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Effect of CO 3 2− Incorporation on the Mechanical Properties of Wet Chemically Synthesized β‐Tricalcium Phosphate (TCP) Ceramics
Author(s) -
Dantas Alan C. S.,
Greil Peter,
Müller Frank A.
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.02208.x
Subject(s) - calcination , materials science , compressive strength , porosity , ultimate tensile strength , sintering , ceramic , phase (matter) , phosphate , nuclear chemistry , precipitation , composite material , chemical engineering , mineralogy , chemistry , organic chemistry , physics , meteorology , engineering , catalysis
Calcium‐deficient hydroxyapatite (CDHA) powders were synthesized by a wet chemical precipitation method using Ca(OH) 2 and H 3 PO 4 solutions. Single‐phase β‐tricalcium phosphate (β‐TCP) powder with a molar (Ca+Mg)/P ratio of 1.5 was obtained after calcination of CDHA synthesized under vacuum. During synthesis in air, CO 2 can be adsorbed and HBO 4 2− is partly substituted by CO 3 2− , resulting in a lower phosphorous content and consequently an increase of the molar (Ca+Mg)/P ratio to 1.53. A two‐phase β‐TCP powder containing 20 wt% hydroxyapatite (HA) was obtained after calcination. Samples prepared from β‐TCP powders synthesized under vacuum achieved a compressive strength of 301±23 MPa at 99.6% fractional density, while TCP/HA samples prepared in air achieved a maximum compressive strength of 132±29 MPa at 91.7% fractional density. This decrease in strength can be correlated to the porosity retaining due to CO 2 release during sintering and residual tensile stresses in the TCP matrix caused by the thermal expansion mismatch of β‐TCP and HA.