Charleville-Mézières, France


Charleville-Mézières, France

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Jelliti S.,Compiègne University of Technology | Jelliti S.,CNRS Risk Management Science and Technology | Richard C.,University of Tours | Retraint D.,CNRS Risk Management Science and Technology | And 3 more authors.
Surface and Coatings Technology | Year: 2013

By means of surface mechanical attrition treatment (SMAT), a nanocrystalline surface layer was formed on a Ti-6Al-4V alloy. The corrosion behavior of Ti-6Al-4V in a Ringer's solution was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Overall results of all studies identified beneficial impacts of SMAT on corrosion behavior of Ti-6Al-4V alloy. The surface oxide film formed on Ti-6Al-4V and its stability in biological environments play a decisive role for the biocompatibility of implants. In this study, passive oxide films formed on Ti-6Al-4V surfaces and their natural growth in a Ringer's solution have been investigated by microhardness and X-ray photoelectron spectroscopy (XPS). © 2013 Elsevier B.V.

Auzene D.,CRITT MDTS | Jacquemin T.,CRITT MDTS | Jacquemin T.,CNRS Biomechanical Engineering Laboratory | Duval J.L.,CRITT MDTS | And 3 more authors.
Powder Metallurgy | Year: 2015

Biological characterisation of materials produced by powder injection moulding (PIM) has been conducted, with the aim of promoting the use of PIM materials for dental applications to widen the potential applications of PIM. The biocompatibility trials focused on two alloys: the titanium alloy TiAl6V4, a well known biocompatible metal used for dental implants in contact with bone tissue; and a homogeneous 90Ti/10ZrO2composite applied for abutments in contact with epithelial tissue. It is concluded that PIM allows the production of materials with good biocompatibility with respect to osseointegration as well as soft tissue adhesion, compared with traditional materials for dental practice. © 2015 Institute of Materials, Minerals and Mining Published by Maney on behalf of the Institute.

Demangel C.,CRITT MDTS | Auzene D.,CRITT MDTS | Vayssade M.,CNRS Biomechanical Engineering Laboratory | Duval J.-L.,CNRS Biomechanical Engineering Laboratory | And 3 more authors.
Materials Science and Engineering C | Year: 2012

Metal injection molding (MIM) is a near net shape manufacturing method that allows for the production of components of small to moderate size and complex shape. MIM is a cost-effective and flexible manufacturing technique that provides a large innovative potential over existing methods for the industry of implantable devices. Commercially pure titanium (CP-Ti) samples were machined to the same shape as a composite feedstock with titanium and polyoxymethylene, and these metals were injected, debinded and sintered to assess comparative biological properties. Moreover, we treated MIM-Ti parts with BIOCOAT®, BIODIZE® and BIOCER®, three different anodic oxidation techniques that treat titanium using acid, alkaline and anion enriched electrolytes, respectively. Cytocompatibility as well as morphological and chemical features of surfaces was comparatively assessed on each sample, and the results revealed that MIM-Ti compared to CP-Ti demonstrated a specific surface topography with a higher roughness. MIM-Ti and BIOCER® samples significantly enhanced cell proliferation, cell adhesion and cell differentiation compared to CP-Ti. Interestingly, in the anodization post-treatment established in this study, we demonstrated the ability to improve osseointegration through anionic modification treatment. The excellent biological response we observed with MIM parts using the injection molding process represents a promising manufacturing method for the future implantable devices in direct contact with bones. © 2012 Elsevier B.V. All rights reserved.

