About Mag. Dr. Selma Hansal

Head of R & D, Technical Director, Happy Plating GmbH, Viktor Kaplan Straße 2, A-2700 Wiener Neustadt, Austria

Selma Hansal studied Physical chemistry with emphasis on materials and properties of materials science and electrochemistry at the University of Vienna. She has worked in two BRITE EURAM projects related to surface processing and characterization, and worked from 2000 to 2004 as project manager at the Center for Applied Electrochemistry, Wiener Neustadt, in the work areas of electroplating and surface treatment with a particular focus on applying ultra-thin polymer layers.
She is a "Certified electroplater and Surface Finisher" (CEF-3), a member of the Austrian Chemical Society and of the British 'Institute of Metal Finishing IMF“ and Austria's official representative in "American Electroplater and Surface Finisher Society".
Since the founding of Happy Plating 2004 she works as executive assistant director of technical and scientific business unit of functional surfaces.

Pulse plating of nickel-based alloys

Fig. 1: Cathodic polarisation curves for (a) Ni-Co, (b) Sn-Ni and (c) Ni-W electrolyte systems recorded at a scan rate of 10mVs-1 on a rotating disk electrode at different electrode rotating velocity: 0, 100, 600 and 1000rpm

In the present work, nickel-based alloy coatings (Ni-Co, Sn-Ni and Ni-W) with different microstructures were produced under direct and pulse current conditions. These alloys are of interest as potential replacement for chromium based coatings, especially hard chromium. A replacement for hard chromium coating faces the challenge of providing sufficient hardness values.  For some sliding wear applications, hardness might not be required at the same level as hard chromium, and coating toughness might be more critical.
The effects of the pulse parameters (pulse waveform, pulse frequency and average current density) on the deposit structure and properties of these three systems have been investigated. Pulses have been defined based on the results of electrochemical measurements and numerical process simulation. The surface morphology, microstructure and microhardness of the deposit have been correlated to the pulse parameters applied.
The experimental results showed that applying pulse plating substantially altered the properties of the coatings. The resulting layers exhibited a nano-crystalline microstructure, improved layer compactness and hardness of the nickel-based alloy deposits.