화학공학소재연구정보센터
Journal of the Korean Industrial and Engineering Chemistry, Vol.9, No.7, 998-1003, December, 1998
펄스전류파형을 이용한 Ti 전극위에서 BaTiO3박막의 합성
Synthesis of BaTiO3 Thin Film on Ti Electrode by the Current Pulse Waveform
초록
85℃, 0.4M Ba(OH)2 용액내에서 펄스전류파형을 이용하여 Ti전극위에 BaTiO3박막을 전해 합성하였다. 환원전류 밀도 및 환원시간이 증가함에 따라 BaTiO3의 결정성 및 페러데이 효율이 증가하였으며, 이는 표면 및 전기화학적특성 분석에 의하면 환원 전류 인가시에 H2O의 환원에 의하여 전극표면의 pH가 증가함으로서 산화전류에 의하여 형성된 산화막의 구조변화가 빠르게 진행되기 때문으로 추측된다. 그리고 0.1M H2SO4용액하에서 산화막을 형성시킨 후 BaTiO3형성에 미치는 영향을 분석한 결과, 산화막 두께가 증가함에 따라서 산화막을 통한 Ti+4이온의 이동이 어려워지면서 BaTiO3 형성이 억제되며, 일정두께이상에서는 산화막 결함부위에서 결정이 형성됨을 알 수 있었다.
BaTiO3 thin film was electrochemically deposited on Ti electrode in a 0.4 M Ba(OH)2 solution of 85℃ using a current pulse waveform. Both BaTiO3 crystallinity and faradaic efficiency for the film formation were enhanced with the increase of cathodic current density and pulse time. Based on the suface analysis and electrochemical studies, it was suggested that, during cathodic pulsed, the surface pH increase due to the reduction of H2O accelerates the structural changes of Ti oxides which were formed during anodic cycle. Prior to experiments, Ti oxides were intentionally grown in 0.1 M H2SO4 solution and the effect of initial oxide film thickness on the BaTiO3 film formation was investigated. The migration of Ti+4 ions through the oxide film was retarded with the increase of film thickness and it was observed that the crystallization of BaTiO3 was only limited to the defect area of surface oxides.
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