Evening star., 1949-12-14
New Compound founo
To Resist Intense Heat
Office of Naval Research Reports
On Zirconium-B Boron Tests
BY Thomas X. Henry

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A new compound of elements which viii
withstand temperatures as high as 5000 F.
higher than any other known material
is being developed under an Office of Naval
Research contract.
It may represent the farthest step yet
taken in the search for materials which
will Withstand the extreme high tempera-
lures encountered in jet and rocket engines.
It is a combination OF the rare metal
chromium and the rather common element
boron, which is not metal. The result is
described as a cross between metal and
a ceramic with some of the desirable quail
tiles of both.
Boron. used in the household borax and
as mild eye antiseptic in the form OF boric
acid, is abundant in California and Nevada.
Considerable amounts also are obtained
from the craters of the volcanoes Vulcano
and Stromboli on the Lipari Islands. north
Of Sicily.
Important As Alloy.
Zirconium has come into Importance in
recent years in various metal alloys. 1t is
used to form wires in radio tubes. The chief
source is Brazil. 1t is also found in the
sands of Florida beaches.
The cost of the new compound, develop
ment work on which has been done under
the Navy contract by the American Electro
Metals Corp. of Yonkers, N. Y may be re-
duced considerably by the chromium jewel
produced as bi-product These have the
greatest brilliance of any gem stones, except
diamonds and recently developed crystals
from the element titanium.
Boron also furnishes crystals known as
boron diamonds which are among the hard
est substances known.
Most of the work on the compound to
date has been respecting its heat resistance.
Very little yet is known about its strength.
Tests With Molybdenum.
Meanwhile, the Navy is carrying out ex-
tensive experiments with the relatively rare
metal molybdenum, now used chiefly in steel
alloys to improve the strength and heat re-
sistance. 1t has one of the highest melting
points of all metals-about 2,700 centgrade.
No crucible can hold it-so that until quite
recently melting was impossible
In the United States it is obtained chiefly
as biproduct of copper mining. Near
Climax, Colo, there are two so-called
"molybdenum mountains" whose rocks have
a high content of the element.
Molybdenum, far more heat-resistant than
any steel, is being considered for aircraft
parts which must Withstand extremely high
temperatures. The great disadvantage is
that it is extremely heavy, but on the other
hand it is so strong that it can be used in
extremely thin sheets, compared to almost
any other metal.
Mountains, like gigantic trees. have roots
extending far in the sub-crust of the earth.
This is one of the implications of the most
delicate earth wave measurements ever con-
Quoted in which dynamite explosions in
northeastern Tennessee were detected clearly
more than 900 miles away in New Mexico, in
Wisconsin and in northern Maine.
These tremors were timed to within 200th
of second, according to the report of geo.
physicists of the Carnegie Institution Of
Washington.
The experiments indicate for the first time
that the crust of the earth down to depth
of about 80 miles-the depth of the so-called
Mohorovric discontinuity which has been
long recognized by seismologists- divided
into two or three layers through which
tremors set up by the explosions move at
slightly different speeds.
Near the surface the velocity Of the earth
waves is about 6.1 kilometers second. Be-
low the Mohoroviric layer it is 81 kilometers
a second. In addition the Carnegie tests
indicate layer where the velocity is IL
kilometers second.
Bomb Waves Analysed.
Waves from the Tennessee explosions-in
one of which 100000 pounds of explosive
were USED llaQ 10 pass CnrOugn The top OF
the discontinuity layer under the Appalach-
ians. If the bottoms of the mountains stood
fiat on the surface of the sub-crustal layer
the speed in all directions would be uniform.
Difference in arrival time indicated, how
ever, that the mountains had roots reaching
into the sub-crustal layer and that the
waves moved along an up-and-d down path
instead of in a straight line.
These indications have not been entirely
accepted by the geophysicists who are pro-
posing further explorations of the upper
crust layers near the point of the Tennessee
explosions.