Structure of an alloy based on SmCo5 after disproportionation-recombination

By using the X-ray phase diffraction, metallographic, and micro-X-ray spectral analyses, we study the procedure of solid hydrogenation, disproportionation, desorption, and recombination in KS37 alloy formed by the SmCo₅ and SmCo₃ phases for ≈ 4 MPa at 1158°K. The alloy disproportionates in hydrogen into a mixture of samarium hydride and cobalt with grain sizes ≤ 1 μm. The process of recombination ends by the restoration of the original phases accompanied by the formation of a fine-grained structure of the SmCo₃ phase. As a result, the amount of this phase decreases. The procedure of holding of the alloy for 55 min in the course of recombination leads to the formation of a structure with elongated grains. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 5, pp. 65–68, September–October, 2006.