Microstructure of Chemical Vapor Transport Deposition Single Crystal Tungsten Coating Working at 1600°C

Abstract

Thermionic energy conversion is a process by which thermal energy is transformed into electrical energy directly without the intermediate steps. Microstructure of Chemical Vapor Transport Deposited (CVTD) single crystal tungsten coating working at 1600°C for 1000 h was investigated using optical microscopy and electron backscatter diffraction (EBSD) technique. The experimental results showed that the etching morphology of single crystal tungsten coating was not clear compared to the etching morphology before working. The electro-etched surface of single crystal tungsten coating mainly consist of {110} crystal planes and {112} crystal planes before working at 1600°C. The surface of the single crystal tungsten coating mainly consists of near {110} crystal planes and near {112} crystal planes instead after working at 1600°C.

Microstructures and Kinetics of Tungsten Coating Deposited by Chemical Vapor Transport

“…It works at a high temperature of approximately 1773 K throughout the service period, which requires the high temperature, mechanical strength, and microstructural stability of the emitter material. Tungsten coatings rely on their high electron work function, low diffusion penetrability, and superior hightemperature creep strength, which are vital to the cathode material [2][3][4]. Emitters with high work functions enable electronic fuel components to operate at high voltages and increase their efficiency and load capacity [5].…”