Selective Metallization on CFRP Composites by Laser Radiation and Electroless Plating

Selective metallization of carbon fiber-reinforced polymer composites (CFRP) was conducted by laser ablation with 1064 nm laser radiation and electroless plating in nickel solution. A rough caterpillar-like structure and polar surface with high property of absorption and anchoring for active seeds were produced by laser ablation. The laser treatment produce had a pronounced influence on nickel deposition. After immersed in nickel solution for 150s, a homogeneous and dense nickel film was selectively deposited on the laser treatment area of CFRP by electroless plating successfully. The Ni plating exhibited excellent adhesion on the CFRP. The technique in this study would widespread the application of CFRP in the area of spacecraft microwave components and waveguide antenna.

Importance of anions in electrodeposition of nickel from gluconate solutions

Electrodeposition of nickel from slightly acidic gluconate solutions containing chloride or/and sulfate ions was investigated. Electrochemical measurements correlated with bath speciations showed nickel chloride complex and nickel sulfate complexes as crucial species affecting cathodic reactions in a potential range up to −1.3V. At more negative potentials, nickel deposition was governed by a release of nickel cation from nickel-gluconate complex. This was further evidenced by differences in nucleation modes, morphology, and structure of the deposits. Wettability of as-plated and chemically modified nickel layers were determined and correlated with their morphology and corrosion resistance.

PROPERTIES OF ALUMINIUM/ELECTROLESS Ni-COATED SiC COMPOSITES - A REVIEW

The combination of properties of Al/SiC composites make them very attractive materials for applications in automotive and aerospace industries. Several techniques are used in developing Al/SiC composites but stir casting process is most commonly used because it is the simplest and cost effective technique. However, composites produced via stir casting suffer from limitations such as low wettability and inadequate bonding between the molten Al & SiC particulates and the formation of degrading interfacial products like aluminum carbide (Al4C3) which degrades the mechanical properties of the composite. Some of the techniques to improve Al-SiC wettability include addition of surface active elements such as magnesium, heat treatment of particles and application of metallic coating on the reinforcements before addition to the melt. Wetting agents alter the composition of the matrix alloy, while heat treatment of the reinforcement does not completely prevent the formation of Al4C3 when utilized. To reduce the direct interaction and promote wetting between reinforcements and molten aluminum during processing, the surface of SiC particulates can be modified by coating via oxidation, sol-gel and electroless processes. Of all these methods, electroless nickel deposition produces the best coatings with uniform thickness and adequate strength. In the present study, influence of electroless nickel-coating of SiC on the mechanical, corrosion and microstructural properties of Al/SiC composite has been evaluated. Finally, it can be concluded that the Ni and Ni3P intermetallic phases produced via electroless coating improves the wettability between the SiC and molten aluminium leading to enhanced properties of the composite.

Optimization of Synthesis Conditions of Ni/SBA-15 Catalysts: Confined Nanoparticles and Improved Stability in Dry Reforming of Methane

Despite its economic and environmental advantages, the dry reforming of methane using supported Ni-based catalysts remains challenging due to problems of metal particle sintering and carbon deposition, which lead to loss in catalytic activity. In this study, different silica supports, containing 5 wt% nickel, were prepared and characterized by N2 sorption, XRD, TPR, and TEM/SEM, in addition to Raman and TGA/MS for the spent catalysts. Different synthesis conditions were thus varied, like nickel deposition method, nature of nickel precursor salt, conditions for thermal activation, and nature of support. The results showed that enhanced metal dispersion, good confinement, and efficient stabilization of the active phase inside the pores can be achieved by using a well-structured mesoporous support. Moreover, it was demonstrated that carbon resistance can be improved when small nickel particles are well confined inside the pores. The strategies that affect the final dispersion of nickel particles, their consequent confinement inside (or deposition outside) the mesopores and the resulting catalytic activity and stability include mainly the application of hydrothermal treatment to the support, the variation of the nature of nickel precursor salt, and the conditions for thermal activation. General guidelines for the preparation of suitable Ni-based catalysts highly active and stable for dry reforming of methane (DRM) are thus presented in this work.