ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
Alloy 600 tubing can be repaired by using a Ni electroplating to have an excellent SCCresistance. In order to carry out a successful Ni electrodeposition inside a steam generator tubing,the effects of various parameters on the material properties of the electrodeposit should beelucidated. Hence this work deals with the effects of the applied current density and the dutycycle(Ton / (Ton + Toff)) of the pulse current on the material properties of the Ni electrodepositobtained from a Ni sulphamate bath by analyzing the current efficiency, the potentiodynamic curve,the hardness and the stress-strain curve. Hardness, YS(yield strength) and TS(tensile strength)decreased whereas the elongation increased as the applied current density increased. This was dueto a concentration depletion of the nickel ion at the interface of the electrodeposit/solution, and afractional decrease of the hydrogen reduction reaction. As the duty cycle increased, the hardness,YS and TS decreased while the elongation increased. During an off time at a high duty cycle, theconcentration depletion of the nickel ion could not be sufficiently recovered and the fraction of thehydrogen evolution reaction which is kinetically faster than the nickel ion reduction decreased,which contributed to a coarse grain sized electrodeposit. The experimental results of the hardnessand the stress-strain curves were supplemented by the results of the potentiodynamic curve
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/23/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.119.87.pdf
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