In-situ Diagnostic for Assessing Hall Thruster Wear

Abstract

The design of a new diagnostic to measure the net erosion of Hall thruster surfaces is presented. This diagnostic consists of a pair of optical noncontact profilometer pens mounted to a set of motion stages, which can interrogate the surface features of multiple components of interest including the hollow cathode assembly, magnet front pole covers, and discharge channel. By comparing scans of these surfaces to reference features, estimates of the component erosion rates can be acquired throughout long-duration lifetime tests without venting and removing the thruster from the vacuum facility for external profilometry. This work presents a detailed overview of the diagnostic design including the precision positioning system. In addition, preliminary data are shown which verify diagnostic operation and establish a baseline that will be used to track the erosion of the Hall Effect Rocket with Magnetic Shielding (HERMeS) Technology Demonstration Unit 3 (TDU-3) during an ongoing long-duration wear test.

Service life assessment of yttria stabilized zirconia (YSZ) based thermal barrier coating through wear behaviour

“…Therefore, estimating the period determining the life of the YSZ-coated superalloys is pivotal in selecting for high-temperature applications under the influence of the prevalent failure conditions [ 22 , 23 ]. For this purpose, the wear test has proved to be the first choice for several research studies and industrial experimentation for predicting the approximate service life of TBCs under constant friction and wear attacks [ 24 , 25 ]. Hence, in this present study, an attempt has been made to track the history of wear and degradation of the TBCs through a comparative analysis of the coatings obtained after different intervals of degradation considering multiple modes of failure during the lifetime of the TBC with an aim towards obtaining a rough prediction of the remnant lifetime of the coatings.…”