Production of Ni-Doped SiC Nanopowders and their Dielectric Properties

Abstract

Nanopowders of nickel‐doped β‐silicon carbide (β‐SiC) with improved dielectric properties (compared with pure β‐SiC) were successfully produced using the mechanically activated self‐propagating high‐temperature synthesis method in an argon (Ar) atmosphere. The molar substitution of nickel (Ni) for silicon (Si) was 1%, 3%, and 5%. Powders of poly(tetrafluoroethylene) and ammonium chloride (NH4Cl) were used to promote the combustion reaction. The experimental results indicated an active role of Ni in the mechanism of combustion synthesis of SiC powders, which was reflected in the increase in combustion temperature and the velocity of propagation of the combustion wave, the microstructure of the produced nanopowders with a grain size of 100 nm for 5% Ni, and an improvement in the dielectric properties, specifically the increase in real (ɛ′) and imaginary parts (ɛ″) of the complex permittivity, in the frequency range of 8.2–12.4 GHz, compared with pure SiC. The X‐ray analysis of the produced powders suggests that Ni is accommodated in the lattice of SiC, which shrinks with increasing amounts of Ni.

Ni-decorated SiC powders: Enhanced high-temperature dielectric properties and microwave absorption performance

“…Dielectric, electromagnetic absorption and interference shielding properties of multi-phase composites, such as SiC/CNTs [8], carbon black/SiC [9], Si 3 N 4 -SiC composite ceramics [10], porous yttria-stabilized zirconia (YSZ)/silicon carbide composites [11] and three-phase composites comprising poly(vinylidene fluoride)(PVDF), barium titanate (BT) nanoparticles and β-silicon carbide (β-SiC) whiskers [12], are investigated. Improving microwave loss factor and microwave-absorption performance have also been observed in the doped SiC with other elements, such as B [13,14], N [15][16][17], Al [18][19][20][21], Ni [22], and Al-N [23]. Surface modification is another effective approach to enhance microwave loss factor and microwave-absorption behavior [24,25].…”

Thermodynamic calculations and kinetic verifications on the chemical vapor deposition process of Si–C–N ceramic from the SiCl3CH3–NH3–H2–Ar precursors

“…It was reported that doping of SiC with N (p-type) or B (p-type) or mental (Ti, Ni and Al) had better microwave dielectric loss in the X-band than that obtained pure SiC [8][9][10][11][12]. Silicon carbonitride (Si-C-N) ceramic is a promising material [13] for its attractive properties, such as corrosion resistance, high temperature oxidation resistance, hardness and wide band gap [14][15][16].…”

Gel-cast-foam-assisted combustion synthesis of elongated β-Si3N4 crystals and their effects on improving the thermal conductivity of silicone composites

“…To prepare elongated b-Si 3 N 4 particles, we used a novel gel-cast-foam-assisted CS method. This method is based on conventional combustion synthesis and developed with the favor of gel-casting-foam method [9][10][11][12][13][14].…”