Hiroyuki Teramoto

An analysis of the surface of the Ni–W layer of a tungsten film coating cathode

Abstract Superior characteristics of a cathode operated with higher current density are required for achieving higher brightness and higher resolution of CRTs. An improved Sc 2 O 3 -dispersed-oxide cathode (conventional cathode) with tungsten film coating (new cathode) has been developed. The capability of the new cathode for high-current density operation is 1.8 times that of the conventional Sc 2 O 3 -dispersed-oxide cathode [1] . Investigation of W behavior as well as typical characteristics of the new cathode in CRTs have been reported. This new type of oxide-coated cathode will contribute to higher brightness and higher resolution of CRTs.

25.2 Invited Paper: Recent Trends in CRT Cathodes

Image quality of CRTs has been improved by applying new technologies of electron gun, cathodes and image screen. Recently, new types of cathodes with higher current density have been developed, and have contributed higher definition and higher brightness of CRTs. This paper reviews of the recent technical progress in CRT cathodes, which are classified into thermionic cathodes and cold cathodes. Recently studies concerned with cold cathode for CRT application has been also reported, but this review focuses on thermionic cathodes which consist of Oxide-coated cathodes and Impregnated cathodes.

Development of Innovative Coating Technology, MSCoating, Using Electrical Discharge

MSCoating is a new coating technology using pulse discharge. This coating technology, which is developed by Mitsubishi Electric and IHI, has been put into practical use as an anti-wear coating for low-pressure turbine blades in aero engines. Normally, Z-notch, which is the edge of a low-pressure turbine blade in an aero engine, is treated with anti-wear coating by welding because these edges are frictioned together while the engine is running. However, coating by welding requires pre-heating, removal of excess thickness and advanced skill to ensure high reliability. Therefore, improvement of productivity and cost reduction are required for the anti-wear coating of Z-notch. MSCoating is an innovative coating technology that is able to meet these requirements. MSCoating can eliminate the above processing needed for coating by welding, and has superb productivity and reliability for machine work. It is confirmed that anti-wear performance of the coating formed by MSCoating is about 10 times as high as that formed by welding in a fretting wear test under conditions similar to the real operating condition. It is suggested that hard precipitate such as carbide and oxide of chrome and cobalt oxide in the MSCoating layer play a role in the advantages of the anti-wear performance.© 2010 ASME