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X射线定量相分析,虽然可以通过衍射晶面的选择,使欲测晶面不受其它衍射晶面的干扰,但在混合物(多相)试样分析中,衍射峰的重叠却是难以避兔的。为此,人们曾采用“系数法”等来解决衍射强度的测量。在定量相分析中,往往还由于物质的化学性质极其相似,无法通过相分离,只能用人工合成或别的途径来获得标准样品。这样,会使标准样品和被测物质的颗粒大小、固溶元素的偏异,造成同一衍射晶面的衍射峰在起始角、终止角、衍射中心角和衍射峰形状等的不同,给测量工作带来困难,影响测量精确度。图1中,(a)是人工合成的LiC(102)晶面的衍射峰;(b)是20 cr 1M_o1VNbTiB钢中析出的TiC(102)晶面的衍射峰,该样品是采用电解法从钢样中提取的阳极沉淀物,在这里,微观内应力的影响可以忽略,因此,可以认为衍射峰的宽化完全是由细晶粒所造成的。
X-ray quantitative phase analysis, although the diffraction crystal plane can be selected so that the crystal face to be measured from the other diffraction crystal plane interference, but in the mixture (multi-phase) sample analysis, the diffraction peak overlap is difficult to avoid of. To this end, people have used the “coefficient method” to solve the diffraction intensity measurement. In quantitative phase analysis, often due to the very similar chemical nature of the material, can not be separated by phase, only synthetic or other ways to obtain a standard sample. In this way, the difference between the particle size of the standard sample and the substance to be measured, the dispersion of the solid solution element, and the diffraction peak of the same diffraction crystal plane at the starting angle, the ending angle, the diffraction center angle and the diffraction peak shape, Difficult work, affecting the measurement accuracy. In Fig. 1, (a) is a diffraction peak of a synthetic LiC (102) crystal plane; (b) is a diffraction peak of a TiC (102) crystal plane precipitated in 20 cr 1M_o1VNbTiB steel, In this case, the influence of the microscopic internal stress is negligible. Therefore, it is considered that the broadening of the diffraction peak is caused entirely by the fine grains.