Dielectric properties of composites containing melt-extracted co-based microwires. (October 2016)

• Record Type: Journal Article
• Authors: Luo, Yang; Qin, Faxiang; Liu, Jingshun; Wang, Huan; Scarpa, Fabrizio; Adohi, Pierre; Brosseau, Christian; Peng, Hua-Xin
• Is Part Of: Composites communications. Volume 1(2016)
• Page Start: 20
• Page End: 24
• Publication Date: 2016-10
• Subjects: Ferromagnetic microwire-composites -- Effective permittivity -- Combined current-modulation annealing (CCMA) -- Nb doping
• DOI: 10.1016/j.coco.2016.07.004
• Languages: English
• ISSNs: 2452-2139

Abstract

Abstract: We have investigated the microwave properties of epoxy-based composites containing melt-extracted Co69.25 Fe4.25 B13.5− x Si13 Nb x ( x =0, 1, 3) microwires of various length annealed using a so-called combined current-modulation annealing (CCMA) technique. The observation of a double-peak feature in the permittivity spectra is believed due to the coexistence of the amorphous phase and a small amount of nanocrystallites on the wires with a high Nb content. CCMA was found to be favorable for a better-defined circular anisotropy of microwires and had suppressed the high-frequency peak due to residual stress relief for the composite with 25 mm long wires. Neither the shift of resonance peak nor the characteristic double peak feature was detected for composites containing as-cast 15 or 35 mm long microwires. Highlights: Permittivity of microwire-composites is controlled by structural related parameters. Combined current-modulation annealing is in favor of a well-defined domain structure. Two-peak feature is identified in the permittivity spectra of wire-composites. 25 mm is revealed as the optimal length for the dielectric properties of composites.