PTCR纳米晶粉体的一步法制备及表征

采用一步溶胶－凝胶法制得了含钡、锶、钙、钛、锂、锰、硅和钇等八种元素的无定形干凝胶粉，经７００℃，１ｈ煅烧得ＰＴＣＲ纳米晶粉体，经ＸＲＤ分析测得粉体平均晶粒尺寸范围为１７～３０ｎｍ，且平均粒径随稀土掺杂量（摩尔分数为０．０８％～２．００％）增加呈现先减小后增大的趋势。常温下粉体以立方相存在。粉体经造粒、压片、烧结成瓷具有ＰＴＣＲ特性

Once through Preparation and Characterization of Nanocrystalline Powders Used for Making PTCR Ceramics

Amorphous gel powders containing Ba, Sr, Ca, Ti, Si, Mn, Li and Y elements have been prepared by once through method in Sol Gel process. The nanocrystalline powder was obtained through calcination for 1 h at 700 ℃ in air. It's average particle size was determined by XRD to be from 17 to 30 nm and has a trend of first decrease then increase with increasing y content from 0 08 to 2 00 mol percent. The XRD showed that major crystal structure of the particle at room temperature has cubic perovskite phase. Ceramics made through pelleting, pressing and sintering from the powder has PTCR character.