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Fesches-le-Châtel, France

HMRexpert

Fesches-le-Châtel, France

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Song B.,University of Technology of Belfort - Montbéliard | Dong S.,University of Technology of Belfort - Montbéliard | Coddet P.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | And 3 more authors.
Journal of Thermal Spray Technology | Year: 2013

The performance of atmospheric plasma sprayed FeAl coatings has been remarkably limited because of oxidation and phase transformation during the high-temperature process of preparation. In the present work, FeAl intermetallic coatings were prepared by atmospheric plasma spraying combined with dry-ice blasting. The microstructure, oxidation, porosity, and surface roughness of FeAl intermetallic coatings were investigated. The results show that a denser FeAl coating with a lower content of oxide and lower degree of phase transformation can be achieved because of the cryogenic, the cleaning, and the mechanical effects of dry-ice blasting. The surface roughness value decreased, and the adhesive strength of FeAl coating increased after the application of dry-ice blasting during the atmospheric plasma spraying process. Moreover, the microhardness of the FeAl coating increased by 72%, due to the lower porosity and higher dislocation density. © 2012 ASM International.


Dong S.,Xi'an Jiaotong University | Dong S.,University of Technology of Belfort - Montbéliard | Song B.,University of Technology of Belfort - Montbéliard | Zhou G.,Xi'an Jiaotong University | And 3 more authors.
Surface and Coatings Technology | Year: 2013

The quality of bond coat and top coat of thermal barrier coatings (TBCs) has strong influences on their lifetime at high temperature. Especially, the oxygen content level and the surface roughness of bond coat as well as the porosity of top coat have been demonstrated to play an important role in the thermomechanical behavior of TBCs. In this study, dry-ice blasting was used during the preparation of TBCs which were composed of atmospheric plasma sprayed CoNiCrAlY bond coat and YSZ top coat. Three sets of TBCs deposited with different dry-ice (CO2) blasting treatments were compared with respect to the coating microstructure evolution, the growth behavior of thermally grown oxide (TGO), crack propagation and thermal shock resistance during thermal cycling exposure. It was interesting to find that different microstructures of bond coat and top coat were obtained under different spraying conditions. Moreover, the results showed that CoNiCrAlY bond coats continue to be oxidized during the deposition process of YSZ top coats when they are plasma-sprayed without dry-ice blasting. The three sets of prepared TBCs have different thermal shock lifetime. TBC with APS dry-ice blasted bond coat and APS dry-ice blasted top coat was the most durable and exhibited significant improvement in lifetime. The remarkable decrease in the oxide content and the porosity of bond coat, the increase in the "vertical" porosity of top coat and the improvement in the bonding strength at the bond coat/top coat interface appeared to contribute to the prolonged lifetime. © 2013 Elsevier B.V.


Dong S.,University of Technology of Belfort - Montbéliard | Song B.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbéliard | Coddet C.,University of Technology of Belfort - Montbéliard
Journal of Thermal Spray Technology | Year: 2013

The mechanisms of adhesion improvement of plasma-sprayed Al 2O3 coatings using dry-ice blasting were investigated. In this study, the change of substrate surface characteristics in both the topography and the wettability due to the treatment of dry-ice blasting was mainly studied. The effect of dry-ice blasting on Al2O3 splat morphology with different treatment durations was also examined. The residual stress of plasma-sprayed Al2O3 coatings using dry-ice blasting was measured by curvature method and compared to that of coatings deposited with conventional air cooling. Based on these numerous assessment tests, it could be concluded that the adhesion improvement of Al 2O3 coatings could be attributed to the cleaning effect of dry-ice blasting on different organic substances adsorbed on the substrates and the peening effect. © 2012 ASM International.


Dong S.,University of Technology of Belfort - Montbéliard | Song B.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbéliard | Coddet C.,University of Technology of Belfort - Montbéliard
Applied Surface Science | Year: 2011

Dry-ice blasting, as an environmental-friendly method, was introduced into atmospheric plasma spraying for improving properties of metallic, alloy and ceramic coatings. The deposited coatings were then compared with coatings plasma-sprayed using conventional air cooling in terms of microstructure, temperature, oxidation, porosity, residual stress and adhesion. It was found that a denser steel or CoNiCrAlY alloy coating with a lower content of oxide can be achieved with the application of dry-ice blasting during the plasma spraying. In addition, the adhesive strength of Al 2O 3 coating deposited with dry-ice blasting exceeded 60 MPa, which was nearly increased by 30% compared with that of the coating deposited with conventional air cooling. The improvement in properties of plasma-sprayed metallic, alloy and ceramic coatings caused by dry-ice blasting was attributed to the decrease of annulus-ringed disk like splats, the better cooling efficiency of dry-ice pellets and even the mechanical effect of dry-ice impact. © 2011 Elsevier B.V. All rights reserved.


Dong S.,University of Technology of Belfort - Montbéliard | Song B.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbéliard | Coddet C.,University of Technology of Belfort - Montbéliard
Journal of Thermal Spray Technology | Year: 2013

CoNiCrAlY splats were plasma-sprayed on the stainless steel substrate which was pretreated by dry-ice blasting. Only impact marks were distinguished on the glycerol-polluted substrate, while halo donut splats formed on the pretreated substrate because of the cleaning effect of dry-ice blasting on this organic substance. The proportions of different splat types vary as a function of the treatment time of dry-ice blasting. The condensation phenomenon was also detected on the substrate surface accompanying the cleaning effect after the pretreatment of dry-ice blasting. In this study, dry-ice blasting was investigated to be coupled with substrate preheating to control the substrate temperature. It was found that a regular disk-like CoNiCrAlY splat can be obtained as the substrate temperature is higher than dew point temperature. © 2012 ASM International.


