Extensive Characterization of Dense and Corrosion Resistant Coatings Produced by Improved Shrouded Techniques
| Autor: | C. Rinaldi, L. Ferravante, F. Uberti-Paci, P. Bianchi |
|---|---|
| Rok vydání: | 2001 |
| Zdroj: | International Thermal Spray Conference. |
| ISSN: | 2768-1505 2768-1491 |
| DOI: | 10.31399/asm.cp.itsc2001p1185 |
| Popis: | In a BRITE-EURAM Project gas shroud devices were developed for arc-wire and air plasma spraying processes to obtain cost effective coatings with high density, low defect contents and high corrosion resistance. To test the two devices FeCrAl, NiCrAl and NiCrTi coatings sprayed by shrouded arc were studied for boiler application; AMDRY 995 coatings sprayed by shrouded plasma were analysed for gas turbine blades. In this paper the results are presented of the extensive characterization performed by CESI on the coatings produced with the innovative techniques developed by the other partners. The coatings were sectioned and analysed by metallography and image analysis to determine oxide and porosity contents (total defect levels were less than 5%). Hardness and adhesion were measured following the ASTM standard procedures. On FeCrAl, NiCrAl and NiCrTi coatings sprayed by shrouded arc-wire technique both thermal cycling and corrosion tests were performed. A sulphidizing gaseous atmosphere was used to simulate boiler environment burning sulphur rich fuel as Orimulsion. The corrosion behavior after 1000h at 450°C resulted to be as good as that of an HVOF sprayed similar coating. Moreover coated tubes survived to thermal cycling tests without any delamination. Hot corrosion "Dean tests" were performed on AMDRY995 coatings sprayed by shrouded plasma onto two Ni-base superalloys (Ud 529 and In738). The environment was typical of hot parts in gas turbines; the corrosion resistance results after 1750h at 850°C were comparable to those typically obtained on the same material sprayed by vacuum plasma spray technique. The applicability of the shrouded plasma technique to the field of gas turbines was confirmed. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|