Abstract
Zirconia toughened alumina (ZTA) is a durable and biocompatible ceramic material commonly used in prosthetic hip implants because of its excellent mechanical properties and wear/corrosion resistance. Surface texturing can improve the lubricity and longevity of hip implant bearing surfaces, but precision machining of ceramic materials such as ZTA is very difficult due to suboptimal surface integrity results of traditional machining techniques. This thesis explores the optimization of machining ZTA using electric discharge machining (EDM) - a process usually reserved for conductive metals - to machine holes into the ceramic to create surface textures. EDM is made possible through the assistive electrode method (AEM), in which a combination of metals (gold-palladium and copper) and carbon is first applied onto the ceramic to make the surface conductive, allowing the EDM machine to spark, and machining is conducted in a carbon-based dielectric oil. Voltage, current, and electric discharge time were chosen to find the optimal combination for machining the ceramic that minimized cracks and defects and maximized accuracy, repeatability, and quality of holes. The results indicate that there is a set of parameters that achieves quality machining, despite several parameter combinations that result in catastrophic failure of the EDM tool and/or ceramic workpiece. The optimal parameter set identified (voltage of 71 V, current of 2.4 A, electric discharge time of 80 µs) had high repeatability and efficiency, and great dimensional accuracy. The combination of a gold-palladium, carbon, and copper assistive electrode layer, with the optimal parameter set and designed electrode, led to successful machining of ZTA using EDM. These results will open the door to achieving detailed and reliable surface texturing in ZTA materials, which could transform the world of hip replacement manufacturing.
Degree
MS
College and Department
Ira A. Fulton College of Engineering; Manufacturing Engineering
Rights
https://lib.byu.edu/about/copyright/
BYU ScholarsArchive Citation
Tuffaha, Yazan Eyas, "Enhancing Surface Texturing of Zirconia Toughened Alumina Ceramic Through Optimized Electric Discharge Machining Utilizing the Assistive Electrode Method" (2024). Theses and Dissertations. 10505.
https://scholarsarchive.byu.edu/etd/10505
Date Submitted
2024-08-16
Document Type
Thesis
Handle
http://hdl.lib.byu.edu/1877/etd13343
Keywords
ZTA, AEM, surface roughness, ceramic, conductive, machining parameters, hip implants
Language
english