Abstract
The global demand for rare earth permanent magnets, particularly neodymium-iron-boron (NdFeB) magnets, has surged due to their exceptional magnetic properties, which are crucial for applications in electric vehicles, wind turbines, and consumer electronics. However, the supply chain vulnerabilities and environmental concerns associated with rare earth elements have spurred intensive research into non-rare earth alternatives. Among these, iron-nitrogen (Fe-N) compounds, particularly α"-Fe₁₆N₂ and Sm₂Fe₁₇Nₓ (samarium-iron-nitrogen, or Sm-Fe-N), have emerged as promising candidates. This article reviews the latest research progress in Fe-N compounds, evaluates their current performance limitations, and discusses their potential to replace NdFeB magnets in the future.

1. Introduction
Neodymium-Iron-Boron (NdFeB) magnets are renowned for their exceptional magnetic strength, compact size, and high energy product (up to 52 MGOe). However, their high cost, temperature sensitivity, and susceptibility to corrosion limit their suitability in certain applications. This analysis explores scenarios where ferrite or samarium-cobalt (SmCo) magnets can replace NdFeB magnets, comparing their cost and performance across key parameters.

Introduction to Gradient Magnets
Gradient magnets are specialized magnetic devices designed to produce a magnetic field that varies linearly along a specific direction. This spatial variation in the magnetic field, known as a magnetic field gradient, is fundamental to numerous scientific and industrial applications, particularly in magnetic resonance imaging (MRI), material separation, and precision measurement systems. The design of gradient magnets involves careful consideration of magnetic field uniformity, gradient strength, and coil configuration to meet the specific requirements of each application.

Neodymium magnets, particularly those based on the neodymium-iron-boron (NdFeB) system, are renowned for their exceptional magnetic properties, including high remanence (Br) and coercivity (Hci), which contribute to their superior magnetic energy storage capacity. However, the quest to further enhance these properties and push the boundaries of their performance has led researchers to explore advanced processing techniques such as nanocrystallization and heat treatment. This essay delves into the potential of these processes to break through the current upper limits of magnetic energy storage capacity in neodymium magnets.

The price of neodymium-iron-boron (NdFeB) magnets, the strongest commercially available permanent magnets, is influenced by a complex interplay of factors spanning raw material costs, production processes, market dynamics, and policy interventions. Below is a detailed analysis of the key determinants:

What is China's position in the global Ndfeb magnet supply chain? Where do the technological advantages of other countries (such as Japan and the United States) lie?

Introduction
Magnetic refrigeration technology, based on the magnetocaloric effect (MCE), has emerged as a promising alternative to traditional vapor - compression refrigeration systems due to its potential for high energy efficiency and environmental friendliness. NdFeB (Neodymium - Iron - Boron) magnets, known for their exceptional magnetic properties, are being explored for use in magnetic refrigeration systems, including room - temperature magnetic refrigerators. This paper will discuss the application of NdFeB magnets in magnetic refrigeration technology and analyze the current technical bottlenecks.

Introduction
In the realm of robotics, the precise control of joint movements is of paramount importance for achieving high - performance tasks. NdFeB (Neodymium - Iron - Boron) magnets, known for their exceptional magnetic properties, play a crucial role in the drive systems of robot joints. Understanding how the magnetic force of NdFeB magnets matches with control accuracy is essential for optimizing robot design and operation.

Neodymium-iron-boron (NdFeB) magnets, renowned for their exceptional magnetic properties, play a pivotal role in two cutting-edge technologies: maglev trains and magnetic resonance imaging (MRI) equipment. Their application principles in these fields are rooted in their ability to generate strong, stable magnetic fields, enabling breakthroughs in transportation and medical diagnostics.

The arrangement of neodymium-iron-boron (NdFeB) magnets in wind power generators significantly influences power generation efficiency by optimizing magnetic field distribution, enabling direct-drive systems, and enhancing energy density. Below is a detailed analysis of how these factors contribute to improved performance:

The integration of micro neodymium-iron-boron (NdFeB) magnets into wireless headphones and smartphones represents a triumph of materials science and engineering, enabling devices to achieve unprecedented levels of miniaturization without sacrificing magnetic performance. This balance is critical for core functionalities such as sound quality, wireless charging, and device stability, all of which rely on the unique properties of NdFeB magnets. Below, we explore how these magnets achieve this equilibrium through advanced material design, precision manufacturing, and innovative application strategies.

The Specific Role of NdFeB Magnets in Electric Vehicle Motors and Their Advantages Over Alternative Magnetic Materials