Development of Ni-based and CeO₂-modified coatings by microwave heating

ABSTRACT

In the present investigation the microwave hybrid heating process was used to develop coatings on P20 tool steel substrates. The experiments were carried out in a domestic microwave oven of 900 W and 2.45 GHz frequency for a duration of 360 s. Ni-based clads/coatings without cerium oxide (CeO₂;unmodified coating) and with the addition of CeO₂ (modified coating) with varying wt.% of 1–3 were developed by the microwave hybrid heating process. The effect of CeO₂ addition on the microstructure, X-ray diffraction, and Vickers hardness, and the abrasive wear behavior of the developed clads was studied under varying sliding speeds and grit sizes. Investigation showed that the optimal addition of CeO₂ (1 wt.%) can effectively improve the microstructure, hardness, and abrasive wear behavior of the coatings. The Vicker’s microhardness of the modified coating with 1 wt.% of CeO₂ was 30% higher than the unmodified coating. Abrasive wear resistance of the modified coatings was found higher with an optimal addition of 1 wt.% CeO₂ at varying sliding speeds and grit sizes.

KEYWORDS:

• Cerium oxide
• cladding
• coating
• micro-hardness
• microstructure
• microwave
• Ni alloy
• tool steel

Acknowledgment

The author acknowledges Höganäs India Pvt. Ltd, Belgium, to provide metal powder for research work. The authors are also thankful to Sandeep Mishra, central facility lab, Delhi Technological University, for SEM studies.