| 释义 |
perminvar|ˈpɜːmɪnvɑː(r)|
Also Perminvar.
[f. permeability + invariable a. (n.)]
Any of a series of alloys containing nickel, iron, and cobalt which have an approximately constant magnetic permeability over a range of field strengths.
The name is proprietary in the U.S.
1928Official Gaz. (U.S. Patent Office) 12 June 277/1 Western Electric Company..N.Y. Filed Nov. 8, 1927. Perminvar..For ferromagnetic alloys comprising nickel, iron, and cobalt. Claims use since Aug. 23, 1927. 1928G. W. Elmen in Jrnl. Franklin Inst. CCVI. 318 We have chosen ‘perminvar’ as the name for alloys in the iron-cobalt-nickel series, which are characterized, when properly heat treated, by constancy of permeability for a considerable range of the lower part of the magnetization curve. 1939Chem. Abstr. XXXIII. 6775 Rapidly cooled Perminvar (45% Ni, 30% Fe, 25% Co) exhibits a clear increase in specific heat over a rather broad temp. range. 1962N. H. Codling in G. A. T. Burdett Automatic Control Handbk. viii. 21 Perminvar, comprising nickel, cobalt and iron, subjected to heat treatment, has nearly constant permeability for inductions below 1000 G. 1968S. J. Rosenberg Nickel & its Alloys 131/2 Useful alloys in the Perminvar class include the nickel-iron-alloys Conpernik (50% Ni) and Isoperm (40% Ni). |