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2613 |
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Wednesday, September 28, 2011, Saal B2.1 2:25 PM Cold Spraying 4 |
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B4C/Ni composite coatings prepared by cold spray of blended or CVD coated powders |
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Vincent Guipont* / MINES ParisTech, PSL Research University, MAT - Centre des matériaux, CNRS UMR 7633, C2P - Competence Center for spray Processing, BP 87 91003 Evry, France , FRANCE Chunyang Feng / Mines ParisTech / Competence Center for Spray Processing, France Michel Jeandin/ Mines ParisTech / Competence Center for Spray Processing, France Olivier Amsellem/ Schlumberger Riboud Product Center, France Frederic Pauchet/ Schlumberger Riboud Product Center, France Richard Saenger/ Schlumberger Riboud Product Center, France Sebastien Bucher/ Lifco Iindustrie, France Constantin Lacob/ Lifco Iindustrie, France |
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In the oil industry, logging system involving geological sensors are designed to operate with severe service conditions of deep drills. In this context, metal matrix composites (MMCs) with ceramic reinforcers are applied on components to achieve wear and corrosion resistant systems. The 'cold spray' could be described as a /cold and inert process/ to form coating through severe plastic deformation of a ductile metal. Ceramic/metal MMC coating could be achieved by co-deposition of a ceramic with a ductile material. In this work, it was investigated the achievement of MMC B_4 C-Ni coating from both mechanically milled blends or B_4 C-Ni CVD coated batches. Blends of powders involving Ni powder with fine or coarse powders B_4 C were prepared by mechanical milling. Three CVD coated B4C-Ni powder batches were synthetized with 30, 40 and 50 Ni wt% respectively. Cold spray coatings were achieved with 1 pass and 5 passes to investigate building-up mechanisms and interfaces with AISI316L. Powders and as-cold sprayed coatings microstructures were observed by optical and scanning electron microscopies and further quantitative image analysis was carried to determine the volume content of B_4 C embedded in the Ni matrix of B_4 C-Ni cold sprayed coatings. The highest B_4 C vol.% up to 45% was obtained in case of B_4 C-Ni coated powder. Microhardness values of such MMC coating were also determined through Vickers indentation. The beneficial role on coating formation of the Ni surrounding layer of coated powders is discussed according the very original features of coatings microstructure obtained by cold spray of B_4 C-Ni coated powders. |