Custom Kovar parts
Material: KOVAR/ASTM F-15/4J29
Material Typr: Controlled Expansion Alloy
Chemical Sign: 29 Ni-17 Co-53 Fe
Process: CNC turning
Surface: nickel plating
QC MOLD has the experience, knowledge, and CNC equipment required to machine a wide array of materials, including Kovar. Our custom design and manufacturing services means you receive a unique solution to your complex component problems. Nickel alloys usually harden quite rapidly, and the high pressures that machining creates causes hardening and slows down progress, also causing warping in some of the material.
Kovar alloy is a vacuum melted, iron-nickel-cobalt, low expansion alloy whose chemical composition is controlled within narrow limits to assure precise uniform thermal expansion properties. Extensive quality controls are employed in the manufacture of this alloy to ensure uniform physical and mechanical properties for ease in deep drawing, stamping and machining.
Kovar alloy has been used for making hermetic seals with the harder Pyrex glasses and ceramic materials.
This alloy has found wide application in power tubes, microwave tubes, transistors and diodes. In intergrated circuits, it has been used for the flat pack and the dual-in-line package.
Preparation for Sealing:
All degreased, fabricated Kovar alloy parts should be degassed and annealed in a wet hydrogen atmosphere. Atmosphere is to be made moist by bubbling the hydrogen through water at room temperature. Care must be taken to prevent surface carbon pickup. Furnace should have a cooling chamber provided with the same atmosphere.
Heating should be conducted within the 1540/2010°F temperature range. Time at temperature should be approximately two hours for lowest temperature to 20 minutes for the highest temperature. Parts should then be transferred to the cooling zone and held until below 570°F, then removed.
An oxide film on the metallic part is preferred for metal-to-hard glass sealing. The best oxide film is thin and tightly adhering. The film can be produced by heating the parts to 1200/1290°F in regular ambient atmosphere for a time sufficient to form a dark gray to slight brown oxide.
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