Alnico magnets, an alloy primarily composed of aluminum (Al), nickel (Ni), and cobalt (Co), have been a staple in permanent magnet technology since their development in the early 20th century. Despite the emergence of newer magnet materials like ferrite, samarium-cobalt (SmCo), and neodymium-iron-boron (NdFeB), Alnico magnets continue to hold a unique position, particularly in high-end motor applications. This enduring relevance is due to their exceptional combination of properties, including high-temperature stability, excellent magnetic performance, and robust mechanical characteristics. In this article, we explore why Alnico magnets are indispensable in specific motor types—micro motors, servo motors, and high-temperature motors—and the underlying reasons that compel high-end motor manufacturers to select Alnico over other magnet materials.

Alnico magnets, composed of aluminum (Al), nickel (Ni), and cobalt (Co), have been a reliable choice in permanent magnet technology for decades. Renowned for their excellent temperature stability, high remanence, and robust mechanical properties, Alnico magnets find extensive use in critical industries such as aerospace and military. These sectors impose stringent demands on magnet performance, particularly concerning temperature resistance, radiation resistance, and long-term stability. This article delves into the specific requirements for Alnico magnets in these high-stakes environments, exploring how each指标（here we use the description "characteristic/property" for broader context as "指标" might be context-dependent, but in technical English, we discuss "properties" or "characteristics" ) - temperature, radiation, and stability - influences magnet selection and design.

Alnico magnets, composed primarily of aluminum (Al), nickel (Ni), and cobalt (Co), have been a cornerstone in the field of permanent magnets for decades. They are known for their excellent temperature stability, high remanence, and good mechanical strength. Alnico magnets can be manufactured through two primary processes: casting and sintering. Each method yields magnets with distinct properties, making them suitable for different applications, particularly when considering size and precision requirements. Cast Alnico is typically used for larger magnets, while sintered Alnico is preferred for smaller, precision magnets. Understanding the application boundaries between these two forms involves examining their manufacturing processes, material properties, and the specific demands of various industries.

AlNiCo (Aluminum-Nickel-Cobalt) magnets, renowned for their high remanence, low temperature coefficient, and exceptional thermal stability, are widely utilized in high-temperature sensor applications, particularly Hall sensors and magnetic sensors. This paper delves into the magnetic uniformity requirements of AlNiCo magnets in these sensors, analyzing their performance across temperature ranges of 300°C, 400°C, and 500°C. By comparing AlNiCo with other permanent magnet materials such as SmCo and high-temperature NdFeB, the paper highlights the unique advantages of AlNiCo in high-temperature environments and underscores the critical role of magnetic uniformity in ensuring sensor accuracy and reliability.

1. Introduction
Precision instrumentation, including ammeters, voltmeters, and tachometers, relies on permanent magnets to generate stable magnetic fields for accurate measurements. In high-temperature environments (300°C, 400°C, 500°C), the selection of magnets becomes critical due to the degradation of magnetic properties with increasing temperature. This analysis compares the performance of AlNiCo (Aluminum-Nickel-Cobalt), SmCo (Samarium-Cobalt), and high-temperature NdFeB (Neodymium-Iron-Boron) magnets in extreme thermal conditions, providing a selection priority based on their suitability for precision instrumentation.

1. Introduction to AlNiCo Magnets
AlNiCo (Aluminum-Nickel-Cobalt) magnets are a type of permanent magnet developed in the 1930s, known for their excellent thermal stability, high residual magnetism, and low-temperature coefficient. These magnets are composed primarily of aluminum (Al), nickel (Ni), cobalt (Co), and iron (Fe), with trace amounts of copper (Cu) and titanium (Ti). AlNiCo magnets are manufactured through two primary processes: casting and sintering, with casting being the more common method for producing magnets with complex shapes and superior magnetic properties.

Alnico magnets, composed primarily of aluminum (Al), nickel (Ni), cobalt (Co), and iron (Fe), with occasional additions of trace elements like copper (Cu) and titanium (Ti), have been a cornerstone of magnetic technology since their development in the early 20th century. Despite the emergence of advanced rare-earth magnets such as neodymium-iron-boron (NdFeB) and samarium-cobalt (SmCo), alnico magnets continue to occupy a unique niche in industrial and consumer applications due to their exceptional thermal stability, corrosion resistance, and specific magnetic properties. This article explores the core advantages of alnico magnets and identifies scenarios where they remain irreplaceable by other permanent magnets.

Alnico magnets, composed primarily of aluminum (Al), nickel (Ni), cobalt (Co), and iron (Fe), are renowned for their high remanence, excellent temperature stability, and corrosion resistance. However, surface oxidation can occur over time, potentially affecting their magnetic performance. This article explores the impact of surface oxide layers on the magnetic properties of Alnico magnets and discusses various methods for removing these layers to restore or maintain optimal performance.

1. Introduction to Alnico Magnets
Alnico magnets, composed primarily of aluminum (Al), nickel (Ni), cobalt (Co), and iron (Fe), are a type of permanent magnet material known for their high remanence (Br), excellent temperature stability, and corrosion resistance. However, they also exhibit low coercivity (Hc), making them susceptible to demagnetization under external magnetic fields or improper handling. This characteristic necessitates careful consideration when stacking multiple Alnico magnets for storage or use.

Alnico magnets, due to their strong magnetic properties, pose significant risks during transportation, especially in aviation. Magnetic interference can disrupt aircraft navigation and control systems, necessitating magnetic shielding. This article explores the reasons for magnetic shielding of alnico magnets during transportation, common shielding materials, and their effects, providing a comprehensive reference for related industries.

Alnico magnets, composed primarily of aluminum (Al), nickel (Ni), cobalt (Co), and iron (Fe), are renowned for their exceptional thermal stability, corrosion resistance, and mechanical durability. These properties make them suitable for applications requiring consistent magnetic performance under extreme conditions, such as aerospace, military, and industrial sensors. However, proper storage is crucial to maintaining their magnetic integrity over extended periods. This article explores the storage environment requirements for Alnico magnets and examines whether long-term storage can lead to self-demagnetization, oxidation, or rusting.

Alnico (Aluminum-Nickel-Cobalt) magnets are a class of permanent magnets composed primarily of aluminum (Al), nickel (Ni), cobalt (Co), and iron (Fe), with minor additions of copper (Cu) and titanium (Ti). Developed in the 1930s, Alnico magnets were once the strongest permanent magnets available before the advent of rare-earth magnets like neodymium-iron-boron (NdFeB) and samarium-cobalt (SmCo).