Measurements of 3d occupancy from Cu L2,3 electron-energy-loss spectra of rapidly quenched CuZr, CuTi, CuPd, CuPt, and CuAu.

Abstract

We used electron-energy-loss spectrometry to measure the intensities of the Cu white lines found at the onsets of the ${\mathit{L}}_{2}$ and ${\mathit{L}}_{3}$ absorption edges of rapidly quenched CuZr, CuTi, CuPd, CuPt, and CuAu. Enhancements of the white lines in the alloys as compared to elemental Cu were correlated with changes in the 3d occupancy of Cu atoms upon alloying. We found that the Cu atoms lost 0.2\ifmmode\pm\else\textpm\fi{}0.06 d electrons when alloyed with Ti or Zr, 0.${0}_{\mathrm{\ensuremath{-}}0.0}^{+0.06}$ d electrons when alloyed with Au or Pd, and 0.${03}_{\mathrm{\ensuremath{-}}0.03}^{+0.06}$d electrons when alloyed with Pt. We found no strong correlation between measured 3d- occupancy changes and heats of formation of the alloys, consistent with expectations that outer s electrons play an important role in the alloying of Cu with Pt, Pd, and Au.