Detection of trace contamination on
metal surfaces using the handheld

Efficient adhesive bonding of metal surfaces requires a high level of cleanliness of the surfaces.

The 4100 ExoScan FTIR and the 4300 Handheld FTIR with a grazing angle sample interface enables identification and quantification of metal surface cleanliness in the field. After the metal has been cleaned, the analyzer can be used to detect the presence of organic and some inorganic contaminants. Even very low amounts of contamination can severely decrease the ultimate bond strength; the highly sensitive 4100 ExoScan or the 4300 Handheld FTIR can detect trace levels of contaminants.

Using a grazing angle sample interface, IR is sensitive enough to measure contaminants at very low levels. However, grazing angle IR reflectance has typically been measured on small test samples using traditional benchtop FTIR spectrometers in laboratory environments. The Agilent Handheld FTIR overcome this limitation by offering a sensitive, handheld IR spectrometer that can be applied to the analysis of components of virtually any size in manufacturing or maintenance facilities.
This application demonstrates the use of the handheld FTIR with a grazing angle sample interface to measure small amounts of contaminants on metal surfaces.

Diagram showing the sample interface of infrared reflection absorption spectroscopy (IRRAS) in both the grazing angle (red) and specular reflectance (blue) geometries. The grazing angle geometry has an increased pathlength through the contaminant.

The Agilent Handheld FTIR system, equipped with grazing angle sample optics, can provide the level of sensitivity required for the detection and identification of a large number of organic and inorganic contaminants on metal surfaces.

Even with a quick 10 second measurement, a limit of detection of 0.17 μg/cm2 can be obtained for a silicone mold release agent on aluminum surfaces.

Methods can be created to present the measurement results in easy to understand categories for use by field personnel. The Agilent Handheld FTIR enables field measurement of surface cleanliness at detection levels required for efficient bonding.

Excerpt from Agilent Technologies Application Note 5990-7799EN