An Integrated Tribological and Vibration Signal Behaviour of TiN and AlCrN based PVD Coatings for Roller Bearings

Objective: The goal of current work is to check the suitability of Titanium Nitride (TiN) and Aluminium Chromium Nitride (AlCrN) coatings for the outer race of roller bearings. Methods: Physical Vapour Deposition (PVD) method of coating is employed since it provides less coating thickness. Tribological behaviour is studied for wear rate and co-efficient of friction using PIN-ON-DISC machine. Statistical method of Vibration analysis is performed by extracting values such as kurtosis, skewness, crest factor and RMS from time domain signals captured. Findings: It is revealed in the results that wear rate for TiN coated bearing is 0.03mm3/min which is less than that of AlCrN coated bearing and uncoated bearing. Findings of the vibration study showed that kurtosis value is 7.6 for worn out AlCrN coated bearing compared to 4.4 for worn out TiN coated bearing. This clearly shows that TiN offers better wear resistance which supports the results of wear analysis. It is observed in SEM images of morphological studies that more wear tracks and ploughing marks occurred in uncoated and AlCrN coated bearing surfaces compared to TiN coated bearing. Application/Improvements: Current work provides a good integrated approach for tribological and vibration signal behavior of TiN and AlCrN based PVD coatings thus improving correlation between the two methods and it can be prolonged for prognosis.