Influence of Gradient Index and Pores on the Properties and Internal Stress of Continuous Transition Ceramic–Metal Coating

Abstract

Thermal-sprayed ceramic coatings are widely used in industry due to their favorable mechanical properties. However, traditional ceramic coatings are prone to failure due to the differences in physical properties between the bonding coating and the ceramic coating. In order to solve this problem, a continuous transition zone was introduced between the ceramic coating and the bonding coating, then air plasma spraying was used to prepare traditional coatings and continuous transition coatings. The Vickers hardness analysis results show that the existence of the continuous transition zone made the change of hardness between the ceramic coating and the bonding coating more gradual. To understand the stress distribution inside the continuous transition coating, models were established to express the interface between ceramic and metal in the continuous transition zone. Simulation analysis found that the existence of the continuous transition zone can significantly reduce the stress gradient inside the coating, and the gradient index of the continuous transition zone also has a great influence on the stress distribution inside the coating model. SEM (Scanning Electron Microscope) analysis found many pores inside the coating; modeling the pores and simulating the influence of pores on the internal stress of the coating showed that the existence of pores inside the coating can reduce the stress gradient at the interface.