In the case of thermal spraying of cermet powders using HVOF with longer barrel, such as a JP-5000 and a Diamond Jet 2700, spitting and clogging troubles tend to be brought about on the inner wall of the barrel. This phenomenon comes from the existence of fine particles (in spray powders) which tend to fully melt through barrel. This investigation has been carried out to realize the influence of powder particle strength and particle size distribution of agglomerated and sintered Cr3C2-25%NiCr powders during HVOF spraying. It is found that the finer and weaker the powder particles, the higher the deposit efficiency. However, the finer and weaker the powder particles, the easier is the onset of spitting and clogging phenomena. On the contrary, it is found that the coarser and stronger the powder particles, the lower the deposit efficiency with less spitting and clogging phenomena. Finally optimum powder particle strength and particle size distribution of Cr3C2-25%NiCr powders have been found in this study using a JP-5000 system.
1/7/2005
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