Overview of composition and technique process study on 2:17-type Sm–Co high-temperature permanent magnet

Abstract

Sm–Co permanent magnets are widely used in aerospace equipments, tubes, sensors and hybrid electric vehicles due to their excellent magnetic properties at both room and high temperatures. Compared to that of Nd–Fe–B magnets, the capability of reliably operating at temperatures up to 500 °C is the biggest preponderance of Sm–Co permanent magnets. However, the reliable high-temperature magnetic properties are susceptible to composition and technique processes. So, appropriate composition and matched technique processes are prerequisites for good high-temperature magnetic properties. This review mainly emphasizes the influences of Sm, Fe, Cu and Zr contents and technique processes on development of high-temperature performance and discusses the controversial high-temperature coercivity mechanism of 2:17-type high-temperature Sm–Co magnets.