From Adhesives Technology Handbook

3.1 General Considerations

As adhesive bonding is a surface phenomenon, preparation of the contact surface is vital for strong bond formation. Surface preparation (or surface pretreatment) is carried out to render adherend surfaces receptive to the development of strong, durable adhesive joints. It is desirable to expose the adherend surface directly to the adhesive, with no intervening layer of oxide film, paint, chromate coating, chromate-free coating, phosphate coating, or silicone release agent. Such layers are called "weak boundary layers," and in their presence the adhesive does not contact the adherend surface directly.[1]

Table 3.1 shows a list of surface treatment processes for metallic and non-metallic substrates and the main effect of each treatment procedure on the material surface.

Table 3.1: Surface Treatment of Materials to Enhance Adhesion

Substrate

Treatment Method

Effect of Treatment

Metals

Degreasing

Cleaning of the surface

Metals

Grit blast

Loose material (weak boundary) removal from the surface and increase in contact surface area

Metals

Acid etch/liquid pickling

Surface oxidation

Plastics

Corona treatment

Weak boundary layer removal and surface oxidation

Plastics

Flame treatment

Weak boundary layer removal and surface oxidation

Plastics

Chemical etching

Weak boundary layer removal and surface oxidation

Fluoroplastics

Chemical etching

Surface defluorination and oxidation

3.2 Surface Treatment of Metals

Preparing the surface of a metallic sample involves multiple steps, all of which are not always taken. It is not possible to obtain a strong adhesive bond without cleaning (and abrading) the metal surface. Metals have high energy surfaces and absorb oils and other contamination...

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Finishing and Surface Treatment Services
Finishing and surface treatment services pretreat or finish the surfaces of manufactured components to meet roughness or surface condition requirements.
Coating Services
Coating services apply a thin layer of material onto parts or products provided by a client. These services are used by companies that do not have coating technology and equipment in house.
Resurfacing, Recoating, and Refinishing Services
Resurfacing, recoating and refinishing services alter or restore damaged coatings and surfaces to a usable condition.
Thin Film Coating Services
Thin film coating services apply very thin layers of specialized materials to part surfaces. They perform processes such chemical vapor deposition (CVD), physical vapor deposition (PVD), ion implantation, electrochemical deposition (ECD), plasma etching, rapid thermal processing (RTP), and titanium nitride coating.

Topics of Interest

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6.1 Introduction Since adhesives and sealants must function by surface attachment, the nature and condition of the substrate surface are critical to the success of any bonding or sealing operation.

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