Niobium

This is a piece of niobium bar that was zone refined using an electron beam-the metal is heated equally around its circumference in a small band, melting one short area of the bar, and the molten zone is moved along the bar to segregate impurities to one end. Imagine shaking up a container with oil and water, and letting the less-dense oil float up to the top- it is a similar effect, though not necessarily because of density. This is an excellent process for increasing the purity of metals and some other materials, except that it is quite expensive--it requires a high vacuum chamber which must be "baked out" before use to remove moisture and other volatile chemicals, and then the zone refining itself is a slow process which is very delicate and tricky to do just right, resulting in a very small amount of finished material. This sample was zone refined along a short length of it, and was intended to be sliced lengthwise, polished, and etched in a special mixture of acids to view the difference in internal microstructure between the raw bar and the zone-refined section, though this piece was not actually prepared except for the initial slices.

This is a sample of niobium crystal bar, produced by the same basic method as the Van Arkel/de Boer (Iodide) crystal bar process used to purify hafnium, zirconium, titanium, and occasionally thorium, though with different chemical precursors and reaction conditions in order to adapt the process to niobium.

Some of you may be scratching your heads, saying "But I thought the iodide crystal bar process was only used for the metals just mentioned--I've never heard of it being used for niobium." Pat yourselves on the back--you're 100% correct. This piece of niobium crystal bar is, as far as I have ever heard, one of only three or four small pieces in the world, leftover from an experiment on niobium reduction and purification performed about 45 years ago. Some more was produced, but the rest was melted down. If you have any information about this experiment or another like it, please email. I am not sure of exactly what they did, but from how the bar is half-melted, I would guess that the crystal bar was produced, cleaned, and vacuum induction melted into a round bar before it was to be zone-refined and then analyzed for final purity.

Most importantly, though, look at those fabulous crystals. Niobium is a very tough, hard metal that is extremely chemically resistant- left to its own devices on Earth, those beautiful crystalline facets would likely last millions of years, unless they were subducted into the mantle or happened to be in the direct path of a volcanic eruption.

This is vapor-deposited niobium from some sort of CVD reaction. Unlike the other sample of vapor-deposited niobium, this one was performed on a large heated surface or large-diameter electrode, thus the pipe-like nature of it. In fact, there's a good-to-high probability that this experiment was performed in order to test the possibility of making niobium pipe (used in chemical and nuclear reactors, for example, as well as other demanding applications such as rocket engines) by a simple vapor-deposition process where the outer surface could simply be lathed to size, rather than by painstakingly rolling it in to appropriately sized foil, fabricating it into a tube shape and then joining it by electron-beam welding, where especially the final step is very expensive and time-consuming. I doubt the as-deposited niobium in this case would have possessed the homogeneity and microstructure necessary to give niobium its ideal mechanical properties, but would be nifty to say the least if it worked.

This auction is for a very unusual, what I think would be called a Salesman Sample, of 5 exotic metal disks. The brown plastic case that measures 2.50 in. by 6 in., was received by my Father when he visited the Kawecki Berylco Industries in the 1970's. The company was bought by Cabot Corp. in the late 70's. The disks measure 1.25 in. dia. by .1in. thick. According to the description in the case the 5 metals are Beryllium, Lockalloy, Beryllium Copper, Columbium [an older name for niobium], Tantalum.

I believe that Royal Selangor (the company that produces FDCs (First Day Covers) for Malaysia) put metal cachets on FDCs because they are an expert in making metal objects/arts. So they want to show their ability to make those cachets.There are other versions of cachets like pewter and silver, but I don't think you are interested in such naive metals, and they can't be anodized to create colors. Royal Selangor started their business with pewter because there are a lot of tin deposits (in the form of cassiterite) in Malaysia and the southern part of Thailand.

The tantalum cachet I gave you is the only one they have produced! Now they only use niobium for making colorful cachets for FDCs since tantalum is much more expensive than niobium.

Best wishes,
Warut

This auction is for a very unusual, what I think would be called a Salesman Sample, of 5 exotic metal disks. The brown plastic case that measures 2.50 in. by 6 in., was received by my Father when he visited the Kawecki Berylco Industries in the 1970's. The company was bought by Cabot Corp. in the late 70's. The disks measure 1.25 in. dia. by .1in. thick. According to the description in the case the 5 metals are Beryllium, Lockalloy, Beryllium Copper, Columbium [an older name for niobium], Tantalum.

(4) the possession, and transportation upon his person, of any switchblade knife with a blade three inches or less in length by any individual who has only one arm.

Hi. I noticed that your Aeschynite sample is from Iveland in Norway. The small community of Iveland is actually famous for their mines and minerals. Here's a folder with some information about a local exhibition. They also have at least 5 mines that are open to the public for a small price, where you can dig for minerals yourself.