Key Takeaways & Executive Findings
- •• FeCoNi medium entropy alloy (MEA) was successfully synthesized via sol–gel and co-precipitation precursors followed by carbothermal and hydrogen reduction at 1500°C. • Hydrogen reduction yielded a more uniform and higher-purity FeCoNi MEA compared to carbothermal reduction, which introduced carbon contamination. • The hydrogen-reduced FeCoNi MEA exhibited superior soft magnetic properties, with higher saturation magnetization and lower coercivity, making it promising for magnetic storage applications. • The liquid-phase precursor approach offers a cost-effective and environmentally friendly route for producing FeCoNi MEA, potentially utilizing waste Fe, Co, and Ni resources.
Abstract
In recent years, medium entropy alloys have become a research hotspot due to their excellent physical and chemical performances. By controlling reasonable elemental composition and processing parameters, the medium entropy alloys can exhibit similar properties to high entropy alloys and have lower costs. In this paper, a FeCoNi medium entropy alloy precursor was prepared via sol–gel and co-precipitation methods, respectively, and FeCoNi medium entropy alloys were prepared by carbothermal and hydrogen reduction. The phases and magnetic properties of FeCoNi medium entropy alloy were investigated. Results showed that FeCoNi medium entropy alloy was produced by carbothermal and hydrogen reduction at 1500°C. Some carbon was detected in the FeCoNi medium entropy alloy prepared by carbothermal reduction. The alloy prepared by hydrogen reduction was uniform and showed a relatively high purity. Moreover, the hydrogen reduction product exhibited better saturation magnetization and lower coercivity.
1. Introduction
In recent years, the high entropy alloy (HEA) has received extensive attention in advanced materials science [1–3]. The key effects of HEA include high entropy effect, sluggish diffusion, severe lattice distortion, and cocktail effect [4–5]. Medium entropy alloy (MEA) is a kind of alloy system between traditional alloy (low entropy alloy) and HEA, which commonly contains less than four principal elements. The entropy of mixing of FeCoNi MEA is close to that of traditional alloy, while exhibiting excellent properties like HEA, such as high strength, high temperature softening resistance, high hardness [6–11], strong corrosion-resistance [12–14], and well electromagnetic properties [15–21], etc.
Magnetic materials refer to substances composed of transition elements such as Fe, Co, Ni, and their alloys that can directly or indirectly generate magnetism. Table 1 shows the magnetic properties of entropy alloy in FeCoNi system obtained by different preparation methods. In recent years, research has shown that FeCoNi MEA, as a soft magnetic material that is easy to magnetize and demagnetize, has broad application prospects in magnetic storage and ultra-high-density magnetic recording [15,22–23]. The methods for preparing FeCoNi MEA include chemical reduction [15–16], mechanical alloying [17–19], and vacuum melting [20–21]. The saturation magnetization of the products prepared by these methods was similar and showed a big gap in coercivity. It was reported that using the liquid phase method to prepare precursor was beneficial to control the element ratio, refine grain size, and reduce the costs [24–38]. Moreover, some Fe, Co, and Ni resources of waste can be recovered and utilized via this route [39–40].
Loading authentic research manuscript (Pages 1–5)...
Zongyou Cheng, Qing Zhao, Mengjie Tao, Jijun Du, Xingxi Huang, Chengjun Liu (2025). Preparation of FeCoNi medium entropy alloy from Fe3+–Co2+–Ni2+ solution system. Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报). https://doi.org/10.1007/s12613-024-2888-6
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is a medium entropy alloy (MEA)?
A medium entropy alloy (MEA) is an alloy system that lies between traditional alloys and high entropy alloys (HEAs), typically containing less than four principal elements. It exhibits properties similar to HEAs, such as high strength and corrosion resistance, but at a lower cost.
How was the FeCoNi medium entropy alloy prepared in this study?
The FeCoNi MEA was prepared by first synthesizing a precursor via sol–gel and co-precipitation methods, followed by carbothermal and hydrogen reduction at 1500°C. The hydrogen reduction route yielded a higher purity and more uniform alloy.
What are the advantages of using liquid-phase methods for precursor preparation?
Liquid-phase methods, such as sol–gel and co-precipitation, allow for better control of elemental composition, refinement of grain size, and reduction of costs. They also enable the recovery and utilization of waste Fe, Co, and Ni resources, addressing environmental concerns.
