Olszówka-Myalska Anita, Wrześniowski Patryk, Myalska Hanna, Godzierz Marcin, Kuc Dariusz
Institute of Materials Science, Department of Material Science and Metallurgy, Silesian University of Technology, Krasińskiego 8, 40-019 Katowice, Poland.
Materials (Basel). 2019 Oct 4;12(19):3242. doi: 10.3390/ma12193242.
The problem of preparing a ternary powder mixture, which was meant to fabricate sintered heterophase composite, and consisted of micro- and two nanosized powders, was analyzed. The microsized powder was a pure magnesium, and as nanocomponents, a silicon powder (nSi) and carbon nanotubes (CNTs) with 2% and 1% volume fractions, respectively, were applied. The powder mixtures were prepared using ultrasonic and mechanical mixing in technological fluid, and four mixing variants were applied. The morphology of the powder mixtures was characterized with scanning electron microscopy (SEM), and then, composite sinters were fabricated in a vacuum with hot temperature pressing at 580 °C under 15 MPa pressure, using a Degussa press. The reaction between the nSi and the Mg matrix, which caused the creation of the MgSi phase in the fabricated Mg-MgSi-CNT composite, was confirmed with X-ray diffraction (XRD). The porosity and hardness of the composite sinters were examined, and optical microscopy (OM) and quantitative image analyses were carried out to characterize the microstructure of the composites. In the manufacturing process of the Mg-nSi-CNT mixtures, the best results were the following: first separate de-agglomeration of nanocomponents, then their common mixing, and finally, the deposition of nanocomponents at the surface of the microsized magnesium powder. The applied procedure ensured the uniform layer formation of de-agglomerated nanocomponents on the Mg powder, without re-agglomerated nSi and CNTs. Moreover, this type of powder mixture morphology allows to obtain sinters with lower porosity and higher hardness, which is accompanied by precipitation of a finer MgSi phase. In the Mg-MgSi-CNT composite, the carbon phase was present, and it was located in the magnesium matrix and in silicide.
分析了制备三元粉末混合物的问题，该混合物旨在制造烧结异相复合材料，由微米级和两种纳米级粉末组成。微米级粉末是纯镁，作为纳米组分，分别应用了体积分数为2%的硅粉（nSi）和1%的碳纳米管（CNT）。使用超声波和机械搅拌在工艺流体中制备粉末混合物，并应用了四种搅拌变体。用扫描电子显微镜（SEM）对粉末混合物的形态进行了表征，然后在真空中使用德固赛压力机在580℃、15MPa压力下进行热压烧结制备复合烧结体。用X射线衍射（XRD）证实了nSi与镁基体之间的反应，该反应导致在制备的Mg-MgSi-CNT复合材料中生成了MgSi相。检查了复合烧结体的孔隙率和硬度，并进行了光学显微镜（OM）和定量图像分析以表征复合材料的微观结构。在Mg-nSi-CNT混合物的制造过程中，最佳结果如下：首先对纳米组分进行单独解聚，然后进行共同混合，最后将纳米组分沉积在微米级镁粉表面。所采用的工艺确保了在镁粉上形成均匀的解聚纳米组分层，而不会出现nSi和CNT的重新团聚。此外，这种类型的粉末混合物形态能够获得孔隙率较低和硬度较高的烧结体，同时伴随着更细小的MgSi相的析出。在Mg-MgSi-CNT复合材料中，存在碳相，它位于镁基体和硅化物中。
