What is the term for the process where viscous materials undergo a chemical reaction to form a rigid structure?

The term "curing" refers specifically to the process where viscous materials, such as certain types of adhesives, resins, and coatings, undergo a chemical reaction that transforms them from a liquid or semi-liquid state into a solid, rigid structure. This transformation typically involves cross-linking of the molecules within the material, which enhances properties such as strength and durability.

Curing can occur through various mechanisms, such as the addition of catalysts, exposure to heat, or moisture, depending on the specific material being used. This is crucial in low observable aircraft structural maintenance, as proper curing of materials ensures their effectiveness and longevity in applications where maintaining low observability is essential.

In contrast, while "setting," "hardening," and "fusing" may involve changes in the state or consistency of materials, they do not specifically denote the chemical reaction aspect intrinsic to curing. Setting may refer to the initial stage of transitioning from viscous to solid but does not imply the transformative chemical reaction. Hardening generally indicates a firming of a material but can occur without a chemical reaction. Fusing tends to describe the process of joining materials together, often through heat, rather than a transformation of a viscous material into a solid form.