Flame Spraying of Titania and Magnetite
Dr. Deidre A. Hirschfeld1, Scott S. Morton1 and Dr. Aaron C. Hall2, 1Materials and Metallurgical Engineering, New Mexico Institue of Mining and Technology, 801 Leroy Place, Socorro, NM 87801, 2Joining and Coating Department, Sandia National Laboratories, P.O. Box 5800, MS 1130, Albuquerque, NM 87123-1130

The effect of process conditions on flame spraying of titania (TiO2) and magnetite (Fe3O4) was investigated. Designed experiments were conducted to find the spraying conditions, specifically total combustible gas flow, stand off distance, and oxygen/acetylene ratio that produce high deposition efficiency (DE) and dense coatings.  Along with DE, particle temperature and velocity were determined and correlated with process conditions.  Results indicate that for both titania and magnetite, hot and high velocity molten particles result in higher DE and lower porosity coatings.  Micrographs of coating cross-sections and surface were taken with both field emission scanning electron microscope (FESEM) and a light microscope.  X-ray diffraction analysis shows that the titania coating retained its rutile structure while the magnetite coating had small amounts of maghemite (g-Fe2O3) in addition to magnetite. 

Ceramics and Thermal Barrier Coatings

The Preliminary Program for International Thermal Spray Conference And Exposition (ITSC) (May 15-18, 2006)