On-Line Fastener Finish Quality Monitoring by Electrochemical Impedance Spectroscopy

A fastener finish quality monitor based on electrochemical impedance spectroscopy (EIS) has been successfully demonstrated on coated steel fasteners. The coating qualities can be assessed by comparing the measured spectrum with stored spectra of known samples, or by determining values of the coating-specific parameters extracted from the spectrum. Three areas of applications have been identified: (1). Quality control in the plant, (2). Coating process development, and (3). Accelerated corrosion evaluation.