2010 MoSAIc cohort www.me.iastate.edu/mosaic ISUMEREU 1 Thin Film Composite for Friction and Wear Analysis Jack Stransky Dr. Sriram Sundararajan Chris Tourek
Mar 28, 2015
2010 MoSAIc cohort www.me.iastate.edu/mosaic
ISUMEREU
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Thin Film Composite for Friction and Wear Analysis
Jack Stransky
Dr. Sriram SundararajanChris Tourek
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Outline
• Motivation and objectives• Sputter Deposition• Tribometry • Current Status
• Film Deposition• Film thickness measurements – Profilimetry
• Timeline
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Motivation and objectives
• Motivation: to create a thin film composite material which has the best physical properties of its constituents. This coating will be compared to the single material coatings by friction and wear analysis.
• Objective: Create thin film composites using sputter deposition. Materials to be used are:• Tungsten disulfide – Solid state lubricant, high melting point
(1250 C)• Titanium nitride – Extremely hard, protective material
Source: wikipedia.org
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Sputter Coating
• Free e- from electrode are accelerated at Ar atoms, driving e- off Ar, forming Ar+ ions
Source: http://www.ajaint.com/whatis.htm
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Sputter Coating
• Ar + ions are accelerated into negatively charged electrode, blasting target material loose
Source: http://www.ajaint.com/whatis.htm
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Sputter Coating
• Free e- recombine with Ar – ions, causing release of photons causing the glow of the plasma
Source: http://www.ajaint.com/whatis.htm
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Tribometer
• Friction and wear analysis• Friction is determined by applying normal load and
comparing this to the lateral force on the sample. The slope between these is the coefficient of friction.
• Wear is determined by applying a normal force back and forth against the sample and determining the amount of material that has been worn away using profilometry or AFM
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Current status
• Depositing, analyzing, and optimizing properties of films of pure WS2 and TiN
• Using AFM and Profilometer to determine film thickness
• Too much dispersion in samples to obtain accurate film thickness, new samples will be deposited using a method to reduce dispersion between glass and film to better analyize thickness
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Profilometer
Step Height (nm) of WS2
film
270.2
233.5
172.1
192.1
273.8
357.6
437.3
Average = 276.8 nm Standard deviation Surface roughness Ra
276.8 nm 86.3 nm 56.9 nm
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Timeline
This Week
• Deposit and analyze better WS2 coatings• Begin TiN coatings
Week of July 19th
• Deposit and Analyze TiN coatings
• Begin composite film deposition
Week of July 26th
• Begin frictional tests of coatings
Week of August 2nd
• Friction and wear testing
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Extra: AFM
• Currently using AFM to determine film thickness
2010 MoSAIc cohort www.me.iastate.edu/mosaic
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Extra: Ra
• Arithmetic average of absolute values of height deviations from the mean or the average of the peaks and valleys
• A term used to describe surface roughness
• L = evaluation length• Z(x) = profile height function
Source: http://www.harrisonep.com/resources/faq.html#ra