Fabrication of core‐shell structured TiC–Fe composite powders by fluidized bed chemical vapor deposition

Abstract

Fluidized bed chemical vapor deposition (FBCVD) was an effective way of preparing the core-shell structured TiC-Fe composite powders by employing FeCl 3 as a precursor. Fully covered TiC-Fe composite powders with the controllable Fe contents were readily achievable. An excellent interfacial bonding was formed between the TiC and the deposited Fe coating. The defluidization caused by the directional growth and self-nucleation-aggregation of the deposited Fe particles was the major barrier to depositing high-Fe-content composite powders. But it could be prevented by controlling the gas partial pressure of precursor and further eliminating the directional growth mode and self-nucleation behavior of Fe atoms. The optimal deposition temperature was 600°C and the partial pressure was about 20 kPa, corresponding to the gasification temperature of 275°C. K E Y W O R D Sceramic-metal systems, chemical vapor deposition, composites, core-shell structures, sinter/sintering

Reaction behaviors and specific exposed crystal planes manipulation mechanism of TiC nanoparticles

“…On the one hand, it is critical to first determine the structural–functional properties of the exposed crystal planes and then explore the relationships between those planes and the corresponding bonding interface, which is conducive to delivering their performance superiorities into specific alloy manipulation. This endeavor is focused on the interfacial characteristics, including interfacial bonding, work of adhesion, and electronic properties between the TiC(100) or TiC(111) planes and the crystal planes of some metals 6,25,26 . Zhang et al 27 found that the interplanar spacing mismatch between the (100) Al and (100) TiC was as low as 6%, strongly suggesting the TiC nanoparticles could serve as the α‐Al heterogeneous nucleation substrates.…”

“…This endeavor is focused on the interfacial characteristics, including interfacial bonding, work of adhesion, and electronic properties between the TiC(100) or TiC(111) planes and the crystal planes of some metals. 6,25,26 Zhang et al 27 found that the interplanar spacing mismatch between the (100) Al and (100) TiC was as low as 6%, strongly suggesting the TiC nanoparticles could serve as the α-Al heterogeneous nucleation substrates. Solidification microstructure manipulation assisted by TiC nanoparticles has been extensively implemented on the basis of well-controlled TiC/substrate interface in various fabrication processes, such as stir casting, welding, or laser additive manufacturing, and is conducive for obtaining fine equiaxed grain microstructures in alloys, improving the work reliability and service life.…”