Additive Manufactured Waveguide for E-Band Using Ceramic Materials

Ceramic materials are chemical- and temperature-resistant and, therefore, enable novel application fields ranging from automotive to aerospace. With this in mind, this contribution focuses on developing an additive manufacturing approach for 3D-printed waveguides made of ceramic materials. In particular, a special design approach for ceramic waveguides, which introduces non-radiating slots into the waveguides sidewalls, and a customized metallization process, are presented. The developed process allows for using conventional stereolithographic desktop-grade 3D-printers. The proposed approach has, therefore, benefits such as low-cost fabrication, moderate handling effort and independence of the concrete waveguide geometry. The performance of a manufactured ceramic WR12 waveguide is compared to a commercial waveguide and a conventionally printed counterpart. For that reason, relevant properties, such as surface roughness and waveguide geometry, are characterized. Parsing the electrical measurements, the ceramic waveguide specimen features an attenuation coefficient of 30–60 dB/m within the E-Band. The measured attenuation coefficient is 200% and 300% higher compared to the epoxy resin and the commercial waveguide and is attributed to the increased surface roughness of the ceramic substrate.

A mathematical model of metallization of titanium-magnetite ores of Kachkanar deposit in Midrex shaft furnace

Development of a technology for obtaining direct reduction iron from titanium-magnetite ores, which will be the main ore base of the Ural ferrous metallurgy in the future, is one of the urgent tasks of metallurgical science. The world and domestic experience of the development of direct iron reduction processes, which are the most environmentally friendly of all existing methods of obtaining iron from ore considered. It was shown that the technology of metallization of iron ore materials in the Midrex shaft furnace has received the most widespread application. It is noted that the accumulated experience of using Midrex technology in Russian Federation will allow increasing the production of metallurgical raw materials with a reduced carbon footprint. An algorithm and a block diagram for calculating technical and economic indicators of the metallization process for the Midrex process shaft furnace are described. A methodology for calculating material and thermal balance of the Midrex process has been developed, taking into account the use of iron ore raw materials containing vanadium and titanium in the charge. On its basis, an algorithm was developed and a mathematical model of the metallization process was implemented, calculations of the metallization process of titanium-magnetite pellets obtained from the ores of the Kachkanar deposit in the Midrex mine furnace were performed. A comparison of the indicators of the metallization process of titanomagnetite pellets carried out in the shaft furnace of JSC “OEMK named after A.A. Ugarov” and obtained using the created software product showed satisfactory convergence of the results.

Activation of polyethylene granules by finely dispersed zinc

The results of experimental researches of features of mechanical activation of polyethylene granules with finely dispersed zinc in a ball mill, and also results of research of chemical copper plating of activated polyethylene granules are given. The influence of the ratio of polyethylene granules and fine zinc, the speed of rotation of the ball mill and the duration of activation, as well as the degree of loading of the components in the activation process of polyethylene granules was studied. It is established that the condition of activation of polyethylene granules with finely divided zinc has a significant impact on the metallization process and the copper efficiency of activated polyethylene granules.

PECULIARITIES OF METALIZATION OF PULLED POLYETHYLENE

The results of experimental studies of the peculiarities of metallization of granular polyethylene are presented. The influence of concentration factors on the metallization process of zinc-activated polyethylene granules of brand Liten PL-10 was investigated. It is established that by changing the concentration of copper sulfate and sodium hydroxide, as well as the degree of loading of polymeric raw materials, it is possible to effectively regulate the amount of recovered copper on granules of polyethylene, and therefore the thickness of the metal layer formed on them. The use of the method of preliminary processing of activated polyethylene granules in a solution of copper sulfate can significantly reduce the induction period and increase the rate of recovery of copper ions.

New approach of friction AlN ceramics metallization with the initial FEM verification

Although, the friction method is well known for metals surface modification, the novelty of the article is based on the new idea of ceramics surface treatment with metal. The paper describes AlN ceramic metallization process by titanium coating deposition, obtained in friction surfacing method, which has been developed by the authors. The friction energy is directly transformed into heat and delivered in a specified amount precisely to the joint being formed between the metallic layer and the ceramics substrate material. The stress and temperature fields (as factors promoting the formation of diffusion joints) induced in the joint during the metallization process were qualitatively determined with the finite element method analysis and these results were verified experimentally. Finally, obtained structures of the metallic coatings were investigated and the results are discussed in the paper. As a novelty it was found, that the conditions of frictional metallization can favour the formation of a coating-substrate bond based on diffusion phenomena and atomic bonds of the coating components with the components of the substrate, despite the fact that it happens for metal–ceramics pairs. This type of connection is usually associated with long-term heating/annealing in chamber furnaces, because for diffusion in a solid state the most effective factor is time and temperature. It was shown that other components of the chemical potential gradient, such as temperature gradient, gradient and stress level, load periodicity and configuration of pairs of elements with high chemical affinity may play an important role in friction metallization. As a result, the relatively short time of operation (friction) is compensated.

The Metallurgical Characterization of Iron-Containing Concentrate

The expediency of processing iron-containing concentrate with low iron content, increased content of manganese and copper is considered in the article. To process such a concentrate, a metallization process is proposed to produce sponge iron with a reducing agent - carbon. It was found that in solid-phase reduction at 1150 °C iron is reduced to a greater extent, as well as small particles with a copper content of about 95%, manganese is not recovered. The simulation process of metallization with carbon at a temperature of 1250 °C shows that iron is mainly distributed in the metallic phase, to a lesser extent in slag phases, manganese is distributed in two phases - metal and slag, copper is presented as a separate phase of metallic copper in the composition with iron alloys, and also composes a part of iron alloys. The reduction degree from concentrate to the metallic part is 80 - 91% for iron and 95 - 98% for copper. The presence of metallized particles of various sizes, representing phases of iron with manganese and copper was found in the slags.