4J29
Kovar — Fe-Ni-Co expansion alloy for glass-to-metal and ceramic-to-metal seals in electronics packaging.
Introduction
§01 — General4J29 (Kovar) is an iron-nickel-cobalt controlled expansion alloy whose thermal expansion coefficient closely matches that of borosilicate glass and alumina ceramics. It is the universal standard for hermetic glass-to-metal seals in electronic packages, transistor headers, microwave tubes and optoelectronic housings.
Quick Facts
- Density
- 8.17 g/cm³
- Max Service Temp
- 450°C
- Series
- Precision
Available Product Forms
§02 — FormsKey Characteristics
§03 — FeaturesTypical Uses
§04 — ApplicationsFrequently Asked Questions
4J29 FAQWhat is 4J29 used for?
4J29 is a Precision alloy used in Transistor and IC hermetic packages and Microwave tube windows. It offers Thermal expansion matches borosilicate glass and Kovar / ASTM F15 standard.
What is the chemical composition of 4J29?
4J29 is a controlled-composition Precision alloy supplied to ASTM F15 and GB/T 14986. Contact us for full mill test certificate with heat-specific chemistry.
What forms is 4J29 available in?
4J29 is regularly supplied in Wire, Strip, Bar & Rod, Plate & Sheet. Custom forms and dimensions available on request.
What is the maximum service temperature of 4J29?
4J29 is rated for service up to 450°C. Contact our metallurgy team for specific application recommendations.
Need 4J29 material?
Request a quote with your specification — grade, form, dimensions and quantity.