Surface energy and solute strain energy effects in surface segregation

Auger study of preferred sputtering on binary alloy surfaces

Predictions for surface segregation in intermetallic alloys

The influence of ion bombardment on the composition of surfaces was investigated by means of ESCA. The bombardment of metal oxides with inert gas ions results, not only in sputtering of the surface, but also in reduction of the oxides. The rate of reduction is particularly high when the oxide/metal interface is within the range of the bombarding ions. Ion induced reduction was found in oxide layers, thinner than the escape depth of the photoelectrons, on Mo, W, Nb, Ta, Ti, Zr, Si, and Bi. The relationship between reduction phenomena, on the one hand, and the ion energy, angle of incidence, mass of the gas used for bombardment, and ion current density, on the other hand, was investigated in the case of the Mo/Mo-oxide system. Ion bombardment of surfaces may also result in the formation of new compounds. Two examples of this are the formation of carbides through the bombardment of contaminated surfaces and the ion induced formation of C-F compounds from a mixture of K2SiF6 and carbon.

W. Färber

Papers

AES studies of surface composition of AgCu alloys