Excellent find … Thanks

Unfortunately, your second link doesn’t work for me

MichaelG.

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Edit: __ but this does:

https://nvlpubs.nist.gov/nistpubs/Legacy/LC/nbslettercircular444r1935.pdf

Edited By Michael Gilligan on 19/08/2021 19:23:23

No problem … I got good value for my meagre effort

MichaelG.

An interesting 'discovery'! I liked the bit in the NBS letter Circular about the alloying of copper – one of the most difficult materials I have ever had to machine has been CuBe (Copper Beryllium alloy of 1.5% Beryllium) which would blunt a HSS hacksaw in a few strokes and would require the very sharpest carbide to stand a chance of lasting. It has some amazing properties such as a very high capability to dissipate heat allied to a high wear resistance, hence its use as a valve seating material and guides in race ICE engines. Meanwhile Beryllium when alloyed with Aluminium (with small amounts of Nickel, Magnesium, Copper and Titanium) makes an exceptionally strong piston material with exceptionally high strength at elevated temperatures.

The sad aspect of all this is that Metallurgy as a subject has all but disappeared from British University courses, one of the UK's leading establishments was Sheffield's Metallurgy Department which closed a number of years ago.

Martin

Not to forget copper oxide was an early use of a semi-conductor .

Avometers 7 & 8 and most other analogue multimeters had copper oxide rectifiers, which looked like 4 little copper spring in a plastic mount. Never seen a copper oxide on a motor bike, usually a Selenium type on Bantams and Villiers. My Honda 90 had an encapsulated bridge rec, wonderful machines were the 70 & 90. John