Papers by Author: Qing Xia Zhu

Abstract: Zircon nano–powder has been synthesized via the non-hydrolytic sol–gel route, using industral zirconium tetrachloride (ZrCl₄) and tetraethoxysilane (TEOS) as precursors, lithium fluoride (LiF) as mineralizer, PEG1000 as dispersant. The effects of solvents on the synthesis and dispersion of zircon nano-powder were investigated by means of XRD and TEM. The results indicate that the aprotic solvent N, N-dimethyl formamide (DMF) is not conducive to the nucleophilic substitution reaction, which directly affect the zircon synthesis, and the particles are easy to agglomerate due to the large surface tension; the powder with size of 30nm and good dispersion can be obtained using dichloromethane (CH₂Cl₂) as solvent; different anhydrous alcohols as solvents influence zircon synthesis, the order of the synthesis ratio is listed as EtOH›propanol (PrOH)› isopropanol (PrⁱOH). Powder particles are larger than 50nm with wide distribution and serious agglomeration when taking PrOH and PrⁱOH as solvents. Nano-zircon with good dispersion and synthesis ratio up to 94.5% can be obtained via using ethanol as solvent.

Abstract: The carbonated hydroxyapatite (CHA) was synthesized by precipitation-calcination method. The influences of carbonate subsitution on high-temperature sintering, thermal expansion coefficient (CET) and flexural strength were investigated by the high-temperature dilatometer, scanning electron microscopy (SEM) and universal testing machine. The results showed that the sintering temperatures of CHA were related to the initial carbonate contents. The sintering temperature decreased with increasing initial carbonate contents. The CET of CHAs decreased with the increase of carbonate content, due to the stoma caused by the partially decompostion of CHAs. The CHA ceramics tested were as strong in flexure strength when compared to non-carbonated hydroxyapatite.