Salient features of SrO doping in Al₂O₃-5 wt.% ZrO₂ reaction sintered composite ceramics

SrO doping (concentration range approximate to 5000 ppm) in Al2O3-5 wt.% ZrO2 ceramic system offers the unique features of reaction sintering to produce dense composite ceramics of finer sized matrix grains with nearly homogeneous multiphase microstructures for improving the room-temperature structural properties (e.g. hardness, strength, and toughness). Reaction sintered product, the strontium hexaluminate (SrAl12O19) forms in-situ as an interphase boundary in the ceramic composite during the stages of reaction sintering. This creates new low energy Al2O3/SrAl12O19 chemical interfaces in the matrix of alumina. Typical issues based on prominent role of in-situ formed low energy Al2O3/SrAl12O19 interfaces on the properties of reaction sintered composite ceramics (SrO doped Al2O3-5 wt.% ZrO2) are discussed. (C) 2020 Elsevier B.V. All rights reserved.