Prior treatments of the scattered x‐ray intensity from diffusion zones in two component crystalline systems lack a formal basis and tend to be intuitive in approach. Relatively simple and useful results can be obtained if the continuous composition changes are approximated by either a series of steps or by a system of linear segments. This paper develops equations for the coherent scattering from both approximations. Summing the scattering from all segments leads to the formation of intensity bands. Equations, containing an absorption correction, are given for planar diffusion zones in the micron and submicron range.