Electrolytic corrosion, 1.5

ASTM D3482-90 (2000) Standard practice for determining electrolytic corrosion of copper by adhesives. 

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McCoUum and Logan, Electrolytic Corrosion of Iron in Soils, Technical Paper No. 25, Bureau of Standards, Washiagton, D.C., 1913, p. 7. 

The Electrolytic Corrosion Test. Also developed for use on nickel—chromium and copper—nickel—chromium decorative automobile parts is the electrolytic corrosion (EC) test (44). Plated specimens or parts are made anodic in a corrosive electrolyte under controlled conditions for 2 min, and then tested for penetration to the substrate. 

The Journal fur Gasbeleuchtung mentions electrolytic corrosion damage caused by direct current cables in Berlin in 1892, and a few years later damage by tramway currents was reported in 14 German towns. As early as 1894 the electrolytic processes of stray current corrosion were explained in detail in this Journal by G.Rasch [65]. 

The current I is called the total current. In free corrosion, i.e., without the contribution of external currents (see Fig. 2-1), it is always zero, as given by Eq. (2-8). and are known as the anodic and cathodic partial currents. According to Eq. (2-10), generally in electrolytic corrosion anodic total currents and/or cathodic redox reactions are responsible. 

All metallic materials can suffer electrolytic corrosion. Fractures caused by cathodic hydrogen only occur when the activity of the absorbed hydrogen and the level of the tensile stress, which can be external or internal, reach a critical value. In general, critical hydrogen absorption is achieved only in the presence of promoters. However, under very severe conditions such as at very low pH or very negative potential, critical hydrogen absorption can occur. Steels with a hardness greater than HV 350 are particularly susceptible. 

In electrolytic corrosion, an anodic partial reaction takes place according to Eq. (2-3)... 

Electrolytic corrosion occurs in regions I and IV with the formation of soluble iron ions. Solid corrosion products which can have a protective effect are formed in region II. This is the region of surface film passivity. Certain corrosive sub-... 

In general, according to Eq. (2-10), two electrochemical reactions take place in electrolytic corrosion. In the experimental arrangement in Fig. 2-3, it is therefore not the I(U) curve for one reaction that is being determined, but the total current-potential curve of the mixed electrode, E,. Thus, according to Eq. (2-10), the total potential curve involves the superposition of both partial current-potential curves ... 

Fig. 2-5 Partial and total current densities in electrolytic corrosion of a homogeneous mixed electrode.

Another important factor is the corrosiveness of the adhesive. This may be especially important in those cases where the PSA has direct contact with the bare wire, the electronic component, or the silicon wafer in a dicing operation. In those cases where an electrical current is running through the device, electrolytic corrosion processes may occur, especially if moisture can penetrate into the adhesive or bond line. 

Electrolytic corrosion may also occur on the inside of cable sheaths by the passage of current from the cable sheath to the wire . 

In the USA, interest has been particularly concentrated on leakage currents from inter-urban and street railway tracks, and the 1921 Report of the American Committee on Electrolysis summarises the problem and the methods of controlling electrolytic corrosion applied both in America and in memy European countries. 

Cable sheaths may be covered with paper and hessian wrappings impregnated with bituminous compounds or with extruded or taped plastics outer sheaths. At pinholes or discontinuities in protective coatings the sheath will be particularly liable to electrolytic corrosion in stray-current areas, and it is desirable to supplement this form of protection by drainage bonds or direct cathodic protection. 

Table 19.2 Electrolytic corrosion test composition of test solutions (A, B) and indicators (C, ) 5S-i58...

Test methods for determining electrolytic corrosion with electrical insulating materials Method for determination of resistance to intergranular corrosion of austenitic stainless steels copper sulphate-sulphuric acid method (Moneypenny Strauss test) Specification for electroplated coatings of tin/lead alloys... 

Electrodeposited chromium coatings. Electrolytic corrosion testing Coatings cathodic to the substrate-rating of electroplated test specimens subjected to corrosion tests... 

Chemical that reduces the tendency of iron to oxidize (rust) to ferrous ion, such as chromate which suppresses that part of the electrolytic corrosion process occurring at the anodic sites on a metal surface. 

Nickel can be used as an anode for fluorine generation, but losses due to electrolytic corrosion make it impractical for commercial production. 

Electrolytic corrosion (EC) test, 9 790 Electrolytic etching, of silicon,... 

A PTFE-lined pipe was placed into the anolyte loop to demonstrate the resistance of P IPE (Teflon), a material of construction to be used in the full-scale system, to electrolyte corrosion attack. This pipe was removed and inspected at the end of the DMMP run. 

On a clean surface of an Fci7Cr alloy in a 0.5M NaCl electrolyte, corrosion is accelerated as pitting corrosion when a potential pulse of 1 s duration extending from the passive region and above the pitting potential is applied. Gugler et al. ° showed by in situ AFM that in this case the pitting corrosion was initiated close to an inclusion on the surface (Fig. 8). Such a surface defect may act as a center for pit nucleation, as was... 

The electrical conductivity of ethanol is higher than hydroprocessed, conventional fuels. This theoretical safety advantage is of benefit and can help to prevent static buildup or discharge during transfer and loading of fuel. However, the high electrical conductivity can enhance galvanic and electrolytic corrosion of steel, especially in water-contaminated systems. 

Bonding permits the joining of dissimilar materials, and since adhesives are generally dielectric materials, their use minimizes the possibility of electrolytic corrosion when different metals are joined. 

DEZINCIFICATION. A form of electrolytic corrosion observed in sume brasses where the copper-zinc alloy goes into solution with subsequent redepnsition of the copper. The small red copper plugs thus formed in the brass are usually porous and of low strength. In recent years, the term dcziticilicalion lias also been applied in a more general sense to signify any metallic corrosion process that dissolves one of the components from an alloy. 

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