發(fā)布時間：2018-10-30 10:09

【摘要】：本文利用工業(yè)純的原始粉料通過氧化物陶瓷工藝制備了低功耗Mn-Zn鐵氧體材料。系統(tǒng)研究了主配方含量、預(yù)燒溫度、二次球磨時間、燒結(jié)溫度、燒結(jié)氣氛以及添加劑含量對Mn-Zn功率鐵氧體的微觀結(jié)構(gòu)與磁性能的影響。 本文首先研究了主配方含量、預(yù)燒溫度、二次球磨時間、燒結(jié)溫度和氣氛對Mn-Zn功率鐵氧體的微觀結(jié)構(gòu)與磁性能的影響。結(jié)果表明，適合的主配方含量比為Fe2O3: ZnO: MnO=52.75:10.45:36.8(mol%)。隨著Fe2O3和ZnO含量的增加，燒結(jié)樣品μi-T曲線的II峰和功率損耗的最低點均移向低溫。二次球磨時間對粉料的粒徑平均值與峰值、比表面積和活性均有較大的影響，從而影響到燒結(jié)樣品的固相反應(yīng)過程，使樣品呈現(xiàn)出不同的微觀結(jié)構(gòu)和磁性能。隨著二次球磨時間的增長，由鋼球的磨損產(chǎn)生的Fe2+對磁晶各向異性常數(shù)K1的補償作用得到加強，使燒結(jié)樣品μi-T曲線的II峰和功率損耗的最低點均移向低溫。當(dāng)預(yù)燒溫度和二次球磨時間分別為920℃和2h時，燒結(jié)樣品呈現(xiàn)出最佳的微觀結(jié)構(gòu)和磁性能。樣品欠燒(1320℃)時，其細小的晶粒較多，晶粒的均勻性較差；樣品過燒(1400℃)時，部分晶界發(fā)生明顯的變形，局部區(qū)域出現(xiàn)熔融的夾雜物。欠燒或過燒的樣品，其磁性能均相對較低；而經(jīng)1340-1380℃燒結(jié)的樣品，，其磁性能較為接近。此外，樣品在最佳溫度(1360℃)并配合二次還原氣氛燒結(jié)時，可以增大磁性能的提升幅度。 其次，利用已經(jīng)確定的主配方含量和球磨、預(yù)燒、燒結(jié)工藝，對比了微米和納米TiO2的添加量對Mn-Zn功率鐵氧體的微觀結(jié)構(gòu)和磁性能的影響。結(jié)果表明，適宜含量的微米和納米TiO2添加，均能提升Mn-Zn功率鐵氧體的磁性能。當(dāng)納米TiO2的添加量超過0.05wt%時，樣品XRD譜中的峰位明顯地移向高角度一側(cè)。晶格的收縮使樣品的內(nèi)應(yīng)力升高，從而使樣品的磁性能發(fā)生惡化。此外，微量的納米TiO2添加可以使樣品內(nèi)部的氣孔和不純物被隔離到晶界，從而使樣品呈現(xiàn)出更加均勻的晶粒結(jié)構(gòu)。100℃時，當(dāng)微米TiO2的添加量逐漸增加到0.07wt%時，燒結(jié)樣品的總功耗線性下降至315kW/m3。樣品在90-120℃的溫度范圍內(nèi)的總功耗低于330kW/m3。可見，微米TiO2的最佳添加量高于0.07wt%。此外，適宜含量的微米或納米TiO2添加，均能提高Mn-Zn功率鐵氧體的熱穩(wěn)定性。 最后，本文還研究了ZrO2含量對Mn-Zn功率鐵氧體的微觀結(jié)構(gòu)和磁性能的影響。結(jié)果表明，適宜含量(0.02wt%)的ZrO2添加，使燒結(jié)樣品呈現(xiàn)出最佳的微觀結(jié)構(gòu)和磁性能。然而，過量的ZrO2添加，將會導(dǎo)致樣品的晶粒表面出現(xiàn)大量的裂口，使ZrO2顆粒通過裂口析出到晶粒表面并發(fā)生團聚。晶粒表面的氣孔連同團聚的ZrO2顆粒對疇壁形成較大的釘扎效應(yīng)，從而導(dǎo)致了樣品磁性能的降低。
[Abstract]:In this paper, Mn-Zn ferrite materials with low power consumption were prepared by using industrial pure raw powder through oxide ceramic process. The effects of main formula content, pre-firing temperature, secondary ball milling time, sintering temperature, sintering atmosphere and additive content on the microstructure and magnetic properties of Mn-Zn power ferrite were systematically studied. In this paper, the effects of main formula content, pre-sintering temperature, secondary ball milling time, sintering temperature and atmosphere on the microstructure and magnetic properties of Mn-Zn power ferrite were studied. The results showed that the suitable content ratio of main formula was Fe2O3: ZnO: MnO=52.75:10.45:36.8 (mol%). With the increase of Fe2O3 and ZnO content, the II peak and the lowest point of power loss of the 渭 i-T curve of sintered samples are shifted to low temperature. The secondary milling time has a great influence on the average and peak particle size, specific surface area and activity of the powder, thus affecting the solid state reaction process of the sintered samples, and making the samples exhibit different microstructure and magnetic properties. With the increase of secondary milling time, the compensation effect of Fe2 produced by ball wear on the magnetocrystalline anisotropy constant K1 is strengthened, and the II peak and the lowest point of power loss of the 渭 i-T curve of sintered samples are moved to low temperature. When the pre-sintering temperature and the secondary milling time are 920 鈩

本文編號：2299703