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本文探讨了采用氢还原法,以硫酸亚铁盐为原料制取高密度、高质量磁记录所需针状铁磁金属(合金)超微粒子的工艺过程及工艺条件。着重研究了铁磁金属(合金)超微粒子的稳定性以及掺杂处理对其磁性能及物理性能的影响。结果表明,在采用氢还原法制取针状铁磁金属(合金)超微粒子时,均匀、密实、表面平滑的针状α-FeOOH超微粒子的制取是关键之一;同时,合适的热处理及还原工艺,可减少颗粒的孔洞,防止颗粒的断裂、球化和烧结;而在α-FeOOH中掺加适量的Al、P杂质,可改善铁磁金属超微粒子的物理性能及磁性能。颗粒经过钝化后,由于每个颗粒的表面均形成一层致密、连续的氧化膜从而可减缓其进一步氧化。
In this paper, the technological process and technological conditions of using hydrogen reduction method to make acicular ferromagnetic metal (alloy) ultrafine particles required for high-density, high-quality magnetic recording using ferrous sulfate as raw material are discussed. The stability of ferromagnetic metal (alloy) ultrafine particles and the influence of doping on its magnetic and physical properties are emphatically studied. The results show that the preparation of acicular ferromagnetic fine particles with uniform, dense and smooth surface is one of the key points in the preparation of acicular ferromagnetic metal (alloy) ultrafine particles by hydrogen reduction. At the same time, proper heat treatment and reduction Process can reduce the pores of the particles to prevent the particles from breaking, spheroidizing and sintering. However, adding a proper amount of Al and P impurities into the α-FeOOH can improve the physical properties and the magnetic properties of the ferromagnetic metal particles. Passivation of particles, the surface of each particle to form a dense, continuous oxide film which can slow its further oxidation.