Electrochemical Synthesis of Core–Shell-Structured NbC–Fe Composite Powder for Enforcement in Low-Carbon Steel

Abstract

An NbC–Fe composite powder was synthesized from an Nb2O5/Fe/C mixture by electrochemical reduction and subsequent carbonization in molten CaCl2–NaCl. The composite has a core–shell structure, in which NbC acts as the cores distributing in the Fe matrix. A strong bonding between NbC and Fe is benefit from the core–shell structure. The sintering and electrochemical reduction processes were investigated to probe the mechanism for the reactions. The results show that NbC particles about several nanometers were embraced by the Fe shell to form a composite about 100 nm in size. This featured structure can feasibly improve the wettability and sinterability of NbC as well as the uniform distribution of the carbide in the cast steel. By adding the composite into steel in the casting process, the grain size of the casted steel was markedly deceased from 1 mm to 500 μm on average, favoring the hardening of the casted steel.

Electrolysis Synthesis of Carbides and Carbon Dioxide Capture in Molten Salts

“…The structure can inherit the hardness of carbide and the plasticity of metal, thus overcoming the defects of low wettability, poor sinter ability and difficulty in forming integral materials. [90][91][92] The synthesis of composites Ni/TaC, [93] Fe/TiC, [61] Fe/NbC, [94] Sn/NbC, [95] NbC/Nb 5 Si 3 /Nb, [96] etc. has also undergone similar reactions.…”

Growth of NbC Thin Film Using CH4 as a Carbon Source and Reducing Agent

“…Recently, TMCs are being increasingly utilized as supporting materials for various electrocatalyst materials [10,11] or as electrocatalyst materials themselves [12,13]. Among the various carbide materials, niobium carbide (NbC) has excellent abovementioned properties (highest melting point: 3610 • C, high Young's modulus: 380-480 GPa) and superconducting properties (below 12 K), which make it promising for various applications such as a reinforced phase in an iron matrix, hard coating, and wear protection [14][15][16][17]. Furthermore, NbC is potentially applicable as an electrical contact coating material owing to its low electrical resistivity (3.5 × 10 −5 Ω•cm) [18] and excellent wear-resistance [19], replacing the noble metal with a low wear resistivity and high cost.…”