Date of Graduation

8-2018

Document Type

Thesis

Degree Name

Bachelor of Science in Mechanical Engineering

Degree Level

Undergraduate

Department

Mechanical Engineering

Advisor/Mentor

Zou, Min

Abstract

Polytetrafluoroethylene (PTFE) is one of the most low friction and corrosion resistant solid lubricants. Prior studies have shown that a polydopamine (PDA) underlayer enhances the durability of PTFE thin coating. In this study, 100, 200, and 300 µL of aqueous silica nanoparticle (NP) solutions were added to the PDA deposition solution. The durability and coefficient of friction of PDA/PTFE thin coatings on stainless steel substrates are investigated with and without incorporating the silica NPs. The coatings were tested in dry contact conditions using a Universal Mechanical Tester (UMT) with a ball-on-flat configuration in a reciprocating motion. It was found that the durability of the PDA/PTFE coating are significantly improved when 100 µL of aqueous SiO2 NP solution were added during the deposition of the PDA underlayer. Formation of transfer film was also observed on the counter face. The significant improvement in the durability is attributed to the increased adhesion of the PTFE coating to the PDA underlayer and the enhanced mechanical strength provided by the NPs as well as the enhanced transfer film on the counterface.

Keywords

Polytetrafluoroethylene (PTFE); Polydopamine (PDA); Silica (SiO2); nanoparticles; wear; durability

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