What were the magnetic properties of the FeCoNi MEA produced by hydrogen reduction?
The hydrogen-reduced FeCoNi MEA exhibited better saturation magnetization and lower coercivity compared to the carbothermal reduction product, indicating superior soft magnetic properties suitable for applications like magnetic storage.
Why is the FeCoNi MEA considered promising for magnetic applications?
FeCoNi MEA is a soft magnetic material that is easy to magnetize and demagnetize, with high saturation magnetization and low coercivity. These properties make it suitable for magnetic storage and ultra-high-density magnetic recording applications.
Related Technical Papers & Translations
Direct Repair of the Crystal Structure and Coating Surface of Spent LiFePO4 Materials Enables Superfast Li-Ion Migration
The rapid accumulation of spent LiFePO4 (LFP) cathodes from retired lithium-ion batteries necessitates the development of effective and environmental-friendly recycling strategies. In this context, direct regeneration has emerged as a promising approach for reclaiming LFP cathode materials, offering a streamlined pathway to restore their electrochemical functionality. We report an integrated regeneration protocol that simultaneously repairs the degraded crystal structure and reconstructs the damaged carbon coating in spent LFP. The regenerated cathode material had superfast lithium-ion diffusion kinetics and a stable cathode–electrolyte interface, giving a remarkable rate capability with specific capacities of 122 mAh g−1 at 5C and 106 mAh g−1 at 10C (1C = 170 mA g−1). It also maintained capacities of 110.7 mAh g−1 (5C) and 84.1 mAh g−1 (10C) after 400 cycles. It could be used in harsh environments and could be stably cycled at subzero temperatures (−10 and −20 °C) and in solid-state electrolyte batteries. Life cycle assessment combined with economic evaluation using the EverBatt model reveals that this direct regeneration approach has high economic and environmental benefits.
Oxide Semiconductor for Advanced Memory Architectures: Atomic Layer Deposition, Key Requirement and Challenges
Oxide semiconductors (OSs), introduced by the Hosono group in the early 2000s, have evolved from display backplane materials to promising candidates for advanced memory and logic devices. The exceptionally low leakage current of OSs and compatibility with three-dimensional (3D) architectures have recently sparked renewed interest in their use in semiconductor applications. This review begins by exploring the unique material properties of OSs, which fundamentally originate from their distinct electronic band structure. Subsequently, we focus on atomic layer deposition (ALD), a core technique for growing excellent OS films, covering both basic and advanced processes compatible with 3D scaling. The basic surface reaction mechanisms—adsorption and reaction—and their roles in film growth are introduced. Furthermore, material design strategies, such as cation selection, crystallinity control, anion doping, and heterostructure engineering, are discussed. We also highlight challenges in memory applications, including contact resistance, hydrogen instability, and lack of p-type materials, and discuss the feasibility of ALD-grown OSs as potential solutions. Lastly, we provide an outlook on the role of ALD-grown OSs in memory technologies. This review bridges material fundamentals and device-level requirements, offering a comprehensive perspective on the potential of ALD-driven OSs for next-generation semiconductor memory devices.
Laser powder bed fusion of biodegradable Zn-4Cu alloy: Processing, microstructure and properties
Zn's natural degradability and biocompatibility make it a promising candidate for implants, however, its mechanical properties remain insufficient for bone applications. In this study, the performance of Zn was enhanced by developing Zn-Cu alloys via laser powder bed fusion (LPBF). Optimal LPBF parameters for forming stable tracks were achieved by adjusting laser power and scanning speed. Under optimized conditions of 100 W and 100 mm/s, high-density (99.58%) Zn-Cu alloys with improved hardness (68.2HV) and yield strength (160 MPa) were achieved. These improvements are attributed to solid solution strengthening, segregation strengthening, and grain refinement. The Zn-Cu alloys also demonstrated favorable degradation behavior, with a rate of 0.16 mm/year. This degradation is primarily driven by micro-galvanic corrosion between the CuZn5 phase and Zn matrix, along with refined grains and increased grain boundary density. This work demonstrates a viable strategy for fabricating Zn-based implants with enhanced structural integrity and mechanical performance via LPBF.