Alloy 52 has thermal expansion characteristics.
Next Generation Metals has this available as rod, bar, plate, strip and coil.
Also known as Pernifer 50, NILO 50, Glass Seal 52.
Specifications:
UNS N14052, UNS K94100, ASTM F-30, MIL 1-23011 Class 2
Applications:
Used in mercury-wetted reed switches, metal seals for electronic tubes, automotive and industrial lamps, specialty hermetic devices.