| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a gas sensor element such that pores of a porous protection layer covering an external electrode of the gas sensor element is not apt to be clogged with a poisoning substance and while the poisoning substance is securely captured, adhesion of the porous protection layer is excellent. <P>SOLUTION: The gas sensor element includes a detection element 10 and a porous protection layer 20 provided to a surface of the detection element. The porous protection layer comprises spinel particles and alumina particles, particles of one kind (hereinafter coarse particles) are larger in particle size than particles of the other kind (hereinafter fine particles), and pores are provided between the particles. Here, when a distribution of logarithmic differential pore volume to pore diameters of the porous protection layer is measured based upon JIS-R1655, two pores which are a large pore C<SB POS="POST">A</SB>having a peak at 1.5-50 μm and a small pore C<SB POS="POST">B</SB>having a peak at 0.05-1 μm are formed, and a peak ratio R, represented as (H<SB POS="POST">A</SB>/H<SB POS="POST">B</SB>), of a peak height H<SB POS="POST">B</SB>of the small pore to a peak height H<SB POS="POST">A</SB>of the large pore is 0.7-10. <P>COPYRIGHT: (C)2012,JPO&INPIT |
