An increase in the corrosion resistance of magnesium and its alloys is achieved by forming hybrid smart coatings. The introduction of a corrosion inhibitor makes it possible to control the degradation rate of the material due to the self-healing effect of the coating. Additional polymer treatment significantly increases the corrosion resistance and wear resistance of the material. The inhibitor efficiency and the mechanism of anti-corrosion protection of the alloy are established.

Plasma electrolytic oxidation has been used to create a sublayer on aluminum alloy to form a composite coating to improve the corrosion properties of the processed material. The evolution of protective characteristics of the resulting coatings were examined by potentiodynamic polarization during the exposure in a salt spray chamber. The absence of pittings after a 10-day test for the entire series of composite coatings on aluminum alloy confirms the high level of barrier properties of the coated samples.

The paper presents the results of the study of corrosion performance of HAp-containing coating obtained on the Mg-0.8Ca bioresorbable magnesium alloy using plasma electrolytic oxidation (PEO). Electrochemical measurements were carried out in minimal essential medium (MEM) using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) and monitoring of open circuit potential (OCP) techniques. It was established that the PEO treatment of Mg-0.8Ca leads to a significant increase in corrosion resistance of the material. Formation of heterooxide layer on magnesium alloy contributes to a decrease in corrosion current density (IC) more than three times. The impedance modulus measured at low frequency (|Z|f=0.1 Hz) for a coated material increased by two times compared to an uncoated one.

vyaly@ich.dvo.ru Abstract: The paper reveals the changes in corrosion properties of the samples with composite coating subjected to atmospheric corrosion test for 6 months. Composite coating (CC) was formed by treatment of oxide layer obtained by plasma electrolytic oxidation (PEO) with suspension of superdispersed polytetrafluoroethylene microparticles (SPTFE) in polyvinylidenefluoride (PVDF). The corrosion current density was compared for the composite coatings, PEO-coated and untreated samples. It is shown that corrosion current density for the sample with CC tested for 6 months (2.9 center dot 10-11 A center dot cm-2) is more than 3 orders of magnitude lower in comparison with the sample with PEO-layer (3.5 center dot 10-8 A center dot cm-2) and almost 6 orders of magnitude less than for uncoated aluminium alloy (1.7 center dot 10-5 A center dot cm-2).

This paper deals with the polymer composite material unique properties on self-restoration after ultimate compressive loads application. Material is based on polydimethylsiloxane elastomeric matrix with carbonyl iron particles isotropic fillers in concentration 75% wt. This composite mechanical characteristic ranges were studied in comparison with the characteristics of conventional polymer based on silicone elastomer without the fillers. The investigated material, the so-called magneto-elastic, demonstrated ability to self-restore its shape after extreme loads removal is a promising direction for the revealed unique property use and will probably be demanded for application in number fields of science and technology. The tests were carried out on an electromechanical testing machine. These materials investigating various compression modes results summarized as: the strain diagrams changes at different load ranges were plotted, the characteristics changes in their deformation properties were analyzed, the compression deformation linear and nonlinear characteristics limits were determined. The proposed compression method in various modes made it possible to determine the load changes ranges causing both irreversible changes in the conventional polymer based on silicone elastomer and its further destruction and the unique capability for self-recovery in a composite material, the so-called magneto-elastic, after similar types ultimate loads application to it.

The paper presents the results of an evaluation of the tribological characteristics of samples with composite coatings during 12 months of atmospheric corrosion. Composite coatings were obtained by treating oxide layer formed by plasma electrolytic oxidation (PEO) with fluoropolymers: superdispersed polytetrafluoroethylene (SPTFE) or polyvinylidene fluoride (PVDF), as well as a suspension of SPTFE in PVDF. It was found that the composite coatings formed in suspension with a ratio of PVDF to SPTFE 1:5 demonstrate the best tribological performance among the studied samples and characterizes by initial coefficient of friction 0.006-0.010. It is shown that samples with composite coatings have 1-1.5 orders of magnitude lower wear rate (9.7.10-5-4.4.10-4 mm3/(N center dot m)), in comparison with the PEO-treated sample (3.9 center dot 10-3 mm3/(N center dot m)).

Объектом исследования являлся наноструктурированный композит на основе свинца, состоящий из смеси фаз PbSO4 и Pb2O(SO4). Цель работы состояла в реализации синтеза наноструктурированного материала на основе серосодержащих соединений свинца методом импульсного высоковольтного разряда. Набором взаимодополняющих физико-химических методов изучены морфологические особенности, состав и структура синтезированного материала. Обнаружено, что композит состоит из наночастиц размером 20 нм, образующих субмикронные и наноразмерные агломераты. При использовании композита в качестве анода литий-ионных аккумуляторов установлено, что электрохимический механизм взаимодействия данных фаз с литием включает как необратимые процессы распада PbSO4 и Pb2O(SO4), так и обратимые реакции формирования интерметаллидов LixPb. В ходе гальваностатического циклирования в диапазоне потенциалов 1,5–0,005 В при токовой нагрузке 150 мкА/см2 композит показал емкость на уровне 390 мА·ч/г, что соответствует составу Li2,96Pb. Дальнейшее циклирование материала продемонстрировало заметную деградацию емкости. Уже на пятом цикле ее значение составило 190 мА·ч/г The object of the study was the lead-based nanostructured composite consisted of mixture of PbSO4 and Pb2O(SO4) phases. The aim of the work was to realize the synthesis of a nanostructured material based on sulfur-containing lead compounds by the method of pulsed high-voltage discharge. Morphology features, composition, and structure of materials were characterized by a number of complimentary physicochemical scientific methods. It was found that the composite consists of nanoparticles with a size of 20 nm agglomerated to submicron and nanosized spheres. The electrochemical mechanism of interactions between these phases and lithium involves both irreversible decomposition of PbSO4 and Pb2O(SO4) and reversible alloying/dealloying reactions through LixPb intermetallic compounds. During the galvanostatic cycling in a potential range of 1.5–0.005 V and current load of 150 µA/cm2, the composite showed a reversible capacity of 391 mA·h/g corresponding to Li2,96Pb. Subsequent cycling of material demonstrated an appreciable degradation of the capacity. During the fifth cycle this parameter equaled to 190mA∙h/g.

