In-situ TiB2–Al2O3 formed composite coatings by atmospheric plasma spraying: Influence of process parameters and in-flight particle characteristics

In the present study, mechanically alloyed Al–12Si, B2O3 and TiO2 powder was deposited onto an aluminum substrate using atmospheric plasma spraying (APS). The effects of mechanical alloying (MA) time and plasma parameters (arc current and primary/secondary/carrier gas flow rate) on in-situ reaction intensity and in-flight particle characteristics (temperature and velocity) have been investigated. It has been observed that MA time has a remarkable effect on powder morphology and relative amount of in-situ formed TiB2 and γ-Al2O3. In-flight particle diagnostic measurements demonstrate that among the plasma parameters arc current has the strongest effect on in-flight particle velocity and temperature. Also, results indicate that in-flight particle velocity is more dominant than temperature on the relative amount of in-situ formed phases.