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Oxidation process of the steel/nc-TiC nanocomposites

Ceramic composites are widely used in various technologies such as tool production, aerospace technology, and nuclear power engineering. Their key features are considerable hardness and resistance to wear and corrosion at high temperature. Because many ceramic nanocomposites are designed to work at high temperature, it is important to determine their high temperature corrosion resistance. The subject of the investigation in this study were nanocomposite MMC (metal matrix composite) materials. As matrix the 316L stainless steel was used and the filler (nanoparticles) was nc-TiC. Using carbonized and purified nc-TiC particles the technology of the production of the nanocomposite structures based on the selective laser melting (SLM) technology was worked out. The MCP HEK Realizer II device was applied. The particles have been depicted by TEM method, whereas characterization of structure and particles size was performed by XRD method. The results of investigations on oxidation process of the steel/ncTiC nanocomposites in dry air have been presented. TG-DSC measurements were carried out under non-isothermal conditions at linear change of samples temperature in time and under isothermal conditions. MS method was used to determine evolved gaseous products.

Analysis of (NH4)6Mo7O24·4H2O thermal decomposition in argon

Nanometric carbides of transition metals and silicon are obtained by using precursors. Control of the course of these processes require data concerning transformations of single precursor, transformations of precursor in the presence of reducing agent and synthesis of the carbide. In this work, the way of investigating such processes is described on the example of thermal decomposition of (NH4)6Mo7O24·4H2O (precursor) in argon. The measurements were carried out by TG–DSC method. The solid products were identified by XRD method, and the gaseous products were determined by mass spectrometry method. There was demonstrated that the investigated process proceeded in five stages. Kinetic models (forms of f(α) and g(α) function) most consistent with experimental data and coefficients of Arrhenius equation A and E were determined for the stages. The Kissinger method and the Coats–Redfern equation were applied. In case of the Coats–Redfern equation, the calculations were performed by analogue method. In this way good consistency between the calculated and determined conversion degrees α(T) at practically constant values of A and E were obtained for distinguished stages and different sample heating rates.

Effect of milling time on thermal treatment of TiC, TiB2/steel powders

The results of investigation on influence of the milling process on mixed powders of nanocrystalline TiC and TiB2, obtained in non-hydrolytical sol–gel synthesis, and 316L stainless steel are presented. The powders have been used as substrates to prepare nanocomposite materials by Selective Laser Sintering/Melting process. In present work thermal analysis results along with the composition and structure of nanocrystalline powders have been presented. During investigation the following analytical techniques have been applied: XRD, TEM, TG-DSC-MS and SEM.

Investigations on NH4VO3 thermal decomposition in dry air

The results of investigations on thermal decomposition of NH4VO3 in dry air have been presented. TG–DSC measurements were carried out under non-isothermal conditions at linear change of samples temperature in time and under isothermal conditions. Characterization of the products structure was performed by XRD method. MS method was used to determine evolved gaseous products. The decomposition of NH4VO3 was described by the following equation:

Mechanical Properties of Metal Matrix Nanocomposites Synthesized by Selective Laser Melting Measured by Depth Sensing Indentation Technique

6 {\text{NH}}_{ 4} {\text{VO}}_{ 3} \to \, \left( {{\text{NH}}_{ 4} } \right)_{ 3} {\text{V}}_{ 6} {\text{O}}_{ 1 6} \to \, \left( {{\text{NH}}_{ 4} } \right)_{ 2} {\text{V}}_{ 6} {\text{O}}_{ 1 6} \to {\text{ V}}_{ 2} {\text{O}}_{ 5}.

Analysis of the Mechanisms of Cracking Selected Transition Metal Carbides

In this work, the results of investigations of manufacturing ceramic materials on the basis of Ti, B, C and N containing systems are presented. The nanocrystalline ceramics were synthesized using a non-hydrolytic sol-gel method. The process was carried out in two stages. In the first low-temperature stage the precursor was obtained. The synthesis of ceramic phases, however, was conducted in the second high-temperature stage, in an argon atmosphere. Depending on the initial composition of the mixtures, the temperature and the time, the following products were obtained: TiCx, TiCxN1−x, TiB2 and B4C.The course of the process was investigated by thermogravimetric and differential scanning calorimetry methods (TG-DSC) coupled with mass spectrometry (MS). The solid state products were identified with use of X-ray diffraction (XRD). The size of the crystallites was estimated by the Scherrer method. The structure and morphology images of nanocrystalline powders were obtained using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Influence of cerium concentration on the structure and properties of silica-methacrylate sol–gel coatings

This work presents an investigation of basic mechanical properties (hardness, Young modulus) of metal matrix composites (MMC) reinforced with non-oxide ceramic nanoparticles by means of nanoindentation measurements. The evaluated materials were manufactured by selective laser melting (SLS/M). As a matrix 316L stainless steel and as a reinforcing phase TiC nanoparticles were used. The influence of nanoscale reinforcement on the mechanical properties of MMC manufacturing with SLS/M process was examined. In this case statistical evaluation of hardness and Young modulus based on nanoindentation data was performed.