ing above 500° F and completely re- 
crystallized by heating for an hour at 
1,550° F. 
Almost all mill products are heated 
and annealed in air, but very light-gage 
sheet and strip (also light sections of 
wire and tubing) anneal better in an 
inert atmosphere or vacuum. 
Descaling Zr differs from Ti in that 
any tight oxide must be removed me- 
chanically. Machinability does not 
differ too much from Ti. 
Zirconium can be are or flash-butt 
welded under inert atmosphere. Be- 
cause of its reactivity with gases, the 
weld area must be shielded. 
Powder Metallurgy 
Four potential reactor uses of pow- 
der-metallurgy zirconium were pointed 
out by H. 8S. Kalish (Sylvania Electric 
Products): (a) special shapes for which 
large quantities of identical parts are 
required; (b) special alloys; for Zr-U 
alloys, better than 99% of theoretical 
density can be attained for all composi- 
tions up to 90% U. Zr-Be and Zr-Mg 
alloys have been successfully made; (c) 
cermets or composite materials; a mix- 
ture of Zr and BeO powders has been 
compacted and sintered to yield the 
Zr-Be eutectic structure; (d) porous 
parts. 
The methods of fabrication can be 
any of five basic techniques: 
1. Cold pressing and sintering. The 
inherent porosity can be eliminated by 
further fabrication. 
2. Cold pressing, presintering, coin- 
ing, and annealing. The item is 
finished by machining. This tech- 
nique minimizes waste, cuts down 
machining costs, and provides high- 
density, high-purity material. 
3. Hot pressing. A blank is hot 
pressed in a graphite die and machined 
to shape. This technique is suitable 
for lower volume production than the 
previous one. It saves considerable 
material and provides a high-density, 
high-purity material. 
4. Powder rolling. This is suitable 
for making plates or rods. Once the 
powder is consolidated, the steel 
sheathing can be stripped and the 
usual fabrication techniques employed. 
5. Powder extrusion. This method 
is successful with electrolytic zirconium 
powder because of its high ductility 
and relatively coarse particle size. 
Electrolytic Zr powder. After the 
conference, J. L. Wyatt (Horizons, 
ne.) reported on Horizons’ latest data 
58 
obtained on zirconium 
powder.* 
Basically, the process involves the 
electrolysis of a fused salt bath of 
sodium chloride and potassium zir- 
conium hexafluoride to produce a 
coarse, granular powder on a metal 
cathode. The product is withdrawn 
periodically, the deposit removed by 
stripping, and the salt-metal mixture 
purified by a simple fluosolids type of 
washing. Single deposits weighing up 
to 40 lb have been produced on a pilot- 
plant scale. 
The majority of the material is 40- 
150 mesh. It is somewhat dendritic 
in nature, consisting of individual 
crystallites and tree-like agglomerates. 
Excellent properties are exhibited in 
applications involving direct extrusion 
from the powder and in the fabrication 
of component parts by powder-metal- 
lurgy techniques. t 
In Nov. ’55, 18 cathodes were pro- 
duced in a laboratory electrolytic cell 
on a continuous basis. The first 
electrolytic 
Looking Ahead 
The growth of the demand for zireo- 
nium depends on many factors: govern- 
ment, industrial, and foreign pro- 
grams; collection of basic metallurgical 
data; improved processing and fabri- 
cating methods; and, as a result of the 
former, price reduction. These factors 
were analyzed by N. C. Bartholomew 
(Carborundum Metals Co.). 
AEC program. Including naval 
work, this program should have a mini- 
mum requirement of 600,000 Ib in 
1957. Some have estimated a far- 
from-conservative 2,300,000-lb demand. 
Industrial power. The Atomic In- 
dustrial Forum, using 1954 as a base, 
predicts the nuclear power industry 
will be at least seven times as large in 
1964 and a maximum of forty times as 
large. The effect will probably be 
something less than proportional—de- 
pending on the price of zirconium and 
the trend in reactor design. 
* At the present time, there is no com- 
mercial production of electrolytic zirco- 
nium. Potential users desiring small quan- 
tities should direct inquiries to C. A. 
Specht, Horizons Titanium Corp., Room 
3418, 30 Rockefeller Plaza, New York 20, 
N. Y. 
+ H. H. Hirsch, Fabrication of zirconium 
by powder metallurgy techniques, Metal 
Progress 68, No. 6, 81 (1955). 
cathode served as a scavenger to re- 
move impurities normally leached out 
of a new crucible during initial opera- 
tions. A blend of the other 17 cath- 
odes was evaluated. Vacuum-fusion 
analyses showed interstitial impurities 
of: oxygen, 0.038%; nitrogen, 0.01; 
hydrogen, 0.005. 
Nitrogen values are probably high, 
Kjeldahl analyses to check this are not 
available, but previous batches of 
metal were analyzed at about 0.003 %. 
A spectrographic analysis of a quar- 
tered sample of this composite is shown 
in Table 3. Hardness determinations 
on a 30-gm as-cast button melted on a 
water-cooled copper hearth showed a 
Brinell value of 86 under a 500-kg load. 
The material was too soft for the 3,000- 
kg-load determination on a pellet of 
this size. 
A melted pellet with an original 
thickness of 5;6 in. was cold-rolled and 
reduced in thickness 97 % with no evi- 
dence of edge cracking. It exhibited 
considerable ductility thereafter. 
eeemeiieere 
Foreign programs. Current reac- 
tor designs abroad do not incorporate 
Zr. Presumably, other countries will 
follow the trend to higher temperatures 
and Zr. Also to be considered—urgent 
need for power, development of Zr pro- 
duction, and how U.S. production and 
transportation costs will affect foreign 
importing. 
Chemical industry. U.S. corrosion 
losses are over $5-billion per year. 
This should be an important market. 
Sponge utilization. Improvement 
in yield from sponge to end product 
hasshown markedimprovement. Fab- 
rication on a conversion basis will end 
—responsibility for quality and losses 
will be assumed by the fabricator. 
Scrap recovery. Only done on a 
laboratory scale now, 80% recovery 
will bring down prices. 
Improved processing. Imminent 
separation and reduction developments 
must be given careful consideration in 
expansion plans. ; 
Specification changes. Current 
specifications are probably more strin- 
gent than necessary. This must be 
verified through experience. 
Price. This is a function of quan- 
tity and quality. Most of the factors 
listed will be determinant. 
