What is the term for the loss of firebrick through cracking and subsequent breaking or crumbling?

The term for the loss of firebrick through cracking and subsequent breaking or crumbling is spalling. This process occurs when firebricks are subjected to thermal cycles, leading to the expansion and contraction of the material. Over time, these repeated thermal stresses can cause the outer layer of the firebrick to crack and break away, resulting in the loss of material.

Spalling is particularly important in the context of kilns and furnaces where firebricks line the interior surfaces to withstand high temperatures. The effectiveness of these bricks as insulators and protectors is compromised when they spall, potentially leading to failures in thermal efficiency or structural integrity.

The other terms do not accurately describe the specific phenomenon of cracking and loss of material from firebricks. Firing refers to the process of heating ceramics or refractories to set their shape, while erosion pertains to the gradual wearing away of materials due to mechanical processes such as wind or water action. Corrosion is the chemical deterioration of materials due to reactions with their environment, typically involving metals and moisture or chemicals, rather than the physical degradation seen with spalling.