X-ray Computed Tomographic Investigation of the Porosity and Morphology of Plasma Electrolytic Oxidation Coatings

0465628 - ÚFM 2017 RIV US eng J - Journal Article
Zhang, X. - Aliasghari, S. - Němcová, A. - Burnett, T.L. - Kuběna, Ivo - Šmíd, Miroslav - Thompson, G. - Skeldon, P. - Withers, P.J.
X-ray Computed Tomographic Investigation of the Porosity and Morphology of Plasma Electrolytic Oxidation Coatings.
ACS Applied Materials and Interfaces. Roč. 8, č. 13 (2016), s. 8801-8810. ISSN 1944-8244. E-ISSN 1944-8252
R&D Projects: GA MŠMT(CZ) ED1.1.00/02.0068
Institutional support: RVO:68081723
Keywords : plasma electrolytic oxidation * porosity * scanning electron microscopy * titanium * X-ray computed tomography
Subject RIV: JK - Corrosion ; Surface Treatment of Materials
Impact factor: 7.504, year: 2016
http://pubs.acs.org/doi/abs/10.1021/acsami.6b00274

Plasma electrolytic oxidation (PEO) is of increasing interest for the formation of ceramic coatings on metals for applications that require diverse coating properties, such as wear and corrosion resistance, low thermal conductivity, and biocompatibility. Porosity in the coatings can have an important impact on the coating performance. However, the quantification of the porosity in coatings can be difficult due to the wide range of pore sizes and the complexity of the coating morphology. In this work, a PEO coating formed on titanium is examined using high resolution X-ray computed tomography (X-ray CT). The observations are validated by comparisons of surface views and cross-sectional views of specific coating features obtained using X-ray CT and scanning electron microscopy. The X-ray CT technique is shown to be capable of resolving pores with volumes of at least 6 μm3. Furthermore, the shapes of large pores are revealed and a correlation is demonstrated between the locations of the pores, nodules on the coating surface, and depressions in the titanium substrate. The locations and morphologies of the pores, which constitute 5.7% of the coating volume, indicate that they are generated by release of oxygen gas from the molten coating.
Permanent Link: http://hdl.handle.net/11104/0264166