The diffusion of Zn was studied, at temperatures ranging from 400 to 900C, by using scanning electron microscope and radiotracer methods. A simple diffusion model was used to analyze the results. The variation (10-11 to 10-9cm2/s) in the diffusion coefficients (figure 22), together with other experimental data, clearly indicated that a complex multi-diffusional process had to be taken into account. It was shown that, when one surface of a slice was prepared for diffusion annealing with a pure Zn source, at temperatures ranging from 550 to 700C, the slice took on a curved shape. This behavior did not occur outside of this temperature range. This was due to a differential stress which was set up across the slice and which was relieved by brittle fracture at temperatures below 600C, or by ductile slip at higher temperatures.

N.Aslam, E.D.Jones, T.C.Q.Noakes, J.B.Mullin, A.F.W.Willoughby: Journal of Crystal Growth, 1992, 117, 249-53