Структурные особенности и физико-механические свойства аморфоподобных покрытий AlN–TiB₂–TiSi₂

Методом магнетронного распыления мишени получено покрытие системы AlN–TiB₂–TiSi₂. При высокотемпературном (900 и 1300 °C) воздействии на покрытие наблюдается его кристаллизация с образованием кристаллитов размером 11−25 нм. Аморфоподобная структура является перспективной при использовании таких покрытий в качестве диффузионных барьеров как самостоятельных элементов, так и контактирующего слоя в многослойных износостойких покрытиях. Использование полученного композита как эффективного защитного покрытия для режущего инструмента позволит повысить его износостойкость на более 30 % при температуре в зоне резания до 1300 °C.Методом магнетронного розпилення мішені отримано покриття системи AlN–TiB₂–TiSi₂. При високотемпературному (900 і 1300 °C) впливі на покриття спостерігається його кристалізація з утворенням кристалітів розміром 11–25 нм. Аморфоподібна структура є перспективною у використанні таких покриттів в якості дифузійних бар’єрів як самостійних елементів, так і контактуючого шару в багатошарових зносостійких покриттях. Використання покриття для ефективного захисту різального інструменту дозволить підвищити його зносостійкість на понад 30 % при температурі в зоні різання до 1300 °С.Using magnetron sputtering method, obtained coatings of AlN–TiB₂–TiSi₂ system. When exposed of a high temperature on coating (900 and 1300 °C) is observed crystallize to form a crystallites with size of 11–25 nm. Amorphous-like structure is promising in the use of such coatings as diffusion barriers, in the form as independent elements, and as a contacting layer in multilayer wear resistant coatings. Use of an effective protective coating for cutting tools will improve the tool life to 1.32 times at a temperature in the cutting zone to 1300 °C

Влияние параметров осаждения нитридов высокоэнтро¬пийных сплавов (TiZrHfVNb)N на их структуру, состав, механические и трибологические свойства

Методами растровой электронной и атомно-силовой микроскопии, энергодисперсионного анализа, анализа Резерфордовского обратного рассеяния ионов, рентгено-дифракционного анализа, измерениями микротвердости и трибологическими испытаниями исследованы нитриды высокоэнтропийных сплавов (TiZrHfVNb)N, полученные при помощи вакуумно-дугового испарения катода. Обнаружено влияние параметров осаждения на структуру, морфологию поверхности, распределение элементов, механические и трибологические свойства исследуемых покрытий.Методами растрової електронної та атомно-силової мікроскопії, енергодисперсійного аналізу, аналізу Резерфордівського оберненого розсіювання іонів, рентгено-дифракційного аналізу, вимірюванням мікротвердості та трибологічними випробуванями досліджено нітриди високоентропійних сплавів (TiZrHfVNb)N, отримані за допомогою вакуумно-дугового випарування катоду. Виявлено вплив параметрів осадження на структуру, морфологію поверхні, розподіл елементів, механічні та трибологічні властивості досліджуваних покриттів.Nitrides of high-entropy alloys (TiZrHfVNb)N, which were obtained by cathode vacuum-arc evaporation, were investigated using methods of scanning electronic and atomic force microscopy, energy-dispersive analysis, analysis of Rutherford ions backscattering, X-ray diffraction analysis, by measuring of microhardness and tribological tests. Influence of deposition parameters on structure, surface morphology, elements distribution, mechanical and tribological properties of investigated coatings was found

Structural features and physico-mechanical properties of AlN-TiB2-TiSi2 amorphous-like coatings

The coating of the AlN–TiB2–TiSi2 system has been produced by the magnetron sputtering of a target. At the hightemperature (900 and 1300°C) actions the coating crystallization to form crystallites of sizes 11–25 nm has been observed. It has been defined that the amorphouslike structure is promising for the use of these coatings as diffusion barriers both as the independent elements and a contacting layer in multilayer wearresistant coatings. It has been shown that the use of the resultant composite as an effec tive protective coating for cutting tools will make it possible to increase the tools wear resistance by more than 30% at the temperature up to 1300°C in the cutting zone

Structural features and physico-mechanical properties of AlN-TiB2-TiSi2 amorphous-like coatings

The coating of the AlN–TiB2–TiSi2 system has been produced by the magnetron sputtering of a target. At the hightemperature (900 and 1300°C) actions the coating crystallization to form crystallites of sizes 11–25 nm has been observed. It has been defined that the amorphouslike structure is promising for the use of these coatings as diffusion barriers both as the independent elements and a contacting layer in multilayer wearresistant coatings. It has been shown that the use of the resultant composite as an effec tive protective coating for cutting tools will make it possible to increase the tools wear resistance by more than 30% at the temperature up to 1300°C in the cutting zone

The microstructure of a multielement nanostructured (TiZrHfVNbTa)N coating and its resistance to irradiation with Au– ions