Pi Y.,LISM URCA | Agoda-Tandjawa G.,LISM URCA | Potiron S.,LISM URCA | Demangel C.,CRITT MDTS | And 2 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2012

In this study, microstructural and mechanical properties of Ti-6Al-4V alloy, before and after the SMA treatment (SMAT) as well as the duplex SMAT/Nitriding process at different treatment conditions, were investigated in order to deepen the knowledge of these properties for biomedical devices. For that purpose, tribological (wear resistance, coefficient of friction) and mechanical (Vickers microhardness) tests were performed. To carry out the microstructural and surface topographical characterization of the samples, the scanning electron microscopy (SEM) and the 3D-SEM reconstruction from stereoscopic images have been used. By means of profiles deduced from the 3D images, the surface roughness has been calculated. The obtained results allowed to find an interesting SMAT condition which, followed by nitriding at low temperature, can greatly improve tribological and mechanical properties of Ti-6Al-4V alloy. It was also shown from SEM characterization and the original method of 3D-SEM reconstruction, that SMAT can reduce the machined grooves and consequently the roughness of the samples decreases. Moreover, we demonstrated, for the first time, that instead of usual etching method, the ionic polishing allowed to reveal the grains, the grain boundaries and the twins as well as the surface nanocrystalline layer generated by SMAT. Thus, the thickness of the SMATed layer decreases with the nitriding temperature, whereas the surface grain size increases. Copyright © 2012 American Scientific Publishers All rights reserved.

Faure J.,CNRS Laboratory of Engineering and Materials Science | Drevet R.,CNRS Laboratory of Engineering and Materials Science | Jaber N.B.,CNRS Laboratory of Engineering and Materials Science | Potiron S.,CNRS Laboratory of Engineering and Materials Science | And 3 more authors.
Key Engineering Materials | Year: 2015

Hydroxyapatite (HAP) and 58S Bioactive Glasses (BG) coatings were successfully synthesized by Electrophoretic Deposition (EPD) on Ti6Al4V alloy subjected to Surface Mechanical Attrition Treatment (SMAT). This process uses steel balls impacts on the Ti6Al4V surface to improve its mechanical properties. However when the Ti6Al4V substrate is treated by SMAT the industrial plasma spray technique is not efficient to obtain adherent HAP coatings. This problem is mainly related to the modifications of the Ti6Al4V surface topography due to the SMAT process. Therefore, in this work we demonstrate that EPD offers an efficient solution to solve this technical problem. Indeed we obtained homogeneous and adherent HAP coatings on the SMATed Ti6Al4V sample surface from a suspension of HAP nano particles in ethanol. Moreover EPD is also successfully employed to produce a 58S BG coating on the SMATed Ti6Al4V samples. Scanning Electron Microscopy (SEM) associated to Energy Dispersive X-Ray Spectroscopy (EDXS) reveals that the coatings obtained by EPD are adherent and compact without alteration of their chemical composition. © (2015) Trans Tech Publications, Switzerland.

Auzene D.,CRITT MDTS | Dausque A.,CRITT MDTS | Cauwe B.,CRITT MDTS | Popot J.M.,CRITT MDTS
International Powder Metallurgy Congress and Exhibition, Euro PM 2013 | Year: 2013

As titanium alloys, CoCrMo is a well known alloy widely used by implantable devices manufacturers due to its properties (biocompatibility, wear strength, etc....). Nevertheless, this alloy is expensive and not easily machinable. Thus, MIM (Metal Injection Moulding) process, the near net shape manufacturing method relevant for small to moderate size and complex shape components, is an attractive way for mass production. Indeed, MIM technology is a cost-effective and flexible manufacturing technique. Consequently, MIM CoCrMo parts have been sintered in different conditions (atmosphere, temperature...). After sintering step, heat treatment with post-HIP treatment have been realized on several samples. The best results (density, mechanical properties, microstructure ...) are obtained in 100% nitrogen sintering atmosphere with heat and post-HIP treatments. At last, these results are in conformity with international standard (ASTM F 2886-10) and revealed that MIM-CoCrMo alloy is comparable to wrought CoCrMo alloy.

