[en] The formation process has been studied of the internal oxidation zone (IOZ) during the oxyden diffusion into the binary copper alloys with oxide-forming elements: Al, Be, Zr, or Si; also the effect of the microadditions of the third elements on this process has been investigated. It is shown, that with the IOZ propagation the size of the precipitates increases, in the presence of the predominant crystallographic growth directions needle-type predicates are formed, the microscopic striation in the structure occurs. It is supposed that the reason of the formation of the abovesaid particularities is the variation, within the reaction front, of the quantitative ratio of oxygen atoms to oxide-forming atoms with the reaction front propagation. The microadditions of the third elements (Ti into Cu-Al alloy, Be, Ti, Zr into Cu-Si alloy), while affecting the nucleation process, increase the degree of the precipitates dispersion. This affects the reacting elements diffusion and, therefore, the character of the structure formation