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Features of Solid Boron Nitride - Grade HP
A completely unique material, Solid Boron Nitride solves problems that could not possibly be tackled with other compositions such as Al2O3 or SiC.
Solid Boron Nitride fights off temperatures over 2,000°C and, depending on the grade, carries a dielectric strength of nearly 1000 volts/mil. Hot pressed in billet form, Solid Boron Nitride can easily be machined into rods, bars, plates and even custom shapes.
The highly exceptional characteristics of Solid Boron Nitride make it ideal for fixture or jig materials for sealing or brazing operations in induction, vacuum and atmosphere furnaces; for molten metal crucibles; heat sinks and high temperature insulators.
Solid Boron Nitride - Grade HP
When higher thermal shock, more spall resistance and lower permanent expansion upon heating is required, Solid Boron Nitride Grade HP is a superior solid grade for formulations of <1,000°C. Additionally, Grade HP has ten times the moisture resistance of Grade A due to the addition of calcium which combines with boric oxide to form calcium borate. Commonly used for many light metal applications such as Al, Ti, Mg and Zn.
Properties of Solid Boron Nitride - Grade HP
The typical properties of Solid Boron Nitride Grade HP includes the following:
Chemically - High corrosion resistance due to the addition of boron nitride; ten times the moisture resistance of other boron nitride solids due to the addition of calcium which combines with boric oxide to form calcium borate.
Thermally - Excellent thermal shock resistance and conductivity - commonly used in many light metal applications such as Al, Ti, Mg, and Zn.
Electrically - Low dielectric constant material - also commonly used in many high temperature insulators.
Machinability - Like other grades of Boron Nitride, Grade HP can be machined using standard high speed 'tool steel' equipment. Machining by grinding may be used if preferred or stringent tolerances are required.
Applications of Solid Boron Nitride - Grade HP
Typical applications of Solid Boron Nitride Grade HP include:
- 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
- Radar components and antenna windows which require exacting electrical and thermal properties
- Setterplates for the processing of other advanced materials which require stable, inert surfaces
- Nozzles for powdered metal spraying
Physical Properties of Solid Boron Nitride - Grade HP
The physical properties of Solid Boron Nitride Grade HP is outlined in the following table.
Table 1. Physical properties of solid boron nitride grade HP
Properties
|
Description
|
Binder
|
Boric Acid
|
Binder Melting Point
|
550°C
|
MAXIMUM USE TEMPERATURE
|
|
Oxidizing
|
850°C (1150°C*)
|
Specific Heat at 700°C (J/g°C) 1.468
|
|
Dielectric Strength (V/mil)
|
1700
|
Hardness-Knoop (kg/mm2)
|
13.79 - 18.95
|
Pressing Direction
|
Para (Perp)
|
Resistivity Ohm-cm RT
|
>1014 (>1015)
|
Loss Tangent at 8.8 GHz
|
|
Dielectric Constant at RT
|
|
THERMAL CONDUCTIVITY
|
|
(W/m/K) at 25°C
|
27.0 (29.0)
|
THERMAL EXPANSION COEFFICIENT
|
|
(RT to 1500°C) (in/in.°Cx10-6)
|
2.95 (0.87)
|
FLEXURAL STRENGTH (psi)*
|
|
at 25°C
|
6430 (8730)
|
at 1500°C
|
1710 (2470)
|
Compressive Strength at 25°C
|
|
Density (g/cc minimum)
|
2.0
|
% Open Porosity
|
3
|
Oxygen %
|
5
|
B2O3 (%)
|
1
|
Calcium (%)
|
2.5
|
Other Impurities (%)
|
0.2
|
*Based on 4-pt bend test-Sample size = 51mm x 4mm x 3mm
This information has been sourced, reviewed and adapted from materials provided by Precision Ceramics.
For more information on this source, please visit Precision Ceramics.