Authors: W Tillmann I Baumann P Hollingsworth IA Laemmerhirt
Publish Date: 2013/01/31
Volume: 22, Issue: 2-3, Pages: 272-279
Abstract
The application of fine powders in thermal spray technology represents an innovative approach to apply dense and smooth nearnet shape coatings on tools with complex geometry However this aim can only be achieved as long as the influence of the handling parameters of the spray process such as the spray angle is sufficiently understood In this study the influence of the spray angle on the deposition rate as well as on the coating properties microhardness roughness and porosity of HVOFsprayed finestructured coatings are investigated A fine agglomerated and sintered WC12Co powder agglomerate size 210 μm WCparticle Fisher subsieve size = 400 nm was used as feedstock material It has been shown that HVOF spraying of fine powders is less susceptible to an alteration of the spray angle than most other thermal spray processes such as plasma or arcspraying The reduction of the spray angle results in a decrease in the deposition rate while no significant degradation of the coating properties is found up to 30° However at spray angles below 30° the coating strength is negatively affected by the formation of pores and cracksThis article is an invited paper selected from presentations at the 2012 International Thermal Spray Conference and has been expanded from the original presentation It is simultaneously published in Thermal Spray 2012 Proceedings of the International Thermal Spray Conference Air Land Water and the Human Body Thermal Spray Science and Applications Houston Texas USA May 2124 2012 Basil R Marple Arvind Agarwal Laura FilofteiaToma Margaret M Hyland YukChiu Lau ChangJiu Li Rogerio S Lima and André McDonald Ed ASM International Materials Park OH 2012
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