Optimization of Cr₃C₂-NiCr Coatings Using ID-HVOF: A Statistical Approach to Key Process Parameters

Cr₃C₂-NiCr is widely applied to industrial components exposed to harsh environments using the conventional high-velocity oxygen fuel (HVOF) spraying process due to its excellent wear resistance, high-temperature oxidation protection, and corrosion resistance. However, internal coating applications present specific challenges, such as limited access to surfaces and the lack of experience of optimal process parameters. Additionally, the industry faces difficulties in producing fine chromium carbides, leading to coarser agglomerated particles compared to powders like WC-CoCr, which are currently more suitable for internal coatings. In this statistical study, a commercially available Cr₃C₂-NiCr powder was used in the ID-HVOF coating process. A Design of Experiments (DoE) approach, using a Central Composite Design (CCD), was employed to investigate the influence of key process parameters—kerosene, hydrogen, oxygen, and powder feed rate—on the ID-HVOF coating process. This approach highlights the role of statistical design in identifying critical factors that impact the performance of Cr₃C₂-NiCr coatings. The findings provide significant insights into optimizing the ID-HVOF process, ensuring enhanced mechanical properties and consistent coating quality for internal surface protection using Cr₃C₂-NiCr powder.