Here are some common materials used in ceramic fiber pipe insulation:

Ceramic fibers

Fine fibers made from materials such as aluminosilicate, magnesium silicate, or zirconia used as the primary insulation material.

Silica

Highly refined silicon dioxide used to enhance insulation properties while controlling shrinkage. Commonly known as silica powder.

Kaolin

A clay mineral known as kaolinite that helps impart strength and resistance to cracking under thermal expansion/contraction.

Starch

A binder and burnout material made from plants that holds the fiber structure together during heating but then decomposes, leaving an open ceramic structure.

Proprietary binders

Specialized blends of inorganic chemicals that add bind ceramic fibers together without degrading insulation performance.

Glass fiber

May be added in some products to improve tensile strength without compromising heat resistance.

Enamel or vitreous coatings

Provide a water-resistant/vapor barrier on the outer skin of pipe wrap sections where exposed to moisture.

The exact ceramic fiber formulations vary between manufacturers but all utilize heat-resistant ceramic-based materials to protect pipes operating at very high temperatures.