Etching aluminium

The organic acid salts, such as EDTA and heptonate, are included for water softening properties, and to assist in the removal of solid particles. Gluconate and heptonate, in particular, are effective in the highly alkaline solutions used for etching aluminium and prevent the precipitation of aluminium hydroxide scale and sludge. 

Acid pickles Some of the acid pickles used to clean and etch aluminium alloy surfaces and remove oxide and anodic films, such as the chromic/ sulphuric acid pickle (method O of DEF STAN 03-2) and other chromic-acid bearing pickles (App. Foi DEF-151) probably leave on the surface traces of absorbed or combined chromate which will give at least some protection against mild atmospheres. 

Conversion coated or etched aluminium surfaces are generally free from organic contamination and easily wetted. A water break test is commonly used to establish that a clean surface has been generated. Such pre-treated surfaces have been described as forming a... 

Davis and Venables [25] state that it is also possible to run the bath at ambient temperature and produce a suitably pretreated aluminium surface compare the micrographs of conventional FPL etched aluminium and P2 etched aluminium in Fig. 6. 

Figure 6 SEM micrographs of FPL etched and P2 etched aluminium alloy [25] (Courtesy ...

He concluded that for aluminium and titanium certain etching or anodization pretreatment processes produce oxide films on the metal surfaces, which because of their porosity and microscopic roughness, mechanically interlock with the polymer forming much stronger bonds than if the surface were smooth . 

Videm, K., Pitting Corrosion of Aluminium in Contact with Stainless Steel , Proc. Conf. on Corrosion Reactor Mater., Salzburg, Austria, 1, 391 (1962) C.A., 60, 1412g Lyon, D. H., Salva, S. J. and Shaw, B. C., Etch Pits in Germanium Detection and Effects , J. Electrochem. Soc., 110, 184c (1963)... 

Black, J. R., Etch Pit Formation in Silicon at Al-Si Contacts Due to the Transport of Silicon in Aluminium by Momentum Exchange with Conducting Electrons , J. Electrochem. Soc., 115, 242c (1968)... 

Fig. 12.27 Sprayed aluminium on steel. Left section taken parallel to substrate and etched, X 75. Right section taken transverse to substrate and etched in FIF, x 75 A aluminium and...

Fig. 13.3 Sprayed aluminium section taken parallel to substrate and etched x 75...

Fig. 13.4 Tranverse section of sprayed aluminium on steel etched in HF. A aluminium and B steel x 75...

Etch priming is widely used on aluminium alloy, and is particularly effective on cadmium and zinc. The adhesion to stainless steel and titanium is good. It has also been used quite widely on bare steel and on magnesium alloy, but on these metals its performance is not, in the opinion of some investigators, always quite reliable. For best protection the etch primer coating is followed with a full paint scheme. 

Kang J, Shin Y, Tak Y (2005) Growth of etch pits formed during sonoelectrochemical etching of aluminium. Electrochim Acta 51 1012-1016... 

Bauer S, Wolff I, Werner N, et al. 1992. Toxicological investigations in the semiconductor industry I. Studies on the acute oral toxicity of a complex mixture of waste products from the aluminium plasma etching process. Toxicology and Industrial Health 8 141-156. 

Evaluation of dry pumps vs rotary vane pumps in aluminium etching N cuum 41,1990,1825-1827... 

Experimentally, although grains have been imaged in polished but not etched specimens of both aluminium (Weaver 1986 Fossheim et al. 1988) and copper (Bray 1981), in both cases the contrast was rather poor. But in nickel and iron and related alloys such as stainless steel, grain contrast can be superb (as it is indeed in many ceramics). It seems that, as in the Story of the... 

Metals such as aluminium, steel, and titanium are the primary adherends used for adhesively bonded structure. They are never bonded directly to a polymeric adhesive, however. A protective oxide, either naturally occurring or created on the metal surface either through a chemical etching or anodization technique is provided for corrosion protection. The resultant oxide has a morphology distinct from the bulk and a surface chemistry dependent on the conditions used to form the oxide 39). Studies on various aluminum alloy compositions show that while the oxide composition is invariant with bulk composition, the oxide surface contains chemical species that are characteristic of the base alloy and the anodization bath40 42). 

Figure 3.2 Electron micrographs, (c) Platelets of nordstrandite (aluminium hydroxide) (x 5000). (d) Replica of an etched copper surface (x 5600)...

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