Sintering, microstructure, and mechanical properties of ZrO₂-doped Al₂O₃

ABSTRACT

In the present work, the effect of Zr-doping on the sintering, microstructure development, and mechanical properties of polycrystalline Al₂O₃ was studied. Dopant concentrations of 830 and 2070ppm cationic ratio of Zr in Al₂O₃ corresponding to 2000 and 5000 wt. ppm of ZrO₂ in Al₂O₃, respectively, were used. The sintering schedule of undoped as well as Zr-doped Al₂O₃ samples was optimised following a series of precoarsening experiments. The Zr-doped Al₂O₃ ceramics exhibited controlled grain size and improved density. Upon increasing the Zr-dopant concentration from 830 cat. ppm to 2070 cat. ppm. Zr-doped Al₂O₃ ceramics having a refined microstructure with a homogeneous distribution of controllably grown ZrO₂ in Al₂O₃ matrix was obtained. Microhardness of the Zr-doped samples showed negligible dependence with Zr-doping, whereas mechanical strength was found to improve with it. The improvement in strength was attributed to the combined effect of improved sinter density, microstructural refinement, and grain-boundary strengthening.

KEYWORDS:

• Al₂O₃
• ZrO₂
• sintering
• microstructure
• hardness
• strength

Acknowledgement

The authors gratefully acknowledge the support of Mr Sarbapi Mukherjee, Almatis India, for the supply of alumina powders for this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors declare that the data supporting the findings of this study and supporting documents will be made available on reasonable request.