Kovar® Strip & Coil – Premium Controlled Expansion Alloy for Hermetic Sealing
Kovar is a controlled expansion alloy. It is a nickel iron alloy with 29% nickel, 17% cobalt and the remaining balance is iron. The expansion characteristics of Kovar match both borosilicate (or Pyrex) glasses and alumina ceramics, making it one of the most popular of the controlled expansion alloys for hermetic sealing applications. Kovar is produced to ensure good properties for machining and deep drawing, and is a porosity free product.
Properties
General
| Property | Temperature | Value |
|---|---|---|
Density | 23.0 °C | 8.36 g/cm³ |
Dimension
| Property | Value |
|---|---|
Thickness | 0.18 - 2 mm |
Width | 304.8 mm |
Dimensions | Available thicknesses: 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm, 0.9mm, 1.0mm, 1.3mm, 1.5mm, 2.0mm |
Mechanical
| Property | Temperature | Value | Comment |
|---|---|---|---|
Elastic modulus | 23.0 °C | 207 GPa | |
Elongation | 23.0 °C | 30 % | in 2 in. |
Hardness, Rockwell B | 23.0 °C | 80 [-] | |
Tensile strength | 23.0 °C | 518 MPa | |
Yield strength | 23.0 °C | 276 MPa |
Thermal
| Property | Temperature | Value | Comment |
|---|---|---|---|
Coefficient of thermal expansion | 100.0 °C | 5.8E-6 1/K | from 30°C to the mentioned temperature |
150.0 °C | 5.6E-6 1/K | from 30°C to the mentioned temperature | |
200.0 °C | 5.4E-6 1/K | from 30°C to the mentioned temperature | |
250.0 °C | 5.3E-6 1/K | from 30°C to the mentioned temperature | |
300.0 °C | 5.1E-6 1/K | from 30°C to the mentioned temperature | |
350.0 °C | 4.9E-6 1/K | from 30°C to the mentioned temperature | |
400.0 °C | 4.6E-6 - 5.2E-6 1/K | from 30°C to the mentioned temperature | |
450.0 °C | 5.1E-6 - 5.5E-6 1/K | from 30°C to the mentioned temperature | |
500.0 °C | 6.1E-6 1/K | from 30°C to the mentioned temperature | |
550.0 °C | 6.8E-6 1/K | from 30°C to the mentioned temperature | |
600.0 °C | 7.5E-6 1/K | from 30°C to the mentioned temperature | |
700.0 °C | 8.7E-6 1/K | from 30°C to the mentioned temperature | |
800.0 °C | 1.03E-5 1/K | from 30°C to the mentioned temperature | |
900.0 °C | 1.08E-5 1/K | from 30°C to the mentioned temperature | |
1050.0 °C | 1.17E-5 1/K | from 30°C to the mentioned temperature | |
Melting point | 1449 °C | ||
Specific heat capacity | 23.0 °C | 460 J/(kg·K) | |
Thermal conductivity | 23.0 °C | 17 W/(m·K) | |
Electrical
| Property | Temperature | Value |
|---|---|---|
Electrical resistivity | 23.0 °C | 4E-7 Ω·m |
Magnetic
| Property | Value |
|---|---|
Curie temperature | 435 °C |
Chemical properties
| Property | Value |
|---|---|
Carbon | 0.02 % |
Chromium | 0.2 % |
Cobalt | 17 % |
Iron | Balance |
Nickel | 29 % |
Silicon | 0.2 % |
Technological properties
| Property | ||
|---|---|---|
| Application areas | Common applications of Kovar: Glass-to-metal hermetic sealing with hard borosilicate glass, ceramic-to-metal sealing, power tubes, microwave tubes, transistors, diodes, integrated circuits, hybrid packages | |
Metal
- Key Factors in Hot Rolled Coil Production at Hot Strip Mills
- QMet™ 200 Strip – High‑Performance Copper Alloy for Superior Conductivity and Reliability
- QMet™ 300 Strip: High-Performance Copper Alloy for Superior Conductivity & Reliability
- Alloy 46 (Ni-Fe) Annealed Strip/Coil – High-Strength, Controlled Expansion
- Alloy 52 Strip/Coil – 51% Ni Controlled Expansion Steel for High‑Performance Applications
- Alloy 42 Annealed Strip/Coil – Premium Nickel‑Iron Alloy with Superior Mechanical Properties
- 200 Series Commercial Nickel Strip & Coil – Pure, Unalloyed Nickel
- Commercial Nickel 201 Strip/Coil – High-Quality Pure Nickel for Industrial Applications
- Kovar® Sheet – Precision Controlled-Expansion Alloy for Superior Hermetic Sealing
- Kovar® Plate – Precision Nickel‑Iron Alloy for Hermetic Sealing