Nor Akmal Fadil

Synthesis and electrocatalytic performance of atomically ordered nickel carbide (Ni3C) nanoparticles

Atomically ordered nickel carbide, Ni3C, was synthesized by reduction of nickel cyclopentadienyl (NiCp2) with sodium naphthalide to form Ni clusters coordinated by Cp (Ni-Cp clusters). Ni-Cp clusters were thermally decomposed to Ni3C nanoparticles smaller than 10 nm. The Ni3C nanoparticles showed better performance than Ni nanoparticles and Au nanoparticles in the electrooxidation of sodium borohydride.

Effect of the formation of CuO flowers and SnO2 on the growth of tin whiskers on immersion tin surface finish

The effect of the formation of CuO flowers and SnO2 on tin whiskers formation and growth in 30°C/60%RH environmental condition for tin surface finish had been studied. Immersion plating method was used to coat a layer of tin onto a copper, Cu substrates. The coated surface was subjected to external stress by micro hardness indenter with 2N load in order to simulate an external stress in coating layer and to promote the formation of tin whiskers. FESEM and EDX was used to study the type and chemical composition of whiskers and oxides formed. Image analyser was used to measure the whiskers length using JEDEC Standard No 22-A121A. After 1 week of the exposure under 30°C/60%RH environmental condition, kinked-type whiskers were formed and the whiskers growth were discontinued at week 4 due to the distruction at the end-tip of kinked-type tin whisker to grow further when it touched the coating surface. An obervation until 52 weeks of exposure time found that the formation and growth of CuO flowers and the oxidation of non-kinked-type of tin whiskers to form SnO2 promoted by external stress also contributed to the discontinuity of whiskers growth.

Optimization of formaldehyde concentration on electroless copper deposition on alumina surface

The effect of formaldehyde concentration on electroless copper plating on alumina wafer was studied. The main composition of plating bath was copper sulphate (CuSO4) as precursor and formaldehyde as a reducing agent. The copper deposition films were assessed by varying the ratio of CuSO4 and formaldehyde. The plating rate was calculated from the weight gained after plating process whilst the surface morphology was observed by field emission scanning electron microscopy (FESEM). The results show that 1:3 ratio of copper to formaldehyde is an optimum ratio to produce most uniform coating with good adhesion between copper layer and alumina wafer substrate.

The effect of organic solvent (Ethanol) on electroless Ni-P deposition

Use of electroless nickel for electronic applications continues to grow and is clearly the most diverse market segment. This project is aimed to investigate the possibility to coat nickel by using organic solvent for nickel composite coating deposition with undissolved-incorporated particles in water using electroless plating and to coat on water-dissolved materials. The work focuses on optimizing the coating parameters of electroless nickel phosphorous (Ni-P) in organic solvent which is ethanol on a copper substrate. The maximum concentration of ethanol was 50% to be added in an aqueous solution of plating bath to dissolve the entire Ni salt, complexing agent, stabilizer and reducing agent. The effect of 50% ethanol on electroless Ni-P deposition and characterization of Ni-P coating were studied. The characterization of coating materials was conducted using X-Ray Fluorescence (XRF) and Field Emission Scanning Microscopy (FESEM) with Energy Dispersive X-Ray (EDX). The result showed that the agglomerated Ni-P deposited on coating surface become bigger when the NiSO 4 concentration increases at the optimum plating time of 20 minutes. The performance of deposited Ni-P in this study showed highest adhesion level when the concentration of NiSO4 was 15 g/L while the thickest coating was formed at 40 minutes of 35 g/L NiSO 4 concentration.

