Ceramic Metal Seal Assemblies
SGJ Electrical Ceramic Vacuum Feedthrough for high voltage and high current
Designed Thread Feedthrough by SGJ-International (Shaanxi Sgj International Co., Ltd.)
| Item |
Parts |
Materials |
Note |
| A |
Ceramic Tube |
96% alumina |
Ends metalizing thin layer of Molybdenum |
| B |
Metal Adapter |
Kovar 4J33 |
JIS Code KV-4(Ni33Co17) |
| C |
Electrode |
OFHC Copper |
Oxygen Free High CondCodeuctivity Copper |
| D |
Weld Lip |
Kovar 4J33 |
JIS Code KV-4(Ni33Co17) |
| X |
Brazing Area |
Silver+Copper Eutectic Alloy |
Complete vacuum brazing |
Kovar Alloy 4J33:
Kovar is a Nickel-Iron-Cobalt, controlled expansion alloy. It's expansion characteristics match alumina ceramics. This alone ensures it is a highly popular controlled expansion alloys for hermetic sealing applications (Mainly used in Ceramic Metal Seal Assemblies)
OFHC Copper TU1:
CTU1/C102 is an oxygen-free copper which has better forming, resistance to hydrogen embrittlement, and brazing characteristics than C110 ETP. CTU1/C102 has good solderability and corrosion resistance and is used for high current applications.
Stainless Steel SUS 304L:
SUS 304L Stainless Steel famous for its resistivity, fall under the category of Stainless Steel Tubes. Threaded, Hot Rolled, Cold Rolled, Heat Exchangers, Annealed, Pickled.... All these products belonging to the SUS 304L Tubes catalog serve as the prime building blocks of electrochemical, shipping, construction and gas industries.
Metallized Alumina Ceramic:
Vacuum brazing of ceramic and metal requires metal coating in the welding area of ceramic. It ensures good air tightness of metal and alumina metallized ceramic brazing joint in vacuum environment. We SGJ have our own unique patented solder formula to ensure the stability and reliability of our products...
The key of Ceramic-Metal structure based on the vacuum tightness, so called sealing. And , Metallized ceramic bonding area Via vacuum brazing technology is the only solution
Alumina Manufacturing Description:
Alumina Ceramics can be produced in a wide range of purities with additives designed to enhance its properties. Typical purities range from 85 to 99.7% although Precision Ceramics generally work over 99.7% material.
It can be injection molded, die pressed, isostatically pressed, slip cast and extruded. Once fired and sintered, it can only be machined using diamondgrinding methods but prior to sintering advanced green and biscuit machining techniques developed by Precision Ceramics allow more complex components to be manufactured using traditional machining methods. In addition Alumina can be readily joined to metals or other ceramics using metallising and brazing techniques.
Alumina can be machined in green, biscuit, or fully dense states. While in the green or biscuit form it can be machined relatively easily into complex geometries. However, the sintering process that is required to fully densify the material causes the alumiuna body to shrink approximately 20%. This shrinkage means that it is impossible to hold very tight tolerances when machining alumina pre-sintering. In order to achieve very tight tolerances, fully sintered material must be machined/ground with diamond tools. In this process a very precise diamond coated tool/wheel is used to abrade away the material until the desired form is created. Due to the inherit toughness and hardness of the material, this can be a time consuming and costly process.
Precision Ceramics specialises in tight tolerance, highly complex work and has extensive in-house machining facilities - including 4th & 5th axis machining centres, drilling, grinding, milling, polishing, sawing, tapping, threading and turning - to enable us to manufacture Alumina components to the highest specifications.
Precision Ceramics is your Alumina machining specialist for your technical ceramic prototyping & manufacturing needs; we are always happy to use our many years of advanced ceramics experience to provide advice on materials, design, and application. If you would like to buy Alumina plates, rods, tubes or custom machined components, please contact SGJ for more details.
Alumina Electrical Ceramics
Alumina electrical ceramics have low dielectric constant, low dielectric loss, high insulation strength, high volume resistivity, good bending strength, high stability, high compressive strength and good cold and hot shock resistance. It is widely used in temperature controller, insulation parts, thermal equipment, electric heating equipment, iron structure building, shipbuilding and so on. Alumina is the most cost effective and widely used material in the family of engineering ceramics. Extremely High Purity, Temperature & Strength; Excellent Corrosion, High Strength, Wear Resistant, Electronic Insulating, Structural & Metalizing, Porous, Easily Degassed & Machinable. The raw materials from which this high-performance technical grade ceramic is made are readily available and reasonably priced, resulting in good value for the cost in fabricated alumina shapes.
Glazed Alumina Ceramics is a kind of material based on alumina, which is used in thick film integrated circuits. Alumina ceramics have good conductivity, mechanical strength and high temperature resistance. Alumina ceramics are widely used. Because of its superior performance, it has been widely used in modern society to meet the needs of daily use and special performance.
SGJ 96% alumina is an easily metallisable ceramic composition:
This material SGJ 96% alumina material is an excellent electrical insulator that can be metallised to facilitate high-temperature brazing of assemblies. This material features:
- Very high volume resistivity
- Low loss, constant high dielectric
- High density, non-porous and vacuum tight
- Resists abrasive wear and chemical attack
The fact that this material can be metallised makes this a good choice for many ceramic to metal or brazed assemblies such as high-vacuum systems, laser equipment (gas, solid-state and waveguide), X-ray tubes and electron microscopes, microwave windows and insulators in medical and scientific equipment.
SGJ 96% Alumina Ceramic Data Sheet:
| Properties |
Units |
Composition |
| Alumina |
% |
96 |
| Tensile |
1000pis |
30 |
| Flexural |
1000pis |
55 |
| Compressive |
1000pis |
300 |
| Density |
g/cc |
3.7 |
| Porosity |
- |
0 |
| Colour |
- |
White |
| Hardness |
Moh's Scale |
9 |
| Thermal Conductivity |
g. cal/cm-sec-ºC |
0.049 |
| C.T.E. |
In/in/ºC x 10-7 |
75 |
| Max. Working Temp. |
ºC |
1600 |
| Dielectric Strength |
D.C. Volts/[email protected]''thick |
230 |
| Volume Resistivity |
0hm/cm3 x 1012 |
2.0 |
| Dielectric Constant |
- |
9.0 |
| Dissipation Factor |
- |
0.0003 |
| Loss Factor |
- |
0.0028 |
Follow Products R&D by SGJ-International (Shaanxi Sgj International Co., Ltd.)
Audited Supplier 
){kind=link}