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Machinable Ceramics
Combat® Boron Nitride -- machinable ceramics solve problems that could not possibly be tackled with other ceramics 
Boron Nitride machinable ceramic is made by hot pressing Boron Nitride powders at high temperature and pressure. Combat Boron Nitride can easily be machined into rods, bars, plates and even intricate custom shapes.
The unique combination of highly exceptional thermal, physical and chemical characteristics of Combat Boron Nitride ceramic makes it ideal for solving tough challenges in a wide range of industrial applications.
- Excellent thermal shock resistance
- High electrical resistivity
- High thermal conductivity
- Good chemical inertness
- High temperature material
- Excellent lubricating properties -- low coefficient of friction
- Non-wetting (without oxidation)
- High dielectric breakdown strength
- Excellent machinability
Combat® BN Machinable Ceramics, Grade AX05
The best in its class, Combat® Machinable Ceramics Grade AX05 is the highest purity hBN available at 99.7%+. With its high purity, it offers the highest temperature resistance in excess of 2000ºC in inert or vacuum environments, while maintaining its outstanding electrical insulator properties at a dielectric strength of >40kV/mm. This makes it an excellent choice for applications where high temperature capabilities and corrosion resistance are important.
AX05 is a unique, binder-less ceramic with exceptional thermal conductivity and thermal shock resistance. Its high purity makes it exceptionally suitable for applications where other hBN ceramics fail - crucibles for high-purity molten metals, nozzles for specialty alloys, insulators for high temperature etc.
Combat® BN Machinable Ceramics, Grade A
Combat® Machinable Ceramics Grade A uses B2O3 binder system to add mechanical strength to hot pressed hBN. One of the legacy products since the scientific community discovered the benefits of hot pressed hBN, Grade A is specified into applications from a long time ago. Grade A offers a practical choice for high temperature insulators, kiln furniture, and general purpose applications, and continues to finds new applications.
Due to the hygroscopic binder system, care must be taken during storage and use to avoid exposure to moisture.
Combat® BN Machinable Ceramics, Grade HP
Combat® Machinable Ceramics HP Grade uses calcium borate binder system. It is particularly useful for applications where low thermal expansion, high thermal shock resistance, and increased spall resistance is required. A great alternative for minimal moisture exposure due to its binder system, Grade HP is Saint-Gobain’s workhorse hBN grade sold in applications worldwide.
Like all other hBN grades offered by Saint-Gobain, both HP and HPL are easily machinable to intricate shapes with precise tolerances.
Combat® BN Machinable Ceramics, Grade M & M26
Combat® Machinable Ceramics Grade M and M26 are unique ceramic composites of hBN in a silica matrix, offered only by Saint-Gobain. Silica (SiO2) binder system contributes to its excellent moisture/thermal shock resistance. These grades can operate up to 1400°C,
M26 Grade has 60% hBN and 40% semiconductor grade SiO2, whereas M has 40%hBN and 60% semiconductor grade SiO2. M26 Grade has an edge in applications where better mechanical strength is required. M has an advantage in applications where higher thermal conductivity and moisture resistance is required.
While both Grades M and M26 are both thermally excellent materials, the most important features these grades offer is the electrical properties - high dielectric strength (>40KV/mm) along with a low dielectric constant k (<4), making them exceptionally useful in microwave environments in the GHz ranges. These grades have successfully passed MIL-I-10A grade of L542 test, a procedure requiring immersion in water for 48 hours prior to testing at elevated frequencies.
Combat® BN Machinable Ceramics, Grade ZSBN
Machinable Ceramic FAQs
First, the density of Boron Nitride is quite low (about 25% lower than alumina) and therefore the thermal mass is lower. Combined with the intrinsic thermal conductivity and zero thermal expansion of pure BN compared to other ceramics, it is virtually unaffected by rapid increases and decreases in temperature.
Our Boron grades are differentiated based on their composition, and therefore the specific properties they offer.
- AX05 is the industry leading highest purity grade that is commonly used for the toughest high temperature environments.
- Grade HP and A are our standard purity grades that offer better strength due to the binder phase.
- M and M26 are composites of BN and silica, commonly used in low-loss, high frequency shielding applications.
- ZSBN is a composite of BN, silica and zirconia, primarily used for direct metal contact applications.
Please contact us for help with grade selection for your application.
It is important to know the properties critical to your application, so parts are machined in appropriate direction. We encourage you clearly mark the desired directionality in your part drawing as well as PO. Without such specification, we cannot guarantee a particular directionality in your parts.
It is important to know the properties critical to your application, so parts are machined in appropriate direction. We encourage you clearly mark the desired directionality in your part drawing as well as PO. Without such specification, we cannot guarantee a particular directionality in your parts.
