The effect of silicon doping on the transformation of amorphous calcium phosphate to silicon-substituted α-tricalcium phosphate by heat treatment. Issue 1 (January 2016)

• Record Type: Journal Article
• Authors: Dong, Gang; Zheng, Yanxia; He, Liyong; Wu, Gang; Deng, Chunlin
• Is Part Of: Ceramics international. Volume 42:Issue 1:Part A(2016)
• Page Start: 883
• Page End: 890
• Publication Date: 2016-01
• Subjects: B. Impurities -- C. Thermal properties -- D. Apatite; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2015.09.013
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In the present study, the effects of silicon dopant contents on the phase composition of silicon-substituted hydroxyapatite (Si-HA) powders were investigated. Si-HA as-prepared samples, with varying silicon (Si) dopant contents, were prepared by an aqueous precipitation method. The phase transformation of the as-prepared samples during sintering was also discussed. The analyses of the as-prepared powders confirmed the formation of well-crystallized Si-HA at low Si dopant concentrations (≤1.5 wt% Si). Contrarily, silicon-substituted amorphous calcium phosphate (Si-ACP) and amorphous silica formed at high Si dopant concentrations (>1.5 wt% Si). Upon sintering at 1000 °C, Si-HA (≤1.5 wt% Si) underwent no phase transformations, whereas Si-ACP (>1.5 wt% Si) transformed to biphasic silicon-substituted α-tricalcium phosphate (Si-α-TCP) and HA (no additional phases such as β-TCP, silicocarnotite or CaO were detected). Rietveld refinement on X-ray diffraction patterns was conducted to determine the percentage contents of ACP and differences of lattice parameters between pure α-TCP and Si-α-TCP. X-ray photoelectron spectroscopy measurements suggested the formation of amorphous silica and decomposition of the Si-ACP to Si-α-TCP were correlated. The results confirmed that Si doping led to formation of Si-ACP, which primarily transformed to Si-α-TCP upon sintering. The current study highlights a possible account of recrystallization of Si-ACP directly to Si-α-TCP at low sintering temperatures.