Abstract: Driven by the urgent demand for green and low-carbon technologies, the development of high-performance and cost-effective rare-earth free permanent magnets has emerged as a key research focus for sustainable energy and advanced electronic applications. Among various candidates, M-type strontium ferrites have attracted considerable attention due to their excellent thermal stability, high magnetocrystalline anisotropy, and abundant raw material availability. In this study, Sr0.41La0.36Ca0.23Fe11.8Co0.2O19 was selected as the base system, and a series of samples were synthesized via a solid-state reaction combined with high-energy ball milling. The synergistic effects of varying CeO2/La2O3 mass ratios (0∶10 to 10∶0) and pre-sintering temperatures (1150~1200℃) on the microstructure and magnetic properties were systematically investigated. Microstructural analyses revealed that moderate Ce substitution effectively induced controlled lattice distortion and promoted densification, which inhibited abnormal grain growth and refined the microstructure. Such structural modulation not only enhanced domain wall pinning but also improved magnetocrystalline anisotropy, leading to a remarkable increase in coercivity. Magnetic measurements confirmed that the composition with a CeO2/La2O3 mass ratio of 2∶8 and pre-sintered at 1180℃, achieved the most balanced magnetic performance, exhibiting enhanced coercivity, sufficient remanence, and stable saturation magnetization.This work provides new insights into the cooperative effects between rare-earth doping ratios and thermal processing parameters, clarifying how lattice defects, grain boundary characteristics, and microstructural evolution collectively govern the magnetic properties of M-type ferrites. The findings establish a practical strategy for tailoring the microstructure-property relationship in rare-earth free permanent magnets, opening an optimized processing window for scalable fabrication of environmentally friendly, high-performance ferrite materials.

Key words: M-type strontium ferrite, Ce/La co-doping, pre-sintering temperature, grain growth suppression, magnetic properties regulation

摘要： 在绿色低碳技术的迫切需求推动下，开发高性能、低成本的无稀土永磁材料已成为可持续能源与先进电子领域的重要研究方向。作为候选材料之一，M型锶铁氧体因其优异的热稳定性、高磁晶各向异性及丰富的原料储量而备受关注。本研究以Sr0.41La0.36Ca0.23Fe11.8Co0.2O19为基础体系，采用固相反应结合球磨工艺合成了一系列样品，系统探究了不同CeO2/La2O3质量比(0∶10~10∶0)与预烧温度(1150~1200℃)对材料微观结构与磁性能的协同调控作用。微观结构分析表明，适量Ce取代可诱导晶格发生可控畸变并促进致密化，进而抑制异常晶粒长大、优化晶界特性。这种结构调控增强了畴壁钉扎效应并提升了磁晶各向异性，从而显著提高矫顽力。磁性能测试结果显示，当CeO2/La2O3质量比为2∶8且预烧温度为1180℃时，材料表现出最优的综合磁性能，具有更高的矫顽力、适宜的剩磁及稳定的饱和磁化强度。本研究揭示了稀土掺杂比例与热处理参数之间的协同优化机制，阐明了晶格缺陷、晶界特性及微结构演化对M型锶铁氧体磁性能的影响规律，为无稀土永磁铁氧体的可规模化制备提供了优化策略与工艺窗口，并为绿色高性能永磁材料的设计与应用提供了新思路。

关键词: M型锶铁氧体, Ce/La共掺杂, 预烧温度, 晶粒生长抑制, 磁性能调控