Effect of martensitic transformation on the performance of coated NiTi surfaces

The comparative mechanical and corrosion performances of electropolished, uncoated NiTi surfaces, NiTi surfaces coated with diamond-like carbon, nitrided NiTi surfaces and NiTi surfaces coated with Ti were evaluated. To understand the effect of strain on coatings, the patterns of the deformation (lo...

Full description

Saved in:
Bibliographic Details
Published in:Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2008-07, Vol.486 (1), p.461-469
Main Authors: Heßing, C., Frenzel, J., Pohl, M., Shabalovskaya, S.
Format: Article
Language:English
Subjects:
Applied sciences
Corrosion
Corrosion mechanisms
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
Martensitic transformation
Martensitic transformations
Materials science
Metals. Metallurgy
Phase diagrams and microstructures developed by solidification and solid-solid phase transformations
Physics
Production techniques
Relief
Strains
Surface treatment
Titanium-coated
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The comparative mechanical and corrosion performances of electropolished, uncoated NiTi surfaces, NiTi surfaces coated with diamond-like carbon, nitrided NiTi surfaces and NiTi surfaces coated with Ti were evaluated. To understand the effect of strain on coatings, the patterns of the deformation (local versus total strain) and alteration of surface topography induced by stress activated transformation in the substrate were examined using light, scanning electron and confocal laser scanning microscopy. Samples were strained in tension mode within the stress–strain plateau (1%, ∼3%, and 5.6% local strain) and above it at ∼8% local strain. In contrast to the substrate material that retained surface integrity, coated surfaces started cracking at very low strains. First cracks were observed at 1% for nitrided and at ∼3% local strain for surfaces coated with diamond-like carbon and Ti, respectively. Cracks developed mostly at the locations of impurity-related particles. A corrosion study conducted in Ringer Solution showed that coated strain-free NiTi surfaces might not have any passivity and material under 8% local strain exhibited deterioration in corrosion resistance.
ISSN:0921-5093
1873-4936
DOI:10.1016/j.msea.2007.09.029