High purity White fused alumina F100 for thermal insulating sand

High-purity white fused alumina F100 (white corundum F100) is used as a thermal insulating sand/anti-stick padding powder for ceramic sintering. Its key features are high purity and low impurities, high temperature resistance, chemical inertness, uniform particle size, good support and isolation properties, reusability, effective anti-sticking, anti-fouling, dimensional preservation, and easy cleaning.

High purity + low impurities, no contamination of the body/glaze

– Al₂O₃ ≥ 99.5%, α-Al₂O₃ ≥ 95%, high whiteness, free of free silicon/iron/heavy metals.

– Low sodium (Na₂O ≤ 0.26%), low silicon (SiO₂ ≤ 0.1%), low iron (Fe₂O₃ ≤ 0.05%), avoiding the formation of low-melting-point glass phases at high temperatures, preventing sticking to the body, glaze seepage, and yellowing.

– No free SiO₂, no silica dust hazards, making the workshop safer.

Ultra-high refractoriness and thermal stability, no deformation at high temperatures

– Melting point ≈ 2050℃, refractoriness ≥ 1850℃, load softening temperature ≥ 1770℃, suitable for high-temperature sintering at 1600–1800℃.

– Extremely low coefficient of thermal expansion (≈8×10⁻⁶/℃), no cracking or peeling under rapid heating and cooling, good dimensional stability, protecting the tolerances of precision ceramics.

– High high-temperature hardness retention (maintains 30%+ of room temperature hardness at 1200℃), no collapse or pulverization under long-term load.

Strong chemical inertness, does not react with the body/kiln furniture

– Resistant to acids and alkalis, resistant to glaze corrosion, does not react with the ceramic body, glaze, or kiln furniture in a solid-phase manner, avoiding sticking, peeling, pinholes, and color difference.

– Inert surface prevents ceramic parts from sticking together, making them easy to shake off and clean after sintering, leaving a smooth, residue-free surface on the green body.

F100 Particle Size Suitability, Excellent Isolation and Support Effect

– F100 particle size: 125–150μm, multi-faceted particles with good flowability, even spreading, multiple support points, and uniform stress distribution, preventing green body deformation and indentation.

– Moderate particle size: not too fine (less dust, no air leakage), not too coarse (no pits, easy leveling), suitable for large-area/stacked sintering.

– Bulk density ≈ 1.5–1.8g/cm³, breathable and heat-insulating, reducing thermal shock and improving sintering consistency.

Typical Application Scenarios

– Electronic ceramics (alumina ceramics, piezoelectric ceramics, ceramic substrates)

– Structural ceramics (ceramic cutting tools, bearings, plungers, seals)

– Special ceramics (zirconia, aluminum nitride, silicon nitride)

– Glazed ceramics/high-temperature glaze sintering isolation

Typical physical properties:

Hardness:	Mohs:9.0
α-Al2O3 conversion ratios	Min 95%
Maximum service temperature:	1900 centigrade
Melting Point:	2250 centigrade
Specific Gravity:	3.95g/cm3
Volume density	3.6g/cm3
Bulk density(LPD):	1.55-1.95 g/cm3
Color:	White
Particle shape:	Angular

Typical Chemical composition:

Item	Guarantee Value	Typical Value
AL₂O₃	≥99.6%	99.68%
NA₂O	≤ 0.2%	0.18%
SiO₂	≤ 0.1%	0.070%
Fe₂O₃	≤ 0.05%	0.041%

Grit size:

Grit	Sieve1	Sieve2		Sieve 3		Sieve 3 and Sieve4		Pan
Grit	100%Passing Mesh	Test Mesh	Max. Residue %	Test Mesh	Min. Residue %	Test Mesh	Min. Residue %	Max.3% Passing Mesh
WFA F24	16	20	25	25	45	25 30	65	35
WFA F30	18	25	25	30	45	30 35	65	40
WFA F36	20	30	25	35	45	35 40	65	45
WFA F40	25	35	30	40	40	40 45	65	50
WFA F46	30	40	30	45	40	45 50	65	60
WFA F54	35	45	30	50	40	50 60	65	70
WFA F60	40	50	30	60	40	60 70	65	80
WFA F70	45	60	25	70	40	70 80	65	100
WFA F80	50	70	25	80	40	80 100	65	120
WFA F90	60	80	20	100	40	100 120	65	140
WFA F100	70	100	20	120	40	120 140	65	200
WFA F120	80	120	20	140	40	140 170	65	230
WFA F150	100	140	15	170 200	40	170 200 230	65	325
WFA F180	120	170	15	200 230	40	200 230 270	65
WFA F220	140	200	15	230 270	40	230 270 325	60