燒結助劑與燒結溫度對鈦酸鍶鋇陶瓷大信號反應的影響

作者:鄭秀鳳、張秋男(國立臺灣師範大學物理學系)

摘要：

本研究利用Sawyer-Tower法，來探討添加施體?之鈦酸鍶鋇(Sr,Ba)TiO₃陶瓷，在高電場作用下的電性反應。綜合實驗中所觀察到的絕緣性樣品之電位移－電場（D-E）電滯曲線與具正電阻溫度係數（PTCR）樣品之電流－電壓（I-V）特性曲線，提出絕緣性鈦酸鍶鋇的導電機制，亦即，絕緣樣品(Sr,Ba)TiO₃的高電阻性係樣品中絕緣晶粒所造成的飽和自發極化（spontaneous polarization）隨助燒結劑三氧化二鋁－二氧化矽－二氧化鈦的含量之增加而減少，這主要歸因於(Sr,Ba)TiO₃中的Ba²⁺ 離子溶解形成二相析出物Ba₆Ti₁₇O₄₀，因此晶粒中的比值Sr²⁺／Ba²⁺增加所形成的。

關鍵詞：正電阻溫度係數、鈦酸鍶鋇、半導電陶瓷、電滯

《詳全文》

Effects of Sintering Aids and Sintering Temperature on Large Signal Response of (Sr0.2Ba0.8)TiO3 Ceramics

Author: Hsiu-Fung Cheng, Chu-Nan Chang(Department of Physics, National Taiwan Normal University)

Abstract：

The electrical response of (Sr_0.2Ba_0.8)TiO₃ : Sb³⁺ ceramic materials to high electric field is examined by Sawyer-Tower technique. It is concluded, from the observed ferro-electric hysteresis D-E characteristics of insulating samples and I-V characteristics of PTCR samples, that the mechanism of high resistivity of the materials is resulting from insulating grains rather than the resistive Schottky barrier at grain boundaries. The satu-rated electric polarization (P_s) of these materials decreases with the amount of A1₂O₃ -SiO₂-TiO₂ sintering aids, which is ascribed to the dissolution of Ba²⁺ions into the sec-ond phase segregations, Ba₆Ti₁₇O₄₀, such that the Sr²⁺/Ba²⁺ ratio in the grains in-creases.

Keywords：PTCR, (Sr,Ba)TiO3，Semiconducting ceramics，Ferroelectric hysteresis