수산화물, 탄산염 및 수산화아파타이트(HAp)의 형성과 해리는 용액의 pH에 따라 달라지며 $Ca-PO_4-H_2O$계로부터 균질하고 미세한 HAp, $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$, 세라믹 분말을 제조하는데 매우 중요한 인자가 된다. 각 복합이온의 용해도는 pH와 직선적인 관계에 있으므로 용해도 도형은 수산화물, 탄산염 및 수산화아파타이트(HAp)의 평형상수와 용해도적으로부터 계산된 대수 몰농도로 그릴 수 있다. $Ca-PO_4-H_2O$계로부터 $25^{\circ}C$에서 단일상의 $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$ 분말을 제조하기 위한 최적의 pH조건은 이론적인 고찰 결과 $10.5{\pm}0.5$로 결정되었다. 실온에서 제조하여 $80^{\circ}C$에서 건조시킨 HAp분말은 75nm의 입자크기를 갖는 미세한 응집분말 이었으며, $1,000^{\circ}C$에서 하소시킨 HAp분말은 450nm 크기의 거의 균질한 형태의 분말을 얻었다. HAp분말들이 응집되어 있었지만 소결후 미세구조는 양호하여 우수한 기계적 특성을 보유하였다.
수산화물, 탄산염 및 수산화아파타이트(HAp)의 형성과 해리는 용액의 pH에 따라 달라지며 $Ca-PO_4-H_2O$계로부터 균질하고 미세한 HAp, $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$, 세라믹 분말을 제조하는데 매우 중요한 인자가 된다. 각 복합이온의 용해도는 pH와 직선적인 관계에 있으므로 용해도 도형은 수산화물, 탄산염 및 수산화아파타이트(HAp)의 평형상수와 용해도적으로부터 계산된 대수 몰농도로 그릴 수 있다. $Ca-PO_4-H_2O$계로부터 $25^{\circ}C$에서 단일상의 $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$ 분말을 제조하기 위한 최적의 pH조건은 이론적인 고찰 결과 $10.5{\pm}0.5$로 결정되었다. 실온에서 제조하여 $80^{\circ}C$에서 건조시킨 HAp분말은 75nm의 입자크기를 갖는 미세한 응집분말 이었으며, $1,000^{\circ}C$에서 하소시킨 HAp분말은 450nm 크기의 거의 균질한 형태의 분말을 얻었다. HAp분말들이 응집되어 있었지만 소결후 미세구조는 양호하여 우수한 기계적 특성을 보유하였다.
The formation and dissolution of hydroxides, carbonates and hydroxyapatite (HAp), which depend on the pH of solution, are important factor for the preparation of homogeneous and fine HAp, $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$, ceramic powder from the $Ca-PO_4-H_2O$ sy...
The formation and dissolution of hydroxides, carbonates and hydroxyapatite (HAp), which depend on the pH of solution, are important factor for the preparation of homogeneous and fine HAp, $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$, ceramic powder from the $Ca-PO_4-H_2O$ system. Since the solubility of each complex ion is a linear function of pH, the solubility diagram can be obtained by plotting the logarithmic molar concentrations calculated from the values of the equilibrium constants and solubility products for hydroxides, carbonates, and hydroxyapatite. The optimum pH condition for the formation of single phase $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$ powder in $Ca-PO_4-H_2O$ system at $25^{\circ}C$ was estimated as $10.5{\pm}0.5$ through the theoretical consideration. The HAp powder dried at $80^{\circ}C$ showed a fine agglomerated particles with a size of 75 nm. The HAp powder calcined at $1,000^{\circ}C$ consisted of nearly homogeneous particles with a size of 450 nm. Even though the dried HAp particles consisted of agglomeration, mechanical properties were superior due to fine microstructure after sintering.
The formation and dissolution of hydroxides, carbonates and hydroxyapatite (HAp), which depend on the pH of solution, are important factor for the preparation of homogeneous and fine HAp, $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$, ceramic powder from the $Ca-PO_4-H_2O$ system. Since the solubility of each complex ion is a linear function of pH, the solubility diagram can be obtained by plotting the logarithmic molar concentrations calculated from the values of the equilibrium constants and solubility products for hydroxides, carbonates, and hydroxyapatite. The optimum pH condition for the formation of single phase $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$ powder in $Ca-PO_4-H_2O$ system at $25^{\circ}C$ was estimated as $10.5{\pm}0.5$ through the theoretical consideration. The HAp powder dried at $80^{\circ}C$ showed a fine agglomerated particles with a size of 75 nm. The HAp powder calcined at $1,000^{\circ}C$ consisted of nearly homogeneous particles with a size of 450 nm. Even though the dried HAp particles consisted of agglomeration, mechanical properties were superior due to fine microstructure after sintering.
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제안 방법
Structural analysis for the resultant phases was performed by X-ray diffractometer(XRD, Phyllips PW 1820, Holland) with Ni filtered CuKα radiation (λ = 1.5418Å), The particle size, morphology and chemical composition of the HAp powder were measured by a scanning electron microscope(SEM, Akashi SX-40, Japan) with energy dispersive spectroscopy(EDS). Inductively Coupled Plasma (ICP) analysis was also employed for determining the metal ion concentration in the residual solution after precipitation.
이론/모형
The heating and cooling rates were ±5℃/min. Sintered density was measured by Archimedes technique. Flexural strength of the test bars were determined in three-point bending(UTM, Instron, U.
Single phase of HAp was obtained by the calculated pH condition as described in Section 2. Specific surface area, S, of the dried HAp powder was 59 ㎡/g by Brunauer-Emmett-Telier(BET) method.
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