The KOVAR part has a linear expansion coefficient similar to that of hard glass in the range of 20~450℃, and can be effectively sealed and matched with the corresponding hard glass. It also has a high Curie point and good low-temperature structure stability.
The oxide film is dense, easy to weld and weld, has good plasticity, and can be machined. It is widely used in the production of electric vacuum components, emission tubes, kinescopes, switch tubes, transistors, and sealed plugs and relay housings. Kovar alloys contain cobalt. The product is more wear-resistant.
The expansion coefficient and low-temperature structure stability performance test specimens specified in the standard are heated to 900℃±20℃ in a hydrogen atmosphere for 1 hour, and then heated to 1100℃±20℃ for 15 minutes, not more than 5℃/min The speed is cooled to below 200 ℃ and out of the oven.
Kovar alloy is a typical Fe-Ni-Co hard glass sealing alloy used internationally. After long-term use in aviation factories, the performance is stable. Mainly used for glass sealing of electric vacuum components such as launch tubes, oscillating tubes, ignition tubes, magnetrons, transistors, sealing plugs, relays, integrated circuit leads, chassis, casings, brackets, etc.
In the application, the selected glass should match the expansion coefficient of the alloy. Strictly inspect its low temperature tissue stability according to the use temperature. Appropriate heat treatment should be carried out during processing to ensure that the material has good deep drawing properties. When forging materials are used, their air tightness should be strictly checked.
The structure and properties of the constituent phases in the alloy play a decisive role in the performance of the alloy. At the same time, the changes in the alloy structure, namely the relative number of phases in the alloy, the grain size, shape and distribution of each phase, also affect the performance of the alloy. Great influence.
Therefore, using the combination of various elements to form a variety of different alloy phases, and then through appropriate treatment may meet a variety of different performance requirements.
Hydrogen storage alloy is an alloy composed of two specific metals, one of which can absorb a large amount of hydrogen to form a stable hydride, while the other metal has a low affinity for hydrogen, but hydrogen can easily move in it. Mg, Ca, Ti, Zr, Y, and La belong to the first metal, and Fe, Co, Ni, Cr, Cu, and Zn belong to the second metal.
The former controls the amount of hydrogen storage, and the latter controls the reversibility of hydrogen release. Through the reasonable preparation of the two, the hydrogen absorption and desorption performance of the alloy is adjusted, and a more ideal hydrogen storage material that can reversibly absorb and release hydrogen at room temperature is prepared.
