Influence of nanosized titanium carbide on the synthesis, structure and properties of a composite material based on titanium carbosilicide

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Obtaining porous titanium carbosilicide and its heat resistance

The results of studies on the production of titanium carbosilicide with porosities of 20, 40, and 60 % are presented. Experimental samples were obtained using a pore former in the form of NaCl crystals. Sintering of porous samples at temperatures up to 1300 °C was characterized using thermomechanical analysis. The pore structure was studied at the macro- and micro-scale levels using the method of optical microscopy. The nature of the oxidation of the studied samples was revealed by the change in their mass from the duration of the tests and the depth of corrosion in air at 1100 °C. It was found that during high-temperature oxidation, predominantly titanium oxide is formed in the form of rutile using X-ray diffraction analysis and Raman spectroscopy. Ill. 6. Ref. 27. Tab. 2.

INFLUENCE OF STRUCTURAL-PHASE CONDITION ON THE MECHANICAL-TRI BOLOGICAL PROPERTIES OF Ti3SiC2 COATINGS OBTAINED BY THE DETONATION METHOD

The article provides the results of the research of the structure and properties of powder coatings based on titanium carbosilicide Ti3SiC2 obtained by detonation spraying on the surface of tool steel U9/У9 (equivalent to N9). Micro-indentation methods and abrasive wear tests for mechanical and tribological properties of Ti3SiC2 based coatings were conducted. The microstructure of the coating has a layered structure. The border between the coating and the base has a characteristic crinkled appearance. It was determined that the phase composition of the coatings changes during detonation spraying is a result of the decomposition of Ti3SiC2 powder into titanium carbide and titanium carbosilicide (secondary phases). Selected consolidation conditions ensure the formation of a Ti3SiC2/TiC composite material. The influence of the second phase content (TiC, TiO2) on the properties of coatings was studied. Studies of the microhardness of samples with coatings showed that, in the entire range of annealing temperatures, the microhardness of the Ti3SiC2/TiC composite material increases compared to the coating before annealing. It was found that the maximum microhardness of the Ti3SiC2/TiC composite material after annealing at a temperature of 800 ○C is explained by an increase in the content of the Ti3SiC2 phase. It was established that, during detonation spraying of Ti3SiC2 powders, a coating with a higher microhardness and wear resistance is formed.

Structure and Properties of Detonation Coatings Based on Titanium Carbosilicide

Как известно ранее, карбиды, силициды и карбосилициды металлов обладают уникальным сочетанием высокой твердости, коррозионной стойкости и износостойкости [1]. Однако получение таких фаз традиционными методами связано с высокой температурой и продолжительностью их синтеза. В то же время технология получения защитных покрытий из таких композиций ограничена. Газотермические методы (электрическая дуга, газовое пламя, плазма, детонация и т. Д.) Являются одними из наиболее широко используемых [2–5]. Во всех газотермических методах при нанесении материалов покрытия на подложку используются высокотемпературные газовые потоки, в которых частицы материала нагреваются и приобретают высокую скорость. Образование покрытия происходит, когда эти частицы взаимодействуют с подлежащим покрытию субстратом. Важным преимуществом газотермических методов покрытия является то, что они позволяют наносить различные материалы покрытия (металлы и их сплавы, оксиды, бориды, карбиды и т. Д.). Анализ классических газотермических методов нанесения покрытий показывает, что наиболее высокие прочностные свойства обеспечивают детонационные покрытия [6]

The effect of aluminum additives on the content and parameters of the fine structure of titanium carbosilicide in SHS powders

The dependence of the phase composition and parameters of the fine structure of titanium carbosilicide in powders obtained by the self-propagating high-temperature synthesis on the concentration of aluminum in the 5Ti/2SiC/1C reaction mixture was investigated. The aluminum concentration was varied in the range of 0.1–0.4 mole fraction while maintaining the total carbon content. It has been established that aluminum additives not only affect the yield of titanium carbosilicide, but also contribute to the predominant formation of Ti5Si3 instead of TiSi2 in synthesis products, which is identified in non-aluminum powders. The introduction of a small amount of aluminum (0.1 mole fraction) leads to the formation of a solid solution of Ti3Si1–xAlxC2 and reduces the content of impurity phases in SHS powders by 6 %. With a higher aluminum content in the reaction mixture, the concentration of carbosilicide in SHS powders decreases, and that of binary compounds (TiC, Ti5Si3, TiAl) increases accordingly. Within the concentration range of 0.1–0.25 mole fraction, no noticeable effect was observed from the introduction of aluminum on the crystal lattice parameters of titanium carbosilicide in SHS powders. A significant increase in the parameters a and c of Ti3Si1–xAlxC2 (from a = 3.067 Å, c = 17.67 Å to a = 3.07 Å, c = 17.73 Å) while maintaining the ratio with с/a within known values (с/a = 5.78) is observed only when the aluminum concentration is 0.4 mole fraction. The crystallite size of titanium carbosilicide depends primarily on the burning parameters. At the same time, the deformation of the Ti3Si1–xAlxC2 crystal lattice in SHS powders monotonically grows with increasing aluminum content in the reaction mixture in the investigated concentration range.