Type
Text
Type
Dissertation
Advisor
Vanketash, T.A. | Sampath, Sanjay | Turunen, Erja | Holmberg, Kenneth.
Date
2011-12-01
Keywords
coating, coating design, process development, thermal spray, tribology, wear mechanism | Materials Science
Department
Department of Materials Science and Engineering
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/71233
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Thermally sprayed ceramic-metallic composite (CerMet) materials consist of ceramic particles mainly in form of carbides reinforced by metallic binder exhibit unique microstructural and mechanical characteristics. Such structure brings in a novel combination of hardness and toughness enabling application of this class of material in wear resistant surfaces. Final deposit microstructure that defines the mechanical properties and wear performance of material depends on process parameters and starting material characteristics. Complex interaction of in-flight particles with supersonic flame, formation of complex defective deposit structure comprising of pores,cracks and splat boundaries make comprehending of interrelation of process, microstructure, properties and performance a difficult task. Additional challenge is development of systematic understanding on mechanical degradation, damage and wear mechanisms of cermet coatings due to their complex structure. This dissertation attempts to address these issues first by taking a systematic step by step approach, process map, to establish a correlation between process, particle state,microstructure and properties. Different strategies were proposed and examined to control the high velocity thermal spray process. This strategy assessment enabled a better control over in-flight particles state in high velocity thermal spray process and provided better understanding on interaction of in-flight particles with the flame. Further, possible advantages of reducing the carbide particle size from micron to nano in terms of mechanical properties and different wear performance were explored. It was suggested that poor wear performance of nano-structured coating is due to presence of brittle phases and less available binder promotes the excessive stress detrimental to load carrying capability of material. Material damage and wear mechanisms of coating under different tribological conditions were examined. The results suggest a correlation between relative abrasive particle size/carbide particle size and observed wear mechanism. Additionally effect of surface open porosities was highlighted. A surface damage mechanisms map was developed for coatings under increasing tangential force. This work has significant implications in improved material and process design of composite wear resistant structures and systems as it provides comprehensive qualitative insight to the wear mechanism of complex composite thermally sprayed structures under different tribological contact conditions. Additionally, this wok provides an establishment between process, microstructure, properties and performance for this class of materials. | 179 pages
Recommended Citation
Ghabchi, Arash, "Wear Resistant Carbide-based Thermal Sprayed Coatings: Process, Properties, Mechanical Degradation and Wear" (2011). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 439.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/439