High performance Nd-Fe-B permanent magnets without critical elements

In this work, an experiment was carried out to investigate the preparation condition of anisotropic, Fe-deficient, M-type Sr ferrite with optimum magnetic and physical properties by changing experimental parameters, such as the La substitution amount and little additive modification during fine milling process. The compositions of the calcined ferrites were chosen according to the stoichiometry LaxSr1-xFe12-2xO19, where M-type single-phase calcined powder was synthesized with a composition of x = 0.30. The effect of CaCO3, SiO2, and Co3O4 inter-additives on the Sr ferrite was also discussed in order to obtain low-temperature sintered magnets. The magnetic properties of Br = 4608 Gauss, bHc = 3650 Oe, iHc = 3765 Oe, and (BH)max = 5.23 MGOe were obtained for Sr ferrite hard magnets with low cobalt content at 1.7 wt%, which will eventually be used as high-end permanent magnets for the high-efficiency motor application in automobiles with Br > 4600 ± 50 G and iHc > 3600 ± 50 Oe.

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Alloying effect on the order–disorder transformation in tetragonal FeNi

Scientific Reports ◽

10.1038/s41598-021-84482-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Li-Yun Tian ◽

Oliver Gutfleisch ◽

Olle Eriksson ◽

Levente Vitos

Keyword(s):

Transition Temperature ◽

High Performance ◽

Density Functional ◽

Permanent Magnets ◽

Positive Impact ◽

Design Strategies ◽

Alloying Effect ◽

Functional Theory ◽

Disorder Transition ◽

Disorder Transition Temperature

AbstractTetragonal ($${\hbox{L1}}_{0}$$ L1 0 ) FeNi is a promising material for high-performance rare-earth-free permanent magnets. Pure tetragonal FeNi is very difficult to synthesize due to its low chemical order–disorder transition temperature ($$\approx {593}$$ ≈ 593 K), and thus one must consider alternative non-equilibrium processing routes and alloy design strategies that make the formation of tetragonal FeNi feasible. In this paper, we investigate by density functional theory as implemented in the exact muffin-tin orbitals method whether alloying FeNi with a suitable element can have a positive impact on the phase formation and ordering properties while largely maintaining its attractive intrinsic magnetic properties. We find that small amount of non-magnetic (Al and Ti) or magnetic (Cr and Co) elements increase the order–disorder transition temperature. Adding Mo to the Co-doped system further enhances the ordering temperature while the Curie temperature is decreased only by a few degrees. Our results show that alloying is a viable route to stabilizing the ordered tetragonal phase of FeNi.

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A Novel High Performance Discrete Flux Integrator for Control Algorithms of Fast Rotating AC Machines

Applied Sciences ◽

10.3390/app11052150 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2150

Author(s):

Claudio Rossi ◽

Alessio Pilati ◽

Marco Bertoldi

Keyword(s):

High Performance ◽

Permanent Magnets ◽

Machine Model ◽

Ac Machines ◽

Fast Calculation ◽

Calculation Time ◽

Digital Implementation ◽

Rotating Speed ◽

Interior Permanent Magnets ◽

Accuracy Performance

This paper deals with the digital implementation of a motor control algorithm based on a unified machine model, thus usable with every traditional electric machine type (induction, brushless with interior permanent magnets, surface permanent magnets or pure reluctance). Starting from the machine equations in matrix form in continuous time, the paper exposes their discrete time transformation, suitable for digital implementation. Since the solution of these equations requires integration, the virtual division of the calculation time in sub-intervals is proposed to make the calculations more accurate. Optimization of this solver enables faster runs and higher precision especially when high rotating speed requires fast calculation time. The proposed solver is presented at different implementation levels, and its speed and accuracy performance are compared with standard solvers.

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High performance Sm-Co permanent magnets for traveling wave tube applications

Fifth IEEE International Vacuum Electronics Conference (IEEE Cat. No.04EX786) ◽

10.1109/ivelec.2004.1316363 ◽

2004 ◽

Author(s):

S.K. Xia ◽

T. Zhai ◽

M.P. Effgen ◽

J. Willhite

Keyword(s):

Traveling Wave ◽

High Performance ◽

Permanent Magnets ◽

Traveling Wave Tube ◽

Wave Tube

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Pavement Technology Elements in Green Highway

Jurnal Teknologi ◽

10.11113/jt.v73.4284 ◽

2015 ◽

Vol 73 (4) ◽

Author(s):

W. N. Aifa ◽

M.R. Hainin ◽

M.Z. Abd.Majid ◽

R. MohamadZin ◽

H. Yaacob ◽

...

Keyword(s):

High Performance ◽

Advanced Technology ◽

Control Element ◽

Highway Design ◽

Priority Level ◽

Highway Engineering ◽

Critical Elements ◽

Weighted Analysis ◽

Green Practices ◽

Weighted Factor

A technology that has been experienced during the construction of a pavement has indicated the improvement in exploring the advanced technology pavement. Types of technologies of pavements applied are always related to the high performance of the pavements during the life span. Indeed, the application of technology in pavement has insisted to reduce the rate of environmental problems such as global warming, abundance of solid waste and so on. The development of technologies in pavement has been identified by the expert in highway engineering as one of the initiatives in response the sustainability requirement that later on will be applied to implement green highway concepts. Nowadays, the process of selecting a variety of green pavement technology element is becoming more challenging to be evaluated qualitatively. This paper aims to determine critical pavement technology element based on ranking of priority to achieve the objective of the green highway design. It is necessary to determine the critical elements in order to identify which elements will most contribute to the green practices based on the priority level of the weighted factor value. Therefore, a questionnaire survey was developed and distributed to the respondent in order to obtain the agreement level for the element. Based on the weighted analysis, it has been shown that the soil erosion control element has achieved first ranking in order to implement green highway and followed by permeable and cool pavement.In conclusion, the identification of critical elementsof green pavement technology is the main key towards sustainable development in the future.

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