In this paper, we have reported a low cost method for depositing the hard alloy materials for electrical contact as well as MEMS structure application. Conventional methods of deposition like co-sputtering, e-beam PVD, etc. required a high running cost and had a high waste generation due to poor selectivity of deposition. The alloy formation was performed using a novel Electroplating method of synthesis. Au–Co alloy is made using a single bath electrodeposition for Au–Co thin films. XRD peaks analysis was used to confirm the alloy formation. AFM analysis was used to study the grains size, and surface roughness and the hardness measurement was performed using micro-indentation. The less surface roughness and high strength (Hardened) gold alloy formation were observed for a neutral pH (6.6 pH) Au–Co Alloy electroplating conditions. The low pH (4.0 pH) solution results to higher surface roughness while higher pH of the solution was not suitable for Au electroplating. © Springer Nature Switzerland AG 2019.