Fracture behavior and thermal shock resistance of alumina-spinel castables-Effect of added fused zirconia-alumina. Issue 13 (September 2020)

• Record Type: Journal Article
• Authors: Yu, Renhong; Zhang, Liyuan; Zhang, Xiaohui; Liu, Pengcheng; Qi, Haoyuan; Wang, Junhao; Liu, Xinhong
• Is Part Of: Ceramics international. Volume 46:Issue 13(2020)
• Page Start: 20732
• Page End: 20741
• Publication Date: 2020-09
• Subjects: Fracture behavior -- Thermal shock resistance -- Alumina-spinel castables -- Fused zirconia-alumina -- Wedge splitting test; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.05.016
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: This study aims to clarify the influence of fused zirconia-alumina (FZA) on the fracture behavior and thermal shock resistance (TSR) of alumina-spinel castables, and discover the relationship between toughness parameters and TSR. Alumina-spinel castables with different FZA contents (0, 2, 4, 6, 8, and 10 wt.%) were prepared using tabular alumina, fused spinel, calcium aluminate cement, ultrafine alumina powder, and FZA as raw materials. The fracture behavior and TSR of alumina-spinel castables were determined by a wedge splitting test (WST) and a water quenching test, respectively. The results show that the flexibility of alumina-spinel castables can be significantly enhanced by introducing FZA. With increasing FZA content, the load-displacement curves change from typical brittle fracture behavior to non-linear fracture behavior. The flexibility parameter (ratio of GF /σNT ) of the castables increases from 8.3 μm to 13.6 μm when FZA content increases from 0 wt.% to 10 wt.%. The flexibility improvement of castables containing FZA can be attributed to the formation of microcracks caused by the transformation of ZrO2 . The TSR of alumina-spinel castables can also be significantly improved by adding FZA. The ratio of residual cold modulus of rupture (CMOR) of the castables increases from 12.3% to 34.2% when FZA content increases from 0 wt.% to 10 wt.%. The improvement in TSR can be attributed to a decrease in the stored elastic energy and a subsequent increase in the specific fracture energy of the castables. Generally, alumina-spinel castables with non-linear fracture behavior have good thermal shock resistance. There is a significant correlation between the flexibility parameter (GF /σNT ratio) and the ratio of residual CMOR; the correlation coefficient is 0.96.