【摘要】 用正电子湮没技术（PAT）研究了掺Na₂O和P₂O₅的β-C₂S正电子寿命谱。按照正电子捕获理论对实验所得的寿命谱参数与硅酸二钙微观结构的关系进行了讨论。结果表明,长寿命成分τ₂（约470ps）相当于钙空位缺陷对正电子的捕获。长寿命成分τ₂的强度I₂随Na⁺掺量增加而减小,随P⁵⁺掺且增加而增加。证实Na⁺进入Ca的位置并产生阴离子空位,而P⁵⁺进入Si⁴⁺的位置并产生Ca²⁺空位;随Na⁺或P⁵⁺掺量增加,阴离子空位或Ca²⁺空位浓度增加。实验表明,正电子湮没技术是研究掺杂β-C₂S微观结构缺陷的一种有效手段。 本文还就硅酸二钙烧成和水化活性与掺杂的关系进行了研究和讨论。更多还原

【Abstract】 The lifetime spectrum of positron in β-C₂S doped with Na₂O or P₂O₅ is studied with positron annihilation technique.According to the theory of the capture of positron, the relationship between lifetime spectrum parameters obtained in experiment and the microstructure of β-C₂S is discussed in the paper. The results show that the long life componet τ₂（about 470ps）represents the capture of positron in the defects of Ca²⁺ vacancies and that the intensity I₂ of τ₂ decreases with the increase of Na⁺ and increases with the increase of P⁵⁺. The results also verify that Na⁺ replaces Ca²⁺ and creates anion vacancy;while p⁵⁺ replaces Si⁴⁺ and creates Ca²⁺ vacancy; vacancy concentration increases with the increase of Na⁺ or p⁵⁺. Our work shows that the positron annihilation technique is useful for studying the change of microstructure defects in doped β-C₂S.The relationship between heat treatment and hydration of doped β-C₂S and its impurities are also studied and discussed.更多还原