Ferric chloride corrosion product

Recommended practice for examination and evaluation of pitting corrosion Test method for determining susceptibility to stress corrosion cracking of high-strength aluminium alloy products Test method for pitting and crevice corrosion resistance of stainless steels and related alloys by the use of ferric chloride solution Recommended practice for preparation and use of direct tension stress corrosion test specimens... 

Ferric chloride tends to be a very low cost product. It may be supplied as a 40% by-product solution, and a typical dose rate is 10 to 150 ppm, as received. It is very corrosive, lowers the pH of the water, is slow to react in cold water, and is sensitive to process variations. Ferric chloride needs close control for good results. 

Sodium hydroxide is a very common solution used for ferrous artefacts. A concentration of 0.5 M will give a pH of approximately 10.5 that is well in the passivity region for this class of materials. The problem is that if any ferrous or ferric chloride type compounds are present within the corrosion products, these may react with the hydroxide to produce solid sodium chloride within the pores in the rust film (Equation (12)). 

Their contribution to locally concentrating chloride ions under tubercles. A tubercle formation starts with the creation of a biofllm upon the metal surface. As Ringas puts it for the case of SRB, the tubercles formed by these bacteria consist of corrosion products and biofilm, and they protect the bacteria from external aggressive bulk environment and thus assist corrosion and pitting. The chemical conditions under the tubercles formed by the bacteria may become very acidic as CF ions combine with the ferric ions produced by lOB... 

The product was satisfactory except for a high iron content. This was believed to arise from the reaction of the niobium pentachloride vapour with the metallic iron of the reactor, away from the crucible. A deposit of niobium trichloride was produced on the reactor wall and ferric chloride entered the vapour phase. From here it was fed to the magnesium along with the niobium pentachloride, to take part in the reaction and allow iron to enter the product. A reactor made from nickel-plated steel was partially successful in reducing the iron content, but the nickel was relatively easily separated from the steel at reactor temperatures. It was expected that a reactor made entirely of solid nickel would have given satisfactory results, vapour-phase corrosion of the nickel itself being reasonably low. 

As noted in Table 3 [77], the results of multiple alloy tests in seawater are correlated to the Pitting Resistance Equivalence (PRE) number [47,48,72,77], which also correlates to alloy pterformance in FeCly. Anderson [78] and Streicher [79] used MCA in seawater tests to compare alloy performance. More recently, a simple, flat, plastic (specifically, polymethylmethacrylate, which is often referred to as "perspex ) washer has been successfully used to evaluate a series of alloys in seawater [77]. One application of the ASTM G 48 test has been in simulating leaking tube-to-tube sheet joints in seawater heat exchangers and condensers [87]. When certain highly corrosion-resistant alloys were paired in a dissimilar metal crevice (DMC) with alloys that would be expected to suffer crevice corrosion in the particular test solution, the more corrosion-resistant alloy was found to corrode due to the accelerating effects of the corrosion products from the less resistant alloy. The results of DMC tests in ferric chloride were confirmed by long-term DMC exposures in seawater [82],... 

TABLE 4.4 FERRITIC-AUSTENITIC STAINLESS STEEL-CABOT WROUGHT PRODUCTS (continued) Crevice-Corrosion Data in 10% Ferric Chloride at Room Temperature for 10 Days... 

The term green rust designates a variety of intermediate reaction products, generally amorphous, that are found during the atmospheric corrosion of steel in the presence of chlorides and/or sulfates. More precisely, these products form during the transformation of Fe(OH)2 into y-FeOOH. Green rust consists of mixed ferric and... 

Lactic acid is commercially produced either by fermentation or by synthesis. The synthetic process is based on lactonitrile that is prepared by reacting acetaldehyde with hydrogen cyanide at up to 200 C. Lactonitrile is then hydrolyzed in the presence of HCl to yield lactic acid. In the HCl-affected areas, suitable materials are limited. Glass-lined materials are prone to breakdowns. Stainless alloys corrode and introduce toxic materials to the process stream. Titanium and its alloys are susceptible to crevice corrosion in hot chloride solutions. Zirconium is virtually ideal for this process. Because lactic acid is produced as a fine chemical, contamination has to be prevented in all areas. Oxidizing HCl conditions resulting from the presence of ferric or cupric ions are avoided. Moreover, zirconium is highly resistant to crevice corrosion in chloride solutions. Since the 1970s, zirconium equipment has provided excellent service in lactic acid production. 

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