Rapid thermal processing for fast sintering of Mn–Cu spinel coatings deposited by electrophoretic deposition

Compact Mn–Cu spinel protective coatings were fabricated on AISI 441 ferritic stainless steel by electrophoretic deposition (EPD) followed by rapid thermal processing (RTP). The proposed approach enabled the formation of compact, adherent and partially densified coatings within significantly reduced processing times (below 1 h). A processing window was identified by varying RTP temperature and dwell time, highlighting the strong influence of thermal parameters on coating densification and adhesion. In situ high-temperature X-ray diffraction (HT-XRD) analysis of the Mn–Cu spinel powder revealed phase evolution during heating, including the growth of CuO-related peaks and spinel instability at 950 °C. Microstructural characterization showed that RTP conditions strongly affect coating morphology, densification behaviour, and thickness uniformity. Crack-free coatings were obtained under optimized conditions, while EDS analysis showed no detectable chromia scale formation at the coating/substrate interface after RTP treatment. The results demonstrate that RTP-assisted EPD is a promising and potentially scalable route for the fabrication of Mn–Cu spinel protective coatings for SOC interconnects, enabling rapid densification while limiting thermal exposure and interfacial degradation phenomena.