Abstract
In the present work the effect of surface roughness on oxidation behavior during the early stages of high temperature exposure of Ni-base superalloy IN 625 is described. The surface roughness was described using standard contact profilometer as well as novel method, fractal analysis. It was found that the different surface preparation resulted in a difference in roughness with a parameter increase of at least one order of magnitude for the ground sample as compared with the polished sample. The oxidation test was performed in a horizontal tube furnace. Post-exposure analyses including glow discharge optical emission spectrometry (GD-OES) and scanning electron microscopy (SEM), which revealed that grinding lowers the oxidation kinetics of IN 625 from 1.76 × 10−12 cm2·s−1, obtained for polished sample, to 9.04 × 10−13 cm2·s−1. It was found that surface preparation influences the oxide scale composition and morphology. The hypothesis explaining the mechanism responsible for the changes in oxidation behavior is proposed as well.
Highlights
The materials used in the hottest parts of stationary gas turbines or jet engines face very aggressive atmospheres at high temperature
DiscussBiootnh methods of roughness description, i.e., standard contact profilometry and fractal analysis, Bsohtohwmedetshimodilasrotfrernodusg, hspneecsisficdaellsyc,rrioputigohnn,eis.se.p, asrtaamndetaerrds wcohnerteacRtap, Rroz,fiRlomamx, eDtr, yLSaFnCd, farnadctLaRl aatn1alysis, showeμdms, iombtialainretdrefonrdgsr,osupnedcsifuircfaalcleys, aroreusguhbnsteasnstipalalyrahmigehteerrtshwanhfeorrepRolai,shRezd, .RInmacxo,nDtr,aLstS, SFRCC, avnaldueLsR at 1 μm, oosbhbtoatawiinneeedddtfhfooarrt gsthurerofuagcnreodupsnruedprsfaauracrfteiasoc,neabaryeresgsurmibnasdtlilanenrgttiihnaalclnryeafhosiergdthhietesrprtoohulaigsnhhefnoderssspu[or1fl5ai]sc.heT.ehAdi.sllIinpnactruoarnmntermtaesertas,ncSslR,eatChrlayvt alues obtained for the ground surface are smaller than for the polished surface
Smooth-rough crossover (SRC) values obtained for the ground surface are smaller than for the polished surface
Summary
The materials used in the hottest parts of stationary gas turbines or jet engines face very aggressive atmospheres at high temperature. Ni-base superalloys exhibit excellent mechanical properties at high temperature, due to their microstructure They possess good oxidation resistance due to the addition of elements forming a protective oxide layer, like Al or Cr [1]. For better protection against oxidation, Ni-base superalloys can be covered by additional oxidation resistant layers such as MCrAlY type coatings [3] or β-NiAl [4], which at high temperatures form the most protective alumina oxide scale. Manufacturing of those coatings generate additional costs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
