噴霧造粒鐵粉之性質及其熱脫脂行為

Abstract

噴霧造粒是產生造粒粉最簡便的方法，噴霧造粒主要的優點在於造粒後的粉末具有流動性、好的成形性以及高的生胚密度。本實驗研究在不同製程參數、泥漿固含量、泥漿黏度、黏結劑種類對於噴霧造粒之影響以及造粒粉的特性。 實驗結果顯示，噴霧造粒確實可以大幅提高粉末之流動性，對於石墨和Fe-30%Ni之複合粉而言，造粒後粉末之流動性可達88 sec/50 g(8 sec/cm3)；而對羰基鐵粉而言，造粒後粉末之流動性可達27 sec/50 g(4 sec/ cm3)。 本實驗也探討羰基鐵粉在不同熱脫脂溫度下碳含量之變化及其顯微結構的改變，以瞭解羰基鐵粉之燒結行為，實驗發現在600℃以上之高溫，羰基鐵粉之洋蔥狀組織會消失，而在600℃和700℃時之羰基鐵粉顯微結構發現有Fe3C顆粒的存在，到900℃以後即消失。

Spray drying is a widely used process for producing granulated powders. It provides spray dried powders with good flowability, good compactability, and high green density. This research examined the effects of different processing parameters, solid content, slurry viscosity, and binder type on spray drying and the characteristics of the resulted granulated powders. The results showed that the flow rates of the powders were 88 sec/50 g(8 sec/cm3) and 27 sec/50 g(4 sec/cm3) for Fe-30%Ni / graphite and carbonyl iron powders, respectively. This study also examined the effects of thermal debinding temperature on the carbon contents and the microstructure of the carbonyl iron powder. The results showed that the onion structure disappeared when the thermal debinding temperature was higher than 600OC. The Fe3C compound was formed at 600OC and 700OC, it then disappear after 900OC.