Bronze disease

I just refuted/corrected parts of your PM to me on this subject, feel free to copy it and post it here if you wish. Otherwise, please let us know where in the literature I can find a reference to "room to grow" WITHIN the boundaries of a physical object. I wish to learn more. Perhaps Mr. Sermarini has an answer.

Happy collecting and thanks for an interesting topic.

 

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There are things called "interstitial spaces", how could metal otherwise shrink and increase during temperature change WITHIN the boundaries of a physical object?

I may not know much about coins but if you want to talk about physics and chemistry then I am open for a debate because fortunately I am doing that everyday at work

 

Unless I misinterpret your statement,

Expansion and contraction of any material ( see reference below and note it is not limited to metals) are due to the size of the atoms including the shells ( due to increase or decrease in kinetic energy which is due to temperature change) so they do NOT stay WITHIN the original size , both the atoms and the Boundaries of the physical object change size, so no empty "interstitial space" is needed or found. There are no references I can find to the presence of interstitial space present in relationship to expansion/contraction, or crystallization. Jim

https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

 

I just refuted/corrected parts of your PM to me on this subject, feel free to copy it and post it here if you wish. Otherwise, please let us know where in the literature I can find a reference to "room to grow" WITHIN the boundaries of a physical object. I wish to learn more. Perhaps Mr. Sermarini has an answer.

Happy collecting and thanks for an interesting topic.

 

More double posts! SORRY. I'll post on CT at home from now as my posts don't enter properly.

BTW, @Pavlos

I'm sure all of us here would like for you to educate us about physics and chemistry. Just please be sure to back up your opinions as IMO there is too much nonsense (not from you of course) posted in these forums.

 

I can help a little with that, Insider, by showing you how to use the very handy Quote function. Clearly you're an intelligent man who enjoys spurring others to think but that is often lost in the multicolor chaos of your posts. It is often difficult to determine when you are writing your own thoughts versus when you are quoting someone, and who you are quoting. Your use of colors to indicate quotes is inconsistent so that hurts more than it helps.

Here are simple instructions for how to use this forum's quote function so your posts will no longer look like the work of an unmedicated manic. There are other ways to the deploy the quote function but for now I'll keep it basic.


Option 1: Quoting an entire post. At the bottom right of the post you wish to quote, "+ Quote".





Option 2: Quoting part of a post. Click and drag your cursor over the text you wish to quote. Upon releasing your finger, the text will remain highlighted and a small pop-up menu will offer the choices of "+ Quote / Reply" will appear. Click "+ Quote". I think you'll like doing it this way since you enjoy critiquing posts sentence by sentence.





You can go through an entire thread clicking quote for various users' posts or portions of their posts. When you've gathered all the posts you wish to address, begin composing your reply. You'll see a button with "Insert Quotes" at the bottom left of the box where you type.




Click "Insert Quotes." For purposes of this tutorial I've selected several snippets from this thread. You'll see a larger pop-up which shows these quotes. You have the option to remove any or all of them and you can rearrange the order if desired. Isn't that great?





After you've reviewed the snippets, click the "Quote These Messages" button at the bottom right of the pop-up window. The quotes will be placed at the current position of your cursor so make sure that cursor is where you want it to be within the body of your message. Below is a screen shot of what this would look like after clicking Quote These Messages:



Now you can type your heart out after each quote and everyone will be able to understand who you are quoting and which comments are your new thoughts. An example is below, with "your" responses in blue so you can more easily see where you are supposed to type. Note that using a special color for your new comments is not necessary now that you know how to use the quote function. The quoted passage will be neatly placed in a colored box once you post the reply. No more confusion, and the board will have just a little less nonsense. Yay!!

 

I used metals as example because we are talking about metals at the moment, copper, tin, nickel, silver etc. Yes, for example the increase of temperature causes an increase in kinetic energy causing the atoms to take more between eachother meaning the interstitial space between the atoms bigger.

Interstitial space has a big relationship in the crystal lattice, as I explained before, if there are too many impurities or other metals/molecules are present, there is no way crystals can be formed or the crystals will be defect.



Here a clearer picture of the crystal structure of an alloy, if there is an interstitial alloy, how can a metal tightly pack together and form an arranged structure? It can't because the interstitial space between the atoms is too big (caused by the other metal or molecule, depends). If you have a substitutional alloy, how can a crystal be formed anyway, the atoms are not the same and randomly distributed, this one is even more impossible (a crystal is the purest form of a molecule or atom).



