4. Joining materials

We have just seen that spark plasma sintering is an emerging technique for shaping nanopowders and refractory materials (metals, ceramics). There is another field in which this material shaping technique appears to hold great promise, and that is the preparation of multimaterials (combinations of materials) or gradient materials. Indeed, the extreme speed of the forming cycle will limit interdiffusion or reaction between two adjacent materials. Gradient (laminated) materials can also be prepared by SPS, significantly enhancing the mechanical properties of hydroxyapatite....