Development of Ceramic Coatings to Enhance Electrical Insulation of Bearings for Electrical Motors
Date of Award
2-23-2023
Publication Type
Thesis
Degree Name
M.A.Sc.
Department
Mechanical, Automotive, and Materials Engineering
Keywords
Ceramic coatings, Bearings, Breaking voltage, Electrical insulation, Electrical resistance, Plasma electrolytic aluminating, Thermal shock resistance, Electric motors
Supervisor
X.Nie
Supervisor
H.Hu
Rights
info:eu-repo/semantics/embargoedAccess
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Abstract
Shaft voltages and bearing currents are among the causes of electrical bearing failures. Imbalanced magnetic fluxes and electrostatic induction produce shaft voltage and bearing current, which likely leads to morphological damage and lubrication failure, seriously affecting the operational performance and reducing the service life of the bearings. In this study, hercynite−alumina composite coatings were formed on the bearing steel surface using the plasma electrolytic aluminating (PEA) technique to protect the bearings against the failures mentioned above. SAE 52100 bearing steel samples were initially used as the coating substrate, followed by the 6208 deep groove ball bearing for subsequent coating experiments. The ceramic coating’s microstructures, chemical compositions, roughness value, insulation properties, hardness and thermal shock resistance were measured. The alumina coatings featured a dense microstructure with some porosity. The coatings were metallurgically bonded to the substrate and ranged in thickness from about 20 to 45 µm. The surface roughness of the coating increased with the increase of the coating thickness and needed to be minimized by polishing. The increased thickness of the ceramic coating could improve the insulation performance of the substrates. Compared to thermal spraying coated bearings, the plasma electrolytic aluminating coating could enhance the insulation performance and maintain coating stability. The PEA coating had high hardness and thermal shock resistance and remained intact after bearing installation tests. The double-sided PEA-coated bearing could be a practical approach for efficiently protecting bearings from electrical erosion and extending the lifespan of the electric motor.
Recommended Citation
Deng, Dewei, "Development of Ceramic Coatings to Enhance Electrical Insulation of Bearings for Electrical Motors" (2023). Electronic Theses and Dissertations. 8994.
https://scholar.uwindsor.ca/etd/8994