Electrodeposition of Ni-Co-Fe_2O_3 composite coatings

Ni-Co-Fe2O3 composite coatings were electrodeposited using cetyltrimethylammonium bromide(CTAB)-modified Watt's nickel bath with Fe2O3 particles dispersed in it.The effects of the plating parameters on the chemical composition,structural and morphological characteristics of the electrodeposited Ni-Co-Fe2O3 composite coatings were investigated by energy dispersive X-ray(EDS) spectroscopy,X-ray diffractometry(XRD) and scanning electron microscopy(SEM).The results reveal that Fe2O3 particles can be codeposited in the Ni-Co matrix.The codeposition of Fe2O3 particles with Ni-Co is favoured at high Fe2O3 particle concentration and medium stirring,and the deposition of Co is favoured at high concentration of CTAB.Moreover,the study of the textural perfection of the deposits reveals that the presence of particles leads to the worsening of the quality of the observed <220> preferred orientation.Composites with high concentration of embedded particles exhibit a preferred crystal orientation of <111>.The more the embedded Fe2O3 particles in the metallic matrix,the smaller the sizes of the crystallite for the composite deposits.

Enhanced electromagnetic-interference shielding effectiveness and mechanical strength of Co-Ni coated aramid-carbon blended fabric

An efficient method was proposed to prepare high-performance conductive AramidCarbon Blend Fabrics(ACBF)with cobalt-nickel(Co-Ni)alloy coatings,which is conducive to industrial production.The grid-like substrate composed of aramid and carbon fibers was innovatively used in flexible Electromagnetic Interference(EMI)shielding materials.The natural network structure is advantageous to the uniform deposition of metal particles to the establishment of conductive pathways subsequently in order to improve conductivity.The induction of a synergistic effect from Electromagnetic(EM)wave-reflection and EM wave-absorption through the whole carbonCo-Ni-ternary system notably enhanced the EMI Shielding Effectiveness(SE)value to an average of 42.57 d B in the range of 30-6000 MHz.On the other hand,together with the inherent toughness of the alloy coatings,the tensile strength of the aramid fibers used for bulletproof made a significant contribution to the desired mechanical properties.The light weight of the resultant composite made it applicable to aerospace vehicles simultaneously.X-ray Photoelectron Spectroscopy(XPS)was conducted to investigate the variations of elements and groups on the sample surface in pretreating process.The elemental components and surface morphologies of fabric samples during different stages of the process were investigated by Scanning Electron Microscope(SEM)and Energy Dispersive spectrometer(EDX)measurements.X-Ray Diffraction(XRD)results indicated that the obtained Co-Ni alloy coating had a combined Hexagonal Closed-Packed(HCP)and FacedCentered Cubic(FCC)crystalline phase.The relatively high corrosion resistance demonstrated in different acid and alkaline conditions was instrumental in more complex environments as well.