CHEMISTRY OF PURE WATER

CHEMISTRY

The growth rate of Corrosion Cracking (SCC) stress from the heated zone 317L (BAA) and metal welding material in pure water high temperature at 290 ° C is measured using double Cantilever beam specimens (CDCB) contoured and current potential decreases (ACPD) in the system Long crash monitoring. The effect of loading modes and dissolved oxygen and hydrogen at the cracked growth rate (CGR) is quantified experimental. Typical Intergranular SCC found in HAC specimens and interdendritic SCC identified in welding metal specimens. HAC specimens and weld metal specimens show a response that is quite similar to loading modes that are applied and chemical water, even though their absolute CGR values ​​are different. The crack growth rate under trapezoid loading is quite high than under constant loading by some tenth percent. Switching water chemistry from oxygen bearing water to water hydrogen bearings drastically reduces the potential of electrochemical and cracked growth rates, and vice versa. The period of time lag for cracked growth was observed after switching water chemistry back to the water of oxygen bearings, where low crack growth rates even dissolved oxygen concentrations and electrochemical potential had become high. Hardening strains and uneven deformation distribution contributed to the increase in the growth of intergranular SCC growth in the Haz area. Creature growth kinetics were analyzed based on deformation / oxidation interactions at the cracked tip, given the importance of electric charge transfers, mass transportation kinetics and cracked end strain levels.Sol-gel alumina coatings are developed on a lightweight steel substrate (zinc-phosphate) surface and then sintered at 300 ° C, 400 ° C and 500 ° C. Alumina Sol is synthesized using aluminum iso-propoxide as a precursor material. FTIR from Gel Boehmite (Alooh) which is sintered at the temperature mentioned above is used to identify the existence of various functional groups. The microstructure and phase analysis of sol-gel coated specimens is done by using each SEM and XRD. Corrosion resistance of sol-gel alumina coatings is evaluated by electrochemical measurements in a 3.5% NaCl solution at room temperature. The abrasive behavior of sol-gel-plated specimens is measured in two body (high stress) conditions. The results of experiments revealed that the soles coated specimens were sintered at 400 ° C have superior wear and corrosion resistant properties compared to soles coated specimens sintered at 300 ° C. However, sol-gel coated specimens were sized at 500 ° C has shown a very bad corrosion and wear properties.

 The poor performance of sol-gel coatings that are sintered at 500 ° C can be explained due to:

•  (i) the presence of many cracks
•  (ii) the absence of organic groups in the layer.

HK-40M alloy corrosion performance is obtained from the noise electrochemical engineering and the polarization curve for 24 hours of exposure to high sulfate (80 mol% NA2SO4-20 mol% V2O5) and high vanadate (80 mol% V2O5-20 mol% Na2SO4) liquid salt at 700 ° C Reported. Electrochemical noise signals are analyzed in the time and frequency domain. Statistical analysis that obtains resistance noise, current standard deviation and localization index is presented and determining the corrosion level. Corrosion levels are supported by X-ray diffraction analysis of corrosion products and scanning analysis of electron microscopes from corrosioned samples. The results of the optical microscope examination of corrosioned samples showed that HK-40M alloy suffered from granular corrosion when exposed to high vanadate salt, while exposed to high sulfate salts, HK-40M rusted through the mixed corrosion process. HK-40M alloy corrosion mechanism is obtained along with corrosion levels, showing different behaviors when describing alloys to high vanadate and high sulfate salts.