new material
Expansion Alloy 4J29 (Kovar Alloy) is a high-performance material known for its excellent thermal expansion properties, mechanical strength, and compatibility with glass and ceramics. This alloy is widely used in various industries, including electronics, aerospace, and telecommunications, where it serves in critical components exposed to demanding environments. Its unique properties make it ideal for applications requiring durability, reliability, and high performance.
Product Overview
4J29 (also known as Kovar Alloy) is a ferrous-nickel-cobalt-based expansion sealing alloy, specially designed for matching and sealing with hard glass. This alloy has a linear expansion coefficient similar to that of hard glass within a specific temperature range, effectively preventing stress concentration at the sealing joint during temperature fluctuations. It is widely used in the electronic vacuum industry.
Features
- Similar Expansion Coefficient to Hard Glass: Exhibits a linear expansion coefficient close to that of hard glass within a specific temperature range, avoiding mismatched thermal expansion.
- Excellent Sealing Performance: Particularly suitable for sealing applications in electronic vacuum devices and hard glass.
- Stable Mechanical Properties: Offers good mechanical performance, ensuring long-term use.
Applications
- Electronic Vacuum Industry: Widely used for sealing in electronic vacuum tubes and other high-precision electronic components.
- Hard Glass Sealing: Used for sealing hard glass, particularly in applications requiring high temperature resistance and thermal expansion matching.
- Precision Instruments: Suitable for thermal sealing needs in precision instruments.
| C | P | S | Mn | Si | Cu | Cr | Mo | Ni | Co | Fe |
| Not more than | ||||||||||
| 0.03 | 0.02 | 0.02 | 0.5 | 0.3 | 0.2 | 0.2 | 0.2 | 28.5-29.5 | 16.8-17.8 | Balance |
| Density | 8.25 g/cm³ |
| Curie Temperature | 430°C |
| Resistivity | 0.48 μΩ·m |
| Tensile Strength (Cold State) | 520 MPa |
| Tensile Strength (Annealed) | 520 MPa |
| Yield Strength (Cold State) | 330 MPa |
| Yield Strength (Annealed) | 330 MPa |
| Elongation (Cold State) | 30% |
| Elongation (Annealed) | 30% |
| Heat Treatment Procedure | Average Linear Expansion Coefficient (ā)/（10-6/℃） | ||
| 20-300℃ | 20-400℃ | 20-450℃ | |
| Heat in hydrogen atmosphere to 900°C±20°C, hold for 1 hour, then heat to 1100°C±20°C, hold for 15 minutes, and cool to below 200°C at a rate of no more than 5°C/min | --- | 4.6-5.2 | 5.1-5.5 |
