Electrical properties of magnetorheological elastomers dependences on temperature and stress

Makarova, L.A.; Rusakova, T.S.; Alekhina, Y.A.; Perov, N.S.

Авторы: Makarova L.A., Rusakova T.S., Alekhina Yu A., Perov N.S.
Сборник: Books of abstract 7th Baikal International Conference BICMM 2016 “Magnetic Materials. New technologies"
Тезисы
Год издания: 2016
Место издания: Irkutsk, Russia Irkutsk, Russia
Первая страница: 207
Последняя страница: 208
Аннотация: Magnetorheological elastomers (MRE) are so-called “smart material”, their physical properties can be changed significantly under external influences (temperature, magnetic field, stress, etc.). MRE represents diamagnetic polymeric matrix with dispersed magnetic micro- or nanoparticles. The purpose of the work was the research of dielectric permittivity of MRE based on iron (2 mkm) and NdFeB (50 mkm) particles. Mass magnetic particles concentrations were 71wt% (iron), 35wt% and 75wt% (NdFeB). To determine the dielectric properties the plate capacitor with MRE filler as dielectric was measured. The magnetodielectric effect (MDE) was revealed in MRE at room temperature, namely, the dielectric permittivity of the samples increased when external magnetic field, which was perpendicularly to the plane of the capacitor, increased. The displacement of the filled particles under external magnetic field can leaded to the MDE. Equipment with the foam plastic measuring cell and the copper-constantan thermocouple was prepared to investigate the low temperature dependence. The capacitor with the sizes 2x2 cm2 with the MRE sample was placed inside the cell, and liquid nitrogen was poured. The measuring of capacitance was occurred with immitance-meter AKTAKOM (model 3016). The heating of the sample was occurred naturally: after evaporation of liquid nitrogen the temperature increased. At the temperature 77 K of liquid nitrogen the MDE became significantly smaller, the dependence of MDE on external magnetic field was non-monotonic. The dependences of MDE of both sample types at room temperature and low temperature are presented at Fig.1. There were also determined the properties of the MRE which were restored above the glass transition temperature during heating and the MDE value reached the initial magnitude (Fig.2). The temperature dependence was reversible with some hysteresis and corresponded to the temperature change of magnetic properties measured with Vibrating Sample Magnetometer (Fig.3). To investigate the mechanical stress influence to the MDE value the measuring cell with plane capacitor with fixed closed side walls and bottom wall and the mobile top wall was prepared. Thus the elastomer placed between the capacitor plates, occupying all the space between them, the top plane fitted snugly to the sample. The mechanical stress to the MRE sample was applied by the screw and a spring, and the value of the stress can be determined by the spring deformation, which was fixed by the micrometer. The volume changers of the MRE sample were also controlled by the micrometer. It was found the influence of mechanical stress to the MDE magnitude, namely, the one became larger when stress applied.
Добавил в систему: Макарова Людмила Александровна

	ИСТИНА	Войти в систему Регистрация
	ИСТИНА ИНХС РАН
	Главная Поиск Статистика О проекте Помощь

ИСТИНА

ИСТИНА ИНХС РАН

Electrical properties of magnetorheological elastomers dependences on temperature and stressтезисы доклада

Прикрепленные файлы