AN INVESTIGATION OF THE VACUUM EVAPORATION OF ZINC FROM SOLID SOLUTIONS

The loss of zinc from solid solution in copper and nickel by evaporation in vacuo results both in the reduction of the external dimensions of the alloy specimen and in the production of internal porosity. The size of these pores which are without interconnection increases with increasing zinc loss. Further heating after dezincification causes a reduction in the pore size. In the early stages of dezincification the pores appear to be bounded by specific lattice planes. It has been shown that these planes are probably the (lll) planes, which are the usual slip planes of the lattice. The diffusion coefficients obtained for zinc in {alpha} brass agree in value with those obtained by other methods. A value for the diffusion coefficient of zinc in {alpha} nickel zinc solid solution his also been obtained. The activation energies estimated from these diffusion coefficients are of the order expected and are in fair agreement with values previously recorded. (auth)