摘要钴铁氧体具有大的磁致伸缩系数和稳定的热响应，还可以用于实现制备复合多铁性材料，具有很大的研究价值。本论文采用固相合成法与共沉积法分别制备出微米级和纳米级钴铁氧体粉末，运用干压法成型和固相烧结法来制得CoFe2O4陶瓷，通过改变成型压力、烧结温度、保温时间并观察不同尺寸粉料的CoFe2O4陶瓷烧结前后的致密度、横向收缩率、微观结构的影响规律。研究发现，钴铁氧体陶瓷的密度随温度升高而升高，微米级CoFe2O4陶瓷在1250℃时密度达到最大4。72g/cm3，此时的收缩率为11。92%，纳米级CoFe2O4陶瓷最大到3。35g/cm3，此时横向收缩率为21。92%。而保温时间对密度的影响规律与温度的影响规律极为相似。成型的压力大小会影响初始密度，但是对最终的密度影响不大。颗粒小的纳米陶瓷烧结后内部空间变化大于颗粒大的微米级，所以纳米CoFe2O4的收缩率总是大于微米级的。由于颗粒小的纳米粉料晶粒生长快，间隙大，其表面粗糙无序，微米级则颗粒生长均匀。86375

毕业论文关键词：钴铁氧体；烧结；致密度；收缩率

Abstract Cobalt ferrite has a large magnetostrictive coefficient and a stable thermal response。 It can also be used in the preparation of composite materials, which has great research value。 This paper by solid phase synthesis method and codeposition of micron and nanometer cobalt ferrite powders were prepared, using dry pressing molding and sintering of CoFe2O4 ceramic, by changing the molding pressure, sintering temperature, holding time and to observe the influence rule of CoFe2O4 ceramic sintering of powder in different sizes before and after the induced density, lateral contraction ratio, the microscopic structure。 The study found that the cobalt ferrite ceramics density with temperature rising and CoFe2O4 micron ceramic in 1250℃when the density reached maximum 4。72g/cm3。 At this time of contraction rate of 11。92%, CoFe2O4 nano ceramic to the largest 3。35g/cm3。 At this time the transverse shrinkage rate is 21。92%。 The influence of holding time on the density is similar to that of the temperature。 The shape of the pressure will affect the initial density, but it has little effect on the final density。 After sintering, the internal spatial variation of the nano ceramic particles is larger than that of the micron scale, so the shrinkage rate of CoFe2O4 is always greater than that of micron level。 Due to the small particle size of the nanometer powder, the gap is large, the surface is rough, and the particle size is uniform。

Key words: Cobalt ferrite; sintering; density; shrinkage ratio

              目  录

第一章  绪论 1

1。1 引言 1

1。2 CoFe2O4研究概况 2

1。3 纳米陶瓷制备工艺 4

1。4 课题研究依据和意义 6

第二章  CoFe2O4陶瓷烧结实验研究 7

2。1 纳米粉体合成 7

2。2 微米粉体合成 9

2。3 坯体成型 10

2。4 陶瓷烧结 12

第三章  粉料尺寸对烧结的影响及机理 15

3。1 粉料尺寸对密度的影响规律 15

3。2 粉料尺寸对横向收缩率的影响规律 20

3。3粉料尺寸对陶瓷结构形貌的影响规律