ZIRCAR Ceramics’ Alumina Rigidizer/Hardener Type AL-R/H is single-part water-based suspension of colloidal alumina hydrate particles. AL-R/H is used as a binder, rigidizer or surface hardening agent in applications with temperatures as high as 1700°C (3092°F). It is nonflammable and is not affected by freezing.
As a hardening agent, AL-R/H is easily applied by brushing, rolling, dipping, sponging or spraying. Coverage depends upon the surface area of the material being treated and the level of hardness desired. One gallon typically covers 100-150 ft² of ceramic fiber board if applied to an absorption depth of 2-3mm (0.08-0.13in.). Stiffening and hardening of treated surfaces occurs upon drying. Curing of treated parts to 600°C (1110°F) is sufficient to remove chemical water from the high-surface-area hydrated alumina.