低氧分压下PtO_(2)的分解机理研究

Research on the Decomposition Mechanism of PtO_(2) in Low-oxygen Atmosphere

高纯铂丝作为标准铂电阻温度计的传感元件,其氧化与分解机理是影响温度计稳定性的关键因素。采用差示量热扫描法与X射线光电子能谱共同分析了2种类型的铂氧化物PtO_(2)和PtO在低氧分压下的分解过程。结果表明:2种氧化物的分解温度对氧气分压有明显的依赖性,氧气分压10 kPa下,570℃时PtO_(2)基本完全分解为Pt单质和PtO;在氧分压为3 kPa下PtO_(2)的起始分解温度约为520℃,565℃以上大量分解为Pt单质,且当温度达到585℃时,PtO_(2)分解为Pt的速度达到最快。研究结果可为铂电阻温度计的制作工艺、计量检定规程的完善提供数据参考和理论支持。

High-purity platinum wires are used as the sensing elements of standard platinum resistance thermometers,the oxidation and decomposition mechanism affects the stability of the thermometers.Differential calorimetry scanning and X-ray photoelectron spectroscopy are used to analyze the decomposition process of two types of platinum oxides PtO_(2)and PtO in low oxygen atmosphere.The results show that the decomposition temperature of the two oxides is obviously dependent on the partial pressure of oxygen.At the partial pressure of 10 kPa,PtO_(2)is basically completely decomposed into Pt and PtO at 570℃.At the oxygen partial pressure of 3 kPa,the initial decomposition temperature of PtO_(2)is about 520℃,and a large amount of Pt is decomposed above 565℃.When the temperature reaches 585℃,the decomposition rate of PtO_(2)into Pt is the fastest.The research results can provide data reference and theoretical support for the improvement of platinum resistance thermometers manufacturing process and metrological verification procedures.