Adhesion energies at a metal interface: the effects of surface treatments and ion implantation

Abstract

Studies the effect of various surface treatments upon the nanometre-scale thermodynamic and plastic properties of titanium interfaces. A mechanical microprobe technique gives curves of electrical contact resistance versus applied load. The curve shape depends upon the state of the original titanium surfaces. A characteristically stable contact area approximately=10^-14 m², can often be achieved through a combination of surface forces and a high enough load, despite the initial microroughness of the surface. With the help of field emission measurements of contact geometry, surface cleanliness and extent of plastic deformation, values of gamma (Dupre adhesion energy) and H (nanometre-scale hardness of the softer of the two samples) are derived. Ion implantation can reduce the value of gamma by a factor of three, and low values may be associated with the improved wear resistance that such treatment can give.