Gevorkyan Edwin, Cepova Lenka, Rucki Mirosław, Nerubatskyi Volodymyr, Morozow Dmitrij, Zurowski Wojciech, Barsamyan Voskan, Kouril Karel
Faculty of Mechanics and Energy, Ukrainian State University of Railway Transport, 7 Feuerbach Sq., 61050 Kharkiv, Ukraine.
Institute of Mechanical Science, Vilnius Gediminas Technical University, J. Basanaviciaus Str. 28, LT-03224 Vilnius, Lithuania.
Materials (Basel). 2022 Aug 29;15(17):5960. doi: 10.3390/ma15175960.
The paper presents and discusses questions on structure formation during the sintering process of CrO-based composites using the hot pressing method, when a chemical reaction between the components takes place. The task was difficult because CrO decomposes when sintered at temperatures above 1300 °C. The proposed novel method allowed for interaction between aluminum and chromia, thus avoiding the decomposition of the latter. Here, ultrafine aluminum powder played the role of the active agent forming a liquid phase and reacting with CrO. The appearance of the solid solutions of (Cr,Al)O with different stoichiometry of Cr and Al depended on the aluminum content in the initial mixture. The solid solution significantly strengthened boundaries between composite phases, resulting in the composite material of high fracture toughness between 5 and 7 MPa m and bending strength of ca. 500 MPa. The best mechanical properties exhibited the cermet with 22 wt.% of the restored chromium.
