scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Formation and characterization of borohydride reduced electroless nickel deposits

TL;DR: In this article, the formation of electroless Ni-B deposits and evaluation of their characteristic properties were studied. And the corrosion resistance of Ni-b deposits, in 3.5% sodium chloride solution, both in as-plated and heat-treated (450°C/1 h) conditions, was also evaluated by potentiostatic polarization and electrochemical impedance studies.
About: This article is published in Journal of Alloys and Compounds.The article was published on 2004-02-25. It has received 136 citations till now. The article focuses on the topics: Electroless nickel & Nickel boride.
Citations
More filters
Journal ArticleDOI
TL;DR: In this article, the effect of borohydride, thallium acetate, ethylenediamine and sodium hydroxide concentrations, and the coating bath temperature on both the coating rate and boron content of the electroless Ni-B films was investigated systematically.
Abstract: The effect of borohydride, thallium acetate, ethylenediamine and sodium hydroxide concentrations, and the coating bath temperature on both the coating rate and boron content of the electroless Ni–B films was investigated systematically. The Ni–B coating rate increased with the increase in thallium acetate and sodium hydroxide concentrations, but it was not very sensitive to the borohydride concentration. Below 90 g L − 1 ethylenediamine concentration the coating efficiency was significantly low and above this value as the ethylenediamine concentration increased the coating rate decreased slightly. Below 85 °C the coating rate was very low and above this temperature it was insensitive to the bath temperature. The boron content of Ni–B film increased with the increase in the borohydride concentration and the bath temperature, and decreased with the increase in thallium acetate and ethylenediamine concentrations. Up to 50 g L − 1 sodium hydroxide concentration, the boron content of the film increased and above this concentration it was insensitive to the sodium hydroxide concentration. As the boron content of Ni–B film increased, both the corrosion resistance and microhardness of Ni–B film increased. Heat treatment brought significant improvement in the microhardness but the corrosion resistance of Ni–B film was observed to decrease due to the disappearance of the amorphous characteristics of the as-deposited Ni–B film and the formation of the Ni–B compound phases.

138 citations

Journal ArticleDOI
TL;DR: In this paper, the hardness of electroless nickel-boron (Ni-B) coatings on a pure (99.99%) copper substrate has been evaluated using an empirical model and regression analysis.

115 citations

Journal ArticleDOI
TL;DR: In this article, the formation of electroless Ni-B coatings obtained using a low temperature bath and evaluation of their characteristic properties are addressed in the form of X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM), respectively.
Abstract: The formation of electroless Ni–B coatings obtained using a low temperature bath and evaluation of their characteristic properties are addressed in this paper. An alkaline bath having nickel chloride as the source of nickel and borohydride as the reducing agent was used to prepare the electroless Ni–B coatings. The influence of concentration of sodium borohydride in bath on the plating rate and the nickel/boron content of the resultant Ni–B coatings was studied. Selected coatings were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM), respectively, for assessing the phase content, phase transformation behaviour and magnetic properties. XRD patterns reveal that the structure of electroless Ni–B coatings in as-plated condition is a function of the boron content of the coating: higher the boron content, greater the amorphous nature of the coating and vice-versa. DSC traces exhibit two exothermic peaks around 300 and 420 °C, corresponding to the phase transformation of crystalline nickel and Ni3B phases at 300 °C and the transformation of a higher phase compound to Ni3B at 420 °C. VSM studies indicate that the magnetic properties of the coating is also a function of the boron content of the coating: higher the boron content, lesser the saturation magnetization.

106 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of boron concentration in the Ni-B alloys on their structure, morphology, electrochemical and corrosion behavior, physico-mechanical and electrical properties was investigated using X-ray diffractometry (XRD), scanning electron microscopy (SEM), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).

104 citations

Journal ArticleDOI
TL;DR: In this article, a comparative hardness study was conducted to assess the influence of load, indent position (free surface or cross section), and heat treatment on the results of the indentation tests.
Abstract: Electroless nickel–boron deposits were synthesized on aluminium alloys and submitted to heat treatments under neutral (95% Ar + 5% H 2 ) atmosphere. Two set of treatment conditions were used: 1 h at 400 °C and 4 h at 180 °C. Micro- and nanohardness measurements were carried out on the free surface of the sample and on polished cross-sections. A comparative hardness study was conducted to assess the influence of load, indent position (free surface or cross section), and heat treatment on the results of the indentation tests. Scratch tests were made on selected coatings to assess their adhesive properties and scratch resistance. Roughness measurements were carried out on the coatings before and after heat treatments. The samples were also investigated by XRD (X-ray Diffraction), SEM (Scanning electron microscopy) and optical microscopy to link their mechanical properties to their composition, structure and morphology.

89 citations

References
More filters
Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effects of concentration of NiCl 2, concentration of NH 4 Cl, pH, temperature, and amount of Ni powder on the rate of decomposition of NaBH 4.
Abstract: To study the mechanism and kinetics of the decomposition of NaBH 4 in an electroless nickel bath, we investigate the effects of concentration of NiCl 2 , concentration of NH 4 Cl, pH, temperature, and amount of Ni powder on the rate of decomposition of NaBH 4 . The results indicate that the decomposition of NaBH 4 is accelerated by H + ions and Ni 2+ ions. The kinetic orders of H + and Ni 2+ in the NiCl 2 /Na 2 C 4 H 4 O 6 system are 0.4 and 1, respectively, but the kinetic order of H + is 0.56 in the NiCl 2 /Na 2 C 4 H 4 O 6 +NH 4 Cl system. The rate of decomposition decreased with addition of NH 4 Cl. The results shows that the rate of decomposition of NABH 4 is accelerated by the presence of nickel powder in the bath. The experimental results and theoretical predictions of the model developed from the proposed mechanism are consistent

25 citations