The influence of composition and process parameters on the microstructure of TiC-Fe coatings obtained by reactive flame spray process
C. S. LIU, J. H. HUANG, S. YIN
JOURNAL OF MATERIALS SCIENCE
Abstract
It has been proved that TiC-Fe ne-grained multiphase and multilayer coatings, composed of alternate TiC-rich and TiC-poor lamellae with different microhardness, can be obtained by reactive ame spray technology using ferrotitanium and graphite as the starting materials. This study was undertaken to assess the inuence of composition and process parameter on the microstructure of the coatings. It is found that parameters related to the melting and reaction of the reactive micropellets are the factors inuencing the hardness of TiC-rich layers. A high hardness can be favored by more titanium reacted with graphite (that is, less Fe content and more C/Ti atomic ratio within the reactive micropellets), smaller micropellets and properly longer spray distance. Among all the variables considered, Fe content (or the expected TiC content) and spray distance are the main parameters to affect the microstructure of the coatings. Because the hardness of the stacking multiphase layers containing very ne and rounded TiC particles depend on the composition and process parameters, the TiC-Fe coatings could be tailored to meet different applications, particularly those needed resistance to crack propagation.
Keywords:lamellae; Fe content; TiC particles; high hardness; uencing; spray process; ferrotitanium; composition and process; TiC-Fe; reactive ame; melting and reaction; reactive micropellets; TiC-rich layers; spray distance
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