Preparation of various calcium-phosphate powders by ultrasonic spray freeze-drying technique

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• 作者：Itatani ; Kiyoshi ; Iwafune ; Kengo ; Howell ; F. Scott ; Aizawa ; Mamoru
• 关键词：A. Inorganic compounds ; B. Chemical synthesis ; C. X-ray diffraction
• 刊名：Materials Research Bulletin
• 出版年：2000
• 出版时间：March 1, 2000
• 年：2000
• 卷：35
• 期：4
• 页码：575-585
• 全文大小：327 K

文摘

Various calcium–phosphate powders with Ca/P ratios ranging from 1.00 to 1.67 were prepared by an ultrasonic spray freeze-drying (USFD) technique: (i) 100 cm³ of aqueous solution containing 0.500 mol·dm⁻³ of calcium acetate (Ca(CH₃COO)₂), 0.300–0.500 mol·dm⁻³ of trimethyl phosphate (PO(OCH₃)₃) and 1.77 mol·dm⁻³ of acetic acid (CH₃COOH) were refluxed at 80°C for 100 h; (ii) the droplets with diameters as small as 2–3 μm, which were formed by the ultrasonic spray of aqueous solution, were introduced into a chamber chilled by liquid nitrogen to freeze the droplets; (iii) the water ice in the frozen droplets was sublimed under reduced pressures; and (iv) the freeze-dried materials were heated at 900°C for 1 h to form calcium phosphates. The β-calcium orthophosphate (β-Ca₃(PO₄)₂) and carbonate-containing hydroxyapatite powders with stoichiometric Ca/P ratios were prepared from the solutions with Ca/P ratio of 1.44 and 1.67, respectively.