The pyrotechnic slowing-down composition on the basis of the modified mixture consisting of polymer and powder of metal, ammonium nitrate, an epoxide resin and chromate of barium is developed. In the development of recipes composition is determined the ratio between the oxidant and fuel, which could provide the stable combustion at low speed. Barium chromate was introduced into composition as the retarder and to reduce the burning rate. The resulting delay composition has a low sensitivity to friction and shock, do not require special storage and special vehicles for transportation, it has a high physical and chemical stability. The gas generator equipped with this delaying composition most suitable for processing bottom-hole zones of oil and uranium wells. It is shown that using methods of mechanochemical modification of components of heterogeneous condensed systems, it is possible to influence actively process of their combustion and to increase their effectiveness and completeness of use.