Electrical insulation property of an alumina coating on a bearing steel SAE 52100
2022-01-0879
03/29/2022
- Event
- Content
- In recent years, bearing electrical failures have been a significant concern in electric cars, restricting electric engine life. The most frequent material used to make bearings is 52100 alloy steel. This work aims to introduce a coating approach for preventing electrical erosion on 52100 alloy steel samples. This paper summarizes the causes of shaft voltage and bearing currents. Meanwhile, the paper discusses standard electrical bearing failure mechanisms, such as morphological damages and lubrication failures. Alumina coatings are suitable for insulating the 52100 alloy steel samples because alumina coatings provide excellent insulation, hardness, and corrosion resistance, among other characteristics. Based on the research, this article briefly discusses employing plasma electrolytic aluminating to coat 52100 alloy steel samples, an eco-friendly and high-efficiency coating process. Coating experiments were conducted over different coating periods to determine the most appropriate thin film for 52100 alloy steel samples. After applying coating layers on samples, FLUKE 1550B Megohmmeter was used to measure breaking voltage and resistivity. Two coatings sample combinations provided the best resistance (121-143 MΩ) and the highest breaking voltage (914-935 V), but longer treatments led to better insulation but a rougher surface. In this case, the grinding operation might need to obtain a smooth surface. Scanning electronic microscopy (SEM) observations indicated that the number of pores reduced as their size and porosity rose with the increased treatment time. The results indicated that extending the coating period increased insulating characteristics of the alumina coating on 52100 alloy steel samples. When the reported process is used for electrical insulation of the bearings, the low process temperature (unlike thermal spraying) may also benefit the bearings in minimum precision distortion.
- Citation
- Deng, D., and Nie, X., "Electrical insulation property of an alumina coating on a bearing steel SAE 52100," SAE Technical Paper 2022-01-0879, 2022, .