Experimental investigations of electrochemical micromachining of nickel aluminum bronze alloy
Sarangapani Palani, Poovazhagan Lakshmanan, Rajkumar Kaliyamurthy
Abstract
The use of nickel aluminum bronze (NAB) is found in components that include landing gear bearings, cast valve bodies, and perforated orifice for pharmaceutical industries. Machining of the NAB alloy in the micro-domain is a great challenge because of its unique mechanical and chemical properties. This work investigates the suitability of electrode materials for anodic dissolution of the NAB alloy through the use of the electrochemical micromachining process. Three distinct electrode materials, namely, brass, copper, and tungsten carbide were chosen for understanding the micromachining characteristics. The nature of the dissolution of NAB alloy and the impact of all three electrodes has been studied by varying the process parameters. Micro-hole making experiments were conducted by response surface methodology (RSM) based central composite design (CCD). The RSM-CCD utilizes quantitative process parameters for choosing qualitative electrode materials based on radial overcut, surface roughness, and material removal rate. SEM pictures examined the morphologies of the micro-holes. All the three electrodes exhibited successful anodic dissolution of NAB alloy under various parametric conditions. NAB alloy machined with tungsten carbide electrode exhibited the least radial overcut and surface roughness, whereas the copper electrode removed the highest materials. The brass electrode exhibited intermediate performance between tungsten carbide and copper electrodes.