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Energy dispersive analysis spectrum with a selected analysis zone for (a) Fe-Si-Al powder and (b) Nd-compound particles.
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The investigation of microstructure, optical and electromagnetic properties of powder prepared from Nd-compound doped Al6Si9Fe85 (Alsifer) alloy. The result of energy-dispersive X-ray spectroscopy is an evidence that the complementary Nd-containing Nd-Fe phase is on the surface of Alsifer particles. The magnetic particles distribution histogram in...
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Context 1
... scattering parameters (S-parameters) of the prepared composites in a coaxial cell were measured using a "Deepace KC901V" vector network analyzer in the transmission line mode in 0.015−7 GHz range. Figure 1 shows the EDA spectra for a particle of the studied magnetic powder. According to the obtained results, it follows that the main fraction of particles contains Fe, Si and Al chemical elements (Figure 1, a) that correspond to the AlSiFe magnetic alloy under study. ...
Context 2
... 1 shows the EDA spectra for a particle of the studied magnetic powder. According to the obtained results, it follows that the main fraction of particles contains Fe, Si and Al chemical elements (Figure 1, a) that correspond to the AlSiFe magnetic alloy under study. However, a detailed study of the surface of the powder in the detection mode of back-reflected electrons showed the microparticles whose contrast shade was significantly different from the main powder under study. ...
Citations
... Further, we can conclude that as a microwave-absorbing filler, produced MgFe 2 O 4 powder is inferior to domestic magnetic microwave-absorbing materials previously studied by us such as magnetic microspheres [28], Fe-Si-Al alloy micropowders [29] or ferrite powders of spinel series [13,[30][31][32][33] (Table 4). However, MgFe 2 O 4 is a practical, easily produced, low-cost, ecological microwave-absorbing material. ...
... Magnesium spinel-type ferrite MgFe 2 O 4 magnetic powder material was successfully synthesized by the glycine-nitrate sol-gel auto-combustion method. Crystallinity and grain size of the Further, we can conclude that as a microwave-absorbing filler, produced MgFe2O4 powder is inferior to domestic magnetic microwave-absorbing materials previously studied by us such as magnetic microspheres [28], Fe-Si-Al alloy micropowders [29] or ferrite powders of spinel series [13,[30][31][32][33] (Table 4). However, MgFe2O4 is a practical, easily produced, low-cost, ecological microwave-absorbing material. ...
The magnesium nanosized ferrite powder with formula MgFe2O4 was synthesized via a pyrochemical sol–gel glycine–nitrate method and annealed consistently at temperatures of up to 1300 °C. The MgFe2O4 ferrite samples’ microstructure was studied by SEM and XRD methods. According to the results of the studies, the increase in MgFe2O4 nanoparticles size from about 15 nm to micron-sized particles was observed when increasing annealing temperatures. The DC electrical conductivity of MgFe2O4 also clearly shows the change in conduction behavior of samples with increased calcination temperatures. The electromagnetic microwave properties of micron-sized particles of MgFe2O4 ferrite powder for a 1200 °C annealing temperature were studied for composites in paraffin matrix with produced magnetic filler mass concentration at 40% and 50%. The filament composites of polymer polylactic acid with MgFe2O4 ferrite powder samples were prepared by the FDM 3D-printing process and their microwave-absorbing properties were investigated. The application of developed PLA–MgFe2O4 ferrite filament for fabricating magnetic microwave-absorbing components also was demonstrated.
The results of studies of the created concrete–micro-powder composites of structural steel St3 for use as radio-absorbing and radio-shielding building materials are presented. Metal ferromagnetic filler in the form of micro-powder St3 is obtained from metal chip waste raw materials. Microscopy methods and measurement of electromagnetic properties have been used to obtain data on the microstructure of the created composites and their frequency dependences of electromagnetic characteristics. According to the data obtained, the studied composite materials are applicable as low-cost radio-absorbing and radio-shielding building materials for protection against microwave radiation.
Keywords: concrete composites, steel micropowders, microwave absorption, microwave shielding, microwave radiation
Приведены результаты исследований созданных композитов бетон–микропорошки конструкционной стали Ст3 с целью использования в качестве радиопоглощающих и радиоэкранирующих строительных материалов. Металлический ферромагнитный наполнитель в виде микропорошка Ст3 получен из металлического стружечного отходного сырья. Методами микроскопии и измерением электромагнитных свойств получены данные по микроструктуре созданных композитов и частотным зависимостям электромагнитных характеристик. Согласно полученным данным композиционные материалы применимы в качестве низкостоимостных радиопоглощающих и радиоэкранирующих строительных материалов для защиты от микроволновых излучений.
Ключевые слова: бетонные композиты, микропорошки стали, радиопоглощение, радиоэкранирование, микроволновые излучения
Composite modification technology is widely used in the materials field. To enhance the property of polyurethane modified asphalt and realize its application in road engineering, the bone glue/polyurethane composite modified asphalt (CMA) was prepared using bone glue, polyurethane, and neat asphalt in this research. The bone glue content ranges 5–10%, that of the polyurethane is 1–5%. The relationship between the modifier’s content and the conventional properties and rheological properties of CMA was revealed by response surface methodology (RSM). The CMA performance was further verified under the optimal content of the bone glue and polyurethane. The differences of properties of styrene–butadienestyrene (SBS) modified asphalt mixture, neat asphalt mixture, and bone glue/polyurethane CMA mixture were compared and analyzed by using the pavement performance test. The results showed that the CMA’s conventional properties and rheological properties are improved. The optimal bone glue content and polyurethane content determined by RSM are 6.848% and 2.759%, respectively. The low-temperature crack resistance and water stability of the CMA mixture are enhanced, better than neat asphalt mixture and SBS modified asphalt mixture. The CMA mixture’s dynamic stability is 85% of SBS modified asphalt mixture, but it is 2.4 times of neat asphalt mixture. The result indicated that the bone glue/polyurethane CMA mixture still has certain advantages of high-temperature stability. In this research, the composite modification of bone glue and polyurethane can significantly enhance the characteristic of asphalt and asphalt mixture and provide a new method for applying and promoting polyurethane modified asphalt in road engineering.
