General Information ZIRCAR Ceramics’ RNKO-HD Alumina-Silica board is a uniquely strong, low-density combination of 1260oC rated Al2O3-SiO2 (RCF) fibers and a stabilized inorganic amorphous SiO2 binder. RNKO-HD is 100% organic free. At 0.85 g/cc (53 pcf) density, RNKO-HD has been developed for applications where a combination of low thermal conductivity and the abilty to withstand high compressive loads at [...]