Salt corrosion

Oxidation tests on Nimonic 90A, in which sodium chloride was introduced into the atmosphere, showed that this constituent produces a significant deterioration in the protective nature of the normally adherent film. Although under certain service conditions the presence of sodium chloride is likely, this is not always so, and thus the general applicability of the results of laboratory tests in sodium sulphate and mixtures involving sodium chloride may be questioned. Test procedures for hot-salt corrosion have been reviewed by Saunders and Nicholls who concluded that burner rig testing is the most appropriate procedure provided contaminant flux rates similar to those found in an operating turbine are used in the rig. 

Dispersants, antifoulants, or sludge fluidizers to control the physical adherence of insoluble salts, corrosion products, oils, fats, and... 

The corrosion of iron is accelerated by the presence of oxygen, moisture, and salt. Corrosion can be inhibited by coating the surface with paint or zinc or by using cathodic protection. 

Salts Corrosion rates for listed construction materials ... 

Titanium s noncorrosive and lightweight properties make it useful in the manufacture of laboratory and medical equipment that will withstand acid and halogen salt corrosion. These same properties make it an excellent metal for surgical pins and screws in the repair of broken bones and joints. 

Dirt, salts, corrosion products, and other particulates... 

Fouling produces dirty and inefficient cooling systems, impeding the flow of cooling water. It involves the physical adherence to surfaces and mutual entanglement of insoluble salts, corrosion products, oils, fats, and other process contaminants, air-blown debris, and the like. Where... 

Dispersant(s) or antifoulant(s) (sludge fluidizers, biodispersants, or mud treatments) to limit the physical adherence of insoluble salts, corrosion products, oils, fats, process contaminants, biofilms, and biomass onto heat-transfer and other water-wetted surfaces... 

Pacification is a technique for removing organics and buffers from HPLC metal and Teflon surfaces and protecting them from salt corrosion with 6 N nitric acid (see Chapter 4). First, remove the HPLC column and replace it with a column bridge. Do not flush this wash into the mass spectrometer. Wash the system with water. Remove the column and replace it with a column blank. Flush with 6 N nitric acid for at least 30min, then overnight with water. Ensure the effluent pH is back to that of lab water. Replace the column and flush with mobile phase. This should be done at least once a month to clean check valves, line, and injectors. Under no circumstances should this wash be done with an HPLC column in place or into the mass spectrometer ... 

Due to its ability to withstand high pressure, its relative low cost, and inertness, stainless steel has become the standard material of columns and other chromatographic components. However, under certain circumstances, stainless steel has been shown to interact with the sample and the mobile phase [39]. The best known example is chloride salt corrosion of stainless steel. Data indicate that nearly all common eluents dissolve iron from stainless steel [39]. It appears that proteins also adsorb to stainless steel [39], The adsorption process is fast, whereas desorption is slow, a result which leads to variable protein recoveries. A number of manufacturers are offering alternatives to stainless components with Teflon -lined columns and Teflon frits. Titanium is being explored as an alternative to stainless steel. A cheaper and simpler procedure is to oxidize the surface of the stainless steel with 6N nitric acid. This procedure should be repeated about every 6 months. 

Agent 765. [VifitcoSA] Fatty amine salt corrosion inhibiter, i gment grinding and dispersion aid antistrippbg agent for paints. 

Synkad . [Ferro/Keil] Borate or car-boxylate salts corrosion inhibitor fur synthetic cutting, towing, and grinding fluids. 

PHENYLHYDRAZINE HYDROCHLORIDE or PHENYLHYDRAZINE MONOHYDROCHLORIDE or PHENYLHYDRAZINIUM CHLORIDE (59-88-1) Combustible solid (flash point about 194 F/90°C). Dust or powder forms explosive mixture with air. A strong reducing agent Reacts violently with strong oxidizers, alkalis, ammonia, ammonium persulfate, bromine dioxide, lead dioxide, nitric acid, perchlorates, permanganates, peroxides, sulfuric acid. Incompatible with alkali metals, chromates, copper salts. Corrosive to metals, nickel. 

A considerable body of data on the oxidation of TiAl is available, albeit for relatively short times at elevated temperatures, 800-1400°C [5-19], Oxidation data at potential operating temperatures within the turbine (650-750°C) is much more scarce, [17], while data on the hot salt corrosion of y-TiAl does not exist. 

This paper therefore concentrates on a study of the hot salt corrosion of 7-TiAl over the temperature range 500-700°C. Limited oxidation data at 700°C is also presented by way of comparison with the hot salt corrosion data, and published high temperature oxidation data. 

The potential of using y-TiAl to replace nickel based alloys within the high pressure compressor and fourth stage turbine requires that the -y-TiAl be resistant, not only to oxidation but hot salt corrosion as well. The level of salt expected at these location is low, typically 0.3-0.5 ig/cm2/h, but nevertheless may have a significant effect on oxidation processes. 

Table 1 and Figure 5, summarise the thermogravimetric studies of hot salt corrosion for y-TiAl over the temperature range 500-700 °C. 

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