University of Rochester

$400,000 Grant Helps Engineers Assess Materials' Surfaces

January 28, 1997

The Department of Mechanical Engineering has received $400,000 to purchase equipment that will help engineers explore a type of chaos that occurs everyday in the Rochester area and around the world: the jockeying that atoms on a glass surface do whenever engineers manufacture high-quality optical components.

A $200,000 grant from the National Science Foundation, together with a matching $200,000 grant from the University, has enabled the department to purchase a nano-indenter and extremely powerful computers to help analyze the data it uncovers.

The device will allow researchers to study the mechanical properties of surfaces by using a digitally controlled system to apply the tiniest of forces to surfaces and to measure how much the surfaces deform. Oftentimes just a slight nudge -- just a fraction of the amount of force used when lightly tapping the tip of a pen on a table, for instance -- is enough to reveal new properties about a material. Film scientists use similar techniques to make a dent barely the size of a grain of salt in film and then study how the defect affects the film.

Engineers from the University will use the facility together with scientists from the optics industry to study the grinding and polishing process used to make glass. Glass makers typically grind glass by using streams of water permeated with tiny abrasive particles, or by embedding the particles in a solid tool. The particles do the actual grinding, and the water removes the particles from the surface and helps keep the glass cool.

During the process there is a molecular free-for-all among the atoms on a glass surface. Some are torn off by the slurry of water bombarding the surface; others jockey for position as cracks appear and disappear; still others adjust to new "neighbors," as molecules of water actually embed themselves into the very top atomic layers of the glass, making the top layer of glass (far less than one-thousandth the width of a human hair) molecularly different from the rest of the material.

Though poorly understood, these molecular arrangements are the key to producing the glass used in telescopes, copiers, CD players, medical imaging devices, and virtually every other piece of modern technology. Rochester engineers hope that by analyzing the process atom by atom, they'll help find new ways to grind and polish glass more efficiently.

About 10 faculty members from several academic departments, including mechanical engineering and optics, will use the equipment, along with scientists at the Center for Optics Manufacturing and the Laboratory for Laser Energetics. Graduate and undergraduate students will also use the facility.

"This nano-indenter facility will foster collaboration between engineers across the University," says John Lambropoulos, professor and chair of mechanical engineering. "With this equipment we'll be able to analyze in a very powerful way what's happening on optical surfaces and other surfaces such as polymers, ceramics, and metals."