From: WVE~ol.com Date: Mon, 30 Aug 1999 14:16:47 EDT Subject: =?ISO-8859-1?Q?Re:=20=5FChromatic=5FRattle=5F&=5FH=5Fohner=B4s=5F? In a message dated 8/30/99 7:07:52 AM Pacific Daylight Time, jjthad~lash.net writes:
> >7. Plated reedplates; electroless nickel, I believe. > Not nickel-chromium? Never heard of electroless plating. How does it work?
I don't know for a fact that it is, but the plating on the Hering reedplates has the "look/feel" of commercially-available electroless nickel plating. I have specified electroless nickel plating on machine parts. It is a very thin plating of the order of .001". It depends only on contact between the plated surface and the solution and not on an electric current in the solution. For this reason, it plates very evenly on parts of complex shapes and inside holes, in contrast to the electrolytic platings that can be uneven with differences of current density. Because it is usually thin, it is used primarily for corrosion-resistance and not for wear-resistance or other mechanical properties.
I have no knowledge of the chemical/ion-transfer mechanisms that make it work.
> >analyze with a mass spectrometer. It is inconceivable to me that all the > >manufacturer's don't know exactly the formulas for their competitor's reeds.
> From an article discussing some of the mysteries of fine prehistoric > metallurgy, I was led to conclude that it isn't all that easy to properly > describe alloys by scientific tests. Is knowledge of the fractional > elemental makeup of an alloy sufficient to be able to reproduce it? Aren't > their matters of crystal size/structure?
You are correct that the % of elements would not be sufficient information to duplicate damascus steel. The quenched-in-blood sword has a certain romantic appeal. The metallurgy of steel is, I believe, much more complex than that of copper alloys. The amount of work-hardening from hammering or cold rolling greatly affects the granular structure, increasing the strength & hardness and reducing the ductility of spring/reed materials. However, this too is determinable by etching and microscopic examination to see the granular details, and by hardness measurements. I believe that if you duplicated the elemental formula and the hardness of a given manufacturer's copper-alloy reed, the difference in performance would be negligible.
Work-hardening is often expressed as the % of work-hardening possible in broad terms such as: "full", "3/4", "half" and "soft or annealed." The mechanical properties of various copper alloys are given in tables that characterize them by the weight percentages of the principal alloying metals and the work-hardened condition. This makes me believe that these percentages are reliable distinguishing characteristics......after you assume a high degree of work-hardening.
One huge advantage available to the modern and not to the primitive metallurgist is the ability to control impurities such as sulphur, phosphorus, and secondary metals such as lead and silver that might impart desirable or undesirable properties to the alloy.
