Predicting Interaction Phenomena in HVOF Thermal Spraying of WC-CoCr: A Hybrid Experimental–Statistical Approach

The development of thermal spray coatings for specific industrial and scientific applications is critical, particularly in the context of sustainable and economical production. This study employs a hybrid experimental–statistical approach to identify the influence of key process parameters and their interactions, based on a systematic design of experiments. Five factors were investigated: total gas flow (TGF), fuel-to-oxygen ratio (F2O), powder feed rate (PFR), standoff distance (SOD), and coating velocity (CV). The effects of these factors on in-flight particle properties, process performance, and coating characteristics were analyzed. Nondestructive evaluations, including deposition efficiency, surface roughness, and surface hardness, were directly compared with microstructural measurements. In contrast to previous studies, TGF emerged as the most influential parameter, exerting a stronger effect on particle properties, process performance, and coating characteristics than F2O. Significant interactions were identified, including the combined effects of TGF and F2O on roughness and hardness, TGF and PFR on deposition efficiency, and TGF and SOD on surface roughness. This investigation advances beyond validating known correlations by uncovering nuanced multidimensional interactions, offering a robust framework for optimizing WC-CoCr coatings. The findings contribute to the broader objective of enhancing the performance and sustainability of modern coating technologies through nondestructive methodologies.