CRITT MDTS

Charleville-Mézières, France

CRITT MDTS

Charleville-Mézières, France
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Belgacem Z.B.,University of Reims Champagne Ardenne | Carre G.,University of Reims Champagne Ardenne | Charpentier E.,University of Reims Champagne Ardenne | Le-Bras F.,University of Reims Champagne Ardenne | And 7 more authors.
PLoS ONE | Year: 2017

In this work, we developed a device capable to generate a non-thermal plasma discharge inside a sealed bag. The aim of this study was to assess the effectiveness of the oxygen, nitrogen and argon plasma sterilization on Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis spores according to the NF EN 556 Norm. Moreover the bag integrity which is a critical key to maintain the sterile state of items after the end of the process was verified by Fourier Transform Infrared (FTIR) and X-ray Photoelectron Spectrometry (XPS) analyses. After plasma treatments, the bacterial counting showed a 6 log reduction of P. aeruginosa and S. aureus in 45 min and 120 min respectively whatever the gas used and a 4 log reduction of B. subtilis spores in 120 min with only oxygen plasma. These results were confirmed by Scanning Electron Microscopy (SEM) observations showing altered bacteria or spores and numerous debris. Taking into account the studied microorganisms, the oxygen plasma treatment showed the highest efficiency. FTIR and XPS analyses showed that this treatment induced no significant modification of the bags. To conclude this non-thermal plasma sterilization technique could be an opportunity to sterilize heat and chemical-sensitive medical devices and to preserve their sterile state after the end of the process. © 2017 Ben Belgacem et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Chemkhi M.,University of Technology of Troyes | Retraint D.,University of Technology of Troyes | Roos A.,University of Technology of Troyes | Demangel C.,CRITT MDTS
Surface and Coatings Technology | Year: 2017

This paper analyses a recently developed duplex process combining a Surface Mechanical Attrition Treatment (SMAT) with low-temperature plasma nitriding. The thickness of the nitrided layer significantly increased by adding a polishing step between SMAT and plasma nitriding at 425 °C for AISI 316 austenitic steel. Contrarily it was also observed that without this polishing step the hardness decreased and the thickness and the homogeneity of the nitrided layer diminished with respect to the standard duplex process. The reason for this phenomenon is not well understood. Therefore, the aim of this investigation is to characterize and to discuss the effect of SMAT on the nitrogen diffusion into an austenitic stainless steel AISI 316 subjected to the duplex surface treatment. A second objective is to study the effects of the intermediate polishing step on the friction coefficient and hardness. In order to better understand the link between the generated microstructures and the diffusion kinetics and tribological responses, samples have been characterised by many different techniques such as Optical and Scanning Electron Microscopy (OM and SEM), X-Ray diffraction, hardness and ball-on-disc tests. Special attention was paid to the formation of oxide layers. The superficial and in-depth chemical composition of the SMATed samples were characterised by Energy Dispersive X-ray spectrometry (EDS) and Glow Discharge Spectrometry Profiles (GDOES), respectively. © 2017 Elsevier B.V.


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.


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.

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