Densification mechanism involved during spark plasma sintering of a codoped α-alumina material: Part I. Formal sintering analysis

Spark plasma sintering (SPS) of a codoped alpha-alumina powder has been investigated at temperatures between 850 and 1200 degrees C. The grain size versus relative density trajectory showed a significant grain growth as soon as the residual porosity closed. The densification mechanism was determined by anisothermal (investigation of the heating part of a SPS run) and isothermal methods. It was proposed that grain-boundary sliding, accommodated by oxygen grain-boundary diffusion, governed densification.