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2017-10-26 - Colloque/Présentation - communication orale - Anglais - 1 page(s)

Bonin Luiza , Bains Narinder, Vitry Véronique , Cobley Andrew, "Electroless deposition of nickel-boron coatings using low frequency ultrasonic agitation: Effect of ultrasonic frequency on the coatings properties and the deposition of electroless Ni-B composite." in 3rd e-MINDS Workshop, Barcelona, Espagne, 2017

  • Codes CREF : Chimie des surfaces et des interfaces (DI1327)
  • Unités de recherche UMONS : Métallurgie (F601)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux)
  • Centres UMONS : Ingénierie des matériaux (CRIM)
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Abstract(s) :

(Anglais) e-MINDS COST Action MP 1407 Workshop October 25-27, 2017, Barcelona, SPAIN Electroless deposition of nickel-boron coatings using low frequency ultrasonic agitation: Effect of ultrasonic frequency on the coatings properties and the deposition of electroless Ni-B composite. L. Bonin1, N. Bains2, V. Vitry1, A.J. Cobley2 1 Metallurgy Lab, UMONS, 20 place du Parc, 7000 Mons, Belgium 2The Functional Materials Research Group, Centre for Manufacturing and Materials Engineering, Faculty of Engineering, the Environment and Computing, Coventry University, Priory Street, Coventry CV1 5FB, UK Abstract A complementar e-MINDS COST Action MP1407 was carried out at the Coventry Univerisy on february 2016 in collaboration with the University of Mons. The 2 e-MINDS institutions have complementary expertise that ensured a successful outcome for the project. The University of Mons has an impresive back ground on the deposition of electroless Ni-B coatings and determination of mechanical properties and corrosion resistance of coatings. In the other side the Coventry University is specialized in the use of ultrasound in electrodeposition and electroless. During the one moth mission the effect of ultrasound on the properties of Nickel-Boron (NiB) coatings was investigated. NiB coatings were fabricated by electroless deposition using either ultrasonic or mechanical agitation. The deposition of Ni occurred in an aqueous bath containing a reducible metal salt (nickel chloride), reducing agent (sodium borohydride), complexing agent (ethylenediamine) and stabilizer (lead tungstate). Deposition was performed in three different configurations: one with a classical mechanical agitation at 300 rpm and the other two employing ultrasound at a frequency of either 20 or 35 kHz. The results showed that low frequency ultrasonic agitation could be used to produce coatings from an alkaline NiB bath and that the thickness of coatings obtained could be increased by over 50% compared to those produced using mechanical agitation. Although ultrasonic agitation produced a smoother coating and some alteration of the deposit morphology was observed, the mechanical and corrosion properties were very similar to those found when using mechanical agitation. The second part of the work was focused on electroless composite coating of nickel–boron (Ni–B) with tungsten carbide (WC) particles. The coatings were produced using an alkaline bath composed of NiCl2 as nickel source and NaBH4 as reducing agent. The WC particles were around 200 nm in size. A preliminary study about the WC particles dispersion in high pH solutions was necessary before starting this study. A comparison of properties of Ni–B, Ni–B–WC and low frequency, high power ultrasound assisted Ni–B–WC coatings in their as deposited states is presented. The surface morphology study reveals the formation of uniform, dense and fine-grained deposit in Ni–B–WC composite coatings deposited with ultrasound assistance. However, in the case of Ni–B–WC without ultrasound the surface analysis shows a deposit with large number of particles agglomeration. When compared with Ni-B samples, for the same time of deposition, the presence of particles increases the coating thickness. The hardness results demonstrate that the addition of WC into the Ni–B matrix results in significant improvement in hardness. As expected after the surface morphology analysis, the roughness increased in the case of the composite coatings, particularly if ultrasound was not used. Acknowledgements The author acknowledges the e-MINDS COST Action MP1407 for financial support in the framework of the short-term scientific mission collaboration.