The parent Billet for our grades HP, M and M26 are 19” x 19” x 16”. Parent billet size for ZSBN is 19” x 19” x 6”. We can make parts that fit the envelop of the parent billet.
Due to the unique processing steps of our industry leading, highest purity grade AX05, we can make parts that fit the parent billet envelop of 19” x 19” x 16”, however the maximum wall thickness can not exceed 1.5”. For example, we cannot supply a rod 12” dia x 12” long, but we can supply a tube 12” OD, 10”ID and 12” long.
Our standard rods offered are --
| 1/4" | 3/8" | 1/2" |
| 5/8" | 3/4" | 7/8" |
| 1" | 1-1/4" | 1-1/2" |
| 1-3/4" | 2" diameter in 8" and 16" lengths | |
Lengths available for ZSBN are 6”.
| 1/4" x 1/4" | 3/8" x 3/8" | 1/2" x 1/2" |
| 5/8" x 5/8" | 3/4" x 3/4" | 1" x 1" |
| 1-1/2" x 1-1/2" | 2" x 2" | 2" x 2" cross section in 8" and 16" lengths |
Lengths available for ZSBN are 6”.
Our standard plates offered are --
| 5" x 6" | 5" x 12" | 10" x 12" |
| Available in thicknesses of 1/4", 1'2", 3/4" and 1" | ||
All plates are available in sawcut and finished tolerances.
Our standard tolerance for saw cut parts are +0.250 (+6.35mm) / -0.000 (0.0mm). Below are our standard tolerance guideline for machined parts, unless specified otherwise by our customers.
| Standard Tolerances | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Part Name | Diameter | Thickness | Length | O.D. | I.D. | |||||
| inches | mm | inches | mm | inches | mm | inches | mm | inches | mm | |
|
Wafers |
±0.015 | ±0.4 | +0.000 -0.004 |
+0.0 -0.1 |
n/a | n/a | n/a | |||
| Rods | +0.020 -0.000 |
+0.5 -0.0 |
n/a | +0.063 -0.000 |
+1.6 |
n/a | n/a | |||
| Discs (<1" thk) |
±0.020 | ±0.5 | ±0.010 | ±0.3 | n/a | n/a | n/a | |||
| Washer / Ring (disc w/I.D.; <1" thk) |
n/a | ±0.010 | ±0.3 | +0.063 -0.000 |
+1.6 -0.0 |
±0.020 | ±0.5 | ±0.010 | ±0.3 | |
| Tubes | n/a | n/a | +0.063 -0.000 |
+1.6 -0.0 |
±0.020 | +0.5 | ±0.010 | ±0.3 | ||
| Crucible | n/a | n/a | +0.063 -0.000 |
+1.6 -0.0 |
±0.020 | +0.5 | ±0.010 | ±0.3 | ||
| Width | Thickness | Length | ||||||||
| inches | mm | inches | mm | inches | mm | |||||
| Bars | ±0.010 | ±0.3 | ±0.010 | ±0.3 | +0.063 -0.000 |
+1.6 -0.0 |
n/a | n/a | ||
| Plates | ±0.010 | ±0.3 | ±0.010 | ±0.3 | +0.063 -0.000 |
+1.6 -0.0 |
n/a | n/a | ||
We have machining facilities inhouse that allow us to serve the customers that want machined components. We ask you send us your drawing or sketch with grade reference, directionality preference if any, and tolerance specifications. All Combat BN grades are easily machined and detailed surfaces, pockets, channels, grooves, holes, threads, etc. can be designed into the finished part.
The key feature to note is that Boron Nitride is machined dry - without coolants or lubricants. Most grades can be machined with standard carbide tip tooling. ZSBN requires diamond tipped tooling for most efficient operation.
Boron Nitride ceramic that has been sitting past its shelf life or has not been stored according to the storage guidelines may have picked moisture and will not perform as intended. The best way to use such material is by baking it to ensure it is restored to its original condition. We recommended soaking for 6 hours or longer in Nitrogen at the rate of 10C/min to 450°C, followed by cooling down at the same rate. If heated too quickly, spalling may take place. Other protecting atmosphere, such as Ar, can also be used. If the materials are in a protecting atmosphere, the soak temperature can be as high as 1200°C.
Boron Nitride ceramic that has been sitting past its shelf life or has not been stored according to the storage guidelines may have picked moisture and will not perform as intended. The best way to use such material is by baking it to ensure it is restored to its original condition. We recommended soaking for 6 hours or longer in Nitrogen at the rate of 10C/min to 450°C, followed by cooling down at the same rate. If heated too quickly, spalling may take place. Other protecting atmosphere, such as Ar, can also be used. If the materials are in a protecting atmosphere, the soak temperature can be as high as 1200°C.