Solid Boron Nitride Grade
AX05 is one of the highest purity hexagonal boron nitride solids
available and a wise choice for applications where corrosion
resistance is more important than wear resistance. It is a
diffusion bonded ceramic and does not depend on B2O3
to other binders for mechanical integrity and, consequently, it is
non-wet by almost all molten metals. This ultra purity advantage
allows for applications and uses not provided by other hot pressed
boron nitride solids, such as crucibles for high-purity molten
metals. Commonly used in applications that demand very high
thermal conductivity such as nozzles with small orifices.
Key Properties
Chemically - Grade AX05 is extremely inert and
non-wet by many molten materials such as metals, glasses, halide
salts and other reagents. The chemical stability allows Grade AX05
to provide a stable, non-reactive material for nozzles, feed-
throughs, crucibles and supports.
Thermally
- Grade AX05 has minimal thermal expansion, high thermal
conductivity and use temperature in certain inert atmospheres over
2000°C. Thermal shock stability is excellent over a wide range of
use temperatures.
Mechanically - Grade AX05
yields increasing relative strength vs. temperature. This
important feature provides higher temperature performance to
applications previously unattainable with B2O3
to other bonded boron nitrides.
Electrically
- Grade AX05 is transparent to microwave energy. It also provides
high resistivity and dielectric strength with a low loss tangent
and dielectric constant. These characteristics make AX05 an
excellent material for high power, low loss insulators, containers
and fixtures.
Machinability - Grade AX05
can be machined to extremely close tolerances using standard high
speed “tool steel” equipment. Machining by grinding may be used if
preferred or stringent tolerances are required. Threads can be
machined using taps and dies. Cutting oils and coolants should not
be used for any reason.
Applications
-
High temperature electrical insulators and vacuum furnace
supports which require electrical resistivity, high
temperature strength, thermal shock resistance and low
chemical reactivity.
-
Crucibles and containers for high purity molten metals
Insulators and source fixtures for ion implantation systems
which require high temperature purity and electrical
insulation.
-
Setterplates for the processing of other advanced materials
which require stable, inert surfaces.
-
Nozzles for powdered metal spraying.
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Typical
Properties
|
|
Binder: |
None |
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Binder Melting Point: |
None |
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Maximum Use Temperature:
|
|
Oxidizing: |
850°C |
|
Inert: |
>2000°C |
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Specific HeatJ/g°C: |
0.35 |
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Dielectric Strength: |
1000 V |
|
Pressing Direction (Para
(Perp)
|
|
Resistivity Ohm-cm RT: |
>1014 (1015) |
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Loss Tangent @ 8.8 GHz: |
.0012 (.0003) |
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Dielectric Constant @ RT: |
4.0 (4.0) |
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Thermal Conductivity
|
|
(W/m/L) @ 25°C: |
78 (130) |
|
Thermal Expansion
Coefficient |
|
(RT to 1500°C) (in/in/°C x 10-6):1.0
(0.3) |
|
|
Flexural Strength (psi)*
|
|
@ 25°C |
2600 (3100) |
|
@ 1500°C |
6200 (11000) |
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Density (g/cc minimum): |
1.85 |
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% Open Porosity: |
12.57% |
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Oxygen - max.: |
1% |
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Carbon - max.: |
0.02% |
|
Calcium - max.: |
0.04% |
|
Other Impurities - max.: |
0.05% |