should be considered, but there should be no second-phase hard particles, otherwise it will cause severe abrasive wear.



2) High temperature wear resistance. When the hard coating is used for high temperature wear conditions, it is not only required to have good high temperature red hardness, that is, to have high high temperature hardness, but also the chemical solubility between the coating and the dual friction material should be small.



3) Corrosion and wear resistance. The wear resistance of the wear-resistant coating in corrosive media also depends on the corrosion resistance of the coating in chemical media. Many hard coatings have excellent corrosion resistance, especially ceramic coatings such as oxides and carbides are good corrosion-resistant and wear-resistant coating materials.



4) Bonding strength between coating particles. There should be a high bond strength between the hard coat particles. For example, WC-Co cermet coating is a well-known wear-resistant coating material. Cobalt has excellent wettability to hard particles such as tungsten carbide, so that the tungsten carbide particles can be firmly bonded together without occurrence of Exfoliation, under this premise, can give full play to the high wear resistance of tungsten carbide hard phase.



Obviously, the successful application of wear-resistant coatings depends not only on the friction and wear resistance characteristics of the coating itself, but also on the reasonable matching of properties between the coating and the substrate.