Abstract: This invention is directed to a detection system for the quantitative analysis of chemical components of an aqueous phosphate conversion-coating bath, in particular, to a system for determining the concentration of zinc ions, phosphate ions, nitrite ions, and the pH of a purified sample of the bath. Optionally, the concentrations of other ions which might be present such as fluoride ions and nickel ions also can be determined. This detection system is preferably an automated on-line detection system employing X-ray fluorescence analysis, and flow injection analysis comprising specific ion electrodes and a flow through colorimeter or spectrophotometer. The automated, on-line detection system comprises computer means for automating said detection system and the computer means may be adapted for recording the resultant determinations and maintaining the chemical components at chosen concentrations in the bath.

Abstract: A method and an apparatus for simultaneously measuring each constituent film in a multi-layer coating. Near Infrared Reflectance (NIR) measurements are taken at the peak and reference wavelength for a series of calibration samples. Based on these measurements, a relationship is established between the film NIR and thickness. A measuring NIR spectrometer is supplied with the relationship and a target sample is irradiated with near infrared radiation at each peak and reference wavelength. The measuring spectrometer measures the amount of NIR and computes the individual film thicknesses using the relationship supplied to it. Individual film thicknesses can be visually displayed, and/or directed to the film applying apparatus. If the thickness of an individual film layer deviates from a predetermined valve, the film applying apparatus is manipulated to apply the desired thickness of film.