Immersion testing specimen preparation

The static immersed test specimens are prepared by heating them in oil formulations with additives, film is formed on oxide contaminated surfaces load is not involved in specimen preparation, only temperature can be a comparable parameter very different compounds are formed from the same additives solution. 

A point often neglected is the handling procedure between preparation of the surface and immersing the specimen in the test medium. For instance, oxide film formation on oxide-passive materials and or tarnishing layers on copper or iron alloys formed at this stage can influence the electrochenucal behaviour considerably these chemical changes on the surface depend on such factors as temperature, humidity and time [5]. 

Section HI covers Types of Tests (H. Hack, Section Editor) includirrg laboratory-accelerated tests, field tests, and service tests. The chapters in this section provide basic principles, describe test techniques and specific considerations such as specimen preparation, test duration and acceleration factors, and cite pertinent standards. Chapters included under laboratory tests are electrochemical, cabinet, immersion, high temperature, and high pressure. Field Tests chapters include atmospheric exposure, seawater, fresh water, and soil. Under service tests are industrial applications and high temperature environments. 

The simplest uniform corrosion tests are those based on coupon immersion and mass loss tests. The tests provide data on the uniform metallic corrosion rate most often expressed in English units as mils per year (mpy) or in metric units as millimeters per year (mm/y). While there are various standards for such tests, the predominant methods are those prescribed by ASTM G 1, "Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens. This standard contains a comprehensive reference list of other ASTM standards that also apply, depending on the type of tests of interest to the investigator. 

In the BOEING wedge test, the test specimens are immersed in water at 50°C for progressive periods of time, and the length of the crack is measured after each period with a microscope. If the siuface preparation was not good enough, then the crack will progress quickly and far, and the aircraft constructors have their own specifications for this test that they perform with various surface preparations such as PAA (phosphoric acid anodization), CAA (chromic acid anodization), etc. 

The alternate immersion test is primarily used for alloy development studies and for quality control of alloys with improved resistance to SCC (Ref 27). This test method is specified in ASTM G 47, which covers the method of sampling, type of specimen, specimen preparation, test environment, and method of exposure for determining the susceptibility to SCC of high-... 

Metal specimens coated with the various blends were immersed in water in an accelerated test to determine the effect of high humidity. Cellulose acetate butyrate blends containing carboxylated polyesters prepared with hexahydroterephthalic acid [H(NPG), T50H(NPG)] were particularly susceptible to moisture and failed the adhesion test after immersion for only 0.5 hour similar blends containing T50I(NPG) extended with dianhydride Via or with PMDA passed the adhesion test after immersion for 16 hours. When coatings on cold-rolled steel of cellulose acetate butyrate (EAB-381-0.5) blends containing 1% of each of the... 

When it comes to textiles, dimensional stability has attracted a lot of standards attention, and there are at least five international methods as well as national equivalents. The ISO methods cover washing and drying [65], free steam [66], cold water immersion [67], and dry heat [68], The fifth standard covers the preparation, marking, and measuring of specimens and garments for dimensional change tests [69]. 

Gassed cores are separated in two groups one group of cores is left untreated, the second group of cores is coated by immersion in various core wash compositions given in Table 15.2. Cores coated with water based and methanol based core washes are allowed to air dry, whereas cores coated with ethanol based core washes standard, hardened-by-gassing, 2 X 2 in sand specimens are soaked in an electric muffle furnace at 850 or 1375°C for 12 min in their own atmosphere, then removed from the fumance and allowed to cool to just above room tempaature, and tested in the Universal Sand Strength Machine. For all cores prepared as... 

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. 

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