Date Approved

2008

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Physics and Astronomy

Committee Member

Weidian C. Shen, PhD, Chair

Committee Member

Natthi Lal Sharma, PhD

Committee Member

Diane Jacobs, PhD

Abstract

As automotive coating technology advances, the manufacturers have developed new generations of after-market coatings as well as OEM (Original Equipment Manufacturing) coatings. The new coatings possess much stronger mar/scratch resistance either with raised elastic modulus and hardness or with the ability of self-healing. These pose new challenges to the auto-body refinish work. In the refinishing process, the after-market coatings are applied to the bodies (surfaces), and then the imperfections, which are inevitable during the application process due to the environmental dust in the shops, will be buffed out to make a smooth and shining surface. The new coatings are very difficult to work with in the refinish process.

Sponsored by 3M Incorporation, the largest producer of the refinish devices and materials, we have carried out a systematic study of the scratching/buffing mechanism of the clearcoats in the refinish work. We measured modulus and hardness at depths of nano/micron meters at the coating surface, checked the heating effect on the mars and scratches at the coating surface, and examined the surface morphologies in nano and micro scales of different coatings at different stages in the refinish process. We also studied the variations of the mechanical and tribological properties of the coatings during the curing process after the baking, etc., using newly developed nano instruments, a Nano-Indenter XP and a Scanning Probe Microscope (SPM). This study has increased our knowledge of the scratching and buffing mechanism of coatings and the refinish process, thus shedding light on the direction for improvement of the technique and devices/materials in the refinish work.

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Physics Commons

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