正の抵抗温度係数をもつ半導性チタン酸バリウム膜の製造法

概要

論文の詳細を見る
Dense and nonporous films of semiconducting barium titanate showing the large positive temperature coefficient of resistivity (PTCR) effect were obtained by a modified doctor-blade method. The mixture of 100mol of BaTiO(C2O4)2⋅4H2O, 0.15mol of Sb(OH)3, 0.87mol of TiO2 and 2.62mol of SiO2 was calcined at 1130°C for 3 hours. The powders were dispersed into polystyrene tetrahydrofuran fluid. Pasty sheets of about 80μ thick were made on a glass plate by an applicator. The sheets were heated on an alumina plate at 600°C for 1 hour in order to decompose and evaporate organic vehicle. Poorly coagulated powders left on the plate were pressed at about 700kg/cm2 onto the polystyrene film. The film was heated on a platinum plate at 800°C for 1 hour first and subsequently at 1240, 1280, 1320 or 1360°C for 1 hour. Thus, dense and nonporous films were obtained. Observing the cross section of the film obtained at 1280, 1320 or 1360°C, the grain size was 19-23μ and the film thickness was 26-30μ.Without pressure pretreatment cracks were found in the films obtained above 1260°C. On the contrary, the present method with pressure pretreatment made possible supply of dense and nonporous films. The semiconducting barium titanate films had resistivity at 30°C by 102-103 ohm⋅cm (two probe method with electroless nickel electrodes) and the PTCR effect was three or more orders of magnitude for the films sintered at 1280°C or 1320°C, while without pressure pretreatment the PTCR effect was negligible small and the resistivity was in the order of 106-107ohm⋅cm because of cracks.
社団法人日本セラミックス協会の論文
1976-03-01

正の抵抗温度係数をもつ半導性チタン酸バリウム膜の製造法

スポンサーリンク

概要

著者

関連論文

スポンサーリンク