Ion nitriding of TiNi shape memory alloys I. Nitriding parameters and microstructure characterization
Journal
Surface and Coatings Technology
Journal Volume
92
Journal Issue
3
Pages
197-205
Date Issued
1997
Author(s)
Abstract
Ti50Ni50 and Ti50Ni40Cu10 shape memory alloys were ion nitrided to modify the surface conditions. The phases and microstructures of the nitrided surface were studied by XRD, EPMA and SEM. Experimental results indicate that the nitrided compound layer of equiatomic TiNi alloy consists of TiN and Ti2Ni phases, and that of Ti50Ni40Cu10 alloy consists of TiN, Ti2N and Ti40(Ni,Cu)60 phases. The surface hardness and the compound layer thickness increase with increasing nitriding temperature and time. These nitrided compound layers are found to exhibit a slight depression on the alloys' martensitic transformation temperatures and their shape recovery ability. A mechanism to explain the formation of the ion-nitrided layer in equiatomic TiNi alloy is also proposed in this study. © 1997 Elsevier Science S.A.
Publisher
Elsevier
Type
journal article