In Situ Particle Behavior of Cast Iron Powder by Suspension Plasma Spraying
- PDF / 643,699 Bytes
- 7 Pages / 593.972 x 792 pts Page_size
- 34 Downloads / 195 Views
. Tekmen, K. Iwata, Y. Tsunekawa, and M. Okumiya (Submitted April 21, 2009; in revised form October 7, 2009) An important issue for atmospheric plasma sprayed metal coatings is the oxidation involved during processing that significantly affects its phase composition and microstructure and thus the overall coating properties. In this study, suspension thermal spraying was used to manufacture cast iron coatings with high amounts of graphite carbon as solid-lubricant, because graphite structure is considerably diminished in molten droplets of the spray material due to the dissolution into molten iron and/or the oxidation. Additional graphite formation based on the soot reaction of liquid hydrocarbon was observed. Oxidation strongly affects the soot reaction during suspension thermal spraying. Therefore, setting-up of a shroud around the plasma plume is quite effective to prevent the oxidation of hydrocarbon.
Keywords
cast iron, graphite, hydrocarbon, plasma spraying, shroud, soot, suspension
1. Introduction In automobile industry, particularly the surface treatment of cylinder bore in aluminum engine blocks remains a key challenge in order to improve the poor tribological properties of aluminum. Among the various surface treatment methods including etching, infiltration, electroplating, aluminum wet liners and laser etching, plasma spraying has proved itself as an alternative method by achieving 4% reduction in fuel consumption and is continuously gaining importance (Ref 1). However, the average cost per unit of plasma sprayed bore compared to cast iron liner is still high; therefore, new approaches are needed to reduce the cost without incurring yet improving the performance. Plasma sprayed cast iron coatings containing graphite as solid lubricant are potential candidates to replace traditional steel or ferrous coatings for the surface modification of aluminum, due to the superior wear resistance arising from the self-lubricating effect of
This article is an invited paper selected from presentations at the 2009 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Expanding Thermal Spray Performance to New Markets and Applications: Proceedings of the 2009 International Thermal Spray Conference, Las Vegas, Nevada, USA, May 4-7, 2009, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2009. C. Tekmen, K. Iwata, Y. Tsunekawa, and M. Okumiya, Toyota Technological Institute, Materials Processing Laboratory, 2-12-1 Hisakata, Tempaku, 468-8511 Nagoya, Japan. Contact e-mail: [email protected].
Journal of Thermal Spray Technology
graphite and relatively low cost of cast iron powder (Ref 2). It has been shown that the wear resistance of cast iron increases with the increase in graphite content (Ref 3). However, the graphite content in cast iron coating strongly depends on the spray parameters as well as the powder properties (size and composition) and mig
Data Loading...
