Phase relations in the CuFeSe system at 300°C

Abstract Phase equilibria in the CuFeSe system and the stability field of the intermediate solid solution (“Se-iss”) in the system have been investigated at 300°C by means of silica tube techniques in combination with microscopic, X-ray, electron microprobe and differential thermal analysis methods. In the Se-rich region of the system, the (Cu,Fe)Se 2−X solid solution coexists stably with Cu 2−X Se, CuSe, CuSe 2 , FeSe 2 and Se-iss while, in the central portion, this last phase coexists with (Cu,Fe)Se 2−X , FeSe 2 , γ -Fe 1−X Se, δ -Fe 1−X Se and Cu 2−X Se. The stability fields of Se-iss at 300°C and 500°C have been divided into quenching zones based on the presence of one or the other of two optically and compositionally different types of Se-iss. It was also determined that β-FeSe dissolves, at 300°C, up to 11.5 at .% of Cu. The stability of the Cu 2−X Se Fe tie-line in the metal-rich region of the system was confirmed.