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Corrosion behaviour and surface analysis of a Co–Cr and two Ni–Cr dental alloys before and after simulated porcelain firing
Author(s) -
Qiu Jing,
Yu WeiQiang,
Zhang FuQiang,
Smales Roger J.,
Zhang YiLin,
Lu ChunHui
Publication year - 2011
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.2011.00791.x
Subject(s) - corrosion , alloy , materials science , metallurgy , microstructure , chromium , stellite , nickel , oxide , electrochemistry , metal , chemistry , electrode
Qiu J, Yu W‐Q, Zhang F‐Q, Smales RJ, Zhang Y‐L, Lu C‐H. Corrosion behaviour and surface analysis of a Co–Cr and two Ni–Cr dental alloys before and after simulated porcelain firing.
Eur J Oral Sci 2011; 119: 93–101. © 2011 Eur J Oral Sci This study evaluated the corrosion behaviour and surface properties of a commercial cobalt–chromium (Co–Cr) alloy and two nickel–chromium (Ni–Cr) alloys [beryllium (Be)‐free and Be‐containing] before and after a simulated porcelain‐firing process. Before porcelain firing, the microstructure, surface composition and hardness, electrochemical corrosion properties, and metal‐ion release of as‐cast alloy specimens were examined. After firing, similar alloy specimens were examined for the same properties. In both as‐cast and fired conditions, the Co–Cr alloy (Wirobond C) showed significantly more resistance to corrosion than the two Ni–Cr alloys. After firing, the corrosion rate of the Be‐free Ni–Cr alloy (Stellite N9) increased significantly, which corresponded to a reduction in the levels of Cr, molybdenum (Mo), and Ni in the surface oxides and to a reduction in the thickness of the surface oxide film. The corrosion properties of the Co–Cr alloy and the Be‐containing Ni–Cr alloy (ChangPing) were not significantly affected by the firing process. Porcelain firing also changed the microstructure and microhardness values of the alloys, and there were increases in the release of Co and Ni ions, especially for Ni from the Be‐free Ni–Cr alloy. Thus, the corrosion rate of the Be‐free Ni–Cr alloy increased significantly after porcelain firing, whereas the firing process had little effect on the corrosion susceptibility of the Co–Cr alloy and the Be‐containing Ni–Cr alloy.