Gold, Silver, Platinum
Specimen Preparation (Class 2 Procedures)
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Precious metals are relatively soft metals and any loose or fracture abrasive particles can easily embed. This makes specimen preparation very difficult because it gums up diamond grinding disks or specimen becomes embedded with fractured SiC particles when ground with SiC papers. The key to preparation of these materials is to use the tougher alumina abrasives and to chemically etch the specimen in between each grinding step. The purpose of etching is to remove the embedded particles so as not to carry them over to the next preparation step as contamination.
SECTIONING
MAXCUT Abrasive blade (Cat. No. MAX-C or MAX-I series)
MOUNTING
Compression Mounting with Phenolic, Epoxy or Diallyl Phthalate compression mounting resins
POLISHING
| Abrasive/surface | Lubricant | Force/ sample | Speed (Head/base) |
Time | Individual Force mode |
Central Force mode |
|---|---|---|---|---|---|---|
| P120 grit ALO paper* P220 grit ALO paper* |
Water | 5-10 lbs | 100/100 rpm | Planar 1 min |
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| P500 grit ALO paper P1200 grit ALO paper |
Water | 5-10 lbs | 100/100 rpm | 1 min 1 min |
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| 1 um DIAMAT diamond on ATLANTIS polishing pad |
Water | 5-10 lbs | 100/100 rpm | 2 min | |
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| 0.05 um Nanometer alumina on MICROPAD polishing pad |
5-10 lbs | 100/100 rpm | 1 min | |
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*Required for central polishing force. Click here for more information on central vs. individual polishing force polishing.
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| 99.9% Silver, etched with ammonia peroxide, 200X B.F |
ETCHING
Common Etchants
CAUTION:Safety is very important when etching. Be sure to wear the appropriate protective clothing and observe all WARNINGS on chemical manufacuters SDS (Safety Data Sheets). Also review the COMMENTS and CONDITIONS Section for each etchant.
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