Deposition and Characterization of the Titanium-Based Coating by a Multi-Chamber Detonation Sprayer

This work introduces some of the aspects of the deposition of titanium-based coating (80-120 μm thick) on aluminium samples using a multi-chamber detonation sprayer (MCDS). The characteristic feature of MCDS is that the powder is accelerated by using combustion products that are formed in MCDS chambers and are converged before entering the nozzle, where they interact with the two-phase gas-powder cloud. The microstructures and properties of the coating were characterized with the use of scanning electronic microscopes (SEM), optical microscope (OM), X-ray Diffraction (XRD) techniques, and Vickers hardness tester with a 50 g test load. Wear tests were carried out using a computer controlled pin-on-disc type tribometer. It was established that MCDS has provided the conditions for formation of a dense titanium-based coating with a porosity of less than 1.0%, microhardness 810±250 HV0.05 and a specific wear rate of 2.077∙10-4 mm3(m∙N)-1

Вплив вмісту дисиліциду молібдену на мікроструктуру та фазові перетворення покриттів ZrB2-MoSi2-10Al після відпалу на повітрі

У роботі композитні покриття на основі ZrB2 з різним вмістом MoSi2 були виготовлені робототехнічним комплексом для детонаційного розпилення покриттів, обладнаним багатокамерним прискорювачем детонації (MCDS). Еволюцію мікроструктури та фазового складу покриттів ZrB2-xMoSi2 (х = 24, 35, 45 мас. %)-10Al аналізували за допомогою диференціального скануючого калориметра, рентгенівської дифрактометрії (in situ HT-XRD) та скануючої електронної мікроскопії при температурі від 25 до 1400 °C (нормальна атмосфера та тиск). Під час аналізу було помічено, що m-SiO2 та ZrSiO4 з'являються при 960 °C. Також при досягненні температури 1235 °С у покриттях ZrB2-xMoSi2-10Al утворюються фіаніт та муліт. В покриттях ZrB2-xMoSi2-10Al при температурі 1400 °С збільшення вмісту MoSi2 у вихідному покритті призводить до майже повного зникнення кубічної фази діоксиду цирконію, а вміст муліту збільшується. Встановлено, що мікроструктура покриття змінюється зі збільшенням вмісту MoSi2 після окислення при 1400 °C від щільної до "більш дефектної". Покриття ZrB2- 24MoSi2-10Al має рівномірну щільну мікроструктуру в порівнянні з покриттями, якф містять 35 та 45 мас. % MoSi2. Це сприяє його хорошій стійкості до окислення при високій температурі.The advantages of carbon/carbon (C/C) composites are low density, high heat capacity, resistance to thermal shock, low coefficients of friction and linear expansion, etc. However, their use in oxygen-containing environment at high temperatures is only possible with special protective heat-resistant gas-tight coatings, which prevent the access of oxygen to carbon. In this work, ZrB2-based composite coatings with different contents of MoSi2 were fabricated on the surface of C/C composites by a Robotic complex for detonation spraying of coatings equipped with a multi-chamber detonation accelerator (MCDS). Flat specimens (10 x 10 x 5 mm3) of 3D C/C composites (density 1.9 g/cm3) were used as substrates. The evolution of the microstructure and phase composition of ZrB2-xMoSi2 (х = 24, 35, 45 wt. %)-10Al coatings were analyzed with differential scanning calorimeter, X-ray diffractometry (in situ HT-XRD) and scanning electron microscopy at temperatures from 25 to 1400 °C (normal atmosphere and pressure). During analysis, it was observed that m-SiO2 and ZrSiO4 appear at 960 °C. Also, upon reaching the temperature 1235 °C, cubic zirconia and mullite are formed in ZrB2- xMoSi2-10Al coatings. In ZrB2-xMoSi2-10Al coatings at a temperature of 1400 °C, an increase in the MoSi2 content in the initial coating leads to almost complete disappearance of the cubic phase of zirconium dioxide, and the mullite content increases. It was found that the microstructure of the coating changed with an increase in the MoSi2 content after oxidation at 1400 °C from a dense to a "more defective". ZrB2-24MoSi2-10Al coating has a uniform dense microstructure in comparison with coatings containing 35 and 45 wt. % of MoSi2. It is contributed to its good oxidation-resistant property at high temperature

