Inside a glass-melting furnace, refractories operate under continuous chemical and mechanical pressures. When failure occurs, it is rarely the result of a single weakness. More often, it reflects the combined effects of chemical corrosion and mechanical stress—the two processes that mainly govern how refractories age in service.

The effects of refractory aging are typically far from uniform because corrosion behavior changes depending on where and how the refractory is exposed.¹