Состав, структура и трибомеханические свойства покрытий TaB2

Abstract

Были получены многослойные покрытия TaB2 с различным периодом по толщине. Методом резерфордовского обратного рассеяния определен состав полученных структур и построены профили распределения примеси по глубине. Выполнены дифракционные исследования систем покрытий TaB2 с различным периодом по толщине. Определены структура, фазовый состав покрытий и характерные размеры структурных элементов покрытий. Выполнены индентационные испытания всех систем покрытие–подложка, установлена корреляция между структурными особенностями покрытий и их механическими свойствами = TaB2 coatings were grown on stainless steel substrate by plasma-enhanced reactive physical vapor deposition of two different targets composed of Ta and B with purity not less than 99.9 %. During the deposition substrates were exposed to targets vapor consistently and periodically with period of 60, 120, 180 and 240 seconds. Number of cycles was fixed at 15 and Boron was chosen as first deposited substance. The composition and structure of sputtered films were investigated by means of Rutherford backscattering spectroscopy and X-ray diffraction analysis. Indentation tests were performed using CSM Ultra Nano Hardness Tester with Berkovich diamond indenter and processed according to Oliver-Pharr method. Composition study of deposited coatings allowed to define depth profiles of constituent elements and revealed slight surface contamination by light impurity. Despite our suggestion that Ta2 and B2 phases could be detected in coatings with large period, only TaB2 peaks were identified by X-Ray diffraction. Strong effect of preferred orientation of crystallites accompanying significant decrement of hardness values for coating with period equal 120 seconds was detected. For all coatings i.e. normal indentation size effect (the hardness decreases with increasing penetration depth) was observed. Mean hardness values for TaB2 coatings according to indentation tests were 37.3 GPa (period 60 seconds), 13.6 GPa (period 120 seconds), 25.1 GPa (period 180 seconds), 34.0 GPa (period 240 seconds)