Interaction between Hydrogen and Ground SmCо₅ Alloy

Abstract

The paper determines the phase composition of products from interaction of ground KS37 alloy (SmCо₅ being the main and Sm₂Cо₇ the impurity phase) with hydrogen at a hydrogen pressure ofO. 1-0.4 MPa and at temperatures up to 950 °C for 5 h after conventional and solid hydrogenation and disproportionation. It is established that products oftheSm2Co7 phase resulting from grinding and forming SmCо₅, and unidentified phases interact with hydrogen to 560 °C. The SmCо₅ phase disproportionates in the temperature range 560-650 °C and pressure range 0.1-0.4 MPa for 2 h. Recombination at 650-950 °C leads to the SmCо₅, Sm₂Cо₇, and Sm₂Cо₁₇ phases. The content of SmCо₅ in the recombined alloy is the highest at 950 °C. It is shown that grinding in hydrogen prior to hydrogenation, disproportionation, desorption, and recombination accelerates the disproportionation reaction owing to the formation of defects during grinding. The fact of high-temperature recombination of the SmCо₅ phase in hydrogen is confirmed.