Deposition and Characterization of the Titanium-Based Coating by a Multi-Chamber Detonation Sprayer

This work introduces some of the aspects of the deposition of titanium-based coating (80-120 μm thick) on aluminium samples using a multi-chamber detonation sprayer (MCDS). The characteristic feature of MCDS is that the powder is accelerated by using combustion products that are formed in MCDS chambers and are converged before entering the nozzle, where they interact with the two-phase gas-powder cloud. The microstructures and properties of the coating were characterized with the use of scanning electronic microscopes (SEM), optical microscope (OM), X-ray Diffraction (XRD) techniques, and Vickers hardness tester with a 50 g test load. Wear tests were carried out using a computer controlled pin-on-disc type tribometer. It was established that MCDS has provided the conditions for formation of a dense titanium-based coating with a porosity of less than 1.0%, microhardness 810±250 HV0.05 and a specific wear rate of 2.077∙10-4 mm3(m∙N)-1

Structure and Properties of the Hardmetal Coatings Cr3C2-25NiCr Formed by a Multi-chamber Detonation Sprayer

The hardmetal Cr3C2-25NiCr (180-220 μm thick) coatings have been produced on a steel substrate by a multi-chamber detonation sprayer (MCDS). The characteristic feature of MCDS is that the powder is accelerated by using combustion products that are formed in MCDS chambers and are converged before entering the nozzle, where they interact with the two-phase gas-powder cloud. The microstructures and properties of the hardmetal coatings were examined with the use of optical microscopy, scanning electron microscopy, X-ray phase analysis, and a Vickers hardness tester with a 300 g test load. Wear tests were carried out using a computer controlled pin-on-disc type tribometer. It was established that MCDS has provided the conditions for formation of a dense hardmetal Cr3C2-25NiCr (180-220 μm thick) coatings with a porosity of less than 0.02%, microhardness 540±210 HV0.3 and a specific wear rate of 9.08∙10-5 mm3(m∙N)-1

Structure and Properties of the Hardmetal Coatings Cr3C2-25NiCr Formed by a Multi-chamber Detonation Sprayer

The hardmetal Cr3C2-25NiCr (180-220 μm thick) coatings have been produced on a steel substrate by a multi-chamber detonation sprayer (MCDS). The characteristic feature of MCDS is that the powder is accelerated by using combustion products that are formed in MCDS chambers and are converged before entering the nozzle, where they interact with the two-phase gas-powder cloud. The microstructures and properties of the hardmetal coatings were examined with the use of optical microscopy, scanning electron microscopy, X-ray phase analysis, and a Vickers hardness tester with a 300 g test load. Wear tests were carried out using a computer controlled pin-on-disc type tribometer. It was established that MCDS has provided the conditions for formation of a dense hardmetal Cr3C2-25NiCr (180-220 μm thick) coatings with a porosity of less than 0.02%, microhardness 540±210 HV0.3 and a specific wear rate of 9.08∙10-5 mm3(m∙N)-1

Ru(III) complexes with lonidamine-modified ligands

A series of bifunctional Ru(III) complexes with lonidamine-modified ligands (lonidamine is a selective inhibitor of aerobic glycolysis in cancer cells) was described. Redox properties of Ru(III) complexes were characterized by cyclic voltammetry. An easy reduction suggested a perspective for these agents as their whole mechanism of action seems to be based on activation by metal atom reduction. New compounds demonstrated a more pronounced antiproliferative potency than the parental drug; individual new agents were more cytotoxic than cisplatin. Stability studies showed an increase in the stability of complexes along with the linker length. A similar trend was noted for antiproliferative activity, cellular uptake, apoptosis induction, and thioredoxin reductase inhibition. Finally, at concentrations that did not alter water solubility, the selected new complex evoked no acute toxicity in Balb/c mice. © 2021 by the authors. Licensee MDPI, Basel, Switzerland