A totally other piece of chemistry, I work a lot with polymers, if 4 of the 100 monomers (let's say it is an isomer) is turned left and the other 96 of 100 is turned right, no crystals will form at all and the polymer stay amorphic. We are talking about the same molecule with the exact same atoms yet because of the orientation of the molecule it can not make tightly packed crystals anymore, so no crystals will be formed.

I hope you understand now the meaning of interstitial space and that an alloy pretty much never crystallizes.

 

Thanks TIF.

It is 5:38. I'm going to push "post reply." When I do, nothing posts from this computer and a dark rectangle at the upper right of my screen with a moving white cursor appears and goes in motion. Sometime later, my post gets entered. It has become a pain in the neck! I can post immediately and carry a discussion in a PM.

When I try to quote a post (I've had no trouble doing this for a year) nothing happens and the black rectangle appears.

It is now 5:42 and I'm posting this.

 

Hey! Thanks a lot for posting this.

Even in high school chemistry, I studied crystals and crystal-growing, and I thought that alloyed metals couldn't become crystallized structures. Thanks for confirming this.

 

If one wishes to search google for scientific articles regarding crystallization of both alloyed metal or pure metal , they will find more than they could read in several years. It seems that for a near nonexistent possibility, a lot of time and effort has been spent and lost.

Search google for : Crystallization of alloy metals

Jim

 

Then sent me an scientific paper stating in the conclusion "we have successfully made a crystalline alloy". Sure there has been done tons of research about it, but that's why we have research, we either fail or succeed.

Second of all I never said it is impossible, I said "An alloy pretty much never crystallizes.". I said that because 1. If I would add 1% tin to copper it is an alloy but there is a possibility it can crystallize. 2. I am not up to date to the newest alloy research but the commercial and well know alloys are amorphous. I am sure someone managed to crystallize an alloy with a specific complex of metals causing a phase transition changing the crystal lattice and therefore can crystallize, or something else maybe?? As I said my research does not lay there.

I have have worked before on green batteries by making a complex of metals for sodium diffusion. The moment I added a special composition it favoured a rhombohedral structure rather then a monoclinic making it very sodium conductive, that rhobohedral structure only appeared at special circumstances and was quickly gone when heating.

 

Pavlos, posted: "Then sent me an scientific paper stating in the conclusion "we have successfully made a crystalline alloy". Sure there has been done tons of research about it, but that's why we have research, we either fail or succeed.

An image of a crystalized bronze coin has been provided. What do you see in it? So has a link to a "paper."

Second of all I never said it is impossible, I said "An alloy pretty much never crystallizes.".

Please! Did you bother to read the article about crystallization in ancient silver coins?

I said that because 1. If I would add 1% tin to copper it is an alloy but there is a possibility it can crystallize. 2. I am not up to date to the newest alloy research but the commercial and well know alloys are amorphous. I am sure someone managed to crystallize an alloy with a specific complex of metals causing a phase transition changing the crystal lattice and therefore can crystallize, or something else maybe?? As I said my research does not lay there.

I have have worked before on green batteries by making a complex of metals for sodium diffusion. The moment I added a special composition it favoured a rhombohedral structure rather then a monoclinic making it very sodium conductive, that rhobohedral structure only appeared at special circumstances and was quickly gone when heating."

Thanks again for you posts! CT has proven to be a great place to learn new things.

In a PM you said you were not from this country so there may be a language barrier - even between esteemed scientists such as yourself. Laymen such as myself may be describing the crystallization in the bronze metal coin I posted or the CHARACTERISTIC crystal pattern found on cast counterfeits and many GENUINE silver ancients using the wrong terminology. Fortunately, laymen such as me can point to more informed scientists. So I suggest you might take this suggestion by another member: "If one wishes to search google for scientific articles regarding crystallization of both alloyed metal or pure metal , they will find more than they could read in several years."

Let me modify an old saying we have in this country: "You can lead a horse to water but he may not be thirsty."

 

Please use the "quote", it is really unclear to read like this.

Fortunately there is something called an "abstract" which can save you some years reading I have definitely read some articles about the crystallization of alloys, and no not on google, I hope if you are an educated person yourself that you use other websites to search for scientific articles. Anyway back to the point, I have read both abstracts and conclusions of several articles in the research of crystallization of alloys, I have found not more then "it might be possible". And this are no alloys of copper and tin, but alloys of around 5 metals, and as I explained before, a specific composition of metals can change the crystal lattice and change it's behavior completely (but this is not the case in bronze).

