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应用XRD和BET方法,研究了四种二元复氧化物在不同配比及不同焙烧温度下界面过渡层的结构。XRD证明各组分都在另一组分表面具有分散阈值,其值远大于单层饱和容量且与焙烧温度无显著关系;“阈值后”剩余晶相量与加入晶相量虽呈线性关系,但斜率并不都近于1,有的明显小于1。BET比表面测定表明,各纯氧化物及不同配比试样的比表面较γ-Al_2O_3的小得多。对过渡层提出了球形八面体二维密置的非单层双向分散模型,计算了各项模型参数,较好地解释了高分散阈值与低比表面积之间的关联,并与O~(2-)密置的单层模型作了对比。讨论了晶相消失的机理,以及非晶相与非单层分散厚度的关联。
XRD and BET methods were used to study the structure of interfacial transition layers of four kinds of binary multi-oxides at different compositions and sintering temperatures. XRD shows that each component has a dispersion threshold on the surface of the other component, which is much larger than the monolayer saturation capacity and has no significant relationship with the calcination temperature. However, there is a linear relationship between the residual crystalline phase after “threshold” But not all slopes are closer to 1, and some are significantly smaller than 1. BET specific surface measurement showed that the specific surface area of each pure oxide and different proportioning samples was much smaller than that of γ-Al 2 O 3. A two-dimensional spherical non-monolayer dispersion model of spherical octahedra is proposed for the transitional layer. The model parameters are calculated, and the correlation between the high dispersion threshold and the low specific surface area is well explained. -) dense single-layer model is contrasted. The mechanism of the disappearance of the crystal phase and the correlation between the amorphous phase and the non-monolayer dispersion thickness are discussed.