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将精确测定点阵参数的单波双线和双波双线法用于符合Vegard定理的连续固溶体和有限固溶体的组分测量。推导了立方晶系连续固溶体中一种组分x与双线衍射角差δ_x的关系 x≈(δ_x-δ_0)/(δ_1-δ_0)其中δ_1,δ_0,δ_x分别为x=1,C,x时双线Bragg角的差,并从典型例子和实验上验证了这个理论方程。对偏离上述线性关系的情形,引入修正项△x,其满足抛物线方程,故最后得 x≈(δ_x-δ_0)/(δ_1-δ_0)+Δx最大4((δ_x-δ_0)(δ_1-δ_x))/(δ_1-δ_0)~2这样就消除了线性近似引入的误差。最后,简要讨论了两种方法的误差。由于整个实验只要求测量衍射角差,消除了零位和试样偏心的影响,因此方法简便、迅速、具有一定的适用性。

The composition of a continuous or a limited solid solution obeyed the Vegard theorem were successfully measured by two diffraction lines with single or double wavelength of X-ray. The relationship between the composition, x, and the diffraction angle difference, δ_x, for cubic crystal system may be deduced as:x≈(δ_x-δ_0)/(δ_1-δ_0) where δ_0, δ_1 and δ_x are the differences between two diffraction angles for x=0, 1 and x respectively. Certain typical examples were used to check the formula. In case of deviating from the linear relation, a correct term, Δ_x, was introduced into it, and Δx vs x plot was found to satisfy a parabolical equation. Thus, the formula may be modified as:x=(δ_x-δ_0)/(δ_1-δ_0)+Δx_(max)4(δ_x-δ_0)(δ_1-δ_x)/(δ_1-δ_0)~2 where Δx_(max) is the deviation at x=0.5, it eliminates the error induced from the linear approximation. Finally, the error of these two methods was discussed briefly. Because these methods depend only on the difference between diffraction angles, the error due to incorrect zero-position and specimen eccentricity can be eliminated, therefore, the methods seem to be simple and rapid, and to have proper applicability as well.