The Open Materials Science Journal

2016, 10 : 89-100
Published online 2016 September 30. DOI: 10.2174/1874088X01610010089
Publisher ID: TOMSJ-10-89

RESEARCH ARTICLE
 Oxide Spallation During Post-isothermal High Temperature Oxidation Cooling of Cr-rich Cast Alloys Highly Alloyed with Hf

Elodie Conrath and Patrice Berthod, *

* Address correspondence to this author at the Faculty of Sciences and Technologies, University of Lorraine, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France; Tel: 0033 383 68 46 66; E-mail: patrice.berthod@univ-lorraine.fr

ABSTRACT

Cobalt, nickel and iron-based alloys containing 25wt.%Cr and strengthened either by chromium carbides or by HfC were oxidized at 1000, 1100 and 1200°C to obtain external oxide scales. The spallation of these oxides during the post-oxidation cooling was studied by exploiting the cooling part of the thermogravimetry curves. The best resistant alloys against scale spallation were the iron-based alloys which did not lose oxide. The nickel-based alloys well behaved too. The worst alloys were the cobalt alloys, principally due to the complex composition of the oxide scales. Beside the base element, the thickness of the oxide was also identified as a major parameter. The presence of Hf with contents much higher than usual was also beneficial for the resistance against spallation.

Keywords:

Chromium, Cobalt alloys, Hafnium carbides, High temperature, Iron alloys, Nickel alloys, Oxidation, Scale spallation.