Analysis of powder particles of high carbon cast iron after air plasma spraying

Structure and phase analysis of high carbon cast iron prepared by plasma spraying was performed using X-ray diffraction and Mossbauer spectroscopy. The sprayed powder particles were trapped in liquid nitrogen to fix their composition during the flight from the plasma torch. The results show decarburization and oxidation of the powder. The carbon content decrease is more pronounced on surfaces of the particles. The fresh powder exhibits an anomalous magnetic transition from ferromagnetic to paramagnetic state during the sample cooling from room temperature down to 28 K. This effect was explained as result of high concentration of defects and strains. The long time ageing at room temperature caused transition to more stable phase composition and diminishing of the anomalous magnetic transition.