It is known that epoxy molding compounds have a significant impact on productivity, service life and reliability of electronic microcircuit components. Wrong choice of a molding mixture can lead to mechanical stresses, deformation, cracking or lamination of the protective packaging followed by microcircuit breakage. The study summarizes information on composition, main operating characteristics and application methods of epoxy molding compounds as well as their impact on microcircuit shape distortion. Main methods for control of physical and mechanical properties of epoxy molding compounds with the most significant impact on microcircuit hermetic sealing and on formation of different kinds of defects in the protective packing.
The research assesses the possibilities of using local minerals to create foundry alloys that are used in conditions of low temperature. The mineral-geochemical composition of iron ore from Verkhnyaya Amga ore occurrences in the Aldan region of the Sakha Republic (Yakutia) was studied in detail. The expedience of using iron ores from this ore occurrence to develop new cold-resistant and high-strength steels was analyzed. The chemical composition and microstructure of the cast alloys were studied. The ore contains oxides of alkaline earth metals: MgO; CaO; Sr0 and BaO, the total content of which is 4.2%, that contributes to the process of deoxidation of the melt during its cooling, and the deoxidation product in the form of oxides and other chemical compounds based on Ca, Sr and Ba floats into slag. During crystallization, the melt is cleaned of detrimental impurities, non-metallic inclusions, gases, pores, etc. Alloy is smelted from enriched ore, samples for static tension and toughness are made in order to study the physicomechanical properties. Microstructure of the obtained alloy and structural steel subjected to static tension at an external load of 0.8 yield strength (σ = 0,8 σт) was investigated. Mechanical properties and dynamic characteristics were measured. Analogues for comparing the strength and plastic properties were given.
The method of direct reduction by hydrogen for iron ores of the Lensk ore field were considered in the work, the particle size, bulk density, a corner of a natural slope of products of grind and reduction of ore were defined, morphological researches, the X-ray spectral microanalysis of particles of the reduced ore material were conducted. Aluminum-based sintered powder materials with the addition of the recovered ore are obtained. It is established that temperature increase of sintering leads to reduction of residual porosity of the compacts. Samples with additive of the reduced ore keep the correct geometrical form practically in all studied ranges of changes of temperature of sintering and content of additive. Measurement of hardness of the sintered composite aluminum-based alloys with additive of powders of the reduced demonstrate that higher values of hardness are observed at structures from 14.4 and 18.7 weight % of additive of the reduced ore.
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