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Nanostructured Composite Films for high temperature tribological applications
|Hanna Wiśniewska Weinert , Volf Leshchynsky , Monika Gierzyńska-Dolna|
Instytut Obróbki Plastycznej (INOP), ul.Jana PawłaII14, Poznań 61-139, Poland
Transition-metal dichalcogenides (MoS2, WS2, etc.) are the most common solid lubricants for high temperature applications. They are applied as powders and coatings burnished the surface from powders, or deposited by spray and vacuum deposition methods. The goal of the paper is to develop nanocomposite coatings made of Boron Nitride and transition-metal dichalcogenide phases by advanced pressure saturation of porous sintered matrix and following severe deformation technique. Modern PM technologies were used to produce low cost high quality bearings with long-term performance and reliability in critical applications (high loads and sliding velocities, high temperatures). To comply with endurance requirements of high temperature applications, the nanostructuring approach was explored. In this technology solid lubricant particles were pressed into a supporting porous matrix and modified into nanostructured composite films by surface deformation. The nanostructured composite films consist of 10-50nm BN crystals and WS2 sheets embedded in nitrided stainless steel powder matrix. These BN/WS2 nanostructured coatings demonstrate low friction and wear in tests performed in humid air at the temperatures up to 5000C. Coatings are found to adapt to the test conditions, which results in BN and WS2 nano-sheets generation and permanent supply of solid lubricant from the surface reservoirs. These adaptive mechanisms achieve low friction coefficients of 0.05-0.1 and high endurance in high temperature exploitation friction tests. Correlations among BN/WS2 chemistry, structure, hardness, friction and wear are discussed. The tremendous potential of such nanostructured solid lubricant composite films for aerospace tribology is demonstrated.
Presentation: Oral at E-MRS Fall Meeting 2006, Symposium A, by Volf Leshchynsky
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-05-05 07:26 Revised: 2009-06-07 00:44