Abstract: X-ray diffraction and infrared absorption analysis were carried out on zinc-doped beta-tricalcium phosphate prepared by a liquid-phase reaction technique. Quantitative
methods and regression analysis were used to calculate the variation of lattice constants of TCP, and the shift or degeneracy of the PO^3-₄ infrared
absorption bands. X-ray diffraction analysis indicates that zinc can substitute calcium up to 20 atom %, inducing a statistically significant
decrease of the lattice constants a and b. As the zinc content in TCP increases beyond 20 atom %, X-ray diffraction analysis shows the appearance
of a new phase α-CaZn₂(PO₄)₂. However, the effect of substitution of zinc on the lattice constant c is abnormal. The substitution
of Zn up to 10 atom % results in a general decrease of the lattice constants c, while it increases as the content of zinc in TCP increases beyond 10%.
FTIR spectra reveal that the substitution of Zn up to 10 atom% results in a statistically significant increase of the asymmetric P--O stretching vibration
absorption band at 1045 and 1120cm^-1 (P<0.05) and a statistically significant decrease of O--P--O bending vibration absorption band at 605cm^-1 (P=0.00085),
respectively.

Key words: tricalcium phosphate, zinc, substitution