The imaging of mineral grains mounted in epoxy resin often results in the grains being surrounded by a damaged area of resin. This is especially true if the sample has been subjected to high e-beam currents used for X-ray mapping, CL and BSE imaging. The resulting isolated grain can be unsuitable for further analytical measurements and so the resilience of the resin to e-beam impact can be an important parameter in determining the resin to use.
Samples of 13 resins were mounted in individual 25mm diameter, 5mm deep, Al-rings. The three Beuhler hot press resins; TransOptic, ProbeMet and KonductoMet were mounted without the Al-rings.
The mounts were then ground using Beuhler UltraPrep nickel bonded diamond 74 micron and 20 micron discs followed by 1200 and 2500 silicon carbide paper. They were polished with 3 micron diamond for 15 minutes and then with 0.3 micron Al-oxide for 10 minutes, washed and then ultrasonically cleaned with 10% Decon 90. The samples were finally cleaned with ethanol prior to carbon coating using a Deton coater to produce a thin conducting film across the sample surface.
The epoxy resins were carbon coated before being loaded into the Scanning Electron Microscope, the electron beam was adjusted so that it had a current of 5nA, 20Kv and scanned an area at 5000x magnification for 10 minutes. The size and depth of the resulting raster pits were measured using the Tencor alpha-step 200 profilometer.
KonductoMet and ProbeMet were both too heterogeneous to produce a disctinct raster pit while TransOptic blistered under the beam showing a positive profile in comparison to the pits produced in the other samples.
|Epoxy Resin||Shore Hardness||Sputter Depth (micons)|
|Robnor Resin||81.4 +/- 0.63||0.9|
|Petropoxy||85.3 +/- 0.78||1.4|
|Epoheat||80.1 +/- 0.5||0.8|
|Korapox||79.4 +/- 0.84||0.9|
|EpoxiCure (Room Temperature)||85.3 +/- 0.46||0.7|
|Specifix||82.8 +/- 0.45||0.8|
|Epothin||79.1 +/- 0.71||1.1|
|Epoifx||80.1 +/- 0.8||0.8|
|Ciba Geigy||82.1 +/- 1.23||0.7|
|Epoxicure (65'C)||84.9 +/- 0.18||0.9|