Synergistic improvement in wear and high-temperature oxidation resistance of Cr3C2 ceramic particles/heat-resistant stainless-steel composites

In rotary hearth furnaces, the service life of spiral blades is determined by their high-temperature wear resistance. This study developed a Cr 3 C 2 ceramic particle/heat-resistant stainless-steel composite that combines both wear resistance and high-temperature performance, specifically targeting the limitations of conventional rotary blades, including insufficient wear resistance, short service life, and high costs. During the sintering process, partial dissolution of Cr 3 C 2 particles released C and Cr elements, which subsequently reacted with the metal matrix to form various carbo-borides, including M 7 C 3 -type carbides, MC-type carbides, M 2 (C, B)-type carbo-borides and M 23 (C, B) 6 -type carbo-borides. At room temperature, the composite with 25 wt.% Cr 3 C 2 demonstrated optimal wear resistance, achieving a hardness of 390.56 HV 10 (2.36 times the matrix material) and reducing wear volume loss to 0.0425 cm 3 (merely 29.07% of the matrix material, 0.1462 cm 3 ). Additionally, small addition of Cr 3 C 2 ceramic particles effectively improved high-temperature oxidation resistance. Composites with ≤20 wt.% Cr 3 C 2 exhibited superior high-temperature oxidation resistance compared to the matrix and reference sample Cr16. The optimal 15 wt.% Cr 3 C 2 composite formed the thinnest oxide layer (2 μm), consisting primarily of Cr 2 O 3 , Fe 2 O 3 , FeCr 2 O 4 , and NiFe 2 O 4 . Under high-temperature wear conditions at 800 °C, the composite containing 25 wt.% Cr 3 C 2 again demonstrated the optimal performance, exhibiting an average friction coefficient of 0.5658 and a wear scar width of 393 μm. In practical applications, the Cr 3 C 2 ceramic particles/heat-resistant stainless-steel composites demonstrated exceptional performance at 1200 °C, achieving 6∼7 times longer service life than conventional Cr28Ni20W20 materials in mixer screw blades.