| Author |
 Replies: 16 / Views: 2,299 |
|
Bedrock of the Community
United States
19951 Posts |
|
|
|
|
Bedrock of the Community
United States
94367 Posts |
I'd say impossible to grade accurately without the coin in hand. No less than AU-58.
|
|
Pillar of the Community
Canada
6244 Posts |
How was exposed to be brown I can not say. Is nice. The MM D put me questions. The brown is normal for coins exposite to temperature changes, UV and humidity.
|
|
Moderator
 United States
56855 Posts |
Looks RB to me.Spot on rev at 5k would bother me. John1  |
|
Bedrock of the Community
 United States
18665 Posts |
I'm seeing an MS coin probably 64 however the coin probably would pull an RB. just too much red peeking through everywhere.
|
|
Bedrock of the Community
United States
19159 Posts |
MS60 can work for me. Perhaps becoming brown.
|
|
Pillar of the Community
United States
5775 Posts |
No question this will be full brown one day. Maybe place on a window sill to speed up the process?
Words of encouragement are one of the major food groups.
We need to consume them regularly to thrive and grow.
|
|
Pillar of the Community
Canada
6244 Posts |
Could be PETE. I know some put on UV lamp to toning the coins.
Edited by silviosi
07/11/2022 2:47 pm
|
|
Rest in Peace
United States
18456 Posts |
I think it's tethering between RB and Bn . MS-63 .  |
|
Bedrock of the Community
United States
36746 Posts |
Grades are all over the place on this one. MS-65RB.
|
|
Bedrock of the Community
 United States
19951 Posts |
Quote:
No question this will be full brown one day. Maybe place on a window sill to speed up the process? For now it resides in an airtite as a 65BN, it's so CLOSE to being RB but in hand it looks more brown. I think the thin BN patina in the redder areas is getting cut with my light. Lincoln Cent Lover!VERDI-CARE™ INVENTOR https://verdi.care/
|
|
Bedrock of the Community
United States
19951 Posts |
Quote:
I know some put on UV lamp to toning the coins. Please explain the scientific mechanism behind this theory. I've never heard of such a thing and, honestly, don't buy it. UV light tends to cleave molecular bonds. |
|
Pillar of the Community
Canada
6244 Posts |
Quote:
Influence of ultraviolet (UV) light irradiation on the corrosion behavior of electrodeposited Ni and Cu nanocrystalline foils in 3.5% NaCl solution was studied by means of electrochemical methods, electron work function (EWF) analysis, and characterization with atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). It was demonstrated that the influence of solar light on corrosion of the metals was non-negligible, which could be very different for different materials. The UV light irradiation resulted in an increase in corrosion resistance of the Cu foil but showed an opposite influence on that of the Ni foil. Based on surface state analysis, it was concluded that the UV irradiation altered the surface oxide films. The UV light induced the formation of Cu2O on Cu, which is more stable and compacted than naturally formed CuO film. However, the UV light accelerated the formation of Ni2O3, which is loose, porous and brittle, compared to naturally formed NiO on Ni. The changes in oxide films were responsible for the opposite variations in the corrosion behavior of the Cu and Ni nanocrystalline foils caused by the UV light irradiation.
Subject terms: Structural materials, Electrochemistry @Bad Thad You have here in the quote the abstract of the study done on structural metals and electrochemistry. Enjoy. I have all study. |
|
Bedrock of the Community
United States
19951 Posts |
I've read this years ago. As I recall, it was performed by undergraduates....little more than an academic project and not really full-on scientific study.
This is not applicable to coins unless you store them in 3.5% salt solution. UV light will not form an appreciable amount of oxidation on air-exposed copper since it's already oxidized. Also, toning is much more complicated than just cupric oxide because other gases/elements are involved.
Edited by BadThad
07/14/2022 1:44 pm
|
|
Pillar of the Community
Canada
6244 Posts |
@Bad: In medical field at McGill we perform same test in capsulate Cu and result was same of developing oxidation. The intensity of the UV was different UVA, UVB and UVC. Two phenomes occurs: UVA and UVB will create cupric oxide and UVC will reduce of polycrystalline cupric oxide (CuO) and cuprous oxide (Cu2O) by UVC irradiation and by atomic hydrogen which was investigated with X-ray photoelectron spectroscopy (XPS or ESCA).
So we have two different reactions which can be use in different ways.
PS. I like to have here on forum somebody for scientific discussions about. Silvio
Me I was involved with the study because I wanted to develop an system to restore the Cu coins and artifacts and also for the oxidation of the possible carcinomic cells. I do not finish the project of restoration because all the necessary are to expensive.
If you do not read yet this study, (I do not know who post on science because many was involve in) I can find the link. It is interesting but if you do not have membership must have to pay.
Edited by silviosi
07/14/2022 4:50 pm
|
|
Bedrock of the Community
United States
18665 Posts |
 that this is way over my paygrade  |
| |
Replies: 16 / Views: 2,299 |
Posted 07/11/2022 12:06 am
