超细海棉镍的烧结行为考察

An Investigation in the Sintering Behaviour of Super Fine Sponge-Nickel

用化学法制得比表面积为７４．７ｍ＾２／ｇ的超细海棉镍，其平均粒度为２－５ｎｍ，在３７５－６００℃范围内的不同气氛中进行烧结，并在一定时间间隔内对样品进行表面积测定，且采用扫描电镜、透射电镜，Ｘ射线衍射等手段对烧结前后的样品进行对比，结果表明，微细镍颗粒在４００℃即已有明显烧结；烧结使表面积减小，颗粒度增大，结晶度提高；在不同气氛中烧结程度不同，在Ｈｅ，Ｎ２，Ｈ２中烧结程度依次减轻，开始烧结阶段。

Super fine sponge-Ni material was obtained by the method of chemistry, which has the surface area of 74. 7 m2/g and average of particle size of 2-5 nm. After sintering in the range of 375￣600℃ and in different gases at each time interval, the samples were taken out and instrumental methods of SSA, SEM, TEM, XRD were used to detect their sintering extents respectively. It is found that the sintering takes place at 400℃ evidently; sintering reduces the surface area, increases the particle size, and develops crystallization: and that in different gases the SSA follows the order: He<N2<H2. In the present work the sintering rate equationis established. it is advanced that during the initial fast sintering stage,the main mechanism is particle migrationi while at the following slow sintering stage,the main mechanism is atom migration. The accompanying phenomena in sintering process are discussed also.