anisotropic hot - worked permanent magnets are made from an r - t - b alloyed powder to which is added a combination internal lubricant including a carbon - based material such as graphite and a glass material such as glass from the b 2 o 3 - sio 2 bio 3 glass system . the internal lubricant provides improved formability during the hot - working step , such as die - upsetting , and provides finished magnet products wherein the individual grains are more uniformly plastically deformed throughout the product .