Synthesis, Cu incorporation, and deposition behavior of apatite-type La sub()

• Published in: Journal of materials science 2016-07, Vol.51 (13), p.6509-6516
• Main Authors: Kato, Sumio, Endo, Tomoyuki, Ogasawara, Masataka
• Format: Article
• Language: English
• Subjects: Apatite; Channels; DEPOSITION; FABRICATION; HEAT TREATING; Heat treatment; Oxidation; Reduction; Synthesis; THERMOGRAVIMETRIC ANALYSIS
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-016-9960-1

Cu-containing, apatite-type phosphate-silicate solid solutions, La sub( x )Ca sub(10-x )(PO sub(4)) sub(6-x )(SiO sub(4)) sub( x )Cu sub( y )O sub( z ) (x = 3, 5, and 6), were synthesized by an impregnating method into the channels of apatite-type lattice by heat treatment after Cu loading. The unit cell volume of the apatite increased with increasing amount of Cu, y = 0-0.6 for x = 3 and 6, indicating successful incorporation of Cu into the channels of the apatite lattice. The result of Rietveld analysis of a La sub(5)Ca sub(5)(PO sub(4))(SiO sub(4)) sub(5 )Cu sub( y )O sub( z ) (x = 5) sample indicated that the distribution of La super(3+) and Ca super(2+) cations in both 4f and 6 h sites were maintained during Cu incorporation. X-ray photoelectron spectroscopy and thermogravimetric analyses revealed that oxidation and reduction of Cu species occurred during heating up to 1100 degree C and cooling in air, respectively. In addition, high-temperature X-ray diffraction analysis of the La sub(3)Ca sub(7)(PO sub(4)) sub(3)(SiO sub(4)) sub(3)Cu sub(0.6)O sub( z ) (x = 3) sample in the temperature range from 500 to 1100 degree C revealed that reversible incorporation/deposition of Cu occurred, accompanied by Cu oxidation/reduction.