Sintering Al2O3-Cr composites made from micro- and nanopowders

This paper presents the results of studies on sintering Al2O3 - Cr composites of different chemical compositions (from 25 to 75 vol.% of each component). The factor analyzed was the influence of time (from 15 to 60 min.), temperature (from 1200-1600degreesC), pressure (0.5 and 30 MPa) and powder graining (for Al2O3 powders - 80nm or 1 mum) on the density of sinters obtained. It was found that nanopowder composites are characterized by a higher density (by about 1-2 %) than the micropowder composite, the remaining conditions of the process intact. Using the pressure of 30MPa allows obtaining of a definite sintering degree at a temperature of about 200degreesC lower than at a pressure of 0.5 MPa.