To provide an ammonia sensor of which the selectivity of ammonia is largely enhanced.
A pair of lead parts (7) and (9) are arranged on an insulating substrate (5) made of alumina and a pair of comb-tooth electrodes (11) and (13) are respectively connected to the respective lead parts (7) and (9) while a responsive layer (15) is arranged on the comb-tooth electrodes (11) and (13) so as to cover the whole of the comb-tooth electrodes (11) and (13). Each of the comb-tooth electrodes (11) and (13) is a mixed electrode mainly composed of a mixture of Pt and Au (or an electrode consisting mainly of an alloy of Pt and Au or an electrode consisting mainly of the mixture of Pt and Au and the alloy of Pt and Au). That is, each of the comb-tooth electrodes (11) and (13) contains Pt and Au, for example, in an amount of 90 wt.% and the content of Pt to Pt-Au is especially set at 1-99 wt.%.
NISHIYAMA HIROYUKI
SUGAYA SATOSHI
YOKOI HITOSHI
