摘要:

The series of compounds Sm2−xGdxCo17−yMnywas studied with regard to its suitability for employment as permanent magnet material in microwave/millimeter‐wave traveling‐wave tubes (TWT′s). The pertinent properties investigated are saturation magnetization, 4&pgr;Ms, temperature coefficient of 4&pgr;Ms, &agr;, and anisotropy field, HA. The composition ranges investigated were from x =0 to 0.6 and y =0 to 2. Values of 4&pgr;Msat 25 C ranged from 12.8 kG for x = 0, y = 1 to 9.4 kG for x = 0.6, y = 2. For the compounds studied, maximum HAoccurs at y = 1 for x = 0. The compounds, whose formulas contain a single atom of manganese, were found to yield excellent temperature compensation via Gd substitution in the range +20 to +150 C with the best coefficient occurring in Sm1.6Gd0.4Co16Mn for which &agr; = −0.008&percent;/C (4&pgr;Ms=10.5 kG).

ISSN:0021-8979    

DOI:10.1063/1.326998

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A recent investigation [1] of the compounds Sm2(Cu,Zr,Fe,Co)17revealed optimal HA,iHc, and Bras well as an energy product of 30 MGOe in the composition Sm2Cu1.6Zr0.16Fe3.3Co12. However, this compound has a nonlinear demagnetization characteristic. We have further investigated this system by varying heat treatment and/or replacing progressively larger amounts of Co by Mn or Cr. Metallography showed the microstructures of these materials to be very complex and sensitive to heat treatment. Magnetization measurements were carried out to determine the reversible temperature coefficient &agr; as a function of annealing conditions and substitutent content. &agr; was found to vary from 0.022&percent;/C to 0.060&percent;/C over the temperature range 15 C to 150 C. The room temperature saturation magnetization of these materials ranged from 4&pgr;Ms=8.64 kG to 11.5 kG. Measurements of anisotropy field HAshowed an enhancement with the replacement of Co by Mn or Cr by as much as 25&percent; above the 92.0 kOe for the original material. This suggests that a higher coercivity and thus a more linear demagnetization curve may result from the Mn or Cr substituents.

ISSN:0021-8979    

DOI:10.1063/1.326999

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An easy axis distribution and a crystal texture in a warm extruded anisotropic Mn‐Al‐C magnet were determined by X‐ray diffraction analyses. Resulting values in (001) pole density are treated by introducing a normalization condition in order to determine the quantitative values. The distribution is expressed only as a function of tilt angle &fgr;, and is found to consist of the following Gaussian distribution term and constant. P(&fgr;) = 3.42 exp [−&fgr;2/(2×30.82) ] + 0.11. Magnetically measured Mr/Ms = 0.88 is significantly higher than 0.74, the value calculated from this total distribution when assuming that the magnetization in every grain points in the direction of each easy axis. The crystal texture is approximated by [001] single fiber texture. The inverse pole figure indicates that among twelve {111} ⟨112⟩ twin systems, four twin systems which preserve CuAu I type superstructure are responsible for the formation of this texture.

ISSN:0021-8979    

DOI:10.1063/1.327000

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Alloys near the composition PtCo can be quenched to retain a disordered fcc phase. Aging at a suitable temperature produces an ordered tetragonal phase of type AuCuI. The C axis is an easy axis of magnetization with an anisotropy constant of ∼ 107erg cm−3. Aging produces a magnetically hard alloy. In the early stages of aging ordered regions of diameter 50–100A˚ were found with their C axes oriented at random parallel to one or other of the three original disordered cubic ′a′ axes. In the optimum high coercivity state particles of like C axis (diameter ∼200A˚) group together on {110} planes; the c axis being at 45° to the {110} plane. In the overaged state like particles merge to form lamellae of one particular C axis the other orientations being consumed. Approaches to a better understanding of the hardening process are discussed.

ISSN:0021-8979    

DOI:10.1063/1.327001

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The saturation magnetization, magnetocrystalline anisotropy and magnetostriction of SmCo5have been measured on single crystal samples from 4.2 K to room temperature and above. (AIP)

ISSN:0021-8979    

DOI:10.1063/1.327003

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The microstructure and magnetic properties of the Fe‐Cr‐15 (wt&percent;) Co hard permanent magnetic alloys with and without V and V+Ti are studied using transmission electron microscopy and transmission Lorentz microscopy. (AIP)

ISSN:0021-8979    

DOI:10.1063/1.327004

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The effect of internal solute oxidation during annealing in H2‐N2‐H2O atmospheres on the magnetic properties of nonoriented Si‐steel electrical sheet has been investigated, using standard magnetic tests, electron and x‐ray re‐emission Mossbauer spectroscopy, metallography, and scanning electron microscopy. A significant correlation was found between the extent of internal oxide penetration into the steel and the degradation of magnetic properties. Permeability was observed to decrease linearly with increasing fayalite content, as determined by Mossbauer spectroscopy.

ISSN:0021-8979    

DOI:10.1063/1.327005

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The quantitative effects of internal oxidation and nitridation on the core loss and a‐c permeability of several silicon‐aluminum non‐oriented electrical steels are described. Zones of internal oxidation have a large and relatively constant effect on the magnetic properties of alloys containing a wide range of silicon concentrations. For 0.64 mm sheet composed of alloys containing 0.5 to 2.5 percent silicon, oxide subscales increase the 1.5 T, 60 Hz core loss from 0.05 to 0.07 W/kg per &mgr;m of subscale thickness. Zones of internal nitridation in aluminum‐bearing alloys have a different influence depending on the size and distribution of the nitride precipitates. Zones of internal nitridation in which the individual precipitates have linear dimensions from 0.1 to 1 &mgr;m increase the 1.5 T, 60 Hz core loss of 0.64 mm sheet by 0.015 to 0.07 W/kg. Subscales composed of coarse nitrides having maximum linear dimensions from 2 to 7 &mgr;m do not increase the core loss significantly.

ISSN:0021-8979    

DOI:10.1063/1.327006

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We report the results of studies on AlN which precipitates during the &ggr;‐&agr; phase transformation in high permeability grain‐oriented silicon steel (HI‐B). We examined the behavior of AlN in each stage of the process by means of chemical analysis, electron microscope observation and hydrogen hot extraction technique. The AlN observed by the electron microscope in each stage of the HI‐B production process can be classified into three types: A type: fine needle‐like precipitate; B type: fine plate‐like precipitate of irregular shape; C type: larger agglomerate plate‐like precipitate. The B type AlN, the most important nitride, precipitates during the &ggr;‐&agr; phase transformation which occurs continuously on cooling after hot band annealing. This irregularly‐distributed fine AlN is believed to play an important inhibiting role in the secondary recrystallization process.

ISSN:0021-8979    

DOI:10.1063/1.327007

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The presence of boron, nitrogen and sulfur provides strong inhibition to normal grain growth in heavily cold‐rolled 3&percent; silicon‐iron, which permits the development of a precise (110) [001] secondary recrystallization texture during the final anneal. The addition of boron to the magnesia coating, which results in the diffusion of boron into the alloy, has a marked effect on the grain growth behavior during the final anneal of silicon‐iron containing these elements for grain growth inhibition. Alloys initially deficient in either boron or sulfur experience more extensive secondary recrystallization, and therefore achieve a higher induction, as a result of boron being added to the coating. While small additions of boron are helpful, larger additions decrease the induction, the optimum boron addition to the coating being related to the nitrogen content.

ISSN:0021-8979    

DOI:10.1063/1.327008

出版商:AIP    

年代:1979

数据来源: AIP