Argon high-temperature alloys

A NMR probe for very high temperature and high pressure was published by Jonas in 1979 [5]. The probe had a relatively low spectral resolution but allowed NMR relaxation measurements at temperatures up to 700 °C. The pressure vessel was made from the IMI-680 titanium alloy and could withstand pressures up to 200 MPa. Because of the high temperatures attained with the probe, gaseous argon was used as the pressure transmitting medium. A first NMR relaxation study of supercritical water performed with this probe was published in 1981 [25]. 

A Co/Ni alloy is the next active catalyst among the binary combinations within the iron-group metals in the arc discharge method (51). Laser vaporization of metal/ carbon composite in argon atmosphere at high temperature (1200°C) can also produce SWNTs (41). Guo et al. (41) reported that the Co/Ni alloy was the most effectual, with a yield of 50-90% in the laser ablation method. 

Argon is an inert, colorless and odorless noble gas. It is used to fill electric light bulbs in order to prevent the evaporation of tungsten in the filament at the high temperature of operation. Argon is also used to protect metals from oxidation in arc welding and heat treatment of alloys. 

Helium and argon are utilized as protection gases in the bright annealing of special steels and other alloys. The noble gas atmosphere prevents the metallic surface from oxidation at the high temperature of the process. 

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