Effect of thermal expansion on the high temperature wear resistance of Ni-20%Cr detonation spray coating on IN718 substrate

• Published in: Surface & coatings technology Vol. 462; p. 129490
• Main Authors: Purushotham, N., Parthasarathi, N.L., Babu, P. Suresh, Sivakumar, G., Rajasekaran, B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-06-2023
• Subjects: Adhesive; Crystallite size; Friction and wear; High-temperature; Ni-20%Cr; Recrystallization; Wear rate; Wear rate; Friction and wear; Recrystallization; Crystallite size; High-temperature; Adhesive; Ni-20%Cr
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2023.129490

The temperature-dependent materials properties on the dry sliding wear resistance of the detonation sprayed Ni-20%Cr coating have been studied. In-situ high-temperature X-ray diffraction (HT-XRD) was used to investigate high-temperature properties such as stress relieving, recrystallization, and thermal expansion. The dry sliding wear test was performed by using a ball-on-disc tribometer by sliding velocities (0.1 m/s), varying loads (6 N and 10 N), and temperatures (25 °C and 850 °C) against alumina (Al2O3) ball. The phase evolution, thermal expansion, crystallite size, and lattice strain were determined by the Williamson-Hall method. Field emission scanning electron microscopy and a non-contact optical profilometer was used to characterize the wear scar and calculate the wear rate. The wear test results demonstrated that the as-deposited coatings coefficient of friction (CoF) and wear rate (ω) continuously decreased as the temperature increased. The primary wear mechanism changed from abrasive and surface fatigue to adhesive and oxidative wear. The impact of stress relieving, recrystallization, and forming a composite tribolayer (Cr2O3, NiO) at elevated temperatures reduced the friction and enhanced the wear resistance. The effect of stress relieving, recrystallization, thermal expansion, and oxidation on the wear resistance of the coating has been discussed with a suitable mechanism.
•The sliding wear behaviour of detonation sprayed Ni-20%Cr coatings on IN718 substrates was studied at 850 °C•The coating showed superior wear resistance at 850 °C compared to the room temperature wear test due to the formation of composite tribolayer (Cr2O3, NiO).•At high temperatures, the wear mechanism shifts from abrasive and surface fatigue to adhesive and oxidative wear, enhancing tribological properties.•Stress relieving, recrystallization, and thermal expansion of coatings have influenced friction and wear resistance.