Operational excellence continual pressure

Sputter-ion pumps of the triode type excel in contrast to the diode-type pumps in high-noble gas stability. Argon is pumped stably even at an inlet pressure of 1 10 mbar. The pumps can be started w/ithout difficulties at pressures higher than 1 10 mbar and can operate continuously at an air inlet producing a constant air pressure of 5 10 mbar. A new kind of design for the electrodes extends the service life of the cathodes by 50 %. 

Graphite is an excellent refractory material with a melting point of about 4473°C, but it must be under a pressure of some 100 atm, otherwise it just simply sublimes. Since graphite oxidizes slowly in air at about 400°C, it should be protected in an inert atmosphere to operate successfully at elevated temperatures and, it is most important that the inert atmosphere at temperatures in the region of 2500°C is quiescent, since otherwise, the surface will be badly eroded as the gas flow sweeping across the surface continually removes the surface graphite by sublimation. 

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