MicroLap allows planar materials with gradient or layered compositions to be analyzed as a function of depth, layer by layer, using FT-IR spectroscopy. MicroLap employs a rotating lap operated with a choice of abrasive sizes, lapping times, and mass (force) loadings to precisely remove thin layers from the surface of a sample. A precision electronic gauge is used to measure the thickness of the removed layer while FT-IR photoacoustic or reflectance spectroscopy determines the sample chemistry as a function of depth as each layer is removed.
Samples are mounted on the Lapping Puck with 3M Removable Double-Stick Tape.
The Lapping Puck is placed on the Lapper for removing a layer of the sample.
Most planar materials, ranging from polymers to coated paper samples, can be dry lapped using an appropriate abrasive type and grit size. Aluminum oxide abrasive works well for general purposes and disks with this abrasive are supplied with MicroLap in 2, 3, 12, 30, and 60 micrometer grit sizes. Typical lapping times range from a 10 to 120 seconds. The lapper design allows for wet lapping but this is not advisable in
most cases because moisture may make the sample swell and water bands to appear
in the spectra.
Since the lapping operation creates fine particles, precaution should be taken if the material is toxic in terms of respiration of particulates. Concerns in this regard are best addressed by operating the lapper in a hood where particulates will be swept out of the occupied space. Wet lapping, when possible, can be used to limit airborne particulates.
Typical MicroLap results are displayed in these plots that show spectral variations as a function of depth in a composite material damaged by exposure to a stream of 617 F air for 15 seconds.