This alloy also caleed Glass sealed and controlled expansion alloy,The alloy has a linear expansion coefficient similar to that of silicon boron hard glass at 20-450°C, a higher Curie point, and good low-temperature structural stability. The oxide film of the alloy is dense and can be well wetted by glass . It does not interact with mercury and is suitable for use in mercury-containing discharge meters. It is the main sealing structure material for electric vacuum devices.
Kovar Alloy Chemical Composition
|Density(g/cm3)||Thermal conductivity(W/m·K)||Electrical resistivity(μΩ·cm)|
|The average linear expansion coefficient a,10-6/ oC|
|Alloy Grades||Specimen heat treatment system||The average linear expansion coefficient α,10-6/ oC|
|Kovar||20-300 oC||20-400 oC||20-450 oC|
|In hydrogen atmosphere heated to 900 ± 20 oC, insulation 1h, and then heated to 1100 ± 20 oC, insulation 15min, to not more than 5 oC / min rate of cooling to below 200 oC released||-----||4.6-5.2||5.1-5.5|
|Alloy Grades||The average linear expansion coefficient a,10-6/ oC|
Round bars/Flat bars/Hex bars, Size From 8.0mm-320mm, Used for bolts,fastners and other spare parts
Supply in welding wire and spring wire in coil form and cut length.
Widths up to 1500mm and lengths up to 6000mm,Thickness from 0.1mm to 100mm.
Standards size and customized dimension can be produced by us with small tolerance
Soft condition and hard condition with AB bright surface, width up to 1000mm
1.Kovar has a wide usage in the electronics industry, such as metal parts bonded to hard glass envelopes. These parts are used for such devices as power tubes and X-ray tubes, etc.
2.In the semiconductor industry kovar is used in hermetically sealed packages for both integrated and discrete circuit devices.
3.Kovar is provided in a variety of forms to facilitate efficient manufacturing of various metal parts. It has thermal expansion characteristics matching those of hard glass. Used for matched expansion joints between metals and glass or ceramics.
4.Kovar alloy is a vacuum melted, iron-nickel-cobalt, low expansion alloy whose chemical composition is controlled within narrow limits to assure precise uniform thermal expansion properties. Extensive quality controls are employed in the manufacture of this alloy to ensure uniform physical and mechanical properties for ease in deep drawing, stamping and machining.
Kovar Alloy Application field：
● Kovar alloy has been used for making hermetic seals with the harder Pyrex glasses and ceramic materials.
●This alloy has found wide application in power tubes, microwave tubes, transistors and diodes. In intergrated circuits, it has been used for the flat pack and the dual-in-line package.