用正电子研究NaCl在NaY沸石上的固溶过程

用正电子湮没谱学研究NaCl与NaY沸石机械混合后, NaCl在NaY中的固溶扩散过程.分别测量不同质量比的NaCl/NaY［(1—20)%］经500℃烘烤1h，NaCl/NaY(15%)经不同温度烘烤1h,以及NaCl/NaY(15%)经500℃烘烤不同时间后的正电子寿命谱.所有寿命谱都出现了5个寿命分量, 其中第3，4，5寿命分别与β笼、超笼及沸石微粒界面空洞的大小和数量相关.实验表明正电子湮没谱学能敏感地表征NaCl在NaY中的固溶扩散过程.关键词：正电子湮没谱学氯化钠沸石

Solid state diffusion of NaCl into NaY zeolite studied by positron annihilation

A series of samples, prepared from mechanical mixtures of NaCl with NaY zeolite and resulting in the dispersion of NaCl in NaY, was studied by position annihila tion spectroscopy. We measured the positron lifetime spectroscopy as a function of the weight ratio of the NaCl-NaY zeolite heated at 500℃ for 1h, as a function of the heating temperature held for 1h, and as a function of the heating duration at 500℃ for NaCl/NaY(15%). All the lifetime spectra were resolved into five components, in which the third, fourth and fifth components are related to the positron annihilation in β cage, supercage and interface void respectively. The experimental results showed that position annihilation spectroscopy is sensitiv e to the change of the dispersion of NaCl in NaY zeolite.