TiO_2(Ti)粉およびTi粉添加(Ba, Sr)TiO_3真空焼結体のPTCR特性に及ぼすTiO_2(Ti)粉中TiO_2量およびTi粉粒度の影響 Effects of TiO_2 Content in TiO_2(Ti)Powder and Particle Size of Ti Powder on PTCR Characteristic of (Ba, Sr)TiO_3 Vacuum-Sintered Compacts Added with TiO_2(Ti)and Ti Powders
The effects of TiO<SUB>2</SUB> contents (or thickness of TiO<SUB>2</SUB> surface layer) in TiO<SUB>2</SUB>(Ti) powder and the grain size of Ti powder (or interparticle spacing of Ti particles) on the PTCR characteristic of the (Ba, Sr)TiO<SUB>3</SUB> compact added with TiO<SUB>2</SUB>(Ti) or Ti, which were sintered in vacuum at 1623K for 3.6ks, were investigated.<BR>The results obtained were as follows; (1)With increasing TiO<SUB>2</SUB> content of the TiO<SUB>2</SUB>(Ti) from 12.5mass% to 25 and 37.5mass%, the range of metallic Ti content in TiO<SUB>2</SUB>(Ti) needed for the development of PTCR characteristic became 1.7 times larger at maximum. (2)For the sintered compact added with 2μm Ti powder, the range of Ti content needed for the development of PTCR characteristic was larger than that of the compact with 18μm Ti powder. (3)The above phenomena seemed to be due to the homogenization of oxygen ion concentration in (Ba, Sr)TiO<SUB>3</SUB> particles which are caused by increasing thickness of TiO<SUB>2</SUB> layer or decreasing interparticle spacing of Ti particles.
粉体および粉末冶金 46(4), 358-363, 1999-04-15
Japan Society of Powder and Powder Metallurgy