Microstructure, Mechanical and Corrosion Resistance Behavior of SiO2f/SiO2 Composites for Coke Oven Hot Repair

Fused quartz bricks are frequently employed as hot repair masonry in coke ovens due to their exemplary high-temperature resistance, thermal shock resistance and mechanical strength. However, fused quartz bricks are prone to a crystallization transformation at elevate temperatures, whereby the amorphous silica gradually transforms into cristobalite. The volume effect can result in a number of undesirable outcomes, including the formation of cracks within the quartz brick, erosion of the brick, and, in extreme cases, the peeling off of the brick's surface. These effects have the potential to significantly impact the service life of the quartz brick. It is of the utmost importance to enhance the mechanical strength and corrosion resistance of fused quartz bricks in order to extend the lifespan of coke ovens. This paper examines the impact of varying quartz fiber (SiO_2f) contents on the mechanical properties and high-temperature alkali erosion resistance of fused quartz bricks. The findings illustrate that SiO_2f/SiO₂ composites exhibit augmented resistance to high-temperature erosion. The incorporation of quartz fibers into the composite structure has been observed to impede the erosion of alkali salts, as well as subsequent penetration. This has resulted in a notable reduction in the concentration of the K element, with a decrease of 4.86% observed. The composites doped with 0.5 wt% of quartz fibers exhibited the highest flexural strength (28.68 MPa), representing a 26.7% increase in flexural strength of SiO_2f/SiO₂ composites relative to those without quartz fibers doped.