Use of a 3D printed auxiliary module for the quality improvement of Ni-P/SiC nanocomposite coatings A. Chouliara1,2, E. Papaioannou1, K. Mavronasou1, A. Bairamis1, A. Grigoropoulos1, A. Zoikis Karathanasis1 1Creative Nano PC, 4 Leventi Street, Peristeri, 12132 Athens, Greece 2Department of Material Science, School of Natural Sciences, University of Patras, 26504 Rio, Patras, Greece e-mail: anastasiachouliara22@gmail.com; e.papaioannou@creativenano.gr INTRODUCTION Ni-P/SiC composite electroplated coatings are considered as one of the most cost-effective and best-performing combinations that could replace hard chromium coatings, due to their excellent microhardness, as well as wear and corrosion resistance. These properties depend, among others, on the phosphorus content of the Ni-P matrix and the amount, distribution and particle size of the embedded SiC nanoparticles (NPs) [1]. Ni-P/SiC coatings can be divided in three main categories: low (1-5%), medium (5-8%) and high phosphorous content (above 9%) [2]. Pillai et al. observed that the incorporation of phosphorous in the nickel lattice can reduce the nickel grain size from microns to nanometers.[3] In addition, the utilization of pulse current electroplating has been shown to improve the quality and the properties of the Ni-P/SiC coatings [4, 5]. Nevertheless, the electroplating process also depends on other factors such as the design and actual set-up of the electroplating cell, the hydrodynamic conditions and the positioning and geometrical characteristics of the anode and the cathode. In this work, the modification of the electrolytic cell set up by designing and printing a plastic auxiliary module, made by ABS with the aid of a Fused Filament 3D printer is presented. This module was installed in the bath to alter the hydrodynamic conditions in the area of the cathode. The effect of the current density and the duty cycle on the pulse current Ni-P/SiC electrodeposition was subsequently investigated. REFERENCES [1] X. Yuan et al. (2009), Intern. Journal of Minerals, Metal. and Mater. 16, 444-451. [2] A. Lelevic et al. (2019), Surf. Coat. Tech. 369, 198-220. [3] A. M. Pillai et al. (2012), J. Coat. Technol. Res. 9, 785-797. [4] L. Wang et al. (2006), Scripta Mater. 55, 657-660. [5] A. Zoikis-Karathanasis et al. (2010), J. Alloys Compd. 494, 396-403. This project has received funding from the European Union’s Horizon 2020 research and innovation programmes under grant agreement No 862296, “Sabydoma” and grant agreement No 862583, ‘’NanoPat’’. CONCLUSIONS • A 3D printed barrier designed and printed using ABS filament in a FFF 3D printer was used to improve hydrodynamic conditions during electroplating. • The 3D printed barrier enhances the incorporation SiC NPs in the Ni-P metal matrix. • Optimization of duty cycle and current density in Ni-P/SiC electroplating produced the best Ni-P/SiC coating at f = 10 Hz, duty cycle = 37% and current density= 3 A/dm2 • A microhardness of 865 HV was obtained. Ni/SiC electrolyte g/L NiSO4∙6H2O 260 NiCl2∙6H2O 48 H3PO3 40 H3PO4 20 Saccharin 2 SDS surfactant 2.5 SiC NPs 10 Operating conditions pH = 2, T = 50 °C, Pulsed current with 20, 30, 35, 37and 40 % duty cycle, f = 10 Hz, Current density= 2, 2.3, 2.5, 2.7 and 3 A/dm2 , t = 5 h Figure 5. Optical microscope images (100x) of Ni-P/SiC coatings at (a) 20% (b) 30% (c) 35% (d) 37% and (e) 40% duty cycle at (f) 0.2 (g) 0.23 (h) 0.25 (i) 0.27 and (j) 0.3 A/dm2 current density. Figure 7. Microhardness and SiC content versus duty cycle (left) and current density (right) Figure 3. Comparison of silicon content in Ni-P/SiC coatings w and w/o 3D printed barrier Table 1. Ni-P/SiC electrolyte bath composition and Electroplating conditions Optimization of plating parameters After the establishment of the critical contribution of the 3D printed barrier, the plating parameters were optimized. Firstly, five different values for the duty cycle and the current density were examined. Moreover, particle size was m