The formation of a phase with a FCC lattice of the NaCl structure type is observed following the deposition of a multielement nanostructured (TiZrHfVNbTa)N coating. An increase in pressure results in a change in the preferred orientation of crystallite growth from the [100] axis perpendicular to the growth plane to [111]. The implantation of negative Au– ions with a dose of 1 × 1017 cm–2 and a concentration of 2.1 at % leads to the formation of a disordered polycrystalline structure with no preferred orientation of the FCC phase, reduces the size of nanocrystallites from 8 to 1–3 nm in a layer with a depth of up to 30–35 nm, and increases the nanohardness to 33.0 GPa. The large difference in atomic radii of refractory metals and the reduction in the size of nanograins in the coating contribute to an increase in hardness (51 GPa)

Heat exposure assessment based on individual daily mobility patterns in Dhaka, Bangladesh

Despite a growing body of evidence indicating increasing health impacts from heat exposure secondary to climate change, previous studies have assessed heat exposure based only on the residential locations of individuals. Such assessments may be imprecise as they do not reflect the impact of people's daily mobility patterns. Furthermore, most studies have focused on urban areas in developed countries, whilst relatively little is known about the situation in developing nations, particularly a tropical climate region where heat exposure is severe for residents. As a case study in Dhaka, Bangladesh, we conducted a heat exposure assessment by integrating individual mobility data which was obtained from a questionnaire survey. Estimates of heat exposure were made using remotely sensed land surface temperature data. Population exposures based on residential locations were compared to a dynamic exposure model that incorporated mobility. Especially for people in suburban areas, we found the traditional assessment method based on the static residential model underestimated exposure compared to the dynamic model owing to the fact that some residents migrate into the city center each day where they tend to experience higher temperatures. We found small differences in heat exposure levels between social groups stratified by gender, age, and income based on the dynamic and static models. These results demonstrate that integration of mobility patterns may be important when comparing exposure levels between urban and suburban populations. Our findings may raise issues regarding new remediation measures against urban heat islands, such as reviewing the distribution of health resources or generating a risk map

The microstructure of a multielement nanostructured (TiZrHfVNbTa)N coating and its resistance to irradiation with Au– ions

The formation of a phase with a FCC lattice of the NaCl structure type is observed following the deposition of a multielement nanostructured (TiZrHfVNbTa)N coating. An increase in pressure results in a change in the preferred orientation of crystallite growth from the [100] axis perpendicular to the growth plane to [111]. The implantation of negative Au– ions with a dose of 1 × 1017 cm–2 and a concentration of 2.1 at % leads to the formation of a disordered polycrystalline structure with no preferred orientation of the FCC phase, reduces the size of nanocrystallites from 8 to 1–3 nm in a layer with a depth of up to 30–35 nm, and increases the nanohardness to 33.0 GPa. The large difference in atomic radii of refractory metals and the reduction in the size of nanograins in the coating contribute to an increase in hardness (51 GPa)

Irradiation resistance, microstructure and mechanical properties of nanostructured (TiZrHfVNbTa)N coatings

Nitrides of high-entropy alloys (TiHfZrNbVTa)N were fabricated using cathodic-vacuum-arc-vapor deposition method. Morphology and topology of the surface of the coatings, roughness, elemental and phase composition, microstructure and mechanical properties were investigated. Dependence of deposition parameters on surface morphology and elemental composition was demonstrated. Influence of the heavy negative charged Au ions implantation on phase structure, microstructure and hardness of nitride (TiHfZrNbVTa)N coatings was investigated

Влияние имплантации наноструктурного покрытия (TiHfZrVNbTa)N высокой дозой ионов N⁺(10¹⁸ см⁻²) на его микроструктуру, элементный и фазовый состав и физико-механические свойства

Изучены структура и свойства наноструктурных многокомпонентных покрытий (TiHfZrNbVTa)N, имплантированных очень высокой (10¹⁸ см⁻²) дозой ионов N⁺.Вивчено структуру і властивості наноструктурних багатокомпонентних покриттів (TiHfZrNbVTa)N, імплантованих дуже високою (10¹⁸ см⁻²) дозою іонів N⁺.The structure and properties of multicomponent nanostructured coatings (TiHfZrNbVTa)N implanted with very high (10¹⁸ cm⁻²) doses of ions N⁺ were investigated.Работа частично финансировалась в рамках бюджетной тематики: “Разработка материаловедческих основ структурной инженерии вакуумно-плазменных сверхтвердых покрытий с целью достижения необходимых функциональных свойств”, номер государственной регистрации 0115U000685. Авторы признательны А. В. Пшику за помощь в измерении нанотвердости и приведенного модуля упругости, Д. А. Колесникову за измерения на скретч-тестере, доктору Neonila Levintant-Zayots за имплантацию образцов. Выражаем благодарность NanoBioMedical Centre (университет Адама Мицкевича, Познань), за предоставленную возможность проводить измерения на приборе Triboindentor TI-950

Influence of residual pressure and ion implantation on the structure, elemental composition, and properties of (TiZrAlYNb)N nitrides

The nitrides of highentropy alloys, (TiZrAlYNb)N, fabricated by cathodic vacuum arc evaporation are studied with electron microscopy, atomic force microscopy, laser scanning microscopy; energydispersive Xray analysis, Xray phase analysis, timeofflight secondaryion mass spectrometry; and hardness measurements. It is found that the deposition parameters influence the structure, surface morphology, element distribution, and mechanical properties. The structural–phase state of the coatings before and after the ion implantation of heavy negative gold ions Au– are compared. DOI: 10