Date of Graduation

12-2011

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

Degree Level

Graduate

Department

Mechanical Engineering

Advisor

Min Zou

Committee Member

Uchechukwu Wejinya

Second Committee Member

Rick Couvillion

Keywords

Applied sciences; Aluminum-induced crystallization; Copper substrates; Nanosurface engineering; Nanotextured copper; Thickness effect

Abstract

Nano-engineered-textures on a material surface can dramatically improve the wetting and non-wetting properties of a surface, and they also show promise to address friction issues that affect surfaces in contact. In this work, aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) was used to produce nano-textures on copper (Cu) substrates. A study was performed to examine the effects of changing the annealing conditions and a-Si thickness on nano-texture formation. The creation of various nano-topographies and chemically modifying them using octafluorocyclobutane (C4F8) was performed to control hydrophilicity, hydrophobicity, and oil affinity of nano-textured surfaces. A video-based contact angle measurement system was used to measure the surface wetting properties. Scanning electron microscopy (SEM) was employed to characterize the surface nano-topographies and provide a basis for qualitative and quantitative analysis of the nano-texture formations. Scratch testing was performed using a TriboIndenter to assess the potential of the nano-textured Cu substrates to lower the coefficient of friction (COF). It was found that the thicker a-Si layer generated larger textures overall which contributed to water contact angle (CA) results ranging between superhydrophilic and superhydrophobic, as well as increased oil affinity of Cu substrate. The nano-textured surfaces also achieved COF values that were 40 % lower than as-received (AR) Cu.

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