Metalized Ceramics Brazing Part
ZG supplies custom Metalized Alumina Ceramics designed for high
vacuum, high voltage, and high pressure applications. These
metallized ceramics are essential components for power grid tubes,
vacuum interrupters, RF windows, metallized rings, and various
insulators and sensors.
Material Properties
Alumina is among the most widely used engineering ceramic
materials, providing exceptional hardness, wear resistance, and
superior electrical insulation properties. Our high-purity alumina
ceramics (94-96% Al₂O₃) serve as the base material, with
alternative ceramic materials available upon request.
Manufacturing Process
Our standard metalized alumina ceramics utilize molybdenum-based
paints followed by nickel plating. A specialized coating containing
molybdenum and manganese particles mixed with glass additives and
volatile carriers is applied to the ceramic surface through
hand-painting, spraying, or robotic application methods.
After air drying, the coating undergoes firing in a wet hydrogen
environment at 1450°-1600°C, resulting in a "glassy" metallic
coating measuring 300-500 micro-inches (7.6-12.7 microns) thick.
This process ensures exceptional bond strength between the
metallized layer and ceramic base.
The fired coating is then plated with a 0.001-0.003 inch (25.4-76.2
microns) nickel layer. The nickel plating undergoes sinter-firing
at 850-950°C in a dry hydrogen atmosphere, creating a finished
metallic surface ready for brazing with standard braze filler
metals.
Advantages of Ceramics
- Low dielectric loss with optimal dielectric constant
- High thermal conductivity for efficient heat dissipation
- Compatible thermal expansion coefficients between ceramics and
metals
- Exceptional bonding strength between metal layer and ceramic
substrate
- High operating temperature capability, withstanding extreme
temperature cycles and normal operation at 500-600°C
- Superior electrical insulation properties with high breakdown
voltage resistance
Technical Specifications
| Tensile Strength, Kovar Cup Method | > 20,000 psi, avg. (138N/mm²) |
| Helium Leak Rate | < 10⁻⁹ cc/sec |
| Thermal Shock Resistance (room temperature to 850°C) | Will not burst or leak after five operations |
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