擠壓鑄造法製做金屬負荷磁石之性質及製程研究

Abstract

本研究利用擠壓鑄造法成功地製做出金屬複合磁石。本製程，選用之金屬為鋁合金A356與鋅合金ZAS兩種，分別與快淬釹鐵硼磁粉擠壓製成磁石。 磁性質顯示：此兩種磁石磁能積可達7.6MGOe以上。在相同之Br時，鋁合金複合磁石有稍高之磁能積。此乃鋅合金與磁粉反應生成軟磁相所致。機械性質測式顯示：鋅合金複合磁石有較佳之彎曲強度，平均約比鋁合金複合磁石高出100Mpa。其值分別為250MPa，150MPa（Br=5.5kG）。在腐蝕試驗方面，因鋅比鋁有較強之親電性，所以腐蝕後，鋅合金複合磁石之磁損失不若鋁合金複合磁石嚴重，亦即鋅合金複合磁石有較好之耐蝕性。110°C高溫，300小時時效測試，此兩種複合磁石第一個小時磁通量密度不可逆損失為5％，往後沒有隨時效時間增加而改變。

A new method was developed for forming Nd-Fe-B rapidly quenched ribbon to metal-bonded magnets. The process was carried out by squeeze casting, and A356 aluminum alloy and ZAS zinc alloy was used as a metal binder respectively in the process. Energy product of up to 7.6 MGOe was achieved for both metal-bonded magnets. The energy product of A356-bonded magnets is little higher than that of ZAS-bonded magnets on the same remanence due to soft magnetic phase formed in the process. The bending test showed that The bending strength of ZAS-bonded magnets was higher than that of A356-bonded magnets. The bending strength of both magnets were 250,150 MPa (Br=5.3kG) respectively. The corrosion behavior of both magnets were studied in salt spray test and the flux loss was measured. The results showed that ZAS-bonded has better corrosion resistance owing to cathodic protection. The long term aging test was performed at 110℃ for 300 hours on both metal-bonded magnets and the flux was measured. The flux loss showed that both magnets was stable in this test.