Journal of the American Ceramic Society, Vol.103, No.6, 3528-3540, 2020
Simultaneous accommodation of Dy3+ at the lattice site of beta-Ca-3(PO4)(2) and t-ZrO2 mixtures: Structural stability, mechanical, optical, and magnetic features
Structurally stable beta-Ca-3(PO4)(2)/t-ZrO2 composite mixtures with the aid of Dy3+ stabilizer were accomplished at 1500 degrees C. The precursors comprising Ca2+, P5+, Zr4+, and Dy3+ have been varied to obtain five different combinations. The results revealed the fact that complete phase transformation of calcium-deficient apatite to beta-Ca-3(PO4)(2) occurred only at 1300 degrees C, whereas the evidence of t-ZrO2 crystallization is obvious at 900 degrees C. The dual occupancy of Dy3+ at beta-Ca-3(PO4)(2) and t-ZrO2 structures was evident; however, Dy3+ initially prefers to occupy beta-Ca-3(PO4)(2) lattice until its saturation limit and thereafter accommodates at the lattice site of ZrO2. The typical absorption and emission behavior of Dy3+ were noticed in all the systems and, moreover, the surrounding symmetry of Dy3+ domains has been determined from the luminescence study. All the systems ensured paramagnetic response that is generally contributed by the presence of Dy3+. A gradual increment in the phase content of t-ZrO2 in the composite mixtures ensured a significant improvement in the hardness and Young's modulus of the investigated compositions.