MnZn软磁铁氧体纳米粉末的烧结特性

The Sintering Characteristic of Nanosized Mn-Zn Soft Magnetic Ferrite Powders

锰锌铁氧体纳米粉末具有很强的活性,其烧结特性对于烧结工艺参数十分敏感。采用纳米粉末生产软磁铁氧体可以明显降低烧结温度,缩短烧结时间,有利于铁氧体化学成分和显微组织的控制,进而改善铁氧体的磁性能。研究表明铁氧体纳米粉末在700℃左右烧结后的密度已接近理论值,纳米粉体对加热速度十分敏感,而且由于纳米粉体比表面积大,容易发生氧化,因此烧结气氛必须严格控制,采用氮气气氛,并调节平衡氧分压。本文结合粉末基本的烧结理论以及纳米粉体特性,对MnZn铁氧体纳米粉末的烧结特性进行分析。

Because of the superfine grain, nanosized MnZn ferrite is of strong reactivity, and the sintering characteristic of powders is very sensitive to the sintering process parameters. MnZn ferrite can be prepared from nanosized powders by decreasing the sintering temperature, and reducing the sintering time, which is advantageous to the control of the composition and microstructure, and consequently to the improvement of magnetic properties . It shows that nanosized MnZn ferrite powders can be sintered to nearly theoretical density at temperatures as low as 700℃. However, the nanosized powders are sensitive to the heating rate. Due to the high specific surface area of nanosized powders, they are very susceptible to oxidation. So the sintering atmosphere must be controlled strictly. The sintering should be in a nitrogen atmosphere and the equilibrium oxygen pressure is changed constantly. In this paper, according to the basic sintering theory of powders and the sintering characteristic of the nanosized powders, the sintering characteristic of the nanosized MnZn ferrite is analyzed.