Controlling graphite content in plasma sprayed cast iron coatings via in-flight particle diagnostic

Graphite formation and degradation in thermally sprayed cast iron coatings is a technological barrier for achieving superior wear resistant coatings. Therefore, there is a need to understand the in-flight particle behavior of cast iron powder and introduce new approaches to control the graphite content. In this study, it has been demonstrated that the graphite content can be controlled by means of in-flight particle diagnostic. For this purpose, cast iron coatings were plasma sprayed under a variety of spray conditions and characterized by using an optical microscope, X-ray diffractometer and electron probe micro-analyzer. As a result, a significant amount of graphite with respect to a wide range of in-flight particle temperature and velocity was preserved in cast iron coatings.