Studies of Highly Dispersed Titanium Carbide Powder Obtained from Scrap Tungstenless Cemented Carbide Alloys

The results of research of characteristics of highly dispersed titanium carbide powder obtained from carbide waste of TN-20, TN-25, TN-30 types are presented. The powder particles were studied using analytical methods including scanning microscopy, X-ray diffraction, differential thermal analysis. The obtained results confirm the formation of nanosized particles of titanium carbide of monocrystalline form.

CHANGE IN PROPERTIES OF DIFFUSION-HARDENING SOLDER IN DEPENDENCE ON THE COMPOSITION OF THE LIQUID METAL COMPONENT

В статье обсуждается изменение свойств диффузионно-твердеющего припоя в зависимости от состава жидкометаллической компоненты на основе легкоплавких сплавов галлия: галлий-олово, галлий-индий-олово и галлий-олово-цинк при взаимодействии с порошком сплава медь-олово (ПМОСФ5) подвергнутых низкотемпературной (125 °С) и высокотемпературной (500 °С) термической обработке. Механические свойства оценены измерением микротвердости, а термические исследованы методом дифференциально-термического анализа. Термическая обработка при высоких температурах способствует переходу припоя в равновесное состояние, при этом происходит значительное увеличение твердости. По графикам дифференциальнотермического анализа рассчитаны экзотермические эффекты. Методом рентгенофазового анализа определены образующиеся в результате диффузионного твердения фазы. Показано, что при различных температурах обработки образуются разные фазы - наноразмерные интерметаллические соединения. Экспериментально доказано улучшение механических свойств диффузионно-твердеющего припоя при наличии цинка растворенного в галлиевом жидком сплаве. The article discusses the change in the properties of diffusion-hardening solder in dependence on the composition of the liquid metal component based on low-melting gallium alloys: gallium-tin, gallium-indium-tin and gallium-tin-zinc when interacting with the Spherical copper-tin alloy powder (SCTAP5) subjected to low-temperature (125 °С) and high-temperature (500 °С) heat treatment. The mechanical properties were evaluated by measuring the microhardness, and the thermal properties were studied by differential thermal analysis. Heat treatment at high temperatures promotes the transition of the solder to an equilibrium state, with a significant increase in hardness. The thermal effects of heat treatment of diffusion-hardening solders are calculated and compared. The phases formed as a result of hardening are determined by X-ray phase analysis. It is shown that different phases and nanoscale intermetallic compounds are formed at different processing temperatures. The improvement of the mechanical properties of diffusion-hardening solder in the presence of zinc dissolved in a gallium liquid alloy has been experimentally proved.

SOLUBILITY OF GERMANIUM DISELENIDE IN THE Cu3AsSe4

Differential thermal analysis and powder X-ray diffraction methods were used for phase equilibria studying in the Cu3AsSe4-GeSe2 system. It was established that wide (up to 30 mol.%) solid solutions based on Cu3AsSe4 are formed. GeSe2-rich alloys consist of various heterogeneous mixtures, including phases outside the T–x plane of this section

Processes of structure and phase formation of aerated concrete of non-autoclave hardening containing ferrosilicon as a gasifier

The paper deals with the structure and phase composition of non-autoclave aerated concrete with a density of 600–800 kg m–3 using ferrosilicon as a gasifier. The conditions of formation of porous structure of aerated concrete and preparation of calcium hydrosilicates were considered. Phase composition of the samples was investigated by means of X-ray phase analysis and differential thermal analysis. Analysis of X-ray patterns showed that the test samples contained tobermorite 11.3 Å (5CaO6SiO25.5H2O), xonotlite (6CaO6SiO2H2O) and -dicalcium silicate hydrate (2CaOSiO2H2O) as a binder. It was established that there is an increase in the content of hydrosilicate phases with an increase in the content of gasifier in the vast majority of cases. The obtained data were confirmed by the results of differential thermal analysis.

