Pretreatment metallic substrates

Adhesion of copper films to PMDA/ODA polyimide was determined by peel tests conducted on samples that were prepared by vapor-depositing a thin layer of copper onto the polyimide and then building the thickness of the metal layer to about 18 p,m by electrodeposition of copper. Results of the adhesion measurements correlated well with substrate pretreatment. When the substrate... 

The coating technique starts by applying a solvent-based adhesive on to a previously pretreated metal substrate. The item is then preheated to 200-250°C, the exact time and temperature depending on the metal thickness. It is then dipped in the plastisol which partly gels owing to the... 

The high electrical resistivity of aluminum oxide is believed to be the major reason why coatings continue to exhibit very strong adhesion to aluminium substrates even when localized corrosion is observed to occur. Therefore, by developing a pretreatment process for any metal substrate which produces a metal oxide with high electrical... 

Fig. 17. Cathodic delamination rates of galvanized steel/epoxy-polyamide coating systems when a 0.1 M CoCl2 dipping pretreatment was applied to the metal substrate prior to the application of the coating 91K (Reprinted with permission from Ref. 91Copyright (1981) American Chemical Society)...

A number of techniques have been developed to convert corrosion-prone, clean surfaces to less reactive ones. Three common conversion processes are phosphating, anodizing, and chromating. These processes remove the inconsistent, weak surface on metal substrates and replace it with one that is strong, permanent, and reproducible.58 Figure 15.18 shows the effect of various pretreatments on the durability of aluminum alloy-epoxy joints subjected to aging in water at 50°C. 

Recently a new technique has been reported under the name of the QQC process. It utilizes a combination of lasers and does not require vacuum, ambient or substrate pretreatments. The main source of carbon is CO and the films have been deposited on different metal and ceramic substrates. 

In most cases, the substrates are metals, such as copper, aluminum, etc. The pretreatment of the metal substrate is critical to its performance. In some cases, a primer is applied to impart adhesion, corrosion, and delamination resistance. 

Many processes and techniques are used for pretreating metallic substrates (Table 8.1), [8.1]-[8.4]. 

Hydroxybenzamines of the general formula have been claimed to improve the adhesion of a wide range of coatings to zinc and cadmium and other metallic substrates when used as either pretreatment primers or additives [63]. Ethylenically unsaturated hydroxy-functional amines have been claimed to improve the adhesion of water-based systems [64], and amines have been examined as adhesion promoters for aromatic isocyanate cured adhesives on glass and other substrates [65]. Primary aliphatic amines are claimed to improve the bondability of polyolefines [66] and an oxyethylated polyethylene... 

DeNicola and Bell report the use of bibenzoylmethane and l-(0-hydroxyphenyl)-3-phenyl-1,3-propanediol as wet adhesion promoters for epoxide resin adhesives on low-carbon mild steel [77]. Metal chelating O-hydroxybenzlamine compounds are stated to produce adhesion-promoting films on metals [78], and improved adhesion to titanium is claimed for metal alkoxide primers. Oxazolidines containing trialkoxy or triaryloxysilyl groups are claimed to be adhesion promoters on metallic substrates [79]. Improved adhesion of epoxide resin adhesives to copper substrates can be achieved by pretreatment in a weak solution of a benzoheterocyclic(thiol) compound [80] and benzotriazole and derivatives have been claimed to improve the bond between vinyl polymers and steel [81] and the adhesion of photosensitive compounds to polymeric substrates [82]. Pesetski and Aleksandrova describe the use of dicarboxylic acids as primers for polyamide films on copper [83],... 

Uses Corrosion inhibitor, adhesion promoter for paints or coatings onto metal substrates, for use in baking and air-drying systems with alkyds, polyesters, acrylics, urethanes metal pretreatment Properties Yellowish liq. very strong odor partly sol. in water sp.gr. 1.08 dens. 9.03 Ib/gal vise. 17,000 cps b.p. 137 C flash pt. (PMCC) 38 C 66% NV... 

Uses Adhesion promoter for baked alkyds, polyesters, acrylics, and lacquers onto metal substrates corrosion-inhibiting pretreatment or base coating for galvanized steel and aluminum suitable for food-contact coatings... 

Wet, chemical pretreatment of the polyetherimide substrates was affected via the Standard 2312 process. This scheme was comprised of a surface removal step, typically 0.5 pm is solubilized, polymer oxidation, and catalyzation and electroless metallization. The pretreatment sequence served to "normalize" the polymer surface and left the filler material, if any, unexposed. Either 1-2 pm of copper or -1 pm of nickel was electrolessly deposited. Following deposition of the initial metal layer, a 1 h heat treatment at 110°C was performed. Unless stated otherwise, air was the atmosphere during heat treatment. 

Tables. Effect of Surface Pretreatment on Adhesion of Radiation Curable Coatings to Metal Substrates...

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