Experimental Investigation On The Influence Of DLC Coating On The Wear Behaviour Of Helical Gear

• Main Author: Abdul Hamid, Abdul Hakim
• Format: Thesis
• Language: English; English
• Published: 2019
• Subjects: TA Engineering (General). Civil engineering (General)
• Online Access: http://eprints.utem.edu.my/id/eprint/24659/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=116914

The purpose of this research is to investigate the wear behaviour of amorphous hydrogenated carbon (a-C:H) coating deposited on the helical gears through wear debris analysis and oil analysis. The a-C:H coating were selected from various diamond-like carbon (DLC) coating variant using Pareto optimal analysis and weighted decision matrix, where it is deemed the most suitable for helical gear testing in this study. Helical gears were tested on a power recirculating test rig with constant loads of 100 Nm and speed of 1000 rpm. The tests were conducted for 9×106 cycles or an initial pitting of 1% covering the surface of the teeth. Samplings were obtained for approximately 60 ml of the lubricant for every 3.6×105 cycles which were then analysed through oil analysis which includes wear debris analysis as well as particle counting. The results revealed that the a-C:H coated gear reduces the particle generation by a factor of 3.11 as compared to the baseline testing. However, a-C:H does not improves the condition of the lubricant where in the uncoated gear, the lubricant oxidation increases per cycles while the coated gear is at a lower value while the viscosity of uncoated gear lubricant decreases per cycle as compared to the coated gear. Gear tooth image analysis reveals that the test reaches a micro-pitting stage with no visible pitting yet observed due to carburization of the base gear. However, a-C:H gears had a reduction in micro-pitting formation as compared to the uncoated gear yet peeling of the coating occurs. This suggest an extension of the life of the gear through the application of a-C:H coating is achievable.