AbstractIt is demonstrated that the diffusion model proposed by Varotsos and Alexopoulos implicitely includes a correlation between diffusion energyHand entropySanalogous that deduced by Wert and Zener. For the impurity diffusion via vacancies this correlation betweenHandSis not correct. Thus, the model of Varotsos and Alexopoulos is not applicable to the impurity diffusion. For self‐diffusion the model roughly approximates the temperature function of the diffusion coefficientD0, however, it is unable to describe the curvature of the Arrhenius plot ofD