Muhammed Fatih KILIÇASLAN, Yasin YILMAZ, Bekir AKGÜL

NdFeB esaslı kalıcı manyetik alaşımların manyetik özelliklerine uygulanan ısıl işlemdeki sürenin etkisi

Mevcut çalışmamızda, hızlı katılaştırma yöntemlerinden biri olan, şerit şeklindeki amorf ve/veya yarı kristalin yapıdaki alaşımların üretilmesinde oldukça yaygın olan ergiyik eğirme (melt spinning) yöntemi kullanılarak, NdFeB esaslı kalıcı mıknatıs şerit alaşımları üretilmiştir. Her bir NdFeB alaşımının üretimi esnasında, ağırlıkça %15 oranında atık mıknatıs, alaşımların kompozisyona dahil edilmiştir. Üretilen kalıcı mıknatıs alaşımları, 710 °C lik ısıl işlem sıcaklığı ve 285 K/s lik çok yüksek ısıtma ve soğutma hızları kullanılmak üzere 5 ve 10 dakikalık sürelerde ısıl işleme tabi tutulmuştur. Aynı sıcaklıkta uygulanan ısıl işlem süresinin, şerit alaşımların manyetik özelliklerine etkisi incelenmiştir. Artan ısıl işlem süresi ile manyetik koerzivite ve maksimum enerji ürünü özelliklerinin dikkate değer bir şekilde değişimiyle sonuçlanırken, doyum manyetizasyonu ve manyetik remenans gibi özelliklerde çok fazla bir değişim meydana gelmemiştir. Açıkça görüldüğü gibi, artan ısıl işlem süresi, manyetik koerzivitede 5030.5 Oe’den 2279.4 Oe’ye doğru sürekli bir düşüşe yol açmışken maksimum enerji ürününde önce 62.02 kJ/m3 ten 103.73 kJ/m3 e doğru çarpıcı bir şekilde artış, daha sonra ise 38.63 kJ/m3 e doğru çarpıcı bir azalma görülmüştür, bu da alaşımın kalıcı mıknatıslığındaki düşüşe işaret etmektedir.

Anahtar Kelimeler:

NdFeB, kalıcı mıknatıs, ergiyik eğirme, kalıcı mıknatıslık, ısıl işlem, süre.

Effect of heat treatment time on magnetic properties of NdFeB-based permanent magnetic alloys

In our current study, NdFeB-based permanent magnet ribbon alloys were produced by using melt spinning method, which is one of the rapid solidification methods and very common in the production of ribbon-shaped, amorphous and/or semi-crystalline alloys. During the production of each NdFeB alloy, 15 wt.% of waste magnet was included in the composition of the alloys. The produced permanent magnet alloys were heat treated for 5 and 10 minutes by using a heat treatment temperature of 710 °C and very high heating and cooling rates of 285 K/s. The effect of the heat treatment time applied at the same temperature on the magnetic properties of the strip alloys was investigated. While the increase in heat treatment time resulted in a remarkable change in magnetic coercivity and maximum energy product properties, there was not much change in the properties such as saturation magnetization and magnetic remenance. As clearly seen, increasing heat treatment time resulted in a continuous decrease in magnetic coercivity from 5030.5 Oe to 2279.4 Oe, maximum energy product first showed a dramatic increase from 62.02 kJ/m3 to 103.73 kJ/m3, and then a dramatic decrease to 38.63 kJ/m3, indicating a decrease in the permanent magnetism of the alloy.

Keywords:

NdFeB, permanent magnet, melt spinning, permanent magnetism, heat treatment, time.,

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