Experimental Investigation of Phase Equilibria in the La-Fe-B System at 600 and 800 °C

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Based on the highly efficient diffusion couple and equilibrated alloy methods, phase relations in La-Fe-B ternary system were experimentally investigated by scanning electron microscopy, electron probe microanalysis and electron backscatter diffraction techniques. Isothermal sections of the La-Fe-B system at both 600 and 800 °C were constructed. One ternary phase (LaFe4B42) was detected at 600 °C and two ternary compounds (τ2 and La2Fe14B-τ1) were determined at 800 °C. Seven three-phase zones were found at 600 °C and ten three-phase regions were found at 800 °C. Liquid phase was found in the La-rich corner at 800 °C. The solid solubility of both binary and ternary compounds in the system is negligible. The present experimental results are important for the design of multi-main-phase Nd-La-Ce-Fe-B magnets.

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The financial support from the the National Key Research and Development Program of China (2016YFB0700901), the National Natural Science Foundation of China (51761008, 51961001, 51871066 and 51761007), the Guangxi Natural Science Foundation (2018JJA160250, 2018GXNSFAA294069, 2016GXNSFGA38001), the Guangxi Project of Science and Technology (2017AD23031, 2018AD19088, AD19110078), the Scientific Research Foundation of Guilin University of Electronic Technology (UF18016) and Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials (2019GXYSOF08), and the innovation program of Guilin University of Electronic Technology for students (C99CLM00CL35) and Guangxi Key Laboratory of Information Materials (191012-Z, 171005-Z) are acknowledged. The authors thank the support from the foundation for Guangxi Bagui scholars.

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Wei, Q., Lu, Z., Wang, J. et al. Experimental Investigation of Phase Equilibria in the La-Fe-B System at 600 and 800 °C. J. Phase Equilib. Diffus. (2020).

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  • diffusion couple
  • isothermal section
  • La-Fe-B system
  • phase equilibria