The results indicated that the parameters such as the spraying distance, substrate temperature, coating thickness and substrate roughness were fairly effected the hardness, porosity and surface roughness of Al2O3 coatings.
Finally, it is demonstrated that the effect of substrate compliance has a significant effect on the hardness predictions if the effective stiffness of the substrate is of the same order as the stiffness of the film.
It has also been established by ANOVA that the solution time and ageing temperature have only a little effect on the hardness but the ageing time has considerable effect and prolonged ageing will result in loss of hardness.
The existence of residual stress has a slight effect on the hardness measured by nanoindentation while it has no effect on the measured elastic modulus.
Nevertheless, no detrimental effect in the hardness could be correlated.
The subsequent solution and ageing treatments have a limited effect on the hardness.
Copper has no detrimental effect on the hardness but improves the surface quality.
The self-sharpening was attributed to the combined effect of the hardness and the texture orientation of the microstructure units in Regions I and II.
Pressure by 0.13% and Cf by 0.43%, M.t by 0.94 and time by 2% have the least effect on the hardness.
The presence of chunky graphite in the samples decreased tensile strength and elongation at break, while no significant effect on the hardness and yield strength was measured.
