Electroless Nickel-Phosphorus Plating on Copper Substrate Using Galvanic Starter

Abstract

This study focusses on deposition of nickel layer onto copper substrates. Electroless nickel (EN) deposition is classified as a class of coating that is used to enhance the surface performance characteristics of a substrate. The processes include cleaning, soft etching, pre-dipping, acid dipping and electroless nickel plating. These processes are common for plating. For the first trial, there was no deposition of nickel layer onto the copper substrate with negative deposition speed, -1.7359µm/h. Galvanic starter was used for activation process, in which the iron plate was activated in H₂SO₄ bath before being touched onto copper plates. The optimum activation time for iron plate is 5 min. The time for the activated iron to touch onto the surface of copper is between 10-15 s. Hence, the nickel layer can be seen to be deposited onto the surface of copper substrate by a change of colour of the plate. The deposition speed of nickel layer is 5.3811 µm/h with semi-bright appearances. The performance of EN depends on the various parameters such as pH, operating temperature and deposition time. The standard values of those parameters are 4.4, 90⁰C and 20 mins, respectively. The properties of EN plating were characterized using Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray (EDX) which show the topography and chemical composition of copper substrate. The results show that the copper substrate without iron touch (galvanic starter) has irregular shape on the surface and contain of 96.8 wt.% of copper, 2.8 wt.% of carbon and 0.4 wt.% of oxygen. For the copper substrate with iron touch, the result shows that the chemical composition is 87.3 wt.% of nickel, 10.8 wt.% of phosphorus, 1.7 wt.% of carbon and 0.2 wt.% of oxygen