Hard ferrite (ceramic) magnets were developed in the 1960's as a low cost alternative to metallic magnets. Even though they exhibit low energy (compared with other permanent magnet materials) and are relatively brittle and hard, ferrite magnets have won wide acceptance due to their good resistance to demagnetization, excellent corrosion resistance and low price per pound. In fact, measured by weight, ferrite represents more than 75 percent of the world magnet consumption. It is the first choice for most types of DC motors, magnetic separators, magnetic resonance imaging and automotive sensors.

Magnetic Properties of Sintered Hard Ferrite Chinese standard Grade Remanence Coercivity Force Intrinsic Coercive Force Max.Energy Product Br Hcb Hcj ( BH ) max mT kGs kA/m kOe kA/m kOe kJ/m3 MGOe Y10T 200-235 2.0-2.35 125-160 1.57-2.01 210-280 2.64-3.52 6.5-9.5 0.8-1.2 Y20 320-380 3.2-3.8 135-190 1.70-2.38 140-195 1.76-2.45 18.0-22.0 2.3-2.8 Y22H 310-360 3.1-3.6 220-250 2.77-3.14 280-320 3.52-4.02 20.0-24.0 2.5-3.0 Y23 320-370 3.2-3.7 170-190 2.14-2.38 190-230 2.39-2.89 20.0-25.5 2.5-3.2 Y25 360-380 3.6-4.0 135-170 1.70-2.14 140-200 1.76-2.51 22.5-28.0 2.8-3.5 Y26H 360-390 3.6-3.9 220-250 2.77-3.14 225-255 2.83-3.21 23.0-28.0 2.9-3.5 Y27H 370-400 3.7-4.0 205-250 2.58-3.14 210-255 2.64-3.21 25.0-29.0 3.1-3.7 Y30 370-400 3.7-4.0 175-210 2.20-2.64 180-220 2.26-2.77 26.0-30.0 3.3-3.8 Y30BH 380-390 3.8-3.90 223-235 2.80-2.95 231-245 2.90-3.08 27.0-30.0 3.4-3.7 Y30-1 380-400 3.8-4.0 230-275 2.89-3.46 235-290 2.95-3.65 27.0-32.0 3.4-4.0 Y30H-2 395-415 3.95-4.15 275-300 3.46-3.77 310-335 3.90-4.21 28.5-32.5 3.5-4.0 Y32 400-420 4.0-4.2 160-190 2.01-2.38 165-195 2.07-2.45 30.0-33.5 3.8-4.2 Y33 410-430 4.1-4.3 220-250 2.77-3.14 225-255 2.83-3.21 31.5-35.0 4.0-4.4 Y35 400-410 4.00-4.10 175-195 2.20-2.45 180-200 2.26-2.51 30.0-32.0 3.8-4.0