Ⅰ前言在1969年,Bate 和 Alstad 评述了磁记录材料的制备方法和特性。虽然他们介绍的各种磁粉和薄膜有可能用来制作记录表面,但当时实际记录表面所采用的材料主要还是单畴γ-Fe_2O_3磁粉和 CrO_2磁粉,而后者的使用要少得多。九年之后,这两种材料作了改进,仍然是最常用的材料,但其地位开始受到含钻氧化铁磁粉和金属磁粉的威胁。本文先介绍解决早期氧化铁磁粉的问题和缺点的方法,然后再讨论把钴扩散到γFe_2O_3或 Fe_3O_4的针状磁粉中而制得的新的含钴氧化 I. INTRODUCTION In 1969, Bate and Alstad reviewed the methods and properties of magnetic recording materials. Although the various magnetic powders and films presented by them are likely to be used to make recording surfaces, the material actually used for the recording surfaces at that time was mainly monodomain γ-Fe_2O_3 magnetic powders and CrO_2 magnetic powders, while the latter was used much less. After nine years, both materials have been refined and remain the most commonly used materials, but their status has begun to be threatened by the inclusion of iron oxide magnetic powder and metallic magnetic powder. In this paper, we first introduce the methods to solve the problems and shortcomings of the earlier iron oxide magnetic powders. Then we discuss the new cobalt-containing oxides that are diffused into acicular magnetic powders of γFe_2O_3 or Fe_3O_4