Fiberfrax® Durablanket® Z

Zirconia-reinforced RCF ceramic-fibre blanket for elevated temperature stability, classification 1400°C

---

Fiberfrax® Durablanket® Z is specified for process and furnace applications where standard RCF grades such as Durablanket® S have run out of thermal headroom. Typical placements include the hot face of industrial combustion chambers, burner outlets, kilns rated to the Z temperature class, high-thermal barriers in metallurgy, and refractory assemblies that see cyclic peaks above 1300°C. Relative to Durablanket® S, the Z variant shifts the usable range one temperature class upward. Chemically the fibre is an Al₂O₃-SiO₂-ZrO₂ system (28–32% Al₂O₃, 52–56% SiO₂, 14–18% ZrO₂); the zirconia addition acts as a crystallisation suppressor and slows the formation of mullite and cristobalite under cyclic heat, so the fibre matrix retains its dimensional stability and flexibility for longer service life. Classification temperature is 1400°C, melting point approximately 1740°C, and mean fibre diameter 3.25 μm. The fibre is spun and then needled into a binder- and lubricant-free mat. RCF fibres fall under a different regulatory regime than AES (no Note Q exemption) — handle per current RCF guidelines.