Investigating acute coin discoloration by solution immersion
The third series of the 20 sen and 50 sen coins made of nickel-brass are prone to discolouration after few years of circulation. The discolouration causes tire brass colour golden coins to change greenish in colour. In order to investigate the discoloration, new 20 sen coins were exposed to vario...
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| Main Author: | |
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| Format: | Monograph |
| Language: | English |
| Published: |
Pusat Pengajian Kesihatan
2015
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| Subjects: | |
| Online Access: | http://eprints.usm.my/60032/1/MUHAMMAD%20FAKHRIY%20BIN%20ABLLAH%20-%20e.pdf http://eprints.usm.my/60032/ |
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| Summary: | The third series of the 20 sen and 50 sen coins made of nickel-brass are prone to discolouration
after few years of circulation. The discolouration causes tire brass colour golden coins to change
greenish in colour. In order to investigate the discoloration, new 20 sen coins were exposed to
various environmental conditions to simulate worst case scenario. New coins morphology and
weight recorded and then were submerged in containers containing seawater, river water, well
water, bleaching agent, fizzy drink (Pepsi, Root beer and Orange Mirinda), 10g NaCl solution,
50g NaCl solution and 100g NaCl solution with a control coin not submerged in any solution and
placed in normal room temperature. Daily observations were made in 30 days by using
stereomicroscope to identify the pattern of discoloration of each coin. Results indicate that each
solution can caused corrosion and produced different pattern discoloration of the coins. It is
hoped that a discoloration timeframe is obtained which would be useful for forensic
investigations and that the findings would be usefill for future coin design. |
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