Electrical resistance behavior of vinylester composites filled with glass-carbon hybrid fibers

Abstract

Vinylester (bismethacryloxy derivative of a bisphenol-A type EP resin, VE) composites with glass-carbon hybrid fibers (CF-GF) weight fraction of 50%, were prepared by the compress molding method. The distribution of carbon fiber in the hybrids was observed by stereomicroscope. The electrical resistance behavior of the composites filled with different carbon fiber (CF) weight contents (0.5% to 20%) was studied. The experimental results show that the electrical resistance behaviors of CF-GF/VE composites are different with those of CF/VE composites because carbon fibers' conducting networks are broken by the glass fibers in the CF-GF/VE composites. The carbon fibers distribute uniformly in the networks of glass fibers (GF) like single silk and form the semi-continuous conducting networks. Composite filled with GF-CF hybrid has a higher percolation threshold than that filled with pure CF. At that time, the resistivity of CF-GF/VE composites varies little with the temperature increasing. The temperature coefficient of resistivity in GF-CF/VE composite is less than 317 ppm and the variation of the resistivity after ten thermal cycles from 20 ℃ to 240 ℃ is less than 1.96%.

Experiment on Optimal Selecting for Cutting Tools in Milling of High Hardened Steel

“…When we choose tools, the selected tools are not only to have the required processing capacity, and should be the optimal tool in certain optimization goals. The surface roughness is an important parameter for measuring processed surface quality [5][6], appropriate tool play an important role on surface roughness. Therefore, giving full play to the excellent properties of cutting tool and achieve desired cutting effect, we must choice reasonable tool according to the specific object.…”

In-Situ Synchrotron X-ray Characterization of Corrosion Products in Zr Artificial Pits in Simulated Physiological Solutions

“…Both species were demonstrated to adsorb onto the metal surface but contradictory effects (suppressing or accelerating) were claimed on the corrosion of Zr. 26,27 It has also been reported that the presence of H 2 O 2 reduces the corrosion resistance of thermally oxidized Zr5Ti where surface oxides are mostly composed of ZrO 2 . 29 No studies have been reported on the combined effect of H 2 O 2 and albumin in terms of corrosion and corrosion products.…”

“…25 The increased corrosion rates induced by H 2 O 2 and albumin highlights the complex roles that biomolecules have in mediating corrosion at the implant surface. More recently, very limited work has been carried out on the role of organic species including glycine 26 and albumin 27,28 on corrosion of Zr. Both species were demonstrated to adsorb onto the metal surface but contradictory effects (suppressing or accelerating) were claimed on the corrosion of Zr.…”