Increases in the strength of Si-additive mixture granules by presintering

In order to preserve a spherical granule shape in a porous sintered body, presintering technology was developed to enhance the strength of Si-mixture granules containing Y2O3–Al2O3–CaO as sintering additives prior to shaping. The fracture strength of the granules measured by a compression test was ≤0.2 MPa and ≤20 MPa for as-spray dried granule and presintered granules, respectively. Furthermore, the flowability of the presintered granules was retained by the presintering process done to 1300 °C.