二氧化钛厚膜钯表面扩散状态对氧气响应特性影响  

INFLUENCE OF PALLADIUM APPARENT DIFFUSION STATES IN TITANIA THICK FILM ON OXYGEN RESPONSE CHARACTERISTICS

作　　者：吴向[1] 袁战恒[1] 郑程[1] 

机构地区：[1]西安交通大学电子系,西安710049

出　　处：《硅酸盐学报》2008年第A01期48-53,共6页Journal of The Chinese Ceramic Society

摘　　要：利用二氯化钯(PdCl_2)溶液浸渍法,研究了二氧化钛(TiO_2)厚膜钯(Pd)原子表层扩散对氧气响应特性的影响。扫描电子显微镜显示:Pd扩散后厚膜表面均匀分布着纳米级Pd晶粒。利用Kroger-Vink方程分析了不同扩散时间下对应的lnR-lnpo_2曲线,针对不同斜率的曲线,用缺陷方程分析了Pd元素的分布状态。样品响应特性的伏安法测试结果显示:820℃,2h扩散的敏感膜具有理想灵敏度和响应时间。研究结果表明:Pd元素在敏感膜表面形成了纳米级Pd晶粒,并在TiO_2厚膜表层中存在着少量的钯间隙原子(Pd_i)及替位钯离子(Pd^(2+))。合理的扩散温度和扩散时间,可获得表层Pd氧化量最少、扩散浓度合适的敏感膜,进而获得效果理想的厚膜氧敏材料。lsing the method of palladium chloride （PdCl2） solvent impregnation, the influence of palladium （Pd） atom apparent diffu- sion in titanium dioxide （TiO2） thick film on the oxygen response characteristics was investigated. Through scanning electron micro- scope （SEM）, it was observed that nano-scale Pd crystal grains were evenly distributed on the thick-film surface after Pd diffusion. The lnR-lnpo2 curves for various diffusion times were analyzed by the Kroger-Vink equation. A defect equation was used to analyze the distribution of Pd elements aimed at the different slopes of curves. The testing results of voltammetry of the samples＇ response characteristics displayed that sensing film of two-hours diffusion time at 820 ℃ was provided with optimal sensitivity and response time. The results indicate that the Pd element forms nano-scale Pd crystal grains on the sensing film surface, and a small quantity of Pd interstitial atoms （Pdi） and Pd substitutional ions（Pd^2＋） excited in the surface layer of TiO2 thick film. Sensing film with the least Pd oxidation in the surface layer and appropriate diffusion concentration could be acquired via optimal diffusion time and diffusion temperature, and oxygen sensing materials of optimal effect could be acquired.

关 键 词：二氧化钛 厚膜 钯表面扩散 氧气响应特性 

分 类 号：TQ174[化学工程—陶瓷工业]