Surface degradation of M-type cathodes modified with nanocarbon
Tatyana M. Krachkovskaya1, Yuliya V. Yakimovich1,2, Anna A. Akst1,3, Olga E. Glukhova1,3,4, Aleksandr A. Petrunin3; 1JSC "RPE "Almaz", Saratov, Russia; 2Saratov State Technical University, Saratov, Russia; 3Saratov State University, Saratov, Russia; 4First Moscow State Medical University named after I. M. Sechenov, Moscow, Russia
Abstract
An experimental study was conducted to examine the degradation of the emission surface of impregnated M-type cathodes modified with nanocarbon (polyhedral multilayer toroidal carbon nanostructures—astralens—in the tungsten sponge and carbon nanocluster sulfoadduct—ugleron—in the emission substance) and similar unmodified cathodes. It was found that the degradation of the M-coating, represented by an Os-Ir-Al composite with a thickness of 0.2-0.8 μm, was several times lower for the modified cathodes than for unmodified cathodes, depending on the test temperature. Coating degradation was assessed by comparing the morphology and chemical composition of the cathode emission surfaces after different operating times at temperatures of 1080-1180 °C using a scanning electron microscope (SEM). In addition, the relative degradation of the Os-Ir-Al film thickness during the cathode development process was assessed using an X-ray fluorescence analyzer. A reduction in coating degradation was observed both in the presence of ugleron and in the presence of astralenes alone, with the reduction being greater in the presence of astralenes than in the presence of ugleron. The greatest reduction in coating degradation relative to unmodified coatings was observed for cathodes modified with both types of nanostructures, significantly increasing their service life. For cathodes with an initial film thickness of ~0.5 μm, the developed Deneb2 software package was used to calculate the coefficients of their mutual diffusion and assess the service life of modified and unmodified cathodes based on experimental data on the concentrations of tungsten, osmium, and iridium on the emitting surface, obtained using SEM, after various developments at a temperature of ~1150 °C.
Speaker
Крачковская Татьяна Михайловна
АО "НПП "Алмаз"
Россия
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