ECN publicatie: facebook
Titel:
Corrosion of stainless steel coatings applied by different thermal spray techniques
 
Auteur(s):
 
Gepubliceerd door: Publicatie datum:
ECN Energie Efficiency in de Industrie 1-10-1998
 
ECN publicatienummer: Publicatie type:
ECN-RX--98-055 Artikel wetenschap tijdschrift
 
Aantal pagina's:
17  

Gepubliceerd in: Contribution to EuroCorr Conference, Utrecht, 38 September - 1 October 1998 (), , , Vol., p.-.

Samenvatting:
Stainless steel coatings of type AISI 316 were manufactured with arc wirespraying (AWS), atmospheric plasma spraying (APS) and high velocity oxygen spraying (HVOF) on carbon steel substrates. The AWS coatings was the most porous coating with poor cohesion between the solidified spray particles. The WOF coating was dense with almost no oxide phase. 'Me plasma sprayed coating was less porous than the AWS coating but contained almost the same amount of oxides (1.4-5%). After electrochemical testing in 3% sodium chloride none of the exposed overlayers revealed any form of corrosion. In contrast to the HVOF sample the AWS samples, with poor cohesion between the splashes, showed severe corrosion between coating and substrate interface. For an inert overlayer the permeability, governed by the cohesion between the splashes, determines corrosion protection of the substrates. After exposure to 0.5 M sulphuric acid the AWS coating was corroded half way down the coating thickness. The as-sprayed oxides were dissolved but also the metallic matrix was corroded. Both the APS and the RVOF coatings showed minor attack close to the surface. In the HVOF coating the splash boundaries were broadened indicating crevice corrosion. The main corrosion mechanism in sulphuric acid showed to be dissolution of the oxidic phase facilitated by the poor cohesion in the thermal sprayed coatings. In absence of this species crevice corrosion degrades the coating. 6 refs.


Terug naar overzicht.