Solubility of boron in Mo5+ySi3−y

Using X-ray analysis, optical microscopy, chemical analysis, and electron probe microanalysis (EPMA) it has been determined that the level of boron solubility in Mo5+ySi3−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 Mo5+ySi3−y (T1) have the tetragonal W5Si3 crystal structure, which corresponds to the I4/mcm space group. Within the single phase Mo5+ySi3−yBx (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.