Solid-Particle Erosion of Laser Cladding, and Thermal-Sprayed Coatings for Surface Reclamation of Gray Cast Iron Components at Elevated Temperature

Diesel-type engines utilizing heavy crude oil as fuel often experience accelerated erosion and corrosion within their combustion exhaust ducts. To address this issue, this study proposes various surface reclamation techniques and materials for depositing coatings to rebuild the wall thickness of gray cast iron. Laser cladding and several thermal spray techniques are considered, chosen for their low heat input and limited heat-affected zone (HAZ). The evaluation encompasses various Ni-based alloys (Inconel-718 and NiCrBSiFe) and hard metals (WC-CoCr and CrC-NiCr) under high-temperature erosion conditions. The investigation employs the ASTM G211-14 (modified) standard experimental method as a reference for conducting erosion tests using Al₂O₃ particles. The samples are tested at 500 °C, simulating the actual working temperature of the engine. Remarkably, the resistance of Inconel-718 coatings produced by laser cladding and HVOF processes was outstanding, exhibiting a volumetric erosion rate one-third less than that of the original cast iron. WC-CoCr coatings demonstrated brittle behavior but still a superior resistance compared to the cast iron. The obtained results are thoroughly discussed within the framework of the characterized microstructures, mechanical properties, and erosion mechanisms inherent to each of the proposed coating solutions.