论文部分内容阅读
系统地研究了原料颗粒对磷酸钙骨水泥（ｃａｌｃｉｕｍｐｈｏｓｐｈａｔｅｃｅｍｅｎｔ，ＣＰＣ）水化硬化过程的影响规律．以等摩尔的磷酸四钙（ｔｅｔｒａｃａｌｃｉｕｍｐｈｏｓｐｈａｔｅ，ＴＥＣＰ）和无水磷酸氢钙（ｄｉｃａｌｃｉｕｍｐｈｏｓｐｈａｔｅａｎｈｙｄｒｏｕｓ，ＤＣＰＡ）的混合物为ＣＰＣ粉末作为研究对象．ｐＨ值变化表明ＣＰＣ水化控制步骤在于ＤＣＰＡ的溶解，降低ＤＣＰＡ的粒径会加快ＣＰＣ的水化反应速率；而降低ＴＥＣＰ的粒径会大大促进ＤＣＰＡ的溶解，从而大大加快水化反应速率．水化放热曲线表明降低ＴＥＣＰ粒径会提高水化反应转化率，从而提高水泥样品的抗压强度．但最高抗压强度４９ＭＰａ的ＣＰＣ样品不是由最小粒径的ＤＣＰＡ和最小粒径的ＴＥＣＰ组成的．对于凝结时间而言，颗粒越小，凝结时间越短．ＣＰＣ浆体凝结过程经历了从凝聚结构向凝结—结晶结构的发展过程．由流变模型外推的凝结时间同实测值吻合得很好．交流阻抗谱参数同水泥样品的孔径状态密切关联，其结果进一步证实小颗粒样品的水化反应速率大，抗压强度也相对较大．
The influence of raw material particles on the hydration-hardening process of calciumphosphate cement (CPC) was systematically studied. A mixture of equimolar tetracalcium phosphate (TECP) and dicalciumphosphate anhydrous (DCPA) was taken as the CPC powder. The change of pH value indicates that the CPC hydration control step is the dissolution of DCPA. Decreasing the particle size of DCPA will accelerate the hydration reaction rate of CPC. Decreasing the particle size of TECP will greatly promote the dissolution of DCPA and greatly accelerate the hydration reaction rate. The hydration exotherm shows that decreasing the TECP particle size increases the hydration reaction conversion rate, thereby increasing the compressive strength of the cement sample. However, CPC samples with a maximum compressive strength of 49 MPa were not composed of DCPA with the smallest particle size and TECP with the smallest particle size. For the setting time, the smaller the particles, the shorter the setting time. The slurry coagulation process has undergone a process from condensation to condensation and crystallization. The condensation time extrapolated by the rheological model is in good agreement with the measured values. The AC impedance parameters are closely related to the pore size of cement samples. The results further confirm that the hydration reaction rate and compressive strength of small particle samples are relatively large.