Kovar Alloy Strip / Kovar Alloy Wire / Kovar Alloy Tube / Kovar Alloy Sheet
Classification : the alloy of expansion characteristics
Application: Kovar (trademark of CRS Holdings, inc., Delaware[1]) is a nickel-cobalt ferrous alloy compositionally identical to Fernico 1, designed to be compatible with the thermal expansion characteristics of borosilicate glass (~5 × 10?6 /K between 30 and 200 °C, to ~10 × 10?6 /K at 800 °C) in order to allow direct mechanical connections over a range of temperatures. It finds application in electroplated conductors entering glass envelopes of electronic parts such as vacuum tubes (valves), X-ray and microwave tubes and some lightbulbs.
Chemical Composition in % Kovar
|
Ni 28,5-29,5% |
Fe 51,14-54,5% |
C 0.03% |
Si 0.3% |
Mn 0,4 % |
S o 0.015% |
|
P 0.015% |
o 17-18% |
Ti 0.1% |
Al 0.2% |
Cu 0.2% |
Cr 0,1 % |
| Temperature coefficient of linear expansion αsr ? 10-6 K-1 in the temperature range, ° C |
inflection point temperature, ° C
No less |
Heat treatment regime blanks and samples | ||||||||
| 20-80 | 20-100 | 20-300 | 20-400 | 20-450 | 20-500 | 20-800 | ||||
| - | - | 4,6-5,6 | 4,6-5,2 | - | 5,9-6,4 | - | 420 | samples and blanks annealing in hydrogen, a vacuum or protective atmosphere at a temperature (960 ± 20) ° C, holding 1 hr., cooling with the furnace or container to 200 ° C at a rate not exceeding 10 ° C / min | ||
| Property | sintered | HIPed | ||||||||
| Density / g cm3 | 8.0 | 8.35 | ||||||||
| Hardness / HV1 | 160 | 150 | ||||||||
| Youngs Modulus / GPa | 138 | 138 | ||||||||
| reduction of area at fracture / % | 30 | 30 | ||||||||
| yield strength / MPa | 270 | 270 | ||||||||
| thermal conductivity / W/Km | 17 | |||||||||
| Curie Temperature / °C | 435 | |||||||||
| electrical resistivity Ω mm2 / m | 0.49 | |||||||||
| specific heat J/gK | 0.46 | |||||||||
| 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 | |||||||||
Kovar Alloy Strip / Kovar Alloy Wire / Kovar Alloy Tube / Kovar Alloy Sheet
The name Kovar is often used as a general term for Fe-Ni alloys with these particular thermal expansion properties. Note the related particular Fe-Ni alloy Invar which exhibits minimum thermal expansion.
We referring to the presence of high-power production, offers customers buy alloy Kovar in the required quantities and ensures minimum time shipments of rolled metal products, made on the basis of Kovar.