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topic 5797

Banning Ekaboron in Bats


(2000)

I'm in a chemistry class at Diablo Valley college and have a project concerning the control of the composition of bats by the NCAA. And the banning of the use of ekaboron in their manufacture. Any insight?

Leslie A.
- Concord CA


(2000)

Someone (like maybe your chemistry teacher?) may be putting you on a wild goose chase, I think. (If I am not right, I would like to know it.)

In the 1800's a new element "ekaboron" was predicted, by scientists then, using the new Periodic Table. Later, when it was discovered there was in fact such an element, it became called "scandium". It is a very light, silvery, metallic element most often added in tiny amounts, to intensify the mercury vapor lighting used at ball stadiums, it's most widely published practical use. Other uses have been proposed, such as for spacecraft structures, since it has chemical/metallurgical properties well suited for this. High cost is the primary limiting factor to expanding it's useful applications. I have no knowledge of it being used alone, or as an alloying element for ball bats, but I suppose if you could afford to pay for one, it is possible one could be constructed that might be superior enough to get it banned by the NCAA.

W. Carl Erickson
- Rome, New York

Ed. note: That was interesting history, and you are prescient, Mr. Erikson! See also letter no. 826


(2000)

I have been doing my Ph.D. research with "ekaboron" for 4 years now (just finished!). "Ekaboron" was the name Mendeleev gave to an element he predicted to exist in 1871 which is now knows to as Scandium. Scandium was discovered in 1878 by Lars F. Nilson in Scandinavia, hence it's name "Scandium".

Anyway, my research is concerned with the use of Scandium in Aluminum. When added to aluminum and properly heat treated scandium forms a small intermetallic phase called a "dispersoid". Dispersoids help control the microstructure of the alloy during forming operations by preventing "recrystallization" from occurring. Scandium also controls grain size. What you need to know about recrystallization is very simple. If recrystallization occurs in the alloy there is a substantial drop in the alloy's strength. An unrecrystallized microstructure that has been worked (rolled, forged, etc.) is said to be "work hardened"...meaning it has been strengthened. Products like baseball bats often require large amounts of deformation from the parent material (usually huge slabs of metal alloy) to be made that thin. Deformation plus some heat (often needed to deform the material) can cause recrystallization to occur. Dispersoids help prevent that from happening. Keeping the grain size small also helps to maintain or increase an alloy's strength and increase weldability.

So after you read that a million times all you need to know is:

1)"ekaboron" is the element scandium

2)scandium forms an intermetallic phase with aluminum called a "dispersoid"

3)the baseball bats (which are made by Easton) containing scandium benefit from maintaining strength after processing.

Whether this increases the performance of that bat, I don't know, I've never compared bats with and without scandium. I do know that it has some potentially important uses though. Currently aluminum alloys with scandium in them are being developed for use on airplanes (again....because they are thin and need to be welded). The Russians actually pioneered the use of scandium in aluminum for use in rocket fins that were welded onto missiles which had to be strong enough to be launched from below the surface of polar ice caps without breaking off!

So if you have more questions, or need pictures of what I'm talking about send an email.

How did that topic get chosen for you to study anyway?

Yancy Riddle, Ph.D.

Yancy Riddle
- Chicago, Illinois, USA


(2000)

Thanks Yancy, for bringing us up to date on "ekaboron" (scandium). (You'd think with a scandinavian name like mine, I would have guessed this element was more important then I thought it was). I apologize if I offended anyone by my earlier comments. I have some experience with alloying molten aluminum, and just wondered if it is very difficult to get scandium into the melt without losing some, thus increasing the costs involved? You probably use a master alloy? Without disclosing anything proprietary, could you give some approximation of the scandium that is required. Is it added at ppm or % levels, for example? I have used vanadium, titanium or zirconium at less than 200 ppm levels for similar purposes, historically, and with varying success levels.

W. Carl Erickson
- Rome, New York


(2000)

Offense? My alloys aren't that sensitive. You are correct in assigning Sc to "not very important right now", however, my job is to change that.

To answer your question....I have been using a master alloy of Al-2wt%Sc. Al-Sc master alloys can be purchased from both Standford Metals and Ashurst, as well as some other places. I add pieces of the master alloy to pure Al (or whatever alloy I want to create) to create alloys of whatever composition I desire. I use a resistance furnace and crucible to melt my alloys. No Sc is lost, unlike adding Mg to Al. Mg is lighter than Al so much of it can be released to the atmosphere if improper techniques are used. Scandium is used somewhat like Ti, V, and Zr can be used (although they have other uses too) in Al...as a dilute addition to form secondary precipitates, namely "dispersoids". The dispersoid formed is Al3Sc which is similar in some ways to Al3Zr (the Zr dispersoid). With Al-Zr we are limited by how much we can add to ! Al to about 0.14wt% because of the break in the peritectic arm. Sc can be added up to about 0.38wt%. However, it may not be necessary to add the full amount. This information is available from published Al-Zr and Al-Sc phase diagrams. Both Al3Sc and Al3Zr are used to control recrystallization in wrought products of Al, although Al3Sc is not commercially popular yet (due to insufficient information about it and current cost of Sc ).

Strictly speaking the effectiveness of a dispersion of second phases to resist recrystallization is proportional to the volume fraction / radius ratio, aka fv/r. So increasing the volume fraction and/or keeping the radius small helps. Since we can add more Sc than Zr to Al volume fraction of Al3Sc can be much higher than Al3Zr. Also, the distribution of Al3Sc is always homogeneous (many times Al3Zr is heterogeneously distributed)...this also helps. Al3Sc coarsens slowly so its radius stays fairly small (although Al3Zr coarsens more slowly! ).

These are just a few of the hints we are using to improve Al alloys with Sc. Other uses of dispersoids include controlling recovery processes and grain growth. This information is available in the scientific journals, so none of it is proprietary. With time we'll more completely understand Sc's behavior in Al so it can be confidently used. Next generation civilian aircraft have already accepted Al alloys with Sc in it. Russians have been using Sc in Al for a long time. Cost is becoming less of an issue through market demand, research demand, and finding cheaper ways of reducing Sc from its oxide. If I remember correctly (please don't quote me on these quotes), the same Al-Sc master alloy 's price has reduced a full order of magnitude (from $2000 to$200), from when I started the research (4 years ago) to now.

We've probably gotten way beyond the original question, banning Sc in bats. If they are going to use metal alloy bats at all I don't see a legitimate reason to ban Sc specifically. Take a look at the golfing industry, they've exploited all sorts of alloys, and combinations of alloys within the same club all for the same reason....to increase performance for a given human ability. Sc has been added to some bicycle frames also. Bike frames also come in a very wide range of metallurgical alloys. Why should Sc be discriminated against when many other metal alloys containing such elements as Fe-C (steel), Cr, Al, Cu, Zn, Ti, Zr, Mn, etc. are in common use? There is nothing magic about Sc. All of these alloy's properties are created by skilled control of microstructure and processing. Maybe it would be more legitimate to put limitations on how materials are processed instead.

Viva L'Scandium! (um, yeah, maybe my enthusiasm is a little too high). I'm going back to the lab, ! where I belong.

Yancy Riddle
- Chicago, Illinois



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