| 摘要 |
<p>PROBLEM TO BE SOLVED: To attain a long service life under a high current density load by maintaining an after-diffusion route for a reducer contained in the base metal and smoothly generating a barium free radical. SOLUTION: A metallic layer 12 mainly composed of tungsten and zirconium- tungsten or tungsten-nickel is formed on top of a base metal 6 mainly composed of nickel and formed to contain at least one type of a reducing element. In addition, an electron emission substance layer 8 containing an alkaline earth metal oxide at least containing barium is formed on top of the metallic layer 12. In this case, the metallic layer 12 is available with tungsten, zirconium- tungsten or tungsten-nickel coated on the base metal 6 and then thermally treated. Also, the metallic layer 12 is formed out of grains having a size smaller than the mean grain size of the base metal 6.</p> |
