Abstract ▼ AI-Helper

In oder to manufacture a good priced Nd-Fe-B rare earth alloy permanent magnet, research was carried out that materialized of high residual magnetic flux density due to suppression of ?-Fe formation that resulted from applying strip casting process to alloy that contained less Nd than standard proce...

In oder to manufacture a good priced Nd-Fe-B rare earth alloy permanent magnet, research was carried out that materialized of high residual magnetic flux density due to suppression of ?-Fe formation that resulted from applying strip casting process to alloy that contained less Nd than standard process. The Nd content was reduced from 31% to 29% from common existing process, and the tapping temperature was set at 1450℃ at the moment. To achieve quick cooling of molten metal, copper wheel is used, and the nozzle of 10mm. Turn dish`s entrance length was cut at 150mm and the material used were oxidized titanium and mica. Cooling wheel`s speed was tested within the range of 1.5~3.0 m/s. After fabricating powder using HD and jet mill, magnetic press used for compact, then sintering in 1000~1060℃ for 4 hours, B-H curve tracer was used to evaluate its magnetic characteristic. As observing the strip's microstructure, dendrite structure was formed in the whole spinning speed range. In addition, it was able to verify the easy axis' culture was generally well made up in the cooling direction. As the cooling speed increases, ?-Fe phase's fraction decreases in the range of wheel speed 1.5~3.0 m/s and the price increased again in 3.0 m/s. In the result of the above's alloy all sintered in 1060℃, the magnetic characteristic was the most outstanding in the alloy gained in the cooling speed 2.5 m/s. In this condition, it is interpreted as Nd2Fe14B phase's fraction the highest and soft magnetism phase a-Fe phase's fraction the lowest.