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Fe~(3+)(Cr~(3-))/Fe~(2+)混合离子(M~(3+)/M_(2+)原子比为2:1)共沉淀法制备的Cr_2O_3掺杂量0～14％(质量分数)系列纳米氧化铁XRD Rietveld分析表明全是晶态γ-Fe_2O_3和非晶Fe_2O_3的混合物.非晶丰度范围为21.72％～48.6％.M(?)ssbarer谱分析发现,掺杂量少于2％(质量分数)的氧化铁,晶态和非晶态均是磁性六线谱,大于2％(质量分数)后,另出现强度随掺杂量增加线性递增的超顺磁二线谱.共沉淀过程中,Fe~(3+)为主夹杂定量Cr~(3+)的Fe~(3+)水合配合物网络与Cr~(3+)为主夹杂定量Fe~(3+)的Cr~(3+)水合配合物网络,是形成磁性氧化铁和非晶非磁氧化铁的基础,后者镶嵌在前者中间,阻碍其晶化和晶粒长大,自身形成非晶非磁含铬氧化铁.
The Cr 2 O 3 doped by coprecipitation method was prepared by the coprecipitation method with Fe 3+ Cr 3+ / Fe 2+ mixed ions (M 3+ / M 2+ ratio 2: 1) The results of XRD Rietveld analysis of 0 ~ 14% (mass fraction) series of nano-iron oxides show that all of them are mixtures of crystalline γ-Fe 2 O 3 and amorphous Fe 2 O 3 .The range of amorphous abundance is 21.72% -48.6% It is found that ferrous oxide doped with less than 2% (mass fraction) of the ferrite content is in the magnetic hexagonal spectrum. When the content is more than 2% (mass fraction), the intensity of the other emerging linearly increases with the doping amount (3+) Fe (3+) hydrate complex and Cr 3+ as main inclusions in the coprecipitation process The Fe ~ (3+) Cr ~ (3 +) hydrate complex network is the basis for the formation of magnetic iron oxide and amorphous non-magnetic iron oxide, the latter being embedded in the middle of the former, hindering its crystallization and grain growth, Amorphous non-magnetic chromium oxide formed.