Proust G.,University of Sydney | Retraint D.,University of Technology of Troyes | Chemkhi M.,University of Technology of Troyes | Roos A.,University of Technology of Troyes | Demangel C.,CRITT MDTS
Microscopy and Microanalysis | Year: 2015

Austenitic 316L stainless steel can be used for orthopedic implants due to its biocompatibility and high corrosion resistance. Its range of applications in this field could be broadened by improving its wear and friction properties. Surface properties can be modified through surface hardening treatments. The effects of such treatments on the microstructure of the alloy were investigated here. Surface Mechanical Attrition Treatment (SMAT) is a surface treatment that enhances mechanical properties of the material surface by creating a thin nanocrystalline layer. After SMAT, some specimens underwent a plasma nitriding process to further enhance their surface properties. Using electron backscatter diffraction, transmission Kikuchi diffraction, energy dispersive spectroscopy, and transmission electron microscopy, the microstructural evolution of the stainless steel after these different surface treatments was characterized. Microstructural features investigated include thickness of the nanocrystalline layer, size of the grains within the nanocrystalline layer, and depth of diffusion of nitrogen atoms within the material. © © Microscopy Society of America 2015.

Mezghani S.,University of Reims Champagne Ardenne | Perrin E.,University of Reims Champagne Ardenne | Vrabie V.,University of Reims Champagne Ardenne | Bodnar J.L.,University of Reims Champagne Ardenne | And 2 more authors.
Infrared Physics and Technology | Year: 2016

In this paper, a pulsed Infrared thermography technique using a homogeneous heat provided by a laser source is used for the non-destructive evaluation of paint coating thickness variations. Firstly, numerical simulations of the thermal response of a paint coated sample are performed. By analyzing the thermal responses as a function of thermal properties and thickness of both coating and substrate layers, optimal excitation parameters of the heating source are determined. Two characteristic parameters were studied with respect to the paint coating layer thickness variations. Results obtained using an experimental test bench based on the pulsed Infrared thermography laser technique are compared with those given by a classical Eddy current technique for paint coating variations from 5 to 130 μm. These results demonstrate the efficiency of this approach and suggest that the pulsed Infrared thermography technique presents good perspectives to characterize the heterogeneity of paint coating on large scale samples with other heating sources. © 2016 Elsevier B.V. All rights reserved.

Chemkhi M.,CNRS Risk Management Science and Technology | Retraint D.,CNRS Risk Management Science and Technology | Roos A.,CNRS Risk Management Science and Technology | Garnier C.,CNRS Risk Management Science and Technology | And 3 more authors.
Surface and Coatings Technology | Year: 2013

The combined effect of superficial nanocrystallisation by SMAT (Surface Mechanical Attrition Treatment) followed by plasma nitriding on the mechanical properties of a medical grade austenitic stainless steel was studied. SMAT conditions were optimised to enhance nitrogen diffusion. Experimental observations (energy dispersive X-ray spectroscopy profiles, cross-sectional optical micrographs, phase analysis by X-ray diffraction and micro-hardness profiles) show that polishing away a very thin layer after SMAT and before nitriding significantly improves nitrogen diffusion into the substrate, yielding a 50% thicker nitrided layer. Possible causes for this improvement are discussed. © 2013 Elsevier B.V.

Ben Belgacem Z.,University of Reims Champagne Ardenne | Carre G.,University of Reims Champagne Ardenne | Boudifa M.,CRITT MDTS | Charpentier E.,University of Reims Champagne Ardenne | And 2 more authors.
IRBM | Year: 2016

A prototype that generates non-thermal plasma directly and solely in a sealed bag has been developed (Patent PTC/FR2011/05219) and tested on Pseudomonas aeruginosa biofilms so as to see the bactericidal power of such non-thermal plasma. We assessed the effectiveness of two different plasma produced from gas mixtures of oxygen and nitrogen (5% O2-95% N2 or 15% O2-85% N2) on P. aeruginosa biofilms cultured on disks made of a hydroxyapatite-coated titanium alloy. We consequently obtained a bactericidal effect after a 60-min treatment on biofilms (5.8 log reduction) regardless of the gas mixtures. The relative effectiveness of plasma on bacterial biofilms could be explained by the thickness of biofilms and the difficulties to destroy the bacteria in the deeper layers that featured different physiological states. Another hypothesis dealt with the plasma partial diffusion in the hydroxyapatite porosities that coat the titanium alloy disks. © 2016 AGBM.

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