SENSOR ELEMENT ELECTRODE AND SENSOR ELEMENT

PROBLEM TO BE SOLVED: To provide a sensor element electrode that minimizes sublimation of Pt and increase in electrode resistance for enhanced detection accuracy, and a sensor element having the same.SOLUTION: An electrode is for a sensor element configured to detect a specific substance in a gas under measurement. The electrode is embedded in an insulated substrate 2 having a detection surface 11, to which the specific substance adheres, in such a way that the electrode is partially exposed from the detection surface, and comprises an alloy 7 of Pt and at least one metal selected from a group consisting of Rh, Ru, Ir, Os, and Pd, and granular voids 5 distributed in the alloy, where content of the at least one metal in the alloy is no more than 40 mass%, and the number of the granular voids per unit volume of the sensor element electrode is in a range of 3 per 100 μmto 50 per 100 μm.SELECTED DRAWING: Figure 1 【課題】Ｐｔの揮散と電極抵抗値の上昇を抑制して、検出精度を向上させるセンサ素子用電極及びそれを用いたセンサ素子を提供する。【解決手段】被測定ガス中の特定物質を検出するセンサ素子用電極であって、上記特定物質が付着する検出面１１を有する絶縁性基体２に、上記検出面に一部が露出するように埋設されており、Ｒｈ、Ｒｕ、Ｉｒ、Ｏｓ及びＰｄからなるグループから選ばれる少なくとも１種の金属とＰｔとの合金７と、該合金間に分散配置された粒状空隙５と、を有し、上記合金中の上記金属の含有量が４０質量％以下であると共に、上記センサ素子用電極の単位体積あたりの上記粒状空隙の個数が、３個／１００μｍ3〜５０個／１００μｍ3である。【選択図】図１