THE TEMPERATURE-GRADIENT DIFFUSION COUPLE TECHNIQUE - AN APPLICATION OF SOLID SOLID-PHASE REACTIONS FOR PHASE-DIAGRAM IMAGING

The conventional isothermal diffusion couple technique was modified by introducing a temperature gradient parallel to the diffusion bands. With this technique it is possible to study phase equilibria and phase reactions as a function of both temperature and composition simultaneously. Portions of the phase diagram are essentially direct projections of the observed microstructures ("phase diagram imaging"). With the aid of microprobe techniques, an accurate determination of compositions of coexisting phases is possible. The features of this technique are discussed for portions of the TiN system and several further applications are suggested. © 1991.