Infrared measurements of surface temperatures during oscillating/fretting contact with ceramics

Surface temperatures generated by friction during osculating/fretting contact were measured using an infrared microscope coupled to a digital data acquisition system developed at Virginia Polytechnic Institute and State University. The contact geometry consisted of a stationary test specimen loaded against a vibrating sapphire disk driven by an electromagnetic shaker. Ceramic materials including zirconium oxide, sapphire, aluminum oxide, and tungsten carbide were used as test specimens since they are inert in air, and generate high surface temperatures when used in the oscillating contact system.

Instantaneous fluctuations in surface temperature over a single cycle were measured and recorded. This information was compared with instantaneous friction force and velocity data. The friction force data was measured using semiconductor strain gages connected to a new octagonal ring designed specifically for this research.

Zirconium oxide-on-sapphire experiments were performed at various loads, frequencies, and amplitudes. The resulting temperature rises, friction coefficients, heat generation rates, and wear scar sizes were compared.

Surface temperature rises were measured as a function of position within the contact region. From this data, and scanning electron micrographs of the wear scars, inferences were made about the size, location, and distribution of real contact areas.

Experimental measurements were compared with theoretical predictions obtained using a new numerical model developed by B. Vick and S. J. Foo.