Machinable Ceramics BN-ZS combines the best properties of hBN with the non-reactivity and strength of zirconium oxide and silicon carbide. Most commonly used as Boron Nitride Break Rings on horizontal continuous casters, its excellent thermal, chemical, electrical, abrasive, and machining properties allow for a variety of molten metal contact applications.

BN-ZS is composed of hard ZrO2 particles and soft BN flakes evenly dispersed in a borosilicate glass matrix. It has excellent wear resistance, non-wetting, high thermal conductivity, and excellent high-temperature strength. BN-ZS is ideal for molten metal applications such as cast break rings, metal atomizing nozzles, and thin strip cast side baffles. Other potential areas for BN-ZS include wear parts such as guides and rollers in various glass and light metal baths.

Boron Nitride Break Ring Basic Information & Materials


BNH99, BN99, BN-ZS, BN-AlN



Melting Point

2700 °C


White/White Graphite/Greyish Green

Density, g/cm3

1.6~2.9 g/cm3

Solubility in H2O


Electrical Resistivity, Ω·m


Boron Nitride Materials




Hot pressed at high temperature (1900℃).
Excellent corrosion resistance and thermal conductivity, Limited wear resistance
Self-bonded and high purity (>99%)


General-purpose material
Bonded by boric oxide


Calcium borate bonded boron nitride
Enhanced moisture resistance


BN 60%, SiO2 40%


BN 40%, SiO2 60%


BN-45%, Zr2O3 45%



Boron Nitride Break Ring Advantages & Applications:

-Low wettability to molten metal

-Relatively high thermal conductivity and low thermal expansion

-Excellent thermal shock resistance

-Good chemical inertness

-Excellent machining properties

-Excellent lubrication performance – low friction coefficient

-High temperature material

-excellent corrosion resistance and electrical resistance

Boron nitride Break rings are widely used in the metal casting industry. We offer different boron nitride materials and boron nitride composite materials that match different metal alloys, which can extend the life of the metal.


As a ceramic material, boron nitride is quite fragile in a lot of cases. Our Hot-Pressed Boron Nitride Break Ring is carefully handled to minimize damage during storage and transportation. Suitable outer boxes and inner cushioning materials are used for BN products, vacuum packing is also engaged for some of the parts.