Prediction for Contact Fatigue Life of Plasma Sprayed Coating Based on Weibull Distribution

Abstract

Weibull distribution is one of the most common statistical methods used to deal with and analyze the fatigue life, but in the study of contact fatigue life of coating, most scholars established the Weibull distribution model without multivariate statistical analysis, which affected the accuracy of the model to a certain extent. In this work, NiCrBSi alloy coating was deposited on steel (AISI 1045) substrate using supersonic plasma spraying technique. Rolling contact fatigue (RCF) life of the coating was investigated using a ball-on-disc tester under different loads. The contact fatigue life of the coating was verified by Fan-Montfort test. The results show that the RCF life of different loads accords with Weibull distribution. The map of Weibull distribution failure probability is plotted. The coating failure probability at any number of cycles under the same working conditions can be observed intuitively through the map. The regression equation of RCF life and loading is established, it shows that the logarithm of characteristic life is linear associated with the loading, and the regression model can accurately characterize the contact fatigue life of coatings in a certain range.

Keywords

• Weibull distribution
• best linear unbiased estimate
• Fan-Montfort test
• contact fatigue life