Differences

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--- decap:purple_ceramic [2012/11/09 09:01] – [SEM imaging] azonenberg
+++ decap:purple_ceramic [2012/12/10 22:28] – [EDS] azonenberg
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-Higher magnification backscatter image (composition mode). General lack of Z-contrast suggest granules are mostly homogeneous and of uniform composition. Some in the upper left and sides are darker. These are likely to be regions with lower Cr content.
+Higher magnification backscatter image (composition mode). General lack of Z-contrast suggest granules are mostly homogeneous and of uniform composition. Some in the upper left and sides are darker. These are likely to be regions with lower Cr content. Given the topography of the sample it was difficult to determine how much of the contrast was due to Z variation.
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-The conclusion is that the sample is composed primarily of alumina and silica, with titanium, chromium, and zirconium oxides present in small volume. While the oxidation states cannot be determined from EDS, preliminary reading of chemical properties suggests that Ti2O3, Cr2O3, and ZrO2 are the most probable compounds.
+====== Conclusions ======
+The sample is composed primarily of alumina and silica, with titanium, chromium, and zirconium oxides present in small volume. (No standard-based quantitative calibration was performed so it is impossible to give exact proportions.) While the oxidation states cannot be determined from EDS, preliminary reading of chemical properties suggests that Ti2O3, Cr2O3, and ZrO2 are the most probable compounds.
 Reading of the MSDS for the commercial ceramic linked above, SiO2 and TiO2 are typical impurities in such ceramics. Na2O, CaO, and MgO are also mentioned as possible impurities. No Mg was observed and Na/Ca are present in sweat so the data is inconclusive as to whether they are present in the ceramic itself.
 Based on the above MSDS it is considered unlikely that the Cr in purple-ceramic IC packages is present in the hexavalent form (CrO3) however this is a reddish-purple color so the possibility remains. The bulk ceramic should be relatively harmless in either case however dust-generating operations such as sanding should be avoided and hands washed after contact with it.