Solubility of boron in Mo5+ySi3−y

Abstract Using X-ray analysis, optical microscopy, chemical analysis, and electron probe microanalysis (EPMA) it has been determined that the level of boron solubility in Mo 5+ y Si 3− y at 1800°C reaches a maximum value of approximately 2 at% in a narrow region within the homogeneity range of −0.08⩽ y ⩽0.04. Both the B doped and undoped Mo 5+ y Si 3− y (T1) have the tetragonal W 5 Si 3 crystal structure, which corresponds to the I4/mcm space group. Within the single phase Mo 5+ y Si 3− y B x (T1) region there is a contraction in the lattice volume with increasing boron concentration while there is an increase in cell volume with an increase in Mo:Si ratio.