8mol Yttria-stablized YSZ Oxygen Sensor Zirconia Ceramic Tube ZrO2 One End Closed Sleeve

Yttria-stabilized zirconia (YSZ) is an important ceramic material. It is mainly composed of zirconium oxide (ZrO₂) and yttrium oxide (Y₂O₃). By adding an appropriate amount of yttrium oxide to zirconium oxide, zirconia can form stable cubic and tetragonal crystal phases at room temperature. YSZ with 8 mol% Y₂O₃ can form a fully cubic crystal phase at room temperature. Cubic zirconia has good oxygen ion conductivity, making it important in fields such as solid oxide fuel cells and oxygen sensors, enabling rapid migration of oxygen ions within the material for efficient power generation in fuel cells or accurate oxygen content detection by sensors. Pure zirconium oxide undergoes phase transitions at different temperatures, but after adding yttrium oxide, the ionic radius of yttrium is similar to that of zirconium, allowing it to enter the zirconia lattice, stabilize the lattice structure, and suppress phase transitions during cooling, thus preventing volume changes and material cracking caused by these phase transitions.

• Raw Material Preparation: 8YSZ powder is prepared using the chemical co-precipitation method, followed by spray drying granulation to ensure powder flowability and uniform particle size.
• Forming Process: Primarily uses cold isostatic pressing (pressure 200-300 MPa), with some precision products made by injection molding to ensure uniform green body density (≥5.8 g/cm³).
• Sintering Treatment: Sintered at a high temperature of 1550-1650℃, holding for 2-4 hours, with a controlled heating rate of 5℃/min to ensure sufficient grain growth without excessive sintering.
• Post-processing and Inspection: Grinding and polishing are performed to guarantee dimensional accuracy and surface finish. Before leaving the factory, products must pass airtightness tests (leak rate ≤1×10⁻⁶ Pa·m³/s), ionic conductivity tests (≥0.01 S/cm at 850℃), and thermal shock tests (cycles from -20℃ to 1100℃ five times without cracking).
• Tube structure: The mainstream design adopts a 'tube structure with one end sealed' (similar to a test tube), with the sealed end serving as the ion conduction core area and the open end used to lead out the electrode and connect the reference gas channel; some specialized sensors use a double-tube or multi-tube design to accommodate multi-gas monitoring needs.

Material characteristics:

• Flame resistance, high thermal conductivity.
• Low expansion coefficient.
• High thermal stability.
• Long service life, especially suitable for rapid cold and heating.
• Fast thermal conductivity, low energy consumption, and reduced energy consumption.
• Inner wall light, non-stick powder, reduce the amount of rare earth polishing.

Key performance benefits:

1.Stable working ability in a wide temperature range: Relying on the excellent thermal stability of 8mol YSZ, the zirconia sensor can stably output data in the range of 400-1100°C, and can maintain its structural integrity even under short-term high-temperature shock of 1200°C, far exceeding ordinary oxygen sensors (the upper limit of the normal operating temperature is 800°C).

Although its ionic conductivity is lower than 3mol YSZ in the low temperature range (400-600°C), it can meet the detection needs of medium and low temperature scenarios and adapt to more industrial conditions by optimizing the electrode structure (such as porous platinum electrodes).

2.Ultra-long cycle life and reliability: The high fracture toughness and phase transition resistance of 8mol YSZ zirconia tubes make the sensor significantly improve the cycle stability in repeated temperature rise and fall cycles (such as the start and stop of industrial combustion equipment) - after testing, after 150 high-temperature cycles, the oxygen concentration detection accuracy is attenuated by less than 10%, while the 3mol YSZ sensor attenuates by more than 25% during the same period; In the foam structure sensor design, the cyclic stability (OEC) of the 8mol YSZ base oxygen carrier can reach more than 90%, far exceeding that of traditional particle sensors.

3.Anti-interference and accurate detection: 8mol YSZ ceramic tubes are chemically inert, which can resist the erosion of strong acids, alkalis, sulfides and molten dust in industrial flue gases, and avoid the sensitivity reduction caused by electrolyte pollution; At the same time, the surface smoothness of zirconia ceramic tubes (Ra≤0.8μm) can reduce impurity adsorption, so that the sensor response speed is as fast as 0.1-0.5s, the detection accuracy can reach ±0.1vol%, and the minimum trace oxygen content can be detected below 1vol%, meeting the strict requirements of environmental monitoring and precision industrial control.

4.Low energy consumption and adaptability optimization: The low thermal conductivity (2.0W/(m·K)) of the 8mol YSZ tube can reduce the energy consumption of the sensor heating module, and with the multi-layer heterogeneous structure design (such as compounding with SndC/AO), the operating temperature of the sensor can be reduced by more than 200°C, further reducing the operating cost while ensuring the detection accuracy.

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