All the manufacturer told me about the copper was that is was "pure copper" I'm actually about to order and get more details about that. Apparently when copper is polished it looks like gold. It's still copper just polished
Cool,
Because the BeCu heat sink that I have looks very gold/brass like and interestingly, it doesn't appear to be oxidizing like typical copper. But the thermal conductivity (around 150=200) is worse than pure aluminum. So it would be better to just use Aluminum at that point.
Just make sure they are using a good thermal conductivity grade and not a strength grade copper.
http://www.keytometals.com/page.aspx?ID=CopperGrades&LN=EN
Copper grades are divided into six families: coppers, dilute copper alloys, brasses, bronzes, copper-nickel alloys, and nickel-silver alloys.
The first family, the coppers, is essentially commercially pure copper, which normally is soft and ductile and contains less than about 0.7% total impurities. Commercially pure copper grades are designated by UNS numbers C10100 to C13000. The dilute copper grades contain small amounts of various alloying elements that modify one or more of the basic properties of copper.
Electrolytic tough pitch copper C11000 is made from cathode copper, that is, copper that has been refined electrolytically. C11000 is the most common of all the electrical copper grades. It has high electrical conductivity, in excess of 100% IACS. It has the same oxygen content as C 12500, but differs in sulfur content and in over-all purity. C11000 has less than 50 ppm total metallic impurities, including sulfur.
Oxygen-free copper grades C10100 and C10200 are made by induction melting prime-quality cathode copper under nonoxidizing conditions produced by a granulated graphite bath covering and a protective reducing atmosphere that is low in hydrogen.
Copper-nickel alloys (copper-nickels, cupro-nickels) are copper grades that contain 1.5-45% of nickel (Ni) as the major alloying element. According to the Unified Numbering System (UNS), wrought copper-nickel alloys are designated with the numbers from UNS C70000 through UNS C73499. These alloys are used for manufacturing coins, sea water equipment, evaporators, heat exchanger tubes, automotive hydraulic and cooling systems.
Nickel silver does not contain silver and may be regarded as a brass to which nickel has been added. Nickel contents vary considerably but usually lie between 9 and 30%, depending on its application. The copper content tends to remain the same, approx. 60-65% and the zinc content is reduced as the nickel content is increased. The higher the nickel content the whiter is the color and, although more corrosion resistant, the ductility is reduced.
Nickel silver has been widely used for numerous applications due to its corrosion resistance, color and cold forming qualities. Items made from nickel silver range through car radiators, ball pens, musical instrument keys, transistor casings, electrical contacts, architectural ironmongery, cutlery, etc. According to the UNS, wrought nickel nilvers are designated with the numbers from C73500 through C79999.