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采用Pechini方法制备了以RuO2,IrO2和PdO为主的纳米晶活性氧化物,选择适当的热处理温度可获得氧化物单相组织。热处理对所制备的RuO2,IrO2和PdO晶粒尺寸影响很大。尽管随加热温度升高,晶粒尺寸增大;但温度对晶粒尺度的影响并非简单的增长关系:在所制备的3种贵金属氧化物热处理过程中均出现了两段式生长现象,可以转折点为临界温度Tc分为两段,在低于Tc的温区内,晶粒长大较快,在高于Tc的温区长大速率下降。3种活性氧化物的两段式生长,应该属于贵金属氧化物成长的特有现象。认为两段变化过程可以用线性回归方程D=bT+a加以拟合,拟合的经验方程式可用以实现工业过程对晶粒尺寸的控制。
The nanocrystalline active oxide mainly composed of RuO2, IrO2 and PdO was prepared by Pechini method. The single phase structure of oxide was obtained by selecting proper heat treatment temperature. The heat treatment has great influence on the grain size of RuO2, IrO2 and PdO prepared. Although the grain size increases with the increase of heating temperature, the effect of temperature on grain size is not a simple increase. The two-stage growth phenomenon occurred during the heat treatment of the three precious metal oxides prepared, For the critical temperature Tc is divided into two sections, in the temperature zone below Tc, the grain grows faster, higher than Tc in the rate of growth rate of temperature decline. The two-stage growth of the three active oxides should belong to the peculiar phenomenon of the growth of noble metal oxides. It is considered that the two-stage change process can be fitted by the linear regression equation D = bT + a, and the fitted empirical equation can be used to control the grain size of the industrial process.