Spark plasma sintering of hydrothermally derived ultrafine Ca doped lanthanum chromite powders

摘要

Lanthanum chromite nano-particles, with a composition of La_(0.9)Ca_(0.1)CrO_3 and La_(0.8)Ca_(0.2)CrO_3, were produced by 1 h of hydrothermal reaction at 400 and 425 deg C respectively. The sintering of the powders was conducted using a spark plasma apparatus over the temperature range 1300-1550 deg C for 1 min with a constant loading pressure of 45 MPa. Additional sintering experiments using conventional firing were carried out for comparison. Fully densified (98 percent r.d.) lanthanum chromite pellets with fine equiaxial grains 2.3 mum in size were obtained using the SPS (spark plasma sintering) method. In contrast, a maximum relative density of 97 percent was produced using La_(0.8)Ca_(0.2)CrO_3 sintered conventionally at 1400 deg C for 300 min, and the average grain size of the resulting sintered sample was 6 mum.