Excerpts from an email from Jay Neogi, Serenity Technology to C&C.
<<Bob: As you know when Moissanite is slightly heated in air it has a tendency to form a thin layer of SiO2 (silicon dioxide) layer over the gem and since there is a huge RI (refractive index) mismatch between SiC (Moissanite) and the thin layer of SiO2 that forms, one will see this golden tone when the thickness of this SiO2 layer reaches few nanometer. It is an inherent behavior of Moissanite (SiC) material and this behavior is well documented in various technical journals. . . . . Please note: that golden tone is just the native SiO2 that forms on Moissanite and is falsely claimed by NAGL to be the color enhancement coating.
Please see this technical article and there are numerous such reputed publications that you can find.>>
Silicon oxycarbide formation on SiC surfaces and at the SiC/SiO2 interface
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This paper appears in:
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films
Date of Publication: May 1997
Author(s): Onneby, C.
Department of Materials Science and Engineering, The Pennsylvania State University, 102 Materials Research Institute Building, University Park, Pennsylvania 16802
Pantano, C. G.
Volume: 15 , Issue: 3
Page(s): 1597 – 1602
Product Type: Journals & Magazines
Amorphous and single-crystal α-SiC were exposed to various oxygen sources at room temperature. The oxygen sources included the residual gas in an ultrahigh vacuum environment, ambient air, ozone, and oxygen plasma. X-ray photoelectron spectroscopy (XPS) was used to follow changes in the surface composition and to determine the local bonding environment of the Si atoms. It was found that silicon oxycarbide species are formed when these SiC materials are initially exposed to oxygen. With extended exposure to ambient air, a SiO2 layer is subsequently formed over the silicon oxycarbide. However, the native oxide on the single-crystal SiC consists mainly of silicon oxycarbide species. The thicknesses of these native oxides were calculated using the XPS data. © 1997 American Vacuum Society.
Index Terms are available to subscribers and IEEE members.
Topic(s) : Aerospace ; Engineered Materials, Dielectrics & Plasmas ; General Topics for Engineers (Math, Science & Engineering) ; Geoscience ; Nu
ISSN : 0734-2101
Digital Object Identifier : 10.1116/1.580951
Date of Current Version : Thu Jun 18 00:00:00 EDT 2009
Issue Date : May 1997