Understanding the role of in-flight particle temperature and velocity on the residual stress depth profile and other mechanical properties of atmospheric plasma sprayed Al2O3 coating

• Published in: Journal of the European Ceramic Society 2022-08, Vol.42 (10), p.4353-4368
• Main Authors: Ghara, Tina, Bandyopadhyay, P.P.
• Format: Article
• Language: English
• Subjects: Alumina ceramic; Mechanical properties; Particle monitoring; Plasma spray coatings; Residual stress
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2022.04.019

This report deals with the influence of particle temperature and velocity on the microstructure, mechanical properties and residual stress depth profile of plasma sprayed alumina coating. The coatings were produced by varying the particle temperature while maintaining a relatively fixed particle velocity, and vice versa. Residual stress profiles were acquired by measuring the stress in successive layers using X-ray Sin2ψ technique. A substantial increase in hardness and indentation modulus by 76% and 64%, respectively were observed with an increase in particle temperature. With an increase in velocity, coating porosity was found to decrease initially. However, at a high velocity, porosity again increased to a limited extent. The mechanical properties were found to depend strongly on porosity. An increase in particle temperature resulted in an increase in the tensile residual stress in the coatings. Moreover, partial recovery of the grit blasted compressive substrate occurred during spraying owing to an annealing effect. •The effects of particle temperature and velocity on coating properties were decoupled.•Particle temperature has greater influence as compared to velocity.•Mechanical properties of the coatings improved with a decrease in porosity.•A higher particle temperature produced a higher tensile residual stress on the coating.•Partial recovery by annealing occurs in the substrate during coating deposition.