Corrosive characteristic

Electromagnetic flow meters ate avadable with various liner and electrode materials. Liner and electrode selection is governed by the corrosion characteristics of the Hquid. Eor corrosive chemicals, fluoropolymer or ceramic liners and noble metal electrodes are commonly used polyurethane or mbber and stainless steel electrodes are often used for abrasive slurries. Some fluids tend to form an insulating coating on the electrodes introducing errors or loss of signal. To overcome this problem, specially shaped electrodes are avadable that extend into the flow stream and tend to self-clean. In another approach, the electrodes are periodically vibrated at ultrasonic frequencies. 

The corrosion behavior of plutonium metal has been summarized (60,61). a-Plutonium oxidizes very slowly in dry air, typically <10 mm/yr. The rate is accelerated by water vapor. Thus, a bright metal surface tarnishes rapidly in normal environments and a powdery surface soon forms. Eventually green PUO2 [12059-95-9] covers the surface. Plutonium is similar to uranium with respect to corrosion characteristics. The stabilization of 5-Pu confers substantial corrosion resistance to Pu in the same way that stabilization of y-U yields a more corrosion-resistant metal. The reaction of Pu metal with Hquid water produces both oxides and oxide-hydrides (62). The reaction with water vapor above 100°C also produces oxides and hydride (63). 

Materials of Construction and Operational Stress. Before a centrifugal separation device is chosen, the corrosive characteristics of the Hquid and soHds as weU as the cleaning and saniti2ing solutions must be deterrnined. A wide variety of materials may be used. Most centrifuges are austenitic stainless steels however, many are made of ordinary steel, mbber or plastic coated steel. Monel, HasteUoy, titanium, duplex stainless steel, and others. The solvents present and of course the temperature environment must be considered in elastomers and plastics, including composites. 

Mineral acids are used as catalysts, usually in a concentration of 20— 40 wt % and temperatures of 30—60°C. An efficient surfactant, preferably one that is soluble in the acid-phase upon completion of the reaction, is needed to emulsify the a-pinene and acid. The surfactant can then be recycled with the acid. Phosphoric acid is the acid commonly used in the pine oil process. Its mild corrosion characteristics and its moderate strength make it more manageable, especially because the acid concentration is constandy changing in the process by the consumption of water. Phosphoric acid is also mild enough to prevent any significant dehydration of the alcohols formed in the process. Optimization of a process usually involves considerations of acid type and concentration, temperature, surfactant type and amount, and reaction time. The optimum process usually gives a maximum of alcohols with the minimum amount of hydrocarbons and cineoles. 

Properties. Uranium metal is a dense, bright silvery, ductile, and malleable metal. Uranium is highly electropositive, resembling magnesium, and tarnishes rapidly on exposure to air. Even a poHshed surface becomes coated with a dark-colored oxide layer in a short time upon exposure to air. At elevated temperatures, uranium metal reacts with most common metals and refractories. Finely divided uranium reacts, even at room temperature, with all components of the atmosphere except the noble gases. The silvery luster of freshly cleaned uranium metal is rapidly converted first to a golden yellow, and then to a black oxide—nitride film within three to four days. Powdered uranium is usually pyrophoric, an important safety consideration in the machining of uranium parts. The corrosion characteristics of uranium have been discussed in detail (28). 

Conductivity Expressed as micromhos, specific conductance Conductivity is the result of ionizable solids in solution high conductivity can increase the corrosive characteristics of a water Any process which decreases dissolved solids content will decrease conductivity examples are demineralization, lime softening... 

Hydrofining has been applied to Varsols and various other solvents for the control of odor, sulfur, and corrosion characteristics. For example. Hydrofining of Iranian and Kuwait distillates demonstrated its effectiveness as a means of producing "White Spirit", a high-quality solvent naphtha distributed in the United Kingdom. 

The AFC has some attractive features, such as relatively high efficiency (due to low internal resistance and high electrochemical activity), rapid start-up, low corrosion characteristics, and few precious metal requirements. 

Manufacturers should be contacted for size/rating information, because the efficiency of a design requires proper physical property information as well as system capacity and corrosion characteristics. 

Figure 4-421. Corrosion characteristics of an active passive metal as a function of solution oxidizing power (eiectrode potential). (From Ref. [183].)...

The galvanic probe continuously monitors the corrosion characteristics of the drilling fluid. The probe (Figure 4-473) consists of two dissimilar metal electrodes, usually brass and steel. The electrodes are mounted on, but insulated... 

Such fluids often referred to as 5/95 fluid (that being the ratio of oil to water), have essentially the same properties as water with the exception of the corrosion characteristics and the boundary lubrication properties, which are improved by the oil and other additives. The advantages of this type of fluid are fire resistance, lower fluid cost, no warm-up time, lower power consumption and operating temperatures, reduced spoilage of coolant, less dependence on oil together with reduced transport, storage, handling and disposal costs, and environmental benefits. 

Lennox, T. J., Limitations on the Use of Pourbaix Diagrams to Predict De-alloying or Other Corrosion Characteristics , Discussion, Corrosion, 26, 397 (1970)... 

Generally, the process of manufacture has no appreciable effect on the corrosion characteristics of steel. Slight variations in composition that inevitably occur from batch to batch in steels of the same quality have little effect with the exception of copper, the effect of which is discussed more fully in Section 3.2. 

Potential-current density (E-i) curves, which have been determined for a number of the austenitic cast irons and also for the nickel-free ferritic irons, indicate that in general the austenitic cast irons show more favourable corrosion characteristics than the ferritic irons in both the active and passive states. 

D 2809 1989 Test method for cavitation erosion-corrosion characteristics of aluminium pumps with engine coolants... 

Small lengths of piping (approx. 1 m in length) can be fitted to plant using appropriate flanges and can provide valuable data as to plant corrosion characteristics. The spool can only be removed at shut-down. An alternative procedure is to install the spool on a by-pass loop. 

Figure 1. Metal dusting corrosion characteristics of Fe (adapted from ref. 15).

Figure 4. Corrosion characteristics of Inconel 600 (adapted front ref. 1S).

To determine whether certain blend components such as an alkylate, oxygenate or cycle oil will alter the corrosion characteristics of a fuel... 

Bates, J. K., Bradley, C. R. et al. 1994. High-Level Waste Borosilicate Glass A Compendium of Corrosion Characteristics. Technical Report DOE-EM-0177, US-DOE, Washington, USA. 

The problem is somewhat different with an oxidizer such as N204. While N204 is compatible with aluminum and many stainless steels, the presence of a small amount of water as an impurity can increase its corrosive characteristics considerably. In addition, if a leak, even of micron size, is present in the propellant tank, a corrosive condition occurs, caused by reaction of the metal with nitric acid, which formed when the N204 contacts water from the surrounding atmosphere. 

Should not exhibit corrosivity characteristics when placed in intimate contact with steel and aluminum alloy motors. 

In the oil field industry fluids such as well fluids, completion fluids and stimulation fluids [1,2,3] are used. It would be meaningful to know about these fluids and their corrosive characteristics since they have an adverse effect on rubber components such as packings, gaskets and seals exposed to such environment. The details of these fluids are given below. 

Unfortunately, there are no commonly accepted standard procedures for securing reliable corrosion data. Any data collected from any test methods will have value only if they can be interpreted properly. Many corrosion environments can vary widely from day to day and even from hour to hour. Even slight variations in operating procedures can drastically affect the corrosion characteristics of the cooling tower. Therefore, it is important to establish methods on how the corrosion data are to be accumulated, evaluated and put to use. 

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