Geoscience Reference
In-Depth Information
Table 3.1 does not include some of the recent designs and modifications or
upgrades as their applications are restricted to specific studies.
3.2 Selection of Autoclave and Autoclave Materials
When selecting a suitable autoclave, the first and foremost parameter is the
experimental temperature and pressure conditions and the corrosion resistance
in that pressure
temperature range in a given solvent or hydrothermal fluid.
If the reaction is taking place directly in the vessel, the corrosion resistance is, of
course, a prime factor in the choice of autoclave material. The most successful
materials are corrosion-resistant, high-strength alloys, such as 300 series (austenitic)
stainless steel, iron, nickel, cobalt-based superalloys, and titanium and its alloys.
Several workers have reviewed the properties of some alloys used commonly in
the making of hydrothermal autoclaves [3,4] . Tables 3.2
3.4 give certain proper-
ties of these alloys. The critical property for a material used in a hydrothermal
autoclave is its creep-rupture strength, a measure of the length of time until rupture
of a stressed material occurs at a given temperature. Similarly, the ultimate tensile
strength and yield strength are to be taken into account. In the 300 series of
Table 3.2 Properties of Certain Alloys [3]
Rupture Stress (atm)
1000 h, 800 C 1000 h, 600 C
Resistance to Aqueous OH
Low-carbon steel
170
1
Tool steel
1
4140 (similar to EN19)
1
170
Stainless type 340 c
270
1100
19-9-DL (Universal
Cyclops Steel Co.)
?
680
2200
a
Croloy15-15N
1
610
2260
a
Timken17-22-A
1
Inconel X d
?
1200
4500
Stellite e
?
Udimet500 e
?
2100
b
Silver
1
b
Platinum
1
b
Platinum 10% iridium
1
a Denotes the balance of metal in the alloy.
b Cr and Ni values in stainless steels are values , 2 wt%.
c A product of Allegheny Ludlum Steel Corporation, Pittsburgh, Pennsylvania.
d A product of Inco Alloys International, Inc., Huntington, West Virginia.
e
A product of Cabot Corporation, Kokomo, Indiana.
Source: Data from Ref. [4] . Courtesy of the Academic Press, Orlando, FL.
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