Zirconia Alumina

Fused ≈ 2000°C 25% / 40% ZrO₂ High Toughness Self-Sharpening

An electro-fused alumina-zirconia abrasive grain produced by melting alumina and zirconia at around 2000°C in an electric arc furnace, then rapidly quenching, crushing, and sizing. Its fine, homogeneous microstructure delivers high toughness, wear resistance, and self-sharpening performance for bonded and coated abrasives.

TypesAZ40 (40% ZrO₂) & AZ25 (24% ZrO₂)
Density4.35 – 4.65 g/cm³
Knoop Hardness1620 – 1780 kg/mm²
ColorGrey
UseBonded & coated abrasives

Request a Quote Technical Data

Product Overview

Zirconia Alumina (fused alumina-zirconia) is an electro-fused grain made by melting alumina and zirconia raw materials at approximately 2000°C in an electric arc furnace. A controlled quenching, crushing, and resizing process yields precise grain dimensions and a fine, uniform microstructure.

The result is an extremely tough, wear-resistant, anti-friable grain with self-sharpening behaviour — ideal for heavy-duty grinding and cutting where durability and consistent cut rate matter.

Product Types

40% ZrO₂ · Eutectic

AZ40

AZ40-F — engineered for bonded abrasives, from organic-bonded to vitrified-bonded; high material-removal rate, long life, fine finish.
AZ40-P — engineered for coated abrasives; unique fracture behaviour for precise, high-speed cutting and longer-lasting belts, sandpaper, and flap discs.

24% ZrO₂ · Dense & Blocky

AZ25

AZF25 — dense, durable grain for heavy-duty bonded abrasives.
AZS25 — extra-tough, blocky grain re-shaped from AZF25 for extra-duty bonded abrasives in steel conditioning.

Characteristics

Property	AZ40	AZ25
Structure	α-Al₂O₃, m.t–ZrO₂	α-Al₂O₃, m.t–ZrO₂
Absolute Density	4.65 g/cm³	4.35 g/cm³
Knoop Hardness	1620 kg/mm²	1780 kg/mm²
Melting Point	1880°C	1950°C
Color	Grey	Grey

Chemical Analysis

Component	AZ40	AZ25
Al₂O₃	59%	75%
ZrO₂	40%	24%
SiO₂	0.10%	0.20%
Fe₂O₃	0.20%	0.20%
Na₂O	0.08%	0.08%
TiO₂	—	0.15%

Typical Uses

AZ40-F · Bonded Abrasives

AZ40 F-Grade

Cutting stainless and high-alloy steels
High-pressure rough grinding & snagging
Snagging of alloyed steel castings
Large-diameter cut-off wheels
Steel conditioning
ID & OD grinding, centerless, disc, segments, track grinding

AZ40-P · Coated Abrasives

AZ40 P-Grade

Sanding stainless steels (e.g. Cr-Ni steel)
Heavy-duty machining of high-alloy steels
Sanding of parquet floors
Belts
Flap discs
Vulcanized fiber discs

AZF25 · Heavy-Duty Bonded

AZF25

Large-diameter cut-off wheels
Hot-cutting operations
High-pressure rough grinding
Hot-pressed wheels
Rail grinding (high force)
Blasting

AZS25 · Extra-Duty Bonded

AZS25

Cut-off wheels
Pressure blasting
Hot-cutting operations
High-pressure rough grinding
Hot-pressed wheels
Rail grinding (high force)

Packaging

Standard

Bags or jumbo bags

Grain Sizes

To FEPA / customer grit specs

Custom

Packing options on request