Microstructure and mechanical properties of plasma-sprayed LaMgA111O19 thick ceramic coatings

In the research, the effect of different critical plasma spray parameters (CPSP) on the microstructure and mechanical properties of plasma-sprayed LMA coatings with thickness of 797 mu m were investigated. As a result, the porosity of coatings was increased from 12.14% to 24.88% with the decrease of CPSP from 1.20 to 0.86, while bonding strength of coatings was obviously reduced from 15.98 +/- 0.36 MPa to 4.87 +/- 0.7 MPa. Relatively, Young's modulus and hardness of the coatings exhibited a decreasing tendency with the decrease of CPSP. When the CPSP was decreased from 1.20 to 0.97, the residual compressive stress of coating surface varied from -162.10 +/- 12.13 MPa to -93.49 +/- 3.28 MPa, and that obtained from cross-section was decreased from -116.02 +/- 5.92 MPa to -70.68 +/- 3.99 MPa. Meanwhile, the fracture toughness of coating was improved from 0.62 +/- 0.05MPam1/2 to 1.34 +/- 0.05 MPam1/2, which was higher than that of cross-section of coating. The microstructure and mechanical properties of LMA thick coatings were strongly dependent on the CPSP.

Automated summary

The study investigated the effect of different critical plasma spray parameters on the microstructure and mechanical properties of LMA coatings, finding that as the CPSP decreased, the porosity and residual compressive stress increased, while the bonding strength decreased. Additionally, the fracture toughness improved with decreasing CPSP.