Dong S.,University of Technology of Belfort - Montbéliard | Song B.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbéliard | Coddet C.,University of Technology of Belfort - Montbéliard
Materials Letters | Year: 2012

Dry-ice blasting, as an environment-friendly method, was introduced for the first time into atmospheric plasma spraying for improving properties of Al 2O 3 coatings. The tensile adhesion of the coating was examined. The microstructure of the coating was characterized using scanning electron microscopy. The temperature evolutions during the spraying were measured using an infrared pyrometer measurement system. The adhesive strength of Al 2O 3 coating deposited with dry-ice blasting exceeded 60 MPa, which was nearly increased by 30% compared with that of the coating deposited with conventional air cooling. The comparison of adhesions and microstructures of Al 2O 3 coatings plasma-sprayed with dry-ice blasting and with air cooling revealed that dry-ice blasting can optimize the coated substrate besides a cooling effect, and consequently resulted in the improved adhesion of plasma-sprayed Al 2O 3 coatings. © 2011 Elsevier B.V.


Dong S.J.,University of Technology of Belfort - Montbéliard | Song B.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | Liao H.L.,University of Technology of Belfort - Montbéliard | Coddet C.,University of Technology of Belfort - Montbéliard
Materials Research Innovations | Year: 2012

Dry ice blasting, as an environmentally-friendly method, was used during atmospheric plasma spraying for improving coating properties. This process is believed to be capable of reducing the porosity and the oxide of the coating and increasing the deposition efficiency, etc. Considering dry ice pellets are carried and accelerated by compressed air through a convergent-divergent nozzle, the computational fluid dynamic approach was first employed in this study to evaluate the effects of nozzle geometry, accelerating gas conditions as well as properties of pellets, on the pellet velocity variation and further to optimise the process. Moreover, the experiment with a steel powder was then carried out and the results indicate that a denser coating with a lower content of oxide can be achieved with the application of dry ice blasting during the plasma spraying. © 2012 W. S. Maney & Son Ltd.


Song B.,University of Technology of Belfort - Montbéliard | Dong S.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbéliard | Coddet C.,University of Technology of Belfort - Montbéliard
Surface and Coatings Technology | Year: 2014

Steel coatings prepared by atmospheric thermal spraying with dry-ice blasting were studied in terms of phase structure, magnetic and wear behaviors. It was found that dry-ice blasting could suppress the volatilization of carbon during spraying process due to the exclusion effect of carbon dioxide gas sublimated from dry-ice pellets on the oxygen. Moreover, the fractographic observation of the deposited coatings proved the removal effect of dry-ice blasting on the splashing particulates which were distributed with poor bonding strength between the splat layers. In addition, it has been found that the magnetic properties are sensitive to the direction in the coating, although steel coating presents a ferromagnetic character in the parallel and vertical directions. Steel coating deposited with dry-ice blasting possesses a relatively lower saturation magnetization but has a superior wear resistance because of the suppression of decarburization during the spraying process. © 2014 Elsevier B.V.


Dong S.,University of Technology of Belfort - Montbéliard | Song B.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbéliard | Coddet C.,University of Technology of Belfort - Montbéliard
Surface and Coatings Technology | Year: 2013

Dry-ice blasting was introduced into plasma spray as substrate's under-cooling system to improve the microstructure and property of coatings. In this study, steel, CoNiCrAlY and Al2O3 coatings were deposited by plasma spray coupled with the pre-/during-treatment of dry-ice blasting. Moreover, the effect of dry-ice blasting as a pre-/during-treatment and only the during-treatment was examined to discover a better way to use dry-ice blasting during thermal spraying. It is revealed that a denser steel or CoNiCrAlY alloy coating with a lower content of oxide can be achieved with the application of dry-ice blasting during the plasma spraying. Such decrease of the oxide content is mainly attributed to the better cooling effect of dry-ice pellets. Interestingly, it is also found that the pre-treatment of dry-ice blasting on the substrate can help to get metallic, alloy and even ceramic coatings with improved adhesions. The adhesive strengths of steel, CoNiCrAlY and Al2O3 coatings were increased by 14%, 5% and 30%, respectively, compared with those of the coatings deposited with conventional air cooling. The cleaning effect of dry-ice blasting is responsible for the increase of the adhesive strength. Based on the present study, dry-ice blasting can be proposed as a pretreatment and cooling system during plasma spray. © 2012 Elsevier B.V.


Dong S.,University of Technology of Belfort - Montbéliard | Song B.,University of Technology of Belfort - Montbéliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbéliard | Coddet C.,University of Technology of Belfort - Montbéliard
Surface and Coatings Technology | Year: 2013

Dry-ice blasting is applied in atmospheric plasma spray process with an aim to improve the properties of Cr2O3 coatings and save the cost. Microstructure, the tensile adhesive strength and the wear resistance of plasma-sprayed Cr2O3 coatings without and with the treatment of dry-ice blasting were compared. The results indicate that dry-ice blasting has a significant effect on the porosity of Cr2O3 coating. After the treatment of dry-ice blasting, the porosity of Cr2O3 coating decreases from 6.6±1.1% to 2.0±0.1% and a noticeable improvement in the adhesion between the coating and 25CrMo4 substrate has been obtained from 13±2MPa to 46±5MPa. They could be attributed to the sublimation effect of dry-ice pellets on the evaporated Cr and the cleaning effect of dry-ice blasting on the coated substrate. The dry-ice blasted coating was more wear resistant than that deposited without dry-ice blasting. © 2013 Elsevier B.V.

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