Kovar, also known as Nilo K or Alloy K, with the UNS designationis UNS K94610 and W. Nr. 1.3981, is a nickel-iron-cobalt alloy containing approximately 29% nickel and 17% cobalt with a low coefficient of thermal expansion. It is designed to provide a balance of thermal expansion and mechanical properties that make it suitable for a wide range of applications. Kovar is commonly used in electronic and electrical components, glass-to-metal seals, hermetic seals, microwave and RF devices, automotive and aerospace applications, and medical devices. This alloy is valued for its ability to maintain precise dimensions and stability in various demanding environments, making it a popular choice in industries where thermal expansion properties are important.
Whatsapp:
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sales@cocessalloys.comChemical Composition
|
Iron (Fe) |
nominal 53 % |
|
Nickel (Ni) |
nominal 29 % |
|
Cobalt (Co) |
nominal 17 % |
|
Manganese (Mn) |
0.50 % max. |
|
Silicon (Si) |
0.20 % max. |
|
Carbon (C) |
0.04 % max. |
|
Aluminum (Al) |
0.10 % max. |
|
Magnesium (Mg) |
0.10 % max. |
|
Zirconium (Zr) |
0.10 % max. |
|
Titanium (Ti) |
0.10 % max. |
|
Copper (Cu) |
0.20 % max. |
|
Chromium (Cr) |
0.20 % max. |
|
Molybdenum (Mo) |
0.20 % max. |
Physical Properties
|
Density |
lb/in3 |
0.295 |
|
|
g/cm3 |
8.16 |
|
Melting point |
°F |
2640 |
|
|
°C |
1450 |
|
Inflection Point, |
°F |
840 |
|
|
°C |
450 |
|
Thermal Conductivity at 20°C (68°F) |
|
|
|
|
Btu•in/ft²•h•°F |
116 |
|
|
W/m•°C |
16.7 |
|
Electrical Resistivity 20°C (68°F) |
|
|
|
|
ohm•circ mil/ft |
259 |
|
|
microhm-cm |
43 |
|
Expansion coefficent (10ˉ⁶/℃) |
|
|
|
|
from 20°C to 100°C |
6 |
|
|
from 20°C to 150°C |
5.8 |
|
|
from 20°C to 200°C |
5.5 |
|
|
from 20°C to 250°C |
5.3 |
|
|
from 20°C to 300°C |
5.1 |
|
|
from 20°C to 350°C |
4.9 |
|
|
from 20°C to 400°C |
4.9 |
|
|
from 20°C to 450°C |
5.3 |
|
|
from 20°C to 550°C |
6.2 |
Mechanical Properties
|
Temperature |
Tensile Strength |
Yield Strength |
Elongation On 50mm (2inch) % |
Reduciton of Area % |
|||
|
°C |
°F |
MPa |
ksi |
MPa |
ksi |
||
|
20 |
68 |
520 |
75.0 |
340 |
49.0 |
42 |
40 |
Kovar, also known as Nilo K or Alloy K, is a nickel-iron-cobalt alloy known for its low coefficient of thermal expansion. Some typical applications of Kovar/Nilo K/Alloy K include:
1. Electronic and Electrical Components: Kovar is widely used in electronic and electrical components, such as glass-to-metal seals, lead frames, and integrated circuit packaging, where dimensional stability over a wide temperature range is crucial.
2. Microwave and RF Devices: It finds applications in microwave and RF (radio frequency) devices, including in the production of microwave tubes, transistors, and other electronic devices that require stable dimensions under varying temperatures.
3. Hermetic Seals: Kovar is employed in the production of hermetic seals, particularly for sealing glass and ceramics to metal, which is essential in electronic and semiconductor packaging, as well as in the aerospace and telecommunications industries.
4. Automotive and Aerospace Applications: It is used in automotive and aerospace applications, such as in the manufacturing of sensors, where resistance to thermal expansion and contraction is required.
5. Medical Devices: Kovar is utilized in medical devices and equipment, such as in the production of pacemakers, where its thermal expansion properties are valuable for maintaining stable and reliable performance.
Specifications for Kovar include the following:
|
Rod, bar, sheet, strip, tubing, wire |
Wire |
Bars and forgings |
Sheet, strip and plate |
|
ASTM F 15 |
ASTM F 29, SAE AMS 7726 |
SAE AMS 7727 |
SAEAMS 7728 |
Standard product forms of Kovar are pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire. The products are available in a wide variety of sizes. Please contact us at sales@cocessalloys.com for full information.
