1: 5 type and 2:17 type sintered Samarium Cobalt magnets are called as the first generation and second generation of rare earth permanent magnets. 2:17 type is developed based on 1:5 type. Neodymium magnets dominated the market of rare earth permanent magnets since its inception and then Samarium Cobalt magnets are marginalized seriously due to magnetic performance, complex processing technologies, and costs. But in fact, sintered Samarium Cobalt magnet is still playing an irreplaceable role in high-temperature and high temperature stability applications which is not possible for Neodymium magnets. The research of high-performance sintered Samarium Cobalt magnets has never stopped, thus complex multistage heating treatment and microstructure control promoted magnetic performance of Samarium Cobalt magnets to an extreme. United States Department of Defense demanded that enhance the maximum operating temperature of sintered Samarium Cobalt magnet to the 500 degrees Celsius from 300 degrees Celsius to meet the new applications in aerospace in 1997. In the meanwhile, some higher high-end applications like travelling wave tube and internal device also asked reversible temperature coefficient of sintered Samarium Cobalt magnets should have small enough absolute value. Therefore, TbCu7-type structure Sm2Co7-based magnets emerged and gained widely concern.