may happen along the nd rich phase furthermore if the temperature reaches 600 u00b0 c the hydrogen absorbed by the nd rich phase may decrease thus making it difficult to crush same as the embodiment 1 this embodiment of the present invention is capable of controlling the average cooling rate of the molten alloy to obtain a strip casting with evenly crystals and reducing the number of oversize crystals and undersize crystals so that even omitting jet milling process it can obtain desirable powder for compacting in the raw material preparing process nd with 99 5 purity industrial fe u2014 b industrial pure fe co with 99 9 purity and pr dy si ag ti with 99 9 purity are prepared counted in atomic percent and prepared in r e t f a g j h g i d k components preparing in accordance with the five experiments in table 6 each number has been prepared with 100 kg raw material by respectively weighing in the melting process 100 kg of the prepared raw material is put into a magnesium oxide made crucible each time an intermediate frequency vacuum induction melting furnace is used to melt the raw material in 10 u2212 1 pa vacuum below 1700 u00b0 c in casting process ar gas is filled to the melting furnace to 90000 pa after vacuum melting then on a water cooling casting plain disk the quenched alloy is obtained in a cooling rate of 10 2 u00b0 c s u02dc 10 4 u00b0 c s with average cooling rate of 1 10 3 u00b0 c s u02dc 8 10 3 u00b0 c s the thickness of the quenched alloy depends on the rotating rate of water cooling casting plain disk the.