Corrosion tests modifications

Sa.lt Spray Tests. One of the older accelerated corrosion tests is the salt spray test (40). Several modifications of this imperfect test have been proposed, some of which are even specified for particular appHcations. The neutral salt spray test persists, however, especially for coatings that are anodic to the substrate and for coatings that are dissolved or attacked by neutral salt fog. For cathodic coatings, such as nickel on steel, the test becomes a porosity test, because nickel is not attacked by neutral salt fog. Production specifications that call for 1000 hours salt spray resistance are not practical for quahty acceptance tests. In these cases, the neutral salt spray does not qualify as an accelerated test, and faster results from different test methods should be sought. 

Lee, S. and Lifka, B. W., Modification of the EXCO Test Method for Exfoliation Corrosion Susceptibility in 7XXX, 2XXX and Aluminirm-Lithium Alloys, Afew Methods for Corrosion Testing of Aluminum Alloys, ASTM STP 1134, V. S. Agarwala and G. M. Ugiansky, Eds., ASTM International, West Conshohocken, PA, 1992, pp. 1-19. 

At present, there exists only one standard on corrosion testing and evaluation of sintered P/M parts, although many of the methods employed for wrought metals are used for sintered P/M parts with minor modification. In addition, a few nonstandardized tests tire available. 

Corrosion testing in the pulp and paper industry is based both on standards developed for other industries and on methodologies developed by individual researchers in the pulp and paper industry. Relatively few corrosion test standards have been developed for the pulp and paper industry. Corrosion testing has been most often performed either to investigate the performance of alternative materials in existing processes or to assess the effects of process modifications on existing materials of construction. As new processes create new problems, new test procedures will continue to be devised. 

The results of extensive corrosion testing, biocompatibility studies, and clinical evaluation have been used to select the corrosion-resistant metals and alloys that are in use as implants today. In addition, there are new materials being introduced as well as modifications of the currently used ones. Additional information on the biological and chemical reactions at the body/biomaterial interface would be useful in determining short- and long-term effects on the body and in pref>aring the biomaterial for its intended use. 

These surface modifications may significantly affect the resistance of the alloy to dry or wet corrosion. Alternatively, corrosion tests can be used as a probe for determining the surface composition of the alloy. Some of these aspects can be... 

There are variants of the corrosion test with a supply of CO2 to the bath with simulation of the reduction atmosphere to the upper part of the blocks and some other modifications [155-159]. 

S. Lee and B.W. Lifka, Modification of the EXCO Test Method for Exfoliation Coirasion Susceptibility in Ixxx, 2xxx and Aluminum-Lithium Alloys, New Methods for Corrosion Testing Aluminum Alloys, V.S. Agarwala and GA1. Ugiansky, Ed, ASTM, 1992, p 1-19... 

A modification of the specimen shown in Fig. 19.30 may be made simply by lapping a panel of one material over a panel of another one. The greatest effects may be observed when such panels are exposed with the laps facing up so as to favour retention of corrosive liquids along the line of contact. To permit observations of secondary effects of corrosion products, or exhaustion of corrosive constituents, the relative positions of the dissimilar metals should be changed from top to bottom in duplicate test assemblies. 

Early tests of the SCWO reactors (discussed below) indicated significant corrosion and plugging. Plugging problems were solved by procedural modifications that include periodic flushing with clean water at slightly subcritical conditions. The corrosion is mitigated by inserting various composite liners that resist the corrosivity of the different feed streams. 

With small modifications, ASTM standard G48 can be used to determine a CPT. The test is used as a ranking parameter for the resistance to pitting of high-alloyed austenitic stainless steels. In this method, material coupons are typically exposed for 24 or 72 h to a 6% FeCl3 (=1.11 mole/liter) solution at fixed temperatures (typically with 2.5°C intervals). The CPT is defined as the lowest temperature at which the specimen is attacked by pitting corrosion. 

The /main modifications took place in the burners. The boiler itself has not been modified. In the tests it achieved 60% of nominal output of steam. With better monitoring of superheater temperatures, it is expected to achieve an output of 90%. The test program will be developed this year (1980) and will include emission analysis, boiler efficiency, corrosion, and other aspects. CESP also plans to analyse smaller boilers which will operate this same year. 

Flowmeters. Even after modification the pumps usually showed some long-time drift in the pumping velocity, mainly due to changes in valve operation caused by corrosion, dirt accumulation or trapped air bubbles. Thus all flowrates have to be measured at regular intervals and the pumps adjusted when needed. Various devices for flowrate measurements were tested and two were finally selected. 

All Draize-type tests evaluate corrosion and irritation by using albino rabbits as subjects (Table 3). The Federal Hazardous Substance Act (FHSA) adopted one modification as a standard procedure to this method (1997). 

Effect on Confined Systems Corrosion Problems Fracture Fatigue Nano Characterisation Test Methodology Computer Simulation Surface Modification Surface Treatments Surface Problems in Contact Mechanics Fracture Mechanics Coupled Analysis and Experiments Thin Coatings Thick Coatings Contact Mechanics Material Surfaces in Contact Applications and Case Studies Indentation and Hardness Adhesion Bonding. 

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