Die Einwirkung der Te- und s-beimischungen auf die kristallisationskinetik des glasigen selens

The influence of tellurium (up to 6 at %) and sulphur (up to 2 at %) admixtures on the rate and on the activation energy E_Kr of vitreous selenium crystallization was investigated by means of calorimetric method. The results satisfy the Avrami's aquation x = 1 ?exp(?L · c_Kr · τ^z). The exponent z and the product z·E_Kr, are increased due to addition of tellurium admixtures, while the value L · c_Kr is decreased. The admixtures of sulphur decrease the exponent z, but have not any influence on the values L · c_Kr and z · E_Kr.Probably the tellurium admixtures increase the rate of the crystallite growth and the number of the crystallization centres, what accelerates the process. But at the same time, formation of the stable nucleus is prolonged. Sulphur admixtures do not change the contents of the small rings and of the hexagonal regions in vitreous selenium. They produce deffects in the chain structure, what retards the crystallization.