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Title: Hf--Co--B alloys as permanent magnet materials

Abstract

An alloy composition is composed essentially of Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0

Inventors:
; ;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1340535
Patent Number(s):
9,552,911
Application Number:
14/044,078
Assignee:
UT-Battelle, LLC (Oak Ridge, TN) ORNL
DOE Contract Number:
AC05-00OR22725
Resource Type:
Patent
Resource Relation:
Patent File Date: 2013 Oct 02
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY

Citation Formats

McGuire, Michael Alan, Rios, Orlando, and Ghimire, Nirmal Jeevi. Hf--Co--B alloys as permanent magnet materials. United States: N. p., 2017. Web.
McGuire, Michael Alan, Rios, Orlando, & Ghimire, Nirmal Jeevi. Hf--Co--B alloys as permanent magnet materials. United States.
McGuire, Michael Alan, Rios, Orlando, and Ghimire, Nirmal Jeevi. Tue . "Hf--Co--B alloys as permanent magnet materials". United States. doi:. https://www.osti.gov/servlets/purl/1340535.
@article{osti_1340535,
title = {Hf--Co--B alloys as permanent magnet materials},
author = {McGuire, Michael Alan and Rios, Orlando and Ghimire, Nirmal Jeevi},
abstractNote = {An alloy composition is composed essentially of Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 24 00:00:00 EST 2017},
month = {Tue Jan 24 00:00:00 EST 2017}
}

Patent:

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  • Nd[sub 2]Fe[sub 14]BH[sub x] micron-size loose particles have been synthesized through the well known oxide reduction-diffusion (ORD) technique. When excess Ca is used as reducing agent, an exothermic reaction is observed by washing under water, with the production of native hydrogen that diffuses in the interstitial sites of the alloy. Depending on the experimental conditions, different contents of hydrogen intercalation have been observed, with x ranging from x[approximately]0 to x[approximately]4--5. Cell parameters were observed quickly increasing with hydrogen uptake, resulting in a drastic and regular decrease of the coercivity. In order to understand the relation between the coercivity and themore » content of hydrogen uptake, 2 to 4 [mu]m size powders or a highly coercive Nd[sub 2]Fe[sub 14]B industrial alloy have been submitted to a native hydrogen environment obtained through different chemical conditions. A very reliable relationship has been established between the cell parameters (and thus the content or interstitial hydrogen) and the coercivity or the alloy particles. The degradation of the coercivity of industrial magnets submitted to moisture corrosion could well result from the formation of low coercive layers -- with a high hydrogen content -- at the surface of grains, resulting in the possibility to initiate reverse nucleus domains.« less
  • The substitution of cobalt for iron is known to increase the Curie temperature and stabilize the magnetic properties of melt-spun Nd{sub 2}(Fe{sub 1{minus}{ital x}}Co{sub {ital x}}){sub 14}B ribbons. The preparation of optimum permanent magnets from cobalt-substituted materials is, however, complicated by the need for nonstoichiometric starting materials which vary with the level of cobalt concentration. This paper contains the results of selecting compositions which optimize the room-temperature properties of melt-spun ribbons containing Pr{sub 2}(Fe{sub 1{minus}{ital x}}Co{sub {ital x}}){sub 14}B as the principal constituent. The hard magnetic properties of 11 cobalt concentrations were examined spanning the range {ital x}=0 to 1,more » inclusive. For cobalt concentrations up to {ital x}=0.5, the remanence and energy product did not change substantially from the {ital x}=0 values of 8 kG and 12 MGOe, respectively. Remanence and energy product decreased monotonically to their endpoint values of {similar to}5 kG and {similar to}5 MGOe for cobalt-rich alloys ({ital x}{gt}0.5). The coercivity increased smoothly from 13 kOe for {ital x}=0 to 25 kOe for {ital x}=1. There was no evidence of the down turn in {ital H}{sub {ital ci}} normally associated with decreasing anisotropy.« less
  • A permanent magnet of R/sub 2/Co/sub 17/ type crystal structure consists essentially of at least one rare earth metal in an amount of from 24-28% by weight, copper in an amount of from 5-12% by weight, a total combined amount of cobalt and iron from 55-70.8% by weight, said iron being present in an amount of up to 23% by weight, and at least two elements selected from the group consisting of niobium, vanadium, tantalum and zirconium in an amount of from 0.2-5% by weight, the amount of each of said elements being sufficient to create a substantial increase inmore » the coercive force of said magnet compared to the coercive force of a magnet obtained by the inclusion of only one of said elements, said coercive force being increased about 0.5-0.7 kOe, all percentages being based on the total weight of said magnet. A permanent magnet of R/sub 2/Co/sub 17/ type crystal structure consisting essentially of at least one rare earth metal in an amount of from 24-28% by weight, copper in an amount of from 5 to 12% by weight, a total combined amount of cobalt and iron being from 55-70.8% by weight, said iron being present in an amount of up to 23% by weight and at least two elements selected from the group consisting of niobium, vanadium, tantalum and zirconium in an amount of from 0.2-5% by weight, the amount of each of said elements being sufficient to maintain the coercive force of said magnet at about the same level throughout said percentage range of said iron, said coercive force being about 7 kOe, all percentages being based on the total weight of said magnet. A permanent magnet of R/sub 2/Co/sub 17/ type crystal structure consisting essentially of rare earth metal in an amount of from 24-28% by weight, copper in an amount of from 5-12% by weight, iron in an amount of from 15-20% by weight, a total combined amount of cobalt and iron being from 55-70.8% by weight, and a combination of zirconium and niobium in an amount of from 0.2-5% by weight.« less