He pioneered the development of tungsten and molybdenum alloys for many applications, including their use in rocket nozzles.

After retiring from the NMAB, Nate consulted extensively. He received an honorary doctorate in engineering from the Michigan Technological University in 1978. In 1994 he received the National Materials Advancement Award from the FMS.

He published more than 40 papers, co-authored or edited five books, including Advances in Materials Research (1963); Science and Technology of Refractory Metals (1964); and Science, Technology and Application of Titanium; (1970). He lectured extensively. He was credited with advancing the practice of electroplating, which uses electric current to apply a thin, even coat of metal on an object.

Beginning in 2001, Mr. Promisel began what he called an “informal conversation” with his grandson, Brett. He said it was “by no means an autobiography” but “a somewhat random accumulation of snapshots and vignettes fueled by a wistful odyssey down memory lane.” It was dedicated to “those generations of the Promisel clan who have the curiosity to glance back.” The conversation, transcribed by Brett, was a wonderful bonding experience and yielded a fascinating memoir. It displays the qualities that Mr. Promisel passed on to his next generations and for which he was widely respected: integrity, aggressiveness in the pursuit of what one believes in, devotion to family, and curiosity about the world.