I. A.  Veretennikova, E. A. Bogdanova

STUDYING THE HARDNESS AND ELASTIC MODULUS OF A CERAMIC MATERIAL BASED ON HYDROXYAPATITE AND ITS SUBSTITUTED FORMS

The paper studies the hardness and elastic modulus of stoichiometric and fluorine-substituted hydroxyapatite samples obtained by precipitation from solution, after pressing, and after sintering of the pressed samples at temperatures of 800 and 1000 °C. Substitutions of elements in the composition of hydroxyapatite have a significant effect on its mechanical properties. The introduction of fluoride ions is found to increase significantly the hardness of the materials. The modulus values also increase. The influence of the applied load on the obtained values is observed. A lower standard error occurs at a load of 2000 mN, indicating that the data obtained at this load are highly reliable in evaluating the true mean value of the population. The Ca₁₀(PO₄)₆F₂ sample is the most promising hardened ceramic; however, high values of standard deviation and maximum sampling error indicate a low accuracy of the obtained data. Sintering at 1000 °C significantly increases the hardness and elastic modulus values for all the samples studied; however, the high values of standard deviation and maximum sampling error indicate the instability of the mechanical properties of the sintered materials.

Acknowledgment: The work was performed under the state assignment for the IES UB RAS. The equipment of the Plastometriya shared research facilities, IES UB RAS, was used for the research.

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