Steel and aluminium alloy

Various investigations have been carried out on steels and aluminium alloys, by adopting different techniques, in particular radiography, microanalysis and Small Angle Neutron Scattering (SANS). 

Various investigations have been carried out on steels and aluminium alloys, in particular on the following materials AISI 316, AISI 316 L, AISI 304, Fe 410, P-A1 Mg 4,4 UNI 5452, and 08H18N10T austenite stainless steel. The investigated samples belong to base plates as welded or to vessels plates before and after exercise. 

The thiocyanate methods were applied in determinations of titanium in silica [97], glass and quartz [98], steel and aluminium alloys [30], and platinum chloride [2]. 

Interestingly, both processes were also observed in metals (Erlenkamper 1980). Fig. 11.29 and Fig. 11.30 show sequences of AE signals in fracture mechanic experiments with annealed carbon steel and aluminium alloy, respectively. 

Between them the various sub-groups cope with the common industrial materials, particularly steel and aluminium alloys and with many absorbent materials -especially cellulose-based ones. But with few exceptions, such as the polyamides, the family as a whole cannot cope with most thermoplastics though some of the thermoset plastics (normally in the form of PF - phenol/formaldehyde, UF - urea/ formaldehyde, and melamine-based laminates) bond extremely well. 

A related issue is whether roughening a surface increases the strength of an adhesive joint. Harris and Beevers [82] found no difference in adhesion to mild steel and aluminium alloy blasted with alumina grits of different particle sizes. Shahid and Hashim [83] used a structural epoxide adhesive with mild steel adherends in cleavage joints. The surfaces had been grit-blasted or diamond-polished, and surface profiled. The results are shown in Table 15, where all differences in strength seem to be the same, within experimental scatter. 

We are yet to fiilly understand the mechanism by which these multifunctional inhibitors protect the surface however, it appears from the electrochemical and surface characterization evidence for both steel and aluminium alloys that a hybrid film forms in each case. The following summarizes our current understanding of the formation of this surface ... 

Although there is a great difference in potential between stainless steel and aluminium alloys, in the order of 650 mV, it is unusual to see galvanic corrosion on aluminium in... 

Cerium ions have proved to be a very effective additive for silane coatings and clearly improved the corrosion protection of galvanised steel and aluminium alloys. These ions enhance the protective barrier properties and inhibit corrosion activity at induced defects. The presence of cerium ions seems to develop a self-healing effect, hindering the corrosion processes at defects. 

Hybrid silica coatings prepared with TEOS and MTES doped with Ce(N03)3 and (NH4)2Ce(N03)6 on stainless steel and aluminium alloys produce an improvement in corrosion protection with increased immersion time in NaCl solutions. This effect can be explained by the deposition of mixed cerium (III and IV) and chromium hydroxides/oxides on cathodic areas, triggered by an increase in pH. However, thermal treatments at temperatures higher than 350°C are applied to sinter these coatings [20,21]. As a result, these cannot be used to protect metal substrates susceptible to deterioration at lower temperatures. 

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