Product Code : AL-Kovar-NN-CU
Kovar 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. A glass and ceramic sealing alloy, extensive quality controls are employed in its manufacture to ensure uniform physical and mechanical properties for ease in deep drawing, stamping and machining. Kovar is a nickel–cobalt ferrous alloy compositionally identical to Fernico 1, designed to have substantially the same thermal expansion characteristics as borosilicate glass (~5 × 10−6 /K between 30 and 200 °C, to ~10 × 10−6 /K at 800 °C) to allow a tight mechanical joint between the two materials over a range of temperatures.
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Product Information
Kovar 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. A glass and ceramic sealing alloy, extensive quality controls are employed in its manufacture to ensure uniform physical and mechanical properties for ease in deep drawing, stamping and machining. Kovar is a nickel–cobalt ferrous alloy compositionally identical to Fernico 1, designed to have substantially the same thermal expansion characteristics as borosilicate glass (~5 × 10−6 /K between 30 and 200 °C, to ~10 × 10−6 /K at 800 °C) to allow a tight mechanical joint between the two materials over a range of temperatures. It finds application in glass-to-metal seals in scientific apparatus, and conductors entering glass envelopes of electronic parts such as vacuum tubes (valves), X-ray and microwave tubes and some lightbulbs. Kovar not only has thermal expansion similar to glass, but its nonlinear thermal expansion curve can often be made to match a glass, thus allowing the joint to tolerate a wide temperature range. Chemically, it bonds to glass via the intermediate oxide layer of nickel(II) oxide and cobalt(II) oxide. The proportion of iron oxide is low due to its reduction with cobalt. The bond strength is highly dependent on the oxide layer thickness and character. The presence of cobalt makes the oxide layer easier to melt and dissolve in the molten glass. A grey, grey-blue or grey-brown color indicates a good seal. A metallic color indicates lack of oxide, while black color indicates overly oxidized metal, in both cases leading to a weak joint. The name Kovar is often used as a general term for Fe–Ni alloys with these particular thermal expansion properties. The related particular Fe–Ni alloy Invar exhibits minimum thermal expansion.
Synonyms
Controlled expansion alloy, nickel cobalt iron, Fernico 1, ASTM F-15, Pernifer 29182, Dilvar P13, NILO K, Fe54/Ni29/Co17
Kovar Alloy Specification
Size：customized
Purity: customized
Per your request or drawing
We can customized as required
K94610
ASTM F15
1.3981
FeNi29Co17
Properties（Theoretical）
| Appearance | Metallic powder or solid in various forms |
| Density g /cm3 | 8-8,35 |
| Melting Point | 1449 °C |
| Hardness / HV1 | 150-160 |
| Youngs Modulus / GPa | 138 |
| reduction of area at fracture / % | 30 |
| Electrical Resistivity | 40 µΩ·cm |
| yield strength / MPa | 270 |
| thermal conductivity / W/K∙m | 17 |
| Curie Temperature / °C | 435 |
| specific heat J/g∙K | 0.46 |
| Tensile Strength | 518 MPa |
| Thermal Conductivity | 0.17 W/cm °C |
| Thermal Expansion | 5.3 ppm/°C |
| thermal expansion coefficient/10−6 K−1 (25 – 200 °C) | 5.5 |
| (25–300 °C) | 5.1 |
| (25–400 °C) | 4.9 |
| (25–450 °C) | 5.3 |
| (25–500 °C) | 6.2 |
Chemical Composition
| Fe | Ni | Co | C | Si | Mn |
| balance | 29% | 17% | < 0.01% | 0.2% | 0.3% |
We can customized as required
Applications of Kovar Alloy
The alloy is used for making hermetic seals with the harder Pyrex glasses and ceramic materials. It has been widely used in power tubes, microwave tubes, transistors and diodes. It has been used for the flat pack and the dual-in-line package in integrated circuits. Alloy Kovar is primarily used for applications that take account of its magnetic properties.
Packing of Kovar Alloy
Standard Packing:
Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 440 gallon liquid totes Special package is available on request.
ATTs’ High Purity Kovar Alloy is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition.
