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For the sake of pedants and chemists everywhere, I think I should start by saying that cupronickel is not a metal. It is an alloy of usually two elements, namely copper and nickel.
When nickel is alloyed with copper, the resulting alloy is harder than copper alone with the nickel diminishing the ductility of copper, but improving the rolling and working properties of copper alone.
The problem is that cupronickel cannot be defined in terms of a percentage of copper and a percentage of nickel. Some cupronickel alloys contain 25% nickel and 75% copper. This particular alloy is used in the UK for the 5p, 10p, 20p and 50p coinage.
Other cupronickel alloys contain different percentages of nickel and copper, but in general, for an alloy to be called cupronickel it must have a nickel content of between around 10% to 30%.
Now it's time to complicate matters further. Some cupronickel alloys don't only contain copper and nickel. They may also contain manganese, iron and rarely, other metals too.
The point I've tried to make is that there are many different "versions" of cupronickel. They include Constantan, Cupron and the Monel series of alloys.
Because of the variation in composition, it's not possible to assign a true Brinell hardness figure to "cupronickel". All the same, if I was put on the spot and asked if cupronickel was hard or soft, I'd say it's hard.
After all, I don't think my teeth would be very happy if I tried to bite my way through a 50p coin!
When nickel is alloyed with copper, the resulting alloy is harder than copper alone with the nickel diminishing the ductility of copper, but improving the rolling and working properties of copper alone.
The problem is that cupronickel cannot be defined in terms of a percentage of copper and a percentage of nickel. Some cupronickel alloys contain 25% nickel and 75% copper. This particular alloy is used in the UK for the 5p, 10p, 20p and 50p coinage.
Other cupronickel alloys contain different percentages of nickel and copper, but in general, for an alloy to be called cupronickel it must have a nickel content of between around 10% to 30%.
Now it's time to complicate matters further. Some cupronickel alloys don't only contain copper and nickel. They may also contain manganese, iron and rarely, other metals too.
The point I've tried to make is that there are many different "versions" of cupronickel. They include Constantan, Cupron and the Monel series of alloys.
Because of the variation in composition, it's not possible to assign a true Brinell hardness figure to "cupronickel". All the same, if I was put on the spot and asked if cupronickel was hard or soft, I'd say it's hard.
After all, I don't think my teeth would be very happy if I tried to bite my way through a 50p coin!
-- answer removed --
A masterly answer, the prof, but I don't think you meant it when you said that cupronickel is not a metal. That it is an alloy of two metallic elements makes it a metal. Otherwise we would have to declare that brass, bronze, pewter, duralumin and steel are not metals. A mixture of strawberry and chocolate ice-cream (yuk!) is still ice-cream.
chakka35, I couldn�t agree more with you and you're perfectly correct in all that you say.
Let me begin by saying I'm a Professor of Biochemistry at a leading UK research university and a consultant to HM Government. I have Phd, D.Phil, and DSc degrees in Chemistry, Biology and surprisingly, Biochemistry and too many learned society fellowships to list here. Now please don't get the wrong idea and think of me as a pompous, stuffy academic, I'm far from that as many on AB will testify.
Sometime ago here on The Answerbank I answered a question about which metal was liquid at normal temperatures. The obvious answer was Mercury, and someone else posted the answer soon after the question was posted . I thought it would be interesting to discuss a group of alloys called Indalloy in this discussion. Here�s the link:
http://www.theanswerbank.co.uk/Science/Questio n244169.html
Certain Indalloys are metallic in appearance and behave in precisely the same manner as many metals when solid. Other Indalloy�s can be liquid at room temperature just like mercury.
Following my post, a poster by the name of shammydodger pointed out that Indalloy was not a metal or in his/her words, �at least not to a chemist�. Now as the question had seemed relatively simple and was clearly not from an academic, I stuck to my guns and said in essence, that strict convention over alloys and metals was not something that was called for in replying to the question.
(continued)
Let me begin by saying I'm a Professor of Biochemistry at a leading UK research university and a consultant to HM Government. I have Phd, D.Phil, and DSc degrees in Chemistry, Biology and surprisingly, Biochemistry and too many learned society fellowships to list here. Now please don't get the wrong idea and think of me as a pompous, stuffy academic, I'm far from that as many on AB will testify.
Sometime ago here on The Answerbank I answered a question about which metal was liquid at normal temperatures. The obvious answer was Mercury, and someone else posted the answer soon after the question was posted . I thought it would be interesting to discuss a group of alloys called Indalloy in this discussion. Here�s the link:
http://www.theanswerbank.co.uk/Science/Questio n244169.html
Certain Indalloys are metallic in appearance and behave in precisely the same manner as many metals when solid. Other Indalloy�s can be liquid at room temperature just like mercury.
Following my post, a poster by the name of shammydodger pointed out that Indalloy was not a metal or in his/her words, �at least not to a chemist�. Now as the question had seemed relatively simple and was clearly not from an academic, I stuck to my guns and said in essence, that strict convention over alloys and metals was not something that was called for in replying to the question.
(continued)
As you can see from the link, some 68 posts were made, the majority of which involved only myself and this pedantic �apparent� chemist, shammydodger. Towards the end, the individual concerned became quite agitated, abusive and personal in his/her remarks, which are not talents one often sees in graduates during discussions.
Because of this, I now try wherever possible to point out anomalies in questions in a light, humorous manner, just in case such pedants are around and just waiting to pounce and bite my head off about my answers. I suppose you could call it a bad case of once bitten, twice shy.
I did suggest to shammydodger that he went out to tell the man in the street that his car was not made of metal. However, he didn�t take up my offer and preferred to continue his tirade.
At the end of the day, I think the AB editor would be the first to agree that interesting digressions are some of the things that make The Answerbank so appealing to us all. For this we need flexibility not pedantry.
Because of this, I now try wherever possible to point out anomalies in questions in a light, humorous manner, just in case such pedants are around and just waiting to pounce and bite my head off about my answers. I suppose you could call it a bad case of once bitten, twice shy.
I did suggest to shammydodger that he went out to tell the man in the street that his car was not made of metal. However, he didn�t take up my offer and preferred to continue his tirade.
At the end of the day, I think the AB editor would be the first to agree that interesting digressions are some of the things that make The Answerbank so appealing to us all. For this we need flexibility not pedantry.
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