Spark Plasma Sintering (SPS) is a newly developed rapid sintering technique with great potential in achieving fast densification results and minimising the undesired grain growth process and sintering time. It is proven by obtained experimental data, that enhanced sinterability of powders subjected to SPS mainly associated with particles surface activation and increased diffusion rates on the contact zones caused by applied pulse current. Application of rapid heating results in bypassing

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... perature regions where surface-transport-controlled sintering is dominant. This can preserve the powder surface area to temperature levels where bulk transport is significant. However, the nature of activation effects, and especially in regard to acceleration of diffusion processes, is not clearly established. A lot of research works report the occurrence of plasma during the application of pulse electric current. Interaction of particles surface layers with reactive chemical species of plasma are interpreted as the key factors in sintering mechanism. However, the appearance of thermal plasma during SPS process is a controversial issue and particle-plasma interaction is a complex phenomenon. It is clear that significantly more work is required for clear understanding of the nature of the activation effect or effects caused by pulse electric current.