Dysprosium (Dy) is used in Neodymium magnets to increase coercive force of magnets. But Dy is a scarce and expensive element.
Dy is diffused in crystalline of Nd by using conventional High temperature method to add Dy. This leads to much higher consumption of Dy.
TDK a Japanese multinational electronics company has developed HAL process for production of Neodymium magnets.
HAL process diffuses Dy only to those areas in neodymium magnets where they are needed.
Magnets with top class performance are made by optimally diffusing Dy into a neodymium magnet substrate that is made in a low-oxygen process and contains only small amounts of impurities.
Remanent magnetic flux density has been improved by 3-5%.
Uses 20-50% less Dy