Improvement in the properties of low carbon MgO-C refractories through the addition of graphite-SiC micro-composite

• Published in: Journal of the European Ceramic Society Vol. 42; no. 4; pp. 1804 - 1814
• Main Authors: Raju, Mula, K., Sarath Chandra, Mahata, Tapas, Sarkar, Debasish, Maiti, Himadri Sekhar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2022
• Subjects: Fibrous structure of the SiC; Graphite-SiC micro-composite; Hot strength; MgO-C refractory; Oxidation resistance; Strength factor; Fibrous structure of the SiC; Oxidation resistance; Strength factor; Hot strength; Graphite-SiC micro-composite; MgO-C refractory
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2021.11.049

[Display omitted] •Graphite–SiC microcomposites were synthesized via carbothermal reduction route.•SiC reinforced refractories exhibited much improved properties over the standard.•A low oxidation rate of 1.58 × 10−5 cm2 s-1 was observed in SiC based refractories.•Hot strength was enhanced from 42.3 to 57.4 kg cm−2 in SiC fortified refractories.•Designing strength factor above 0.13 with SiC forms a flaw tolerant microstructure. Graphite–SiC micro-composites have been prepared in–house by carbothermal reduction process. Controlling the process parameters including the weight ratio of SiO2 to graphite as well as carbothermal reduction temperature during the micro-composite preparation favors the homogeneous formation of SiC with preferred morphologies like ribbons and whiskers/fibers. The micro-composite modified low carbon MgO-C refractories have exhibited significantly improved bulk properties over the standard composition. To understand the beneficial role of SiC reinforcement on hot strength performance under air oxidizing conditions, we propose a scaling parameter known as strength factor (fs) based on the ratio of hot strength (HMOR) to cold strength (CCS). Correlating the strength factor data (fs) with oxidative damage provides new insights into the reinforcing effects of distinct SiC morphologies in this new class of micro-composite fortified refractory systems over the standard compositions.