Increase of service life of gas-lubricated bearings of onboard power equipment by application of antifriction

This research is aimed at obtaining the experimental dynamic characteristics of new materials (magnetoactive elastomers exposed to the magnetic field). It demonstrates that the strength of a magnetic field has a considerable effect on the increase in the resonant frequencies of tested materials. For tests, we used a vibration stand equipped with virtual meters to visualize the experimental results on a computer display. We herein present an example of recording the frequency response on the magnetic elastomer sample input and output when exposed to vibrations caused by the unbalanced motor forces.

The formation of protective multifunctional coatings on the MA8 magnesium alloy using the method of plasma electrolytic oxidation (PEO) and subsequent treatment with fluorocarbon materials has been suggested. A complex study of tribological characteristics and morphological features of the obtained composite coatings has been carried out. After the treatment of the PEO-coating with fluoroparaffins the wear resistance has increased by more than 10 times as compared to the base PEO-layer. Hydrophobic properties of the composite coatings have been studied. It was established the contact angle changed in the range from 122° up to 137° depending on the flouroparaffin type.

We present results of the study aimed at assessing the effect of duty cycle (D) during plasma electrolytic oxidation (PEO) on protective properties of the coatings produced on 5754 aluminum alloy. It is shown that increasing the duty cycle of a microsecond current pulses leads to increased hardness and reduced abrasive wear of the PEO-layers, improving mechanical properties. The obtained data allowed confirming, that increasing the amount of energy consumed for coating growth leads to the formation of thicker PEO-layers with improved tribological properties. The effect of duty cycle during plasma electrolytic oxidation on protective properties of the produced coatings was assessed.

The work is aimed at improving the efficiency of turbomachinery with gas-lubricated bearings by applying anti-friction coatings and materials. The investigations in the field of anti-friction are mostly held abroad by several organizations. There are various coating techniques and different materials provided. Most recently used materials are graphite, molybdenum sulphate, chromium, carbon and aluminium. The most perspective coating technologies of the working surfaces of the gas-lubricated bearings are described in the article. The proposals and designs from different organizations who conduct research in this area are considered. The description of the experimental plant designed for investigation of the tribological characteristics of the axial bearings with different anti-friction coatings is contained in the article. (C) 2017 The Authors. Published by Elsevier Ltd.

Methods of electrochemical impedance spectroscopy, differential thermoanalysis and thermogravimetry showed a significant influence of the fractional composition of polytetrafluoroethylene and modes of thermal treatment on the state of composite layers on the surface of metals and alloys. The directed selection of temperature conditions depending on the used fraction of PTFE and amounts of layers of the polymer allow to provide maximal penetration of the polymer into pores and to create a uniform and continuous polymeric film on a surface. This information is essential at creation of composition, including multifunction, protective layers on the titanium products working in various temperature conditions in aggressive environments. The expediency of organic and inorganic nanosized materials usage in the process of formation composite layers on the base of PEO-method was thoroughly examined. This technological process was successfully implemented in the Far Eastern Plant “Zvezda” in the end of 2015.

In order to improve the corrosion resistance of magnesium alloys the ways of composite protective coating formation were developed by means of plasma electrolytic oxidation (PEO) as well as electrophoretic deposition methods. Electrochemical, corrosion, tribological, and morphological properties of the MAS magnesium alloy composite coatings were studied. The composite polymer-containing coating decrease the corrosion current density values by three orders of magnitude (Ic = 2.0 · 10−10 A/cm2), in comparison with the base PEO-layer. These polymer-containing layers enable one to expand the practical usage area of Mg alloys. The application of such coatings provides the increasing the bioactivity and regulate the corrosion rate of resorbable magnesium implants.

An inexpensive compact radio-transmitter was developed for the telemetry measurement of body temperature in small and medium-sized mammals. The radio-transmitter allows measuring the temperature from 15 degrees C to 45 degrees C. The signal from the transmitter may be received over the distance as large as hundreds meters and the time of its continuous work is about one year. A decrease in the transmitter dimension and prolongation of its working life without changes in the power supply were achieved, in particular, using ferrite antenna. A small electric capacitor with the temperature-dependent capacity was used as a thermal sensor. The radio transmitter allows to replace easily the battery, which significantly reduces the cost of its operation. The radio transmitter was tested in radio-tracking of common hamsters (Cricetus cricetus L.) along with measuring their body temperature under field conditions, as well as when measuring the body temperature of Russian desman (Desmana moschata L.) in captivity. A method is suggested to check the correctness of the telemetry data immediately in the course of the experiment.

The possibility of the use of Klason lignin extracted from sunflower husks as a cathode-active material for primary lithium battery has been demonstrated for the first time. The chemical composition, morphological and physical features were characterized by X-ray energy dispersive spectroscopy, impedance spectroscopy, scanning electron microscopy, and infrared spectroscopy. Electrochemical behavior of Klason lignin vs. Li/Li+ was studied by galvanostatic discharge and cyclic voltammetry. The reaction mechanism in electrochemical system was discussed. The maximum specific capacity of Klason lignin amounted to 380 mAh g–1 at a current density of 25mA g–1.

The prospects of using organic and inorganic nanosized materials are shown in the process of the formation of surface multifunctional composite protective layers obtained using plasma electrolytic oxidation on metals and alloys.