Background

Typical features of ZIRCAR Zirconia’s Alumina Bulk Fiber Type BusterF include:

· Available in Two Different Forms

· Low Thermal Conductivity

· Highly Refractory

· Low Heat Storage

· Extreme High Temperature Stability

· 97% Pure Alumina

· Lightweight

· Available “Off the Shelf”

Figure 1. Zircar Alumina Bulk Fiber Type BusterF.

Product Overview

Zircar’s Alumina Bulk Fibers Type BusterF are Hi-Alpha alumina fibers available in two different forms, both having useful properties up to 1700°C. These polycrystalline fibers can be vacuum formed into rigid shapes, placed into cavities as loose fill insulation, or added to ceramic bodies and coatings for reinforcement. They are differentiated by fiber length but share the same fiber diameter and calcined chemical composition. Typically these fibers are 3 to 4 microns in diameter.

Properties

Typical properties of Zircar’s Buster alumina bulk fibers.

Property	BusterF	BusterF-10
Nominal Composition, wt%
Al2O3	97	97
SiO2	3	3
Organics	0	<3
Alpha Alumina, wt%	>50	>50
Melting Point, °C (°F)	2038 (3700)	2038 (3700)
Maximum Use Temperature, °C (°F)	1700 (3092)	1700 (3092)
Bulk Shipping Density, g/cc (pcf)	0.08 (5)	0.10 (6)
Fiber Density, g/cc (pcf)	3.4 (212)	3.4 (212)
Approximate Fiber Length, mm (in)	50-100 (2-4)	3-6 (1/8-1/4)
Mean Fiber Diameter, microns	3.5	3.5
Linear Shrinkage, % (1hr at 1538°C (2800°F))	2	2

Zircar’s BusterF fibers exhibit low thermal conductivity, low thermal mass and immunity to thermal shock. A minor addition of silica modifies the fiber's microcrystalline structure and acts as a grain growth inhibitor and prevents embrittlement that usually occurs in pure alumna after extended use at elevated temperatures. Zircar’s BusterF fibers resist attack in aggressive chemical environments due to its high purity & refractory nature. It is stable in vacuum, inert or reducing atmospheres.

Vacuum Formed and Rigid Refractories from BusterF Alumina Fibers

Buster F fibers yield a uniform body of 0.16 - 0.24 gm/cm³ (10-15 pcf) density, when vacuum formed from a water slurry. BusterF-10 fibers will produce higher density vacuum formed boards and cylinders. Silica, alumina and aluminum phosphate binders can be used to form rigid refractory thermal insulation products.

Zircar BusterF Fibers in Furnace Applications

Zircar’s Buster F fiber is useful as insulation packing in furnace spaces, around furnace sight tubes & ports and fill in expansion joints and masonry cracks