Study Of Outgassing Of Sputter-Ion Pump Materials Treated With Three Different Cleaning Procedures

The paper discusses the results of a study performed on the materials used for the fabrication of sputter-ion pumps, namely, stainless steel for the anode and body, and titanium for the cathodes. The TDS technique has been applied to study the efficacy of different cleaning procedures (acid and basic baths and vacuum firing) normally adopted by the vacuum industry to minimize the amount of gases absorbed in these materials. With all the samples studied, one chemical cleaning procedure seems to be enough, instead of the two usually adopted. With the anode and body samples, a second chemical cleaning seems to increase surface contamination; then, with the anode sample, vacuum firing reduces the outgassing to that of the first cleaning. Vacuum firing was found to be very effective in the case of the cathode material. In fact, with titanium cleaned by any of these procedures, hydrogen forms about 97% of all the occluded gases and though vacuum firing reduces outgassing by almost 80%, hydrogen continues to be the major species desorbed. Copyright (C) 1996 Published by Elsevier Science Ltd.