Saltwater immersion

ASTM El524—Standard Test Method for Saltwater Immersion and Corrosion Testing of Photovoltaic Modules for Marine Environments... 

Continuous or Intermittent Saltwater Immersion or Spray Exposure... 

The higher inherent corrosion resistance of aluminum alloys in saltwater, as compared to steel, has led to the use of a wet/dry saltwater immersion-type test being used at the Alcoa Laboratories instead of the ASTM B 117 procedure. In fact, the continuous immersion of aluminum bonded joints in 3.5% sodium chloride solution or even natural seawater may not deteriorate such joints as much as distilled or deionized water exposure. The amount of... 

General immersion tests General immersion tests can be as simple as the standard saltwater immersion test for coatings to be used in the atmosphere, or as complicated as cold wall effect immersion tests for heavy coatings to be used constantly in immersion service. It is essential to reproduce the anticipated conditions of the field exposure as dosely as possible when evaluating coatings for immersion service. 

When a carrot is immersed in saltwater (left), water flows out Into the solution, causing the carrot to shrink. The osmotic pressure outside the cells of the vegetable is greater than that inside. A carrot left in pure water (right) does not shrivel. 

Chloride ion detection for corrosion monitoring. Tang and Wang [40] measured chloride ions in a typical concrete sample immersed in saltwater solutions with different weight concentrations ranging from 0% to 25%. The LPG sensor exhibited a linear decrease in the transmission loss and resonance wavelength shift when the concentration increased. The measurement accuracy for the concentration of salt in water solution was estimated to be 0.6% and the limit of detection for chloride ions was about 0.04%. 

FIGURE 1.13 Steel sample coated with a polyaniline primer and an epoxy topcoat after a 3-yr immersion in saltwater—note the absence of corrosion products in the test solution. 

Neoprene formulations can be produced that provide products with outstanding resistance to water absorption. These products can be used in continuous or periodic immersion in either freshwater or saltwater without any loss of properties. 

I I ou can see the electrolysis of M water by immersing the top of a J disposable 9-volt battery in saltwater. The bubbles that form contain hydrogen gas produced as the... 

Additionally, in order to investigate the synergistic effects of UV and moisture on the degradation, the programmed cube specimens were immersed in saturated saltwater and rainwater at room temperature for 90 days, respectively. They were prepared for the stress recovery test. All these immersed specimens were synehronously exposed to UV. The original foams without environmental attacks were also prepared as eontrol specimens for each group of programmed foams. 

Figure 3.50 Programming (step 1 loading—> step 2 cooling—> step 3 unloading) for the foam and recovery stress-temperature response (step 4) under fully constrained conditions for the programmed foams exposed to UV alone and simultaneously immersed in saltwater and rainwater. Source [84] Reproduced with permission from Elsevier...

Frequently wet by saltwater, involves condensation, splash, spray, or frequent immersion. Oil-based paints presently last 3 years or less. Choices for this application include zinc-rich vinyl, coal tar epoxy, and epoxy. 

Unsworth (1989) in a recent review of the role of R elements in the development of Mg alloys has listed the corrosion rates (table 5) of various experimental and commercially developed alloys when immersed in saltwater solutions. Some alloys contained specific R elements while others contained R additions which were a mix of elements with atomic numbers from 57-71. All of the alloys had been heat treated by solution aimealing followed by age hardening. For comparative purposes, some corrosion rate data from other sources (Uhlig 1963) for pure Mg and commercially pure Mg (99.8%) (Braun 1979) are included. The solid solubility at room temperature of most R s in Mg is very small. Thus, at the levels of R shown, most of them would be present as Mg-R intermetallic phases. 

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