Features of the structure of metal composite alloy obtained by electric slag remelting with controlled magneto-hydrodynamic action

The results of experimental studies on the use of mineral raw materials containing zirconium oxides without its deep technological processing to create alloys by electroslag remelting are presented. Dependences of the transition of zirconium into remelted low-carbon steel on the magnitude of electromagnetic pulses have been established. It has been experimentally proven that zircon concentrate can be used as an alloying component to obtain alloyed alloys and coatings in electroslag technologies. In this case, the concentrate is used in a comprehensive manner, without additional technological processing

Features of the structure of metal composite alloy obtained by electric slag remelting with controlled magneto-hydrodynamic action

The results of experimental studies on the use of mineral raw materials containing zirconium oxides without its deep technological processing to create alloys by electroslag remelting are presented. Dependences of the transition of zirconium into remelted low-carbon steel on the magnitude of electromagnetic pulses have been established. It has been experimentally proven that zircon concentrate can be used as an alloying component to obtain alloyed alloys and coatings in electroslag technologies. In this case, the concentrate is used in a comprehensive manner, without additional technological processing

UHMWPE/CaSiO₃ Nanocomposite: Mechanical and Tribological Properties

This paper studied the effect of additives of 0.5–20 wt.% synthetic CaSiO3 wollastonite on the thermodynamic, mechanical, and tribological characteristics and structure of polymer composite materials (PCM) based on ultra-high-molecular weight polyethylene (UHMWPE). Using thermogravimetric analysis, X-ray fluorescence, scanning electron microscope, and laser light diffraction methods, it was shown that autoclave synthesis in the multicomponent system CaSO4·2H2O–SiO2·nH2O–KOH–H2O allows one to obtain neeindle-shaped nanosized CaSiO3 particles. It was shown that synthetic wollastonite is an effective filler of UHMWPE, which can significantly increase the deformation-strength and tribological characteristics of PCM. The active participation of wollastonite in tribochemical reactions occurring during friction of PCM by infrared spectroscopy was detected: new peaks related to oxygen-containing functional groups (hydroxyl and carbonyl) appeared. The developed UHMWPE/CaSiO3 materials have high wear resistance and can be used as triboengineering materials

Electrolyte exposure time effects on structure, composition and biocompatibility of microarc oxidation coatings on Mg-Ca-Zn alloys

The problem of using magnesium in medicine is biodegradation, which leads to the loss of the implant mechanical integrity before the bone tissue formation. Doping and subsequent coating deposition is an effective solution to this problem. This paper investigates the effects of electrolyte exposure time during micro-arc oxidation of the Mg-Ca-Zn alloy on its phase composition, biodegradation, and biocompatibility. As a result of micro-arc oxidation, a dense coating with a gradient structure is formed on the surface of the Mg-Ca-Zn alloy, consisting of amorphous and amorphous-nanocrystalline parts. The amorphous layers of the coating mainly consist of O, P, and Mg. The nanocrystalline layer is enriched in F, while the diffusion zone is enriched in O, F, and Mg. The coating has a porous structure typical for microarc oxidation. The nonlinear behavior of the diffraction pattern at small diffraction angles indicates the amorphous state of the coating. The amount of amorphous component is increasing with exposure time, indicating an increase in the coating thickness. Scratch testing with a diamond indenter tip indicates good coating adhesion. All coated Mg-Ca-Zn samples show a significant reduction in weight loss compared to the uncoated sample after 21 days in the culture medium. Surgical treatment of rabbit femurs with implants made from coated Mg-Ca-Zn samples demonstrated high biocompatibility. Clinical evaluation of the results showed a complete absence of purulent-inflammatory complications in all animals during the first 28 days after implantation

A Study of the Wear Mechanism of Composites Modified with Silicate Filler

The article considers the effect of a filler based on synthetic wollastonite (CaSiO3), which is introduced into a polymer matrix made of ultra-high molecular weight polyethylene, on the tribotechnical parameters of the produced polymer composite material. Behavioral features of composites after friction were investigated by infrared spectroscopy and scanning electron microscopy. It was found that the introduction of wollastonite into the polymer matrix contributed to a reduction in the friction coefficient by 23% and the wear rate by four times. In the micrographs of the friction surfaces of the obtained composite, the formation of new secondary structures oriented along the friction direction, different from the initial polymer matrix, was revealed. The presence of wear products (oxidized polymer groups) and CaSiO3 on the friction surfaces was recorded by infrared spectroscopy. It was established that the synthesized CaSiO3 particles were deformed under the action of shear forces and participated in tribochemical processes

A Study of the Wear Mechanism of Composites Modified with Silicate Filler

The article considers the effect of a filler based on synthetic wollastonite (CaSiO3), which is introduced into a polymer matrix made of ultra-high molecular weight polyethylene, on the tribotechnical parameters of the produced polymer composite material. Behavioral features of composites after friction were investigated by infrared spectroscopy and scanning electron microscopy. It was found that the introduction of wollastonite into the polymer matrix contributed to a reduction in the friction coefficient by 23% and the wear rate by four times. In the micrographs of the friction surfaces of the obtained composite, the formation of new secondary structures oriented along the friction direction, different from the initial polymer matrix, was revealed. The presence of wear products (oxidized polymer groups) and CaSiO3 on the friction surfaces was recorded by infrared spectroscopy. It was established that the synthesized CaSiO3 particles were deformed under the action of shear forces and participated in tribochemical processes

Tribological Properties of Ti-TiC Composite Coatings on Titanium Alloys

The application of titanium and its alloys under friction conditions is severely restricted, owing to their poor wear resistance. The paper presents the results of studies of the composition, microstructure, and tribological properties of Ti-TiC-based composite coatings formed on titanium alloys by the electroarc treatment in an aqueous electrolyte using a graphite anode. It has been found that TiC grains have a different stoichiometry and do not contain oxygen. The grain size varies from hundreds of nanometers to tens of micrometers, and the micro-hardness of the treated surface reached the value of 29.5 GPa. The wear resistance of the treated surface increased approximately 40-fold, and the friction coefficient with steel decreased to 0.08–0.3 depending on the friction conditions. The formation of a composite material based on Ti-TiC will contribute to the effective protection of titanium alloys from frictional loads in engineering