[en] Zinc diffusion effect on phase formation and structural changes in YBa₂Cu₃O_7-y is studied. It is stated that rhombic phase is presented as a result of zinc diffusion alloying of the samples, but therewith occurence of tetragonal phase in matrix independent on annealing temperature, which quantity grows by increase of annealing temperature (150-500 degC) takes place. On the basis of the temperature dependence of the lattice parameters coefficients of linear expansion of YBa₂Cu₃O_7-y samples, diffusion-alloyed by Zn are determined