Your quote: "You can lead a horse to water but he may not be thirsty.", does not apply here at all... and by the way it is not a quote just from your country, it's origin is from England and is used in many other countries.... It is a pretty commonly used quote, even I know it as a foreigner.

Anyway, again, this is why I request for the second time, please send me an article where it says: "we have successfully made a crystalline alloy". Or please if you are so convinced bronze can crystallize then send me a scientific article showing that it can in fact crystallize, I am eager to read it. All I hear is that bronze is so CHARACTERISTIC for cast counterfeits, but there is no scientific research you ever show me this actually happens.

You know what, to make finally an end of this debate, I am going to contact David R. Sear, a very experienced numismatist, I hope you think the same about him.

 

@Pavlos said: "Please use the "quote", it is really unclear to read like this."

I cannot even post as a normal member! I tried TIF's advice and your request and nothing happens EXCEPT the dark rectangle with moving cursor! I've copied your post in an attempt to comment.

@Pavlos said: "Fortunately there is something called an "abstract" which can save you some years reading I have definitely read some articles about the crystallization of alloys, and no not on google, I hope if you are an educated person yourself that you use other websites to search for scientific articles. Anyway back to the point, I have read both abstracts and conclusions of several articles in the research of crystallization of alloys, I have found not more then "it might be possible". And this are no alloys of copper and tin, but alloys of around 5 metals, and as I explained before, a specific composition of metals can change the crystal lattice and change it's behavior completely (but this is not the case in bronze)."

Your quote: "You can lead a horse to water but he may not be thirsty.", does not apply here at all... and by the way it is not a quote just from your country, it's origin is from England and is used in many other countries.... It is a pretty commonly used quote, even I know it as a foreigner."

I'm glad you edited out how ignorant I am about the origin of this quote. Again, it is a language thing because I did not mention where it ORIGINATED at all. I just paraphrased something that in your words: "...is used in many other countries."

@Pavlos continued: "Anyway, again, this is why I request for the second time, please send me an article where it says: "we have successfully made a crystalline alloy". Or please if you are so convinced bronze can crystallize then send me a scientific article showing that it can in fact crystallize, I am eager to read it. All I hear is that bronze is so CHARACTERISTIC for cast counterfeits, but there is no scientific research you ever show me this actually happens."

Sorry, I'm not able to send you anything as I'm having too much trouble using this site - let along adding an image! I know what I've read and I know what I've personally observed and imaged over the years while authenticating coins. So, you can call the obvious patterns anyone can see in metals anything you wish. I've got images of acid etched surfaces (leaving patterns because different metals in the alloy reacted differently), cast surfaces, and genuine surfaces on coins of every metal and every age. I'm satisfied that metals CAN CRYSTALLIZE under specific conditions or methods of forming.

@Pavlos said: "You know what, to make finally an end of this debate, I am going to contact David R. Sear, a very experienced numismatist, I hope you think the same about him."

Excellent idea! Note that I ORIGINALLY POSTED that I have not seen this type of crystallization on ancient bronze. Furthermore, I suggested we attribute your coins (not yet done by you here) so a layman such as I can look for other specimens to compare their surface fabric!

Hopefully, Mr. Sear will authenticate BOTH of the coins you purchased from the same dealer with identical surfaces. Again, thanks for providing an education for all of us. I hope this posts!

 

Why bother? It will cost more than the coin is worth and there is only one person here who has even remotely questioned the authenticity of your coin. While he has a great deal of experience with modern coins he is not an ancient collector, ancients dealer, or ancients authenticator. If I correctly understood the bulk of Insider's posts, and I'm not sure I did due to the chaotic nature of the posts, he was just asking what led to the surface appearance of your coin.

 

I only have one big remark to make on your response, you say "I'm satisfied that metals CAN CRYSTALLIZE under specific conditions or methods of forming."

You are completely right in this, under specific condition METALS can crystallize, but ALLOYS not. An alloy does not have heterogeneous properties from both (or multiple) metals, it rather is a homogeneous mixture of the metals giving its unique properties. The metals can not crystallize in the alloy, as I explained before many many many times in my posts.

But let's see Mr. Sear response... (by the way I only own the Kyme coin, the other coin is sold by the same dealer, but not to me). Enough debating right now for me, it is getting a bit of a waste of time.

 

That's a quick response from Mr. Sear, I really appreciate that.

"On the basis of your photograph I can see no reason to doubt the authenticity of this piece and I am unaware of the crystallization factor with regard to counterfeits of ancient bronze coins.
Regards,
David R. Sear"

Debate closed....

