Microfibrous oxide

Figure 1 (a) Microfibrous oxide on steel (after Ref. 16) (b) porous anodic oxide on aluminum... 

Fig. 4. Example.s of rough surfaces pretreated for adhesive bonding (a) microfibrous oxide on copper (cf. 29J) (b) a dendritic zinc surface (cf. [30J).

A series of papers by Packham and co-workers [20-26] also emphasizes the improvements in joint strength that may be observed when a microfibrous surface topography is created. In their studies on the adhesion of polyethylene (used as a hot-melt adhesive) to metallic substrates they found that high peel strengths were obtained when a very rough, microfibrous, oxide surface was produced on the substrate. Fig. 3.3a is a scanning electronic micrograph of the... 

Adhesion of polyethylene to copper. Substrate surface after peeling from (a) polished copper and (b) copper with a microfibrous oxide surface... 

The second category was concerned with adhesion to porous or microfibrous surfaces on metals. Aluminium may be anodised to form an oxide surface comprising pores of diameter of tens of nanometers. Electroforming and chemical oxidation can be used to produce microfibrous or needle-like coatings on metals, including copper, steel and titanium. The substrate topography was demonstrated to play an vital part in adhesion to these surfaces [45-48]. 

The common feature of microfibrous surfaces is their topography, rather than their chemical nature. It is well known that certain oxidation conditions produce a whisker or blade-like oxide growth on a metal surface, rather than a film of uniform thickness. Similarly, certain conditions of electrodeposition give dendritic crystals of the deposited metal, not a smooth coating. These are ways of preparing microfibrous surfaces. Details of some typical methods are given in Ref. [1]. 

Wang, Y., M. Aponte, N. Leon, I. Ramos, R. Furlan, S. Evoy, and J. J. Santiago-Aviles (2004). Synthesis and characterization of tin oxide microfibres electrospun from a simple precursor solution. Semiconductor Science and Technology 19(8) 1057-1060. 

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