Laboratory tests chloride

Most hafnium compounds requite no special safety precautions because hafnium is nontoxic under normal exposure. Acidic compounds such as hafnium tetrachloride hydroly2e easily to form strongly acidic solutions and to release hydrogen chloride fumes, and these compounds must be handled properly. Whereas laboratory tests in which soluble hafnium compounds were injected into animals did show toxicity, feeding test results indicated essentially no toxicity when hafnium compounds were taken orally (33,34). 

Dog repeUents available commercially in the 1990s have been generally unsuccessful in laboratory tests. Por example, lithium chloride treatments were usually rejected immediately with no ingestion, and bone oil treatments that contained up to 0.1% of the active ingredient were stiH consumed (93). Oleoresin capsicum [8023-77-6], the essence of red pepper, did have an extended effect on coyotes, even though the deer repeUents mentioned above were attractive to coyotes (93). Although a capsicum-base aerosol repeUent has been described as potentially harmful (94), pepper spray is commercially available in the United States to repel humans, as is Mace. 

Not all sulphates are as readily reduced as sodium sulphate, for instance, calcium sulphate does not usually lead to sulphide penetration, although the presence of other substances with calcium sulphate may lead to accelerated oxidation for other reasons. The results for laboratory tests on a series of metals and alloys in sodium sulphate -F sodium chloride and calcium sulphate + calcium chloride mixtures are shown in Table 7.12 . In many cases sulphide peneration could be noted with the sodium salts but not with the calcium salts. 

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. 

It may be felt that the initiation of a stress-corrosion test involves no more than bringing the environment into contact with the specimen in which a stress is generated, but the order in which these steps are carried out may influence the results obtained, as may certain other actions at the start of the test. Thus, in outdoor exposure tests the time of the year at which the test is initiated can have a marked effect upon the time to failure as can the orientation of the specimen, i.e. according to whether the tension surface in bend specimens is horizontal upwards or downwards or at some other angle. But even in laboratory tests, the time at which the stress is applied in relation to the time at which the specimen is exposed to the environment may influence results. Figure 8.100 shows the effects of exposure for 3 h at the applied stress before the solution was introduced to the cell, upon the failure of a magnesium alloy immersed in a chromate-chloride solution. Clearly such prior creep extends the lifetime of specimens and raises the threshold stress very considerably and since other metals are known to be strain-rate sensitive in their cracking response, it is likely that the type of result apparent in Fig. 8.100 is more widely applicable. 

Composition of the liquid environment The ionic composition, arising from dissolved salts and gases, has a considerable influence on the performance of inhibitors. In near-neutral aqueous systems the presence of certain ions tends to oppose the action of inhibitors. Chlorides and sulphates are the most common examples of these aggressive ions, but other ions, e.g. halides, sulphides, nitrates, etc. exert similar effects. The concentration of inhibitor required for protection will depend on the concentrations of these aggressive ions. Laboratory tests " have given some quantitative relationships... 

The influence of moisture is fundamental, as it is with other forms of corrosion. Long-term contact tests with ponderosa pine, some treated with zinc chloride, in atmospheres at 30, 65 and 95% r.h. showed that at 30 and 65% r.h. plain wire nails were not very severely corroded even in zinc chloride-impregnated wood. At 95% r.h. plain wire nails were severely corroded, though galvanised nails were attacked only by impregnated wood. Brass and aluminium were also attacked to some extent at 95% r.h. Some concurrent outdoor tests at Madison, Wisconsin, showed that the outdoor climate there was somewhat more severe than a 65% r.h. laboratory test. 

Laboratory tests in which the specimen is anodically polarised in a chloride-containing solution to evaluate E, and E. ... 

A common chemical laboratory test for corrosion resistance is a simple exposure test using metal coupons. The ASTM standard G48 —Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by Use of Ferric Chloride Solution—describes a simple exposure test. The material coupons (e.g., 60 x 60 mm) are placed on a glass cradle and immersed in the solution in such a way that the coupons are evenly exposed. 

Systematic investigations were carried out for the preparation of cellulose acetate of D.S. 2,65 and other mixed esters which included cellulose acetate-propionate, cellulose acetate-butyrate, cellulose acetate-benzoate and cellulose acetate-methacrylate. The experimental conditions were optimised for maximum yield of the ester. Flat osmotic membranes were developed from these esters and characterised for their osmotic and transport properties. The nmmbra-nes were evaluated in a reverse osmosis laboratory test-cell using 5OOO ppm sodium chloride solution at 40 bars pressure. Table 1 presents the typical performance data of these membranes. 

For laboratory tests use may be made of a small jacketed metal oven containing heavy mineral oil and coated with asbestos board it is heated by gas and serves to bake loaves of about 150-200 grams prepared by doughing 1 kilo of flour with the required amount of water (about 500 c.c.), 1% of sodium chloride and 20 grams of beer (or pressed) yeast being added and the whole left to rise for 2 hours in an oven at 30-330 C. 

The corrosion rates of rebar in concrete are high when the chloride content of the environment is high. Extensive laboratory test data on the corrosion of rebar in concrete are available.92 Field test data are limited by comparison. 

For example, a 3 per cent, solution of common salt at 10° C. is much more corrosive than tap water at the same temperature but as the temperature rises the relative corrosivity falls, so much so that at 21° C. the salt solution is the 1 ess corrosive of the two. Since sea water contains some 3 per cent, of sodium chloride, it is of interest to inquire into the effect of temperature upon its corrosive powers. The few laboratory tests that have been carried out on the subject2 indicate that at temperatures below 13° C. sea water is more corrosive than tap water, whilst at all higher temperatures it is less so. Now, in the western part of the tropical Pacific Ocean a temperature of 32° C. is sometimes attained, and in the Red Sea and Persian Gulf temperatures of 34 4° C. and 35 5° C. respectively have been registered. Such waters should therefore prove less corrosive than river waters at the same temperatures. 

DMP was successful in recovering alum from WTR based on alum, Al2(S04)3 I4H2O, and ferric chloride (FeCls) coagulants. A series of laboratory tests confirmed that over 70% Al /Fe was easily recoverable. 

Flame photometry involves burning the sample in a hydrogen flame and measuring the characteristic emission of the agent used, e.g. sodium chloride. The method was developed at the Dsd, Porton Down, UK in the 1960s, and is now used extensively throughout the world it is specified in British Standards (BS) (1969) and is also specified as a routine laboratory test in the BS (1992). 

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