Interaction of CdTe with water solutions of nitric acid

It was established that the degree of dissolution of CdTe in water solutions of HNO/sub 3/ at 25/degrees/C can be judged either from the accumulation of products of reduction of nitric acid or the diffusion of the products of oxidation from the surface of the dissolving plate into the bulk of the solution. Raising the temperature of the solutions (above 50/degree/C) and the rate of mixing leads to the fact that the process begins to be limited by the rate of the surface chemical reaction with an apparent activation energy of 75-80 kJ/mole. A film consisting of Te, TeO/sub 2/, and possibly CdTeO/sub 3/ with a thickness of the order of 1 ..mu..m forms on the surface. The formation of the film under the action of nitric acid is explained by the transfer of Cd/sup 2 +/ ions of cadmium telluride into solution and oxidation of Te/sup 2 -/ to Te/sup 0/ and Te/sup 4 +/. On the whole the heterogeneous chemical interaction of CdTe with HNO/sub 3/ can be regarded as a sum of the conjugate processes of anodic dissolution of tellurium and cathodic reduction of nitric acid.