scandium rims?

[tv_vt]

Can anyone tell me the benefits of scandium for rims? Dura Ace 7850, Hed Ardennes - these are two that come to mind that are scandium. Do they brake better (or break better?), are they more durable, ride more smoothly, or what?

Trying to decide if my next wheel purchase will be one of these wheels or a handbuilt w/ DA 7900 hubs, revo spokes and DT rims.

Thanks for any info.

Thom

[Louis]

From Wikipedia. Looks like it improves the material properties in the welds. Given how little there is in any given alloy we would use, I doubt it would change the rim's overall mechanical properties (i.e. stiffness)


Production

World production of scandium is in the order of 2,000 kg per year as scandium oxide. The primary production is 400 kg while the rest is from stockpiles of Russia created during the Cold War. In 2003 only three mines produced scandium: the uranium and iron mines in Zhovti Vody in Ukraine, the rare earth mines in Bayan Obo, China and the apatite mines in the Kola peninsula, Russia. In each case scandium is a byproduct from the extraction of other elements.[14] and is sold as scandium oxide. The production of metallic scandium is in the order of 10 kg per year.[14][15] The oxide is converted to scandium fluoride and reduced with metallic calcium.

Applications

Parts of the Mig–29 are made from Al-Sc alloy.[21]The addition of scandium to aluminium limits the excessive grain growth that occurs in the heat-affected zone of welded aluminium components. This has two beneficial effects: the precipitated Al3Sc forms smaller crystals than are formed in other aluminium alloys[21] and the volume of precipitate-free zones that normally exist at the grain boundaries of age-hardening aluminium alloys is reduced.[21] Both of these effects increase the usefulness of the alloy. However, titanium alloys, which are similar in lightness and strength, are cheaper and much more widely used.[22]

The main application of scandium by weight is in aluminium-scandium alloys for minor aerospace industry components. These alloys contain between 0.1% and 0.5% of scandium. They were used in the Russian military aircraft Mig 21 and Mig 29.[21]

Some items of sports equipment, which rely on high performance materials, have been made with scandium-aluminium alloys, including baseball bats[23], lacrosse sticks, as well as bicycle[24] frames and components. U.S. gunmaker Smith & Wesson produces revolvers with frames composed of scandium alloy and cylinders of titanium.[25]

Approximately 20 kg (as Sc2O3) of scandium is used annually in the United States to make high-intensity discharge lamps.[26] Scandium iodide, along with Sodium Iodide, when added to a modified form of mercury-vapor lamp, produces a form of metal halide lamp, an artificial light source which produce a very white light with high colour rendering index that sufficiently resembles sunlight to allow good color-reproduction with TV cameras.[27] About 80 kg of scandium is used in metal halide lamps/light bulbs globally per year. The first scandium based metal halide lamps were patented by General Electric and initially made in North America, although they are now produced in all major industrialized countries. The radioactive isotope 46Sc is used in oil refineries as a tracing agent.[26] Scandium triflate is a catalytic Lewis acid used in organic chemistry.[28]