Room-Temperature and High-Temperature Wear Behaviors of As-Sprayed and Annealed Cr3C2-25NiCr Coatings Prepared by High Velocity Air-Fuel Spraying

Abstract

Cr3C2-25NiCr coatings were deposited on stainless steel substrates by high velocity air-fuel (HVAF) spraying. Friction and wear behaviors of as-sprayed and annealed coatings were investigated both at room-temperature (RT) and 600 °C (high-temperature, HT). The results show that annealing at 600 °C in air is effective to enhance the wear performances of the coating both at RT and HT. The enhanced wear resistance of annealed coatings is discussed from the oxide growth and the microstructural evolution of the coatings. The wear behavior of the annealed coating follows the abrasive mechanism at RT and changes to an oxidative wear at HT, in which formation of a tribo-oxide layer plays a critical role to reduce the friction coefficient and to protect the underlying coatings from abrasive damage. The findings of this work reveal the significance of oxide-scale growth and microstructural evolution on the HT wear behaviors of the Cr3C2-25NiCr coating, which provides strategies for enhancing the wear properties of such coatings for HT applications.

An HVOF-Sprayed (Cr3C2-NiCr+Co) Composite Coating on Ductile Cast Iron: Microstructure, Mechanical Properties, and Scratch Resistance

“…Reducing the size of the chromium carbide shortens the mean free path in the matrix, thereby enhancing the coating's resistance to deformation, hardness, and reducing the likelihood of binder phase extrusion. [15,21]. The presence of Cr 7 C 3 carbide in the NiCr matrix, originating from the decomposition of Cr 3 C 2 , has the potential to alter the microstructure of the coating, thereby enhancing its resistance to cracking and wear.…”

“…Nevertheless, this process can lead to the formation of brittle structures (Cr 7 C 3 , Cr 23 C 6 ), which may adversely affect durability [15][16][17][18][19][20]. The great advantage of these coatings is the similar expansion coefficient of iron and chromium carbide (Cr 3 C 2 ) [21,22], which has an impact on the minimization of internal stresses in the process of spraying these coatings onto substrates made of iron alloys. According to the studies [23][24][25], starting powders with a regulated morphology and grain size are used in an effort to enhance the mechanical, tribological, and microstructural characteristics of Cr 3 C 2 -NiCr HVOF coatings.…”

Al2O3 Coatings for Protection of Stainless Steel 316L against Corrosion in Zn-Al and Zn-Al-Mg

“…However, the matrix supporting the WC particles was observed to react with liquid Zn alloy, leading to cracking of the WC particles and failure of the coating [4,10]. Ceramic materials show promise due to their inertness in molten metal [11][12][13][14][15]. For example, recent research showed that aluminium oxide (Al 2 O 3 ) is inert to liquid Zn-Al [11].…”