Samarium cobalt magnets are rare earth permanent magnets, which have two kinds of components: SmCo 1:5 & SmCo 2:17. The advantage of SmCo magnet is good performance in Hcb, Hcj & BH max and high working temperature. As the second generation of neodymium magnets, SmCo magnets are also called samarium cobalt magnets, samarium magnets, SmCo permanent magnets or rare earth SmCo magnets. The mixture of the metal Samarium, cobalt and other rare earth elements is melted to be alloy and then smashed, compressed, sintered to be the magnet material. As a member of rare earth magnet family, samarium magnets own three properties: 1. stable magnetism; 2. high working temperature (Most curie temperature is over 800℃. Max working temperature can reach 250-350℃); 3. good performance in corrosion-resistance even without protection coating. As a result, samarium cobalt magnets are widely used in motors, instruments, sensors, detectors, engines, radars, aerospace, war industry, communications, medical equipments and other high-tech area. Samarium permanent magnets can be customized into different shapes such as cylinder, disc, rectangle, segment etc.
Compared with the neodymium magnets, Samarium cobalt magnets are more suitable to work in high temperature environment. It’s good to be used to manufacture different kinds of permanent magnet motors with high performance, and also those products under extremely complex working conditions. Moreover, its anti-corrosion ability is very strong so that its surface does not need to be electroplated. Because samarium, the principal constituent of samarium magnet,
owns low reserves on Earth, the price is extremely expensive.
The cobalt mineral in the SmCo magnet is complex to withdraw and smelt, with low quality, therefore there are various extraction methods, which are complex, while the returns-ratio is low. The process of milling run cobalt ore generally includes the hand sorting, the gravity separation, the froth flotation. This may withdraw 15-25% cobalt ore concentrate.
The counter electromotive force suppression technology is generally divided into three ways. The first kind is the variable magnetic force way, which changes the magnetic force of revolving magnets by using samarium cobalt magnets with variable magnetic force. The second kind is the coil cut way, which divides the stator coil into two parts. The electric current will go through two coils under the slow-speed and go through only one coil under the high speed. The third kind is the exciting coil way, which changes the magnetic flux by changing the electric current through the coil. The motor technology, used in the new generation of electric automobile, the motors with variable magnetic force attracts high attention. The motors with variable magnetic force is a kind of technology that can change the magnetic force in the motors depending on the revolution of the motors. Recently the method of changing the magnetic force of stators starts to be practical. At present Toshiba is developing the method of using the motors with variable magnetic force. Toshiba selects samarium magnets. The magnetization and demagnetization of motors with variable magnetic force is realized with the high short pulse electric current through the stator. Toshiba has used this motor on the washer. This makes high torque possible under slow-speed of revolution when lavation, and simultaneously realizes the high efficiency under high speed when dehydration. From this Toshiba reduced the power consumption by 16%.