Spheres of the metallic glass Au55Pb22.5Sb22.5 and their surface characteristics

Abstract

Spheres of the metallic glass Au₅₅ Pb_22.5 Sb_22.5 have been formed up to a size of approximately 1.5 mm in diameter. X‐ray diffraction was used to establish the glassy nature of the samples and to provide evidence of two phase‐separated glass regions. Scanning electron microscopy provided a direct visual observation of the two‐phase amorphous network on the surface of the sphere. The physical dimensions of the phase‐separated regions were observed to be cooling‐rate sensitive. Energy dispersive spectroscopy indicated that the compositions of these two glassy phases were Au‐rich and Pb‐rich, respectively, confirming the results of Kim and Johnson. In addition, the spheres exhibited an unusual surface smoothness of better than ±250 Å.