A Setup for Preparation of Glass-Carbon Coatings on TiO2-Nb2O5 Intended for Hip Joint Prostheses

A setup for preparation of glass-carbon coatings on TiO2-Nb2O5 ceramic materials, intended for implants for surgery of hip joint prostheses, is described. The setup described consists of vacuum tight ceramic chamber; programmable high temperature furnace and a system for controlled introduction of inert gas into the chamber. The setup allows working with temperatures up to 1350 oC, controlled heating rates from 1 to 15 oC/min and chamber pressures down to 10-2 mmHg

Investigation of Titanium Hydride Produced from Titanium Waste

The work presents an original method for titanium hydride production by hydrogenation and dehydrogenation of titanium waste in a specially designed for this purpose vacuum chamber. Laboratory quantities of titanium hydride were prepared using LaNi5 hydrogen accumulator as a source of pure hydrogen. Chemical, X-ray, DTA, TG and granulometric analysis of the obtained hydride were made. The analyses carried out in the temperature range, 680-1070 К, DTA, TG and mass-spectrometry analysis allowed determining the activation energy of decomposition of the obtained TiH2 which was approximately E = -135.5 kJ/mol and the standard enthalpy of formation ΔH = -140 kJ/mol

Study of the Sintering Process of Iron Powders Coated with Nano-Hydrocarbon and the Resulting Microstructure at Temperatures up to 1200°C

The objective of the research is development and study of a new ecologically friendly and technologically advanced method for introduction of carbon during sintering of low alloyed iron powders ASC 100.29. The method is based on using hydrocarbon coating of the green powder, which transforms into carbon nanolayers between the powder particles, during the sintering process. The method avoids the use of graphite as alloying element and reductant, and allows for a much better homogenization, less porosity and overall increase of the quality of the final sintered product. The research presented is focused on the processes related to apparent density, fluidity and compressibility of the coated powder and resulting porosity after pressing and sintering. The aim is to determine the optimal coating conditions, and to acquire experimental data concerning key processes during the sintering and the originated microstructure. The sintering process was monitored in situ through DTA measurements and measurement of the exhaust gases pressure. Results obtained so far show better handling conditions for the green coated powders, compared to those using classical approach and higher homogeneity of the sintered specimens

Glass-Carbon Bioactive Coatings on a TiO2- Nb2O5 Substrate

The research carried out studies the processes of coating and impregnation of non-active glass carbon coatings on TiO2-Nb2O5 substrates, intended for surgery implants for hip joint prostheses. It was found that the coating procedure implemented and the subsequent impregnation, lead to filling of the substrate’ pores with glass carbon, thus resulting in a substantial decrease of the substrate’s roughness. It was found that preliminary treatment of the substrate aiming at a formation of TiC on its surface is important for the subsequent buildup of a stable glass-carbon coating. The tribological measurements carried out show substantial decrease of the friction coefficient of vitreous carbon (VC) – hip joint, which is the prerequisite for using these coatings as surgery implants for hip joint prostheses

Numerical Investigation of the Air Flow Effects on Amorphous Alloy Ribbon Formation

During the amorphous ribbon production process, the mechanisms that cause uneven thickness and herringbone on two surfaces of the ribbon are very complicated. The high velocity rotating roller causes periodic air eddies near the surface and air flow around the contact zone. The air flow might be the major reason that causes the non-uniformity thickness and the ripples. In this paper, a two-dimension model was developed to simulate the air flow eddies and a three-dimensional simulation was performed for the air flow field around the puddle zone. Simulation results show that the higher velocity of air flow around the puddle edges is closely related to thicker ribbon rim. The continuous air eddies along the roller surface and the air flow fluctuations along the roller width are the major reasons causing non-uniform convective heat transfer during ribbon solidification. The frequency of air eddy matches well with the nominal ripple frequency along the ribbon length, and the air flow fluctuation coincides with the herringbone wavelength along the ribbon width. The influences of the air flow on cooling, ribbon thickness, and herringbone phenomena are all discussed here

Aluminum Surface and Bulk Nanocomposites

В этой книге демонстрируется использование метода порошковой металлургии для получения объемных нанокомпозитов с алюминиевой матрицей и электронно-лучевой обработки поверхности нанокомпозитов с наполнителями из наночастиц. В нем разъясняются микроструктура и свойства поверхностных и объемных нанокомпозитов на алюминиевой основе, а также исследуется роль наночастиц в процессе формирования микроструктуры и упрочнения нанокомпозитов. В книге также моделируется процесс формирования структуры в сплаве AlSi12Cu2NiMg, подвергнутом электронно-лучевой обработке, с использованием программного обеспечения MAGMASOFT®.Используемые программы Adobe AcrobatThis book demonstrates the use of the powder metallurgy method for producing bulk aluminum matrix nanocomposites and electron beam treatment for the surface nanocomposites with nanoparticle fillers. It clarifies the microstructure and properties of the surface and bulk nanocomposites on the aluminum base, and explores the role of nanoparticles in the process of microstructure formation and strengthening of nanocomposites. The book also simulates the structure formation process in AlSi12Cu2NiMg alloy, subjected to electron beam treatment, using the MAGMASOFT® software