Research Of The Process Of MnZn Ferrite Preparation With Solid Phase Synthesis

As solid phase synthesis has many advantages, such as preparationprocess is simple, ingredients is easy to adjust, suitable for mass production, etc, it hasbeen used for preparing MnZn ferrite by most of enterprises. Research of themechanism of MnZn ferrite preparation process with solid phase synthesis has animportant significance for the better preparation of MnZn ferrite. The developmentstatus of MnZn ferrite products, performance parameter, powder preparationtechniques and additive research progress are interviewed in this article. ThermalAnalysis and X-Ray Diffraction techniques were used for investigating the reactionsof pure MnCO₃system, Mn ferrite system, Zn ferrite system and MnZn ferrite systempreparation process under the heating rate of10K/min, and the Thermal Analysistechnique was used for studying the effects of different heating rate on pure MnCO₃system, Mn ferrite system, Zn ferrite system and MnZn ferrite system preparationprocess. Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods were used forcaculating the reaction activation energy of MnCO₃in pure MnCO₃system, Mn ferritesystem and MnZn ferrite system preparation process. The results are as following:Compared with the reactions of pure MnCO₃system, Mn ferrite system and Znferrite system preparation process, the reactions of MnZn ferrite system preparationprocess has been confirmed. For MnZn ferrite system preparation process under theheating rate of10K/min: MnCO₃â†'MnO（OH） reaction takes place near the region268-500℃; MnO（OH）â†'MnO₂â†'Mn₂O₃and Mn₂O₃+ZnOâ†'ZnMn₂O₄reactionstakes place near542℃; ZnMn₂O₄â†'Mn₂O₃+ZnO, Fe₂O₃+ZnOâ†'ZnFe₂O₄andMn₂O₃â†'Mn₃O₄reactions take place near the region702-1050℃; ZnFe₂O₄+Mn₃O₄â†'MnZnFe₂O₄reaction take place near the region1250℃.Under the condition of different heating rate（5,10,20,30and40K/min）, the endtemperature and rate of weight changes of MnCO₃â†'MnO（OH） reaction in MnZnferrite system rises and the conversion rate of MnCO₃â†'MnO（OH） reaction moves tohigh temperature region with increasing of the heating rate. The value of activationenergy of MnCO₃â†'MnO（OH） reaction in MnZn ferrite system caculated by FWOand KAS methods are67.94kJ/mol and64.31kJ/mol respectively; the value ofactivation energy in pure MnCO₃system are90.51kJ/mol and87.59kJ/molrespectively; the value of activation energy in pure MnCO₃system are74.48kJ/moland67.85kJ/mol. For the reaction of MnCO₃â†'MnO（OH）, The value of activation energy of the reaction is minimum in MnZn ferrite system, and maximum in pureMnCO₃system. The value of activation energy of MnCO₃â†'MnO（OH） reactioncaculated by FWO method is higher than those caculated by KAS method.