基于自反应喷射成形技术制备Mn-Zn铁氧体片状吸波剂

Preparation of Mn-Zn ferrite flake absorber by self-reactive spray forming technology

以Fe＋MnO2＋Fe2O3＋ZnO 为反应体系,采用自反应喷射成形技术成功制备了Mn-Zn铁氧体片状吸波剂.计算了反应体系的焓值和体系的绝热燃烧温度Tad,研究分析了片状锰锌铁氧体的形成机制.采用SEM 和XRD 分析了吸波剂的形貌和成分. 结果表明,体系Tad为2055K,满足自蔓延反应的条件,且大于反应产物熔点,保证了反应产物以熔滴形式撞击基板实现扁平化.制备的吸波剂大部分颗粒呈片状,长约150μm,厚约20μm,由Mn0.5Zn0.5Fe2O4相和少量Fe2O3 相组成. 利用网络矢量分析仪测定其在0.5-18-Hz频段内的电磁参数,吸波剂在16-Hz附近存在一个吸收峰,峰值最高达-14dB,低于-10dB的频率带宽达5-Hz,吸波性能较好,具有一定应用价值.

Fe,MnO2,Fe2O3 and ZnO as the reaction system,Mn-Zn ferrite flake absorber was prepared successfully by self-reactive spray forming technology.Enthalpy(H)and adiabatic temperature(Tad)of system are calculated to analyses the formation mechanism.SEM and XRD were used to characterize the pattern and phase of sample.According to the excess,Tadis 2 055 K,self-propagation reactive can be ignited and products can be melted,the product molten drops impacted onto cupreous plate to achieve flattening.The results showed that most of absorber were flake with diameters of 150μm long and 20μm thick,constituted by Mn0.5Zn0.5Fe2O4 phase and few Fe2O3 phase with spinel crystal structure.Absorption test showed that absorber had one absorbent peak,the maximum value of microwave reflection loss was-14 dB and the frequency range was 5GHz where the microwave absorption values are less than-10 dB.The results showed the Mn-Zn ferrite flake absorber provided with preferable property,is worthy of further study.