Modification of surface properties by dynamic recoil mixing

Abstract

In dynamic recoil mixing (DRM) a layer of constant optimum thickness of a material A is maintained on a substrate of material B whilst the surface of A is bombarded with energetic particles. Under the correct conditions the irradiating particles deposit their maximum energy at the interface between A and B, causing considerable mixing of these species. Thus new combinations of materials can be created or well-bonded layers of A on B can be formed. An apparatus for producing DRM layers is described and experimental methods for looking at the layers formed and determining optimum parameters for DRM are presented. The results for gold and antimony films are reported and compared with those predicted by a simple computer model of the process. Specific applications of the technique are discussed including the formation of hard layers and wear-resistant surfaces (silicon nitride on steel), electrochemical sensors (gold on titanium), catalytic layers (platinum on titanium) and thermojunctions (antimony on bismuth). Some preliminary results on the bonding of DRM layers are given and other applications of the technique described.