Kovar ASTM F15, Ni 29,Co 17 Balance Fe

Product Details

With a team of highly skilled engineers and updated machinery, we are offering a wide range of  Kovar Alloys. These kovar alloys are manufactured with the help of modern techniques using utmost quality material. Offered kovar alloys are thoroughly examined on different quality parameters for make certain its superiority at our end. The offered kovar alloys are available at pocket friendly price from us. Kovar was invented to meet the need for a reliable glass-to-metal seal, which is required in electronic devices such as light bulbs, vacuum tubes, cathode ray tubes, and in vacuum systems in chemistry and other scientific research. Most metals cannot seal to glass because their coefficient of thermal expansion is not the same as glass, so as the joint cools after fabrication the stresses due to the differential expansion rates of the glass and metal cause the joint to crack. Kovar not only has thermal expansion similar to glass, but its nonlinear thermal expansion curve can often be made to match a glass, thus allowing the joint to tolerate a wide temperature range. Chemically, it bonds to glass via the intermediate oxide layer of nickel(II) oxide and cobalt(II) oxide; the proportion of iron oxide is low due to its reduction with cobalt. The bond strength is highly dependent on the oxide layer thickness and character.[4][6] The presence of cobalt makes the oxide layer easier to melt and dissolve in the molten glass. A grey, grey-blue or grey-brown color indicates a good seal. A metallic color indicates lack of oxide, while black color indicates overly oxidized metal, in both cases leading to a weak joint.[2] The name Kovar is often used as a general term for Fe–Ni alloys with these particular thermal expansion properties. The related particular Fe–Ni alloy Invar exhibits minimum thermal expansion. Application:Glass to Metal sealingWe can supply NICKEL Alloys from "AUERHAMMER METALLWERK GmbH, Germany" in any forms like STRIPS & FOILS.