Distinguishing Test for Phosphor Bronze

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Distinguishing Test for Phosphor Bronze

This topic has 10 replies, 5 voices, and was last updated 7 December 2018 at 07:48 by Phil Boyland.

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6 December 2018 at 10:07 #384117
Michael Gilligan
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@michaelgilligan61133
I need to make a small leaf spring, and Phosphor Bronze would seem the most appropriate material.

The original component was 0.020" thick, but 0.5mm should be near enough

Material is available, but not inexpensive; so I thought I might see if I had anything in my stock of offcuts and salvage.

This brings the problem of identification.

An internet search disclosed one helpful 'Distinguishing Test' published in 1930

**LINK**

https://books.google.co.uk/books?id=OigDAAAAMBAJ&pg=PA92&lpg=PA92

I am guessing that this detects the Phosphorous content; so the questions are:
1. by what reaction ?
2. is there an easier/cheaper alternative test ?
Thanks

MichaelG.

Edited By Michael Gilligan on 06/12/2018 10:08:08
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6 December 2018 at 10:07 #29873
Michael Gilligan
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@michaelgilligan61133
Is there a Chemist in the House ? …
6 December 2018 at 12:56 #384133
Phil Boyland
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@philboyland37326
If you can file some off and post it I can check the chemical composition on our electron microscope in work for you.

All for free
6 December 2018 at 13:12 #384137
Michael Gilligan
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@michaelgilligan61133
Posted by Phil Boyland on 06/12/2018 12:56:52:

If you can file some off and post it I can check the chemical composition on our electron microscope in work for you.

All for free

.

Phil,

That's an amazing offer … Many thanks

I will send you a personal message later today.

MichaelG.
6 December 2018 at 13:13 #384138
Fowlers Fury
Participant
@fowlersfury
I've relied on a quick test before now, no guarantee of its infalibility.
Thoroughly degrease and immerse the metal in dilute mineral acid (I use HCl). Those bronzes containing Zn usually acquire a "copper colour" as the surface Zn is dissolved away. PB, containing no Zn, remains uncoloured.
6 December 2018 at 13:28 #384139
SillyOldDuffer
Moderator
@sillyoldduffer
I've got an old Chemistry Book on Qualitative Inorganic Analysis that's good on test tube methods: guess what – it's nowhere to be found!

From first principles though, a solution of Ferric Chloride with Hydrochloric Acid would dissolve copper. (Ferric Chloride is used to etch printed circuit boards.)

I guess the solution removes a layer of Copper from the test alloy and in the process creates a complex mix of ions. Then the Iron ions react with any exposed Phosphorous to form something like Iron Phosphate. Iron Phosphate is the blue-black layer left by some rust treatments.

Phil's electron microscope is the bees knees! Test tube analysis was on the way out back when I was at school with Noah. Although many basic chemical tests are easy, others required a lot of skill. I'm always amazed at what people achieved in the past with simple equipment and clever technique. We truly stand on the shoulders of giants.

Dave
6 December 2018 at 13:36 #384142
Michael Gilligan
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@michaelgilligan61133
Thanks to FF and S.O.D.

Although Phil's offer obviously trumps everything, it would be good to continue this discussion so that we have a DIY answer available for next time.

MichaelG.
6 December 2018 at 13:45 #384145
Michael Gilligan
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@michaelgilligan61133
Posted by SillyOldDuffer on 06/12/2018 13:28:56:

… Then the Iron ions react with any exposed Phosphorous to form something like Iron Phosphate. Iron Phosphate is the blue-black layer left by some rust treatments.

.

Yes, that was my thinking … like Jenolite treatment, but with all the right chemicals in all the wrong places !

MichaelG.
6 December 2018 at 14:29 #384148
Phil Boyland
Participant
@philboyland37326
Ok cool, will look out for a message.

Composition can be measured by measuring the x-rays coming off the sample whilst it's bombarded with electrons. This is a useful by product of the electron stream being used to create an image. Will send you a few screenshots too if you like as it always looks fascinating…….well to me at least. Science nerd!!
6 December 2018 at 19:27 #384183
Pete Rimmer
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@peterimmer30576
is that similar to how the zapper guns work that the scrap yard use?
7 December 2018 at 07:48 #384278
Phil Boyland
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@philboyland37326
I think they work on X Ray fluorescence principle(XRF) where as I am working on the Energy Dispersive X ray principle(EDX). I don't user the former, but you can only look at a whole sample with XRF so if you have several different materials present, it would not tell you the alloy just a % of the elements present that you would not be able to classify. This is more suited to samples you know already are only one material.

With EDX you can pin point a particular particle in a sample and get its composition. Excellent for jumbled up metallic debris in a engine filter for example..
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