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Fesches-le-Châtel, France

Dong S.,University of Technology of Belfort - Montbeliard | Song B.,University of Technology of Belfort - Montbeliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbeliard | Coddet C.,University of Technology of Belfort - Montbeliard
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. Source


Dong S.,University of Technology of Belfort - Montbeliard | Song B.,University of Technology of Belfort - Montbeliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbeliard | Coddet C.,University of Technology of Belfort - Montbeliard
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. Source


Song B.,University of Technology of Belfort - Montbeliard | Dong S.,University of Technology of Belfort - Montbeliard | Coddet P.,University of Technology of Belfort - Montbeliard | 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. Source


Dong S.,University of Technology of Belfort - Montbeliard | Song B.,University of Technology of Belfort - Montbeliard | Hansz B.,HMRexpert | Liao H.,University of Technology of Belfort - Montbeliard | Coddet C.,University of Technology of Belfort - Montbeliard
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. Source


Dong S.,Xian Jiaotong University | Dong S.,University of Technology of Belfort - Montbeliard | Song B.,University of Technology of Belfort - Montbeliard | Zhou G.,Xian 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. Source

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