Study on Zirconia Based Hydroxylapatite Graded Coating Material

Zirconia based bioglass-hydroxylapatite coatings were prepared using slurry-dipping and sintering method. Mechanical and thermal properties of the coatings were investigated. The results obtained in the experiment showed that the hydroxylapatite content in composite materials has great effect on their thermal expansion properties. This is due to the main phase change from bioglass phase to hydroxylapatite phase in the microstructure. Thermal stress in the graded coatings was theoreticajly calculated, whicll showed that the difference of thermal expansion properties between coating and substrate has a greater effect on the thermal stress in the coating. Bollding strength between coating and substrate was tested according to ASTM-C633, and the result is in accordance with the calculated thermal stress in tile coating.