R28 Refractory Coating is a mixture of alumina and silica that is used for treating surfaces of ceramic fiber products to form a protective surface to improve the resistance to chemical attack, mechanical wear, high gas velocity.
Increase surface hardness of ceramic fiber blanket and board
Increase resistance to erosion of high velocity gas
Bond composites and laminates
Easily applied by brushing, dipping, rolling or spraying method.
Thermal shock resistant
Upper using temperature 2800°F
Surfaces to be coated should be free of any grease and oil. Surfaces with high water absorption should be wetted with water before using the coating
Mix coating well because material may settle while transported or sitting.
Coating can be applied by brushing, rolling, and spraying (by add water to a suitable viscosity). Respiratory protection and ventilation are required when applied by spraying.
Coating receives its hardening action by air-drying for about 24 hours from the removal of physical water. The curing process can be accelerated by heating. Curing is a function of the coating thickness, size, and geometry, as well as humidity. However, the coating dried at room temperature is not water-proof. Final curing should be done at high temperature (>1000 °F).
One pound of coating can cover an area of approximately 5-30 square feet, depending on how to use it.
After curing, R28 coating will render a hard surface without completely hardening the interior of the ceramic fiber body.