King-Nd: Sintering and Casting AlNiCo Magnet

Short Description:

Alnico permanent magnet is an alloy made of aluminum, nickel, cobalt, iron and other trace metal elements. It’s the earliest permanent magnet material developed in history, tracing back to 1930s. At that time, it was the strongest magnetic material with small temperature coefficient and most widely used in permanent magnet motors. After the 1960s, with the advent of ferrite magnets and rare earth permanent magnets, the proportion of AlNiCo motors showed a downward trend, which means the application of AlNiCo permanent magnets in motors has been gradually replaced.

Alnico permanent magnet materials can’t be designed as structural parts due to the features of low mechanical strength, high hardness, brittleness, and poor machinability. Only a little grinding or EDM can be used during processing, other methods like forging and other machining can’t be used.

AlNiCo is mainly produced by casting method. In addition, powder metallurgy can also be used to make sintered magnets, which has slightly lower performance. Cast AlNiCo can be processed into different sizes and shape while sintered AlNiCo products are mainly small-sized. And the workpieces of sintered AlNiCo have better dimensional tolerances, the magnetic properties are a little bit lower but the machinability is better.

The advantage of AlNiCo magnets is high remanence (up to 1.35T), but the shortage is that the coercive force is very low (usually less than 160kA/m), and the demagnetization curve is non linear, so AlNiCo is a magnet easy to be magnetized and also easy to be demagnetized. When magnetic circuit designing and device manufacturing, special attention should be paid and the magnet must be stabilized in advance. In order to avoid partial irreversible demagnetization or distortion of magnetic flux density distribution, it is strictly forbidden to contact with any ferromagnetic substances during use.

Cast AlNiCo permanent magnet has the lowest reversible temperature coefficient among the permanent magnet materials, the working temperature can reach up to 525°C, and the Curie temperature to 860°C, which is the permanent magnet material with the highest Curie point. Due to good temperature stability and aging stability, AlNiCo magnets are well applied in motors, instruments, electroacoustic devices, and magnetic machinery, etc.

Application

AlNiCo magnets have stable performance and excellent quality. They are mainly used in water meters, sensors, electronic tubes, traveling wave tubes, radar, suction parts, clutches and bearings, motors, relays, control devices, generators, jigs, receivers, telephones, reed switches, speakers, handheld tools, scientific and educational products, etc.

Media Contact
Company Name: Shanghai King-Nd Magnet Co., Ltd.
Email: Send Email
Country: China
Website: https://www.kingndmagnet.com/