Fabrication and microstructure evolution of Al2O3/ZrBN-SiCN/Al2O3 high-temperature oxidation-resistant composite coating

摘要

The oxidation-resistance of thin film sensors, particularly at high temperatures, is critical for the lifetime and performance of the sensor. The preparation and oxidation-resistance of an Al2O3/ZrBN-SiCN/Al2O3 composite film with a sandwich-structure was performed using reactive magnetron sputtering. The microstructure evolution of the composite film is examined herein using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analysis. Oxygen diffusion was significantly inhibited by the formation of crystalline Al2SiO5 and Zr-B-C amorphous phase inside the composite film. The Pt-13%Rh/Pt thin film thermocouple (TFTC) with the Al2O3/ZrBN-SiCN/Al2O3 composite film as a protective layer was fabricated and calibrated. Both the stability and lifetime of the TFTC was significantly enhanced for temperatures up to 1000 degrees C. The test error of the TFTC was reduced by half, compared with that of the TFTC with the Al2O3 protective layer, indicating an excellent oxidation-resistant performance of the composite film.