Date of Award


Publication Type

Master Thesis

Degree Name



Mechanical, Automotive, and Materials Engineering


Xueyuan Nie


Cathodic plasma electrolysis, friction, surface texturing, Taguchi analysis




Cathodic plasma electrolysis (CPE) was used to create surface texturing on gray iron samples, which could reduce the friction and increase the wear resistance. During the treating process, cast iron sample served as a cathode where the plasma discharging occurred, increasing the surface hardness and leaving an irregular array of micro craters on the surface. Modified surface morphology was determined from scanning electron microscope (SEM) and surface profiler. Recessed and protruded surface textures were observed when the CPE was applied at low and high voltages, respectively. Pin-on-disk tribotests were conducted on CPE-treated samples and untextured sample. The friction of as-treated samples could be reduced in boundary lubrication regime at low sliding speed due to the ability to store lubricant. Besides that, the surface texture generated extra hydrodynamic pressure that separated two sliding surfaces, increased the oil film thickness and accelerated the transition from boundary to mixed lubrication at high sliding speeds.