Effect of pH on electroless nickel deposition on alumina substrates for chip resistor application

Alumina has been used widely in electronics industry specifically for chip resistor application. Currently, the deposition of nickel on alumina surface using electrodeposition method suffered from the insufficient bonding between the metallic coating (nickel) and the ceramic substrate (alumina). Electroless deposition method however can produce strong adhesion between the metallic coating and ceramic substrate. In this research, the effect of pH on the electroless nickel on alumina substrate was investigated. The electroless deposition of nickel on alumina substrate was conducted at pH 4.0, 5.6 and pH 10.0 for 3, 5, 10, 20 and 30 minutes at constant temperature. The crystal structure of the substrate and coating was characterized by using X-ray diffraction (XRD). The surface morphology of the coating was observed by using scanning electron microscopy (SEM) and the coating thickness was measure by X-ray fluorescence (XRF). The coating performance was tested by using Standard ASTM D3359 (Tape-Test). It was found that the optimum pH of plating solution was 10.0 with the maximum thickness was obtained at 30 minutes of deposition with thickness of 1.15 μm. These optimum coating parameters shows homogeneous and uniform nickel deposition on the alumina surface as observed by SEM. Nickel deposition by electroless method at pH 4.0, 5.6, and 10.0 have excellent bonding with alumina substrate as shown by tape test analysis.

Synthesis of Intermetallic Ni–Al Nanoparticles by Wet Chemistry Synthesis of Niacac2 and Alcl3 Precursors

The synthesis of intermetallic Ni–Al nanoparticles by coreduction approach of several organometallic precursors with sodium naphthelide in nonaqueous solution was studied. The state of the art in nanoparticles synthesization is the selection of suitable precursors and the adaptation of colloid chemistry to nonaqueous media. The reduction of two organometallic precursors, bis(cyclopentadienyl)nickel, Ni(Cp)2, and nickel (II) acetylacetonate, Ni(Acac)2 as a source of Ni element of the intermetallic, in tetrahydrofuran (THF) solution under a dry Ar atmosphere at room temperature gave black particles, characterized by powder X-ray diffraction (p-XRD). The nanoparticles synthesized from Ni(Acac)2 precursor produce pure Ni nanoparticles, that are air stable and has stronger magnetic property compared to Ni(Cp)2, while nanoparticles synthesized from Ni(Cp)2 yielded Ni3C. The particles were investigated in more detail by hard X-ray photoemission spectroscopy (HX-PES). The HX-PES spectrums confirmed that the black particles synthesized from Ni(Cp)2 is Ni3C instead of pure Ni. In the meanwhile, Al source was determined by synthesis Al(°) from ethyl aluminum dichloride, AlEtCl2 in toluene and aluminum trichloride, AlCl3 in toluene as well as THF. By using the same synthetic method, the synthesis of intermetallic Ni–Al nanoparticles was studied with various ratio of Ni precursor to Al precursor. The results showed that the NiAl nanoparticles were successfully synthesized by using selected precursors, Ni(Acac)2 and AlCl3 in THF solvent. Ni–Al nanoparticles synthesized by this approach reached 10 at.% of Al.

Wet chemical synthesis of Ni-Al nanoparticles at ambient condition

The synthesis of intermetallic Ni-Al nanoparticles by co-reduction approach of several organometallic precursors with sodium naphthelide in non-aqueous solution was studied. The state of the art in nanoparticles synthesisation is the selection of suitable precursors and the adaption of colloid chemistry to non-aqueous media at the room temperature under inert atmosphere. The reduction of an organometallic precursor, nickel (II) acetylacetonate, Ni(Acac)2 as a source of Ni element of the intermetallic, and aluminum trichloride, AlCl3 in tetrahydrofuran (THF) solution gave a black particles. The powder X-ray diffraction spectroscopy (pXRD) result shows an expansion of lattice parameter for FCC-Ni indicating the cooperation of Al atoms in Ni structures. The estimation value of Al concentration using Scherrer’s equation is 10 at%. The particles were investigated in more detail by hard X-ray photoemission spectroscopy (HX-PES). The HX-PES spectrums confirmed that the black particles has binding energy consistent to standard materials of Ni3Al. The absence of organic residues shown by the Fourier-transform infrared, FTIR spectrometer indicates that the as prepared Ni-Al nanoparticles are free from by-products.