Seeing the surface in different ways and how this affects the design of standards.

By Charles Frenzel

If you see the surface as a transition zone or layer you are characterizing the surface properties as changing from the bulk property of the material at some point to a material that may not exhibit much of any of the bulk properties other than a similar chemical makeup. At least, this would be the most common case and the one I will consider, here. Examples would include polycrystalline materials transitioning to amorphous material, granularly ordered structures to chaotic structures, aggregates transitioning to different zonal patterns, etc..

Examples of Surface Treatment where one might expect to find a transition zone include abrasive blasting. A Surface Preparation Standard considering these conditions will be mainly concerned with any kind of procedure which involves Large Surface Areas. Such procedures include things like the mechanical adhesion and cohesive characteristics of paints and coatings, the sensitivity to corrosive attack, the resistance to surface stress patterns on aging.

If you see the surface as part of the bulk properties of the material, then you are considering the case in which the change between "inside and outside" is very abrupt compared to the size of the reference volume inside the material used to characterize the bulk properties. Two extremes of reference volumes would be concrete and graphite.

A Surface Treatment where one might find the revealed surface to have a minimal transition zone would be water jetting, where it is possible, for example, to find nearly undisturbed the granular structures of steel at the freshly processed surface. A Standard related to this condition will be associated with Small Surface Areas and adhesive properties of paints and coatings rather than mechanic characteristics. Such surfaces may exhibit far less sensitivity to highly localized corrosion attack, but may include "bulk" effects not visible on chaotically distributed surfaces.

Two microscopic images of surface conditions on "clean" standard test panel. Is the corrosion considered rust back and active, or is this flash rust and inactive?

Visit the Lydia Frenzel Conference Series Website for training and education on Surface Standards, Painting Standards, and Surface preparation.

Visit the Advisory Council for extensive libraries of technical information on various surface treatments, Surface Standards, Painting Applications, Environmental impacts, and Surface Preparation.

Visit Water Jetting for pictures of surfaces and information on how testing is used in the development of Surface Standards, Surface Preparation, Coatings Applications, and Environmental considerations.

Visit the Image Trust for a short discussion on surface treatment prior to printing on antique papers.