Improvement in energy channelization behaviour during micro hole formation in Y-SZ ceramic with magnetic field assisted ECSM process

Abstract

In the present investigation, an energy channelization behavior was improved while machining micro holes in the Yttria–stabilized zirconia (Y-SZ) under magneto hydrodynamic conditions. The integration of magnetic field with electrochemical spark machining (ECSM) process forms the stable and thin gas film on the tool electrode. The subsequent breakdown of this film improves the discharge frequency and increases the discharge current by 18%. The underlying process and material removal mechanisms were demonstrated by using the evidence from discharge signals, gas film images, SEM, and optical images of work material. The stirring action provided by the magnetic field in ECSM process helps to flush out the sludge and stray bubbles from the machining region. In comparison to the ECSM process, the hole depth and aspect ratio were improved by 84.37% and 120%, respectively. Thermal spalling is the leading phenomenon in the material removal process for Y-SZ instead of melting and chemical etching, as in the case of glass substrates. Energy channelization analysis is also carried out to establish the correlations between energy-based parameters and responses. The combination of higher applied energy with small pulse durations is suggested to produce deep holes. The parametric investigation, regression modeling, and optimization for the MFA-ECSM process are also carried out to explore the process behavior.