Wear and friction characteristics of atmospheric plasma sprayed Cr₃C₂–NiCr coatings

ABSTRACT

The present work focuses on investigating the wear and friction characteristics of the Atmospheric Plasma Sprayed Cr₃C₂-NiCr coatings deposited onto the surface of die steel material. The as-sprayed specimens were characterized. The coating porosity, bond strength and microhardness values were evaluated. Wear tests were performed on the high-temperature pin-on-disc tribometer at room temperatures, 400°C and 800°C under two loads as 25N and 50N in the laboratory. The wear mechanisms of all the worn-out samples were studied by scanning electron microscopy (SEM) technique. The specific wear rates and the coefficient of friction values were analyzed. The developed coating showed better wear resistance than its uncoated counterpart. The coefficient of friction values for coated specimens decreased at elevated temperatures. At room temperatures, the wear mode was observed to be adhesive and further at elevated temperatures of testing, the wear mode was observed to be the combination of oxidative, adhesive and abrasive.

KEYWORDS:

• Die steels
• plasma spray
• Cr₃C₂–NiCr
• wear
• friction

Acknowledgment

The authors would like to thank the Metallizing Equipment Company Pvt. Ltd. Jodhpur (India) for providing The HVOF and Plasma spray coatings services for the die materials. The authors owe special thanks to Dr. Harpreet Singh for extending the necessary facilities and support in conducting the detailed analysis at Indian Institute of Technology Ropar, Roopnagar, Punjab, and Dr. S. Parkash at Indian Institute of Technology Roorkee, Roorkee. The authors would also like to thank IKGPTU, Jalandhar, India for supporting this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors thankfully acknowledge the research grant from Department of Science and Technology, New Delhi (India) under SERB, Science and Engineering – Engineering Scheme [File No. SR/S3/MERC/0072/2012, Dated 28 February 2013] titled-Development of Thermal Spray Coatings to Control Wear during High-Temperature Applications, and [EMR/2015/000234, Dated 11 March 2016] titled-Development of Thermal Spray Coatings to Control Wear during High-Temperature Applications-Phase II, to carry out this research and development work.