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NEI's Technical Info
"Do's & Don'ts" in Designing Heating Elements General Operating and Maintenance Instructions for Heating Elements Ohm's Law Chromel®: The original resistance alloy that first made electrical heating practical. Heating Element Design Fundamentals Selecting a Suitable Resistance Alloy Technical Fundamentals of Electrical Heating Current Carrying Capacity Chromel® "A" Wire
Chromel®: The original resistance alloy that first made electrical heating practical.
In 1906, two patents were granted to the late Albert L. Marsh for his discovery of previously unknown properties in certain nickel-chromium alloys. One patent covered the use of such compositions as electrical heating elements and cold resistor materials; the other applied to their unique thermoelectric characteristics when joined to dissimilar metals to form a thermocouple.
Unlike other base-metal compositions available at that time, Marsh's new nickel-chromium alloys possessed high electrical resistivity. What made then truly practical heating element materials was their remarkably high resistance to oxidation and relatively low cost.
Marsh first sought to commercialize his resistance alloys through several established companies who were then trying to develop an electrical heating device that wouldn't "burn out" after short periods of use. Unsuccessful in these efforts, he brought together a group of investors to form a company and produce his alloys.