Measuring Engine Wear by Surface Layer Activation Extension to Nanometer Increments

SLA IS A METHOD for precisely measuring material loss due to wear, erosion or corrosion in mechanical systems. A marker layer is activated by exposure to a particle accelerator beam. The intensity of gamma rays from this marker is then monitored by a detector mounted externally to the operating system while wear occurs. The decrease in intensity after correction for natural decay half-life results in a direct measure of wear which can be repeated at arbitrary intervals while the system is on-line and operating. Recent applications have been in diesel, gasoline and gas engine components, in utility power plants measuring solid particle erosion and corrosive wear, in oil drilling and piping, in key components in the space shuttle, and in medicine measuring ion release corrosion from prosthetic implants. This paper describes recent efforts to extend the range of this approach to much shallower activation depths and thus improve accuracy. Extreme precision allows tests to be completed in a minimum of operating time. Consequently, this method is ideal for rapidly comparing material properties, designs or surface treatments while it provides the convenience of in situ, on-line and nondestructive results.