Interfacial compatibility and thermal cycle stability for glass-sealed oxygen sensors

The oxygen sensors are extensively utilized in vehicles’ exhaust systems to monitor gases composition and control air-to-fuel ratio, thus reducing harmful emission and improving fuel economy. In equilibrium potentiometric sensors, the sealing performance is essential to ensure data accuracy. In this work, the 64SiO2–18TiO2–10Na2O–7K2O–1Al2O3 (wt%) glass was utilized as seals instead of traditional talcum in zirconium dioxide oxygen sensor. The interfacial compatibility with adjacent components (Fe–16Cr, Al2O3 and 8YSZ) and thermal cycle stability of seals were seriously evaluated in various ways. The equilibrium contact angles were lower 60° at high temperature, exhibiting better wettability and tight bonding at the interface. Besides, the leakage rates between glass and Fe–16Cr alloy were less than 0.01 sccm/cm at 650–800 °C and input gas pressures of 6.9–34.5 kPa. The oxygen sensor coupled with glass exhibited better thermal stability that leakage rate maintained around 0.004 sccm/cm under an input gas pressure of 200 kPa during 100 thermal cycles. Additionally, the oxygen sensor with sealed glass can generate continuous response and recovery, which is better than sealed talcum. Owing to these good performance, the glass is a suitable alternative for oxygen sensor sealing.