Premium
Combined Occupancy of Gadolinium at the Lattice Sites of β‐Ca 3 (PO 4 ) 2 and t ‐ZrO 2 Crystal Structures
Author(s) -
Kumar Ponnusamy Nandha,
Kannan Sanjeevi,
Ferreira José M. F.
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201901208
Subject(s) - chemistry , sintering , composite number , gadolinium , crystallography , apatite , solid solution , mineralogy , lattice constant , crystal structure , phase (matter) , precipitation , analytical chemistry (journal) , nuclear chemistry , composite material , materials science , diffraction , physics , organic chemistry , chromatography , meteorology , optics
An in situ aqueous precipitation with the aid of Gd 3+ as a stabilizer has been used to attain a series of β‐Ca 3 (PO 4 ) 2 / t ‐ZrO 2 composites. Analytical characterization techniques were used to investigate the formation of desired composite during progressive heat treatments. The transformation of calcium deficient apatite to β‐Ca 3 (PO 4 ) 2 , which usually occurs at ≈ 780 °C for pure systems, is delayed to beyond 1100 °C, depending upon the concentration of Gd 3+ /Zr 4+ used in the synthesis. Gd 3+ prefers to accommodate at the lattice sites of both β‐Ca 3 (PO 4 ) 2 and t ‐ZrO 2 . Gd 3+ ensures limited occupancy at the Ca 2+ (1), Ca 2+ (2), and Ca 2+ (3) of β‐Ca 3 (PO 4 ) 2 while t ‐ZrO 2 consumes the excess Gd 3+ . Phase pure β‐Ca 3 (PO 4 ) 2 / t ‐ZrO 2 composite mixtures devoid of any secondary phase alongside enhanced structural stability were accomplished at 1500 °C. The micrographs of the composite specimen revealed good sintering behaviour, and the Youngs modulus and hardness data determined from indentation displayed significant variations depending on the phase content of the individual components in the composite system.