 

My last response also to the idea that alloys can not produce crystals, there are many of these also.This one on alloys that make up airplane engine turbines

" The single-crystal structure isn’t intended to cope with temperature, however; it’s to make the blades resistant to the huge mechanical loads that result from their rotational speed. “Every single blade extracts power from the gas stream equivalent to a Formula One car engine,” Glover said. “And the centrifugal force on them is equivalent to the weight of a double-decker bus.”

Normally, metals are composed of many crystals – ordered structures of atoms arranged in a regular lattice, which form naturally as the metal cools from a molten state. These crystals are typically of the order of tens of microns in size, positioned in many orientations. At high temperatures and under strain, the crystals can slide against each other, and impurities can diffuse along the boundaries between the grains. This is known as creep, and it badly affected early turbine blades, which were forged from steel and later nickel bars.

The first stage in development was to get rid of any grain boundaries at right angles to the centrifugal loading, which led to the development of blades that were cast so the metal crystals all ran from top to bottom. Later, this was optimised further by casting single crystals, with no grain boundaries at all. It’s a highly complex process: not only must the blades be cast with the internal cooling channels already in place, but the crystals are not homogeneous. Rather, zones of different composition and crystallographic structure exist within the blade.


“You can think of nickel superalloys like these as being like composites,” said Rolls-Royce aerofoil turbine materials technologist Neil D’Souza. “It’s a mixture of two phases, one of which – gamma-prime – gives rise to the sustained increase in strength at high temperature.”

When it crystallises, nickel forms a structure known as face-centred cubic (fcc); each cube has a face with five atoms, one at each corner and one in the middle. When alloys are made, generally the atoms just swap in and out of the fcc lattice. But under the right conditions, aluminium and nickel combine in such a way that nickel goes to the centre of the faces and aluminium to the corners. This is known as a precipitate; it forms islands of greater order within the bulk of the alloy, about half a micron in dimension, packed closely together in a rectilinear formation. Because the size of the lattices of the precipitate and the less ordered bulk alloy are almost identical, they are all part of the same crystal. end quote)

https://www.theengineer.co.uk/rolls-royce-single-crystal-turbine-blade/

Now Debate closed on crystallization of alloys if you wish, ( I made no comment on authenticity , nor Did Sears say there is never crystallization in alloys) Jim

 

Pavlos, posts: "You are completely right in this, under specific condition METALS can crystallize, but ALLOYS not. An alloy does not have heterogeneous properties from both (or multiple) metals, it rather is a homogeneous mixture of the metals giving its unique properties. The metals can not crystallize in the alloy, as I explained before many many many times in my posts."

Alloys are composed from different metals. They are not always mixed well. I have posted and example of CRYSTALLATION in a bronze alloy.

We have NOT been debating the AUTHENTICITY of your coin - only the crystalized state of its surface. A highly regarded authenticator of ancient coins has stated: "I am unaware of the crystallization factor with regard to counterfeits of ancient bronze coins." NOTE: I have rarely seen it either! I believe that was the point of my original post.

Therefore, we can assume that you have posted TWO EXTREMELY RARE and EXTREMELY UNUSUAL ancient coins. I wish the one you own belonged to me!

 

You did doubt the authenticity by saying that in your experience the crystallization on bronze indicates that it is a cast counterfeit.

EDIT:
I found a third coin with the same surface, I guess not that extremely rare anymore.



It is clear chemicals were used to remove the patina/clean causing surface etching.

Uhm.... Do you even understand it yourself? Normally there are grain bounderies between the metals in an alloy, what they do is:

“In the bulk alloy, you’d place the balls representing the components of the alloy, about 10 different elements including nickel, aluminium, chromium, tantalum and titanium, pretty randomly, and when you got to the gamma-prime precipitate you’d put in this ordered arrangement of aluminium at the corners and nickel in the middle. It’s all on the same regular lattice, oriented the same way, so it’s all the same crystal, but you have these much stronger regions where there’s the array of gamma-prime precipitate.”

They are performing no crystallization, they arrange all the crystals of those 10 elements in such a way that it becomes 1 crystal.... they are still distinct from eachother.

Why do you think he says: “You can think of nickel superalloys like these as being like composites,”.

A composite is nothing more then several materials constituent combined, producing a material with characteristics different from the individual components. However, the individual components remain separate and distinct within the finished structure.

I have no idea what you want to proof with this because it has totally nothing to do with the CRYSTALLIZATION of an alloy.

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For the interested here, I will one time if I have time in my break measure my coin with EDS on those 'spots'.