Effect of ZrO2 Nanofiller on the Physical Properties of Epoxy Composites: Mechanical, Thermal and Dielectric

In this present work, Zirconia nanoparticles were prepared by precipitation method, Zirconium Oxychloride (ZrOCl2.8H2O) and ammonia (NH3) as starting materials. The synthesized Zirconia nanoparticles were characterized by XRD and the grain size in nanoscale was confirmed. The sheets of neat epoxy resin and epoxy with addition of ZrO2 nanoparticles are primed by solution casting method. The structures of epoxy polymer and hardener were found out using FTIR analysis. The thermal properties were analyzed using Thermo Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). Thermo gravimetric analysis has been employed to investigate the thermal characteristics and their mode of thermal degradation. Differential thermal analysis has been used to determine the glass transition temperature of epoxy nanocomposites. The mechanical properties like tensile and flexural studies were analyzed and thus influences of nanofiller loading on these parameters were found to be very low. Keywords: Epoxy, ZrO2 nanoparticles, Nanocomposites, Thermal stability, Dielectric properties, Tensile strength, Flexural strength.

Hydrothermal synthesis and characterisation of zeolites from metakaolin and water glass

Zeolites were synthetised from two types of metakaolin mixed with water glass and in some samples with water. The mixtures were autoclaved for 24 hours at 130°C. Autoclaved samples were ground to analytical fineness and tested by X-ray diffraction and differential thermal analysis. Polished samples embedded in epoxy resin were studied using of electron microprobe including BSE imaging and WDX analysis of chemical composition of zeolites. Samples with the highest zeolite content were studied by SEM. The obtained results showed that the dominant synthetised zeolite in autoclaved samples is mineral chemically close to chabazite, less phillipsite. Zeolite Na-P1, gmelinite and boggsite were also identified by XRD analyses. The total content of zeolites is up to 29 wt. % in the sample prepared from a mixture containing metakaolin MK1/sodium water glass/water in weight ratio 1.5/2.5/1. The Si/Al of synthetised zeolites varies between 2.1 and 3.2.

Phase diagram studies for the growth of (Mg,Zr):SrGa12O19 crystals

By differential thermal analysis, a concentration field suitable for the growth of Zr, Mg co-doped strontium hexagallate crystals was observed that corresponds well with known experimental results. It was shown that the melting point of doped crystal is ca. 60 K higher than that of undoped crystals. This higher melting points indicate hexagallate phase stabilization by Zr, Mg co-doping and increase the growth window of (Mg,Zr):SrGa12O19, compared to undoped SrGa12O19 that grows from SrO–Ga2O3 melts.

Modification of poly(vinyl chloride) by aromatic amines: application to the extraction of some metal cation

The reaction of poly(vinyl chloride) (PVC) with various aliphatic amines in 1,4-dioxane has been studied. These reactions led to the formation of new polymers (PVC-L), which were characterized by different spectroscopic methods: differential thermal analysis (DTA) and infrared. The extraction percentages were determined by comparing the initial conductivity of the aqueous solution containing the studied metal with the final conductivity of the aqueous solution at extraction equilibrium. One of the obtained polymers gave an extraction rate of 82.05% for Li+, which underlines the importance of the substitution of chlorine atoms by diethylenetriamine groups. A kinetic study of the extraction shows that the optimal duration of extraction was obtained with the polymer most substituted by diethylenetriamine groups.

Investigation of AgI-Based Solid Solutions with Ag2CO3

The formation phenomena of silver carbonate (Ag2CO3)–silver iodide (AgI) solid solutions were investigated by X-ray diffraction, thermogravimetry-differential thermal analysis, and electrical conductivity measurement. Results revealed that AgI and Ag2CO3 reacted with each other when mixed at room temperature. The reaction products were classified into three types: (1) AgI-based solid solutions in the AgI-rich region for x = 10% or less in x Ag2CO3–(1 − x) AgI; (2) Ag2CO3-based solid solutions in the Ag2CO3-rich region for x = 60% or more; and (3) silver carbonate iodides in the intermediate range for x between 10% and 60%. For the AgI-based solid solutions, the incorporation of Ag2CO3 into the AgI lattice expanded the unit cell and enhanced electrical conductivity. The solubility limit of Ag2CO3 into the AgI lattice estimated from the differential thermal analysis was x ≈ 5%.