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The isothermal oxidation behavior of Fe-10Al, Fe-15Al, Fe-20Al alloys with and without the addition of 0.1 at% Y was studied at 800 °C under 1 × 105 Pa of flowing pure O2 for 24 h. The oxidation of three Fe-Al alloys can be divided into transient state and steady state oxidation stages. The oxidation of each stage is approximately in accordance with the parabolic law. The addition of 0.1 at% Y changes the oxidation behavior obviously and leads to a significant increase of the weight gain of Fe-10Al and Fe-15Al. The scale grown on Fe-10Al is much thicker and more complicated than that grown on Fe-20Al, which is composed of an exclusive thin layer of Al2O3 protective film. Due to the formation of a large number of nodules, the scales grown on Fe-15Al cannot provide full protection for the alloy. Scale microstructure of the three Fe-Al-0.1Y alloys is similar to their corresponding Fe-Al alloys. However, nodules with very small size still appear on the surface of Fe-20Al-0.1Y alloy. The critical Al concentration to form an exclusive Al2O3 protective layer for Fe-Al binary alloy is on the borderline between 15 at%–20 at%. For Fe-Al-0.1Y alloy, the presence of 20 at% Al is not enough to inhibit the growth of nodules.

The iso-thermal oxidation of the quaternary Co-20Re-25Cr-3Si alloy at 1,000–1,200 C under laboratory air for 24 h has been studied. The oxidation kinetics at 1,000–1,200 C follow parabolic law perfectly and the value of oxidation activation energy is 220.74 kJ/mol. Unlike the experimental condition of 0.1 MPa pure oxygen, under laboratory air Co-20Re-25Cr-3Si alloy presents a good oxidation resistance due to the formation of a dense and continuous layer of Cr2O3 in contact with the alloy. A 79% drop in oxygen pressure has changed the oxidation mode from catastrophic oxidation to mild oxidation. The thickness of the protective Cr2O3 layer decreases when temperature increases. Therefore, Co-20Re-25Cr-3Si alloy shows the best oxidation resistance at 1,000 C. Moreover, from another perspective, compared with Co-17Re-23Cr-3Si alloy, the addition of about 2% Cr can also improve the oxidation resistance of the alloy greatly by forming the protective Cr2O3 layer.

The oxidation of the quaternary Co-20Re-25Cr-2Si alloy has been studied at 1000−1300 °C for 24 h. On the whole, at high oxygen pressure of 0.1 MPa the alloy shows mass loss while at low oxygen pressure of 3.0×10−5 Pa, however, the alloy shows mass gain. Compared with the irregular kinetics under the oxygen pressure of 0.1 MPa, the kinetics approximately conform to parabolic law under the oxygen pressure of 3.0×10−5 Pa, with the value of oxidation activation energy equal to 262.7 kJ/mol. The scales formed under the oxygen pressure of 0.1 MPa at 1000−1300 °C are very similar. The outermost layer is CoO, followed by a mixed oxide layer probably composed of CoO and CoCr2O4. The innermost layer is probably composed mainly of a thin discontinuous layer of Cr2O3, accounting for the continuous mass loss due to the evaporation of Re element in the form of ReO3. However, the sales formed under the oxygen pressure of 3.0×10−5 Pa are probably composed of an outer thin layer of CoCr2O4 spinel and an inner dense and continuous layer of Cr2O3, which provides the good oxidation resistance for the alloy. The combination of the addition of Si and low oxygen pressure has shown a synergistic effect on the formation of a protective chromia layer.

TiO2, SiO2 and TiO2-SiO2 thin films were prepared by sol-gel dipping method on glass substrates. The pyrolysis behavior of TiO2 and SiO2 dry gel were tested by differential thermal analysis (DTA). The microstructure and optical properties of the TiO2, SiO2 and TiO2- SiO2 were studied by X-ray diffraction (XRD) and ultraviolet and visible spectrophotometer. The results showed that the phase structure of the films was affected by the composition. All the films were transparent in the visible region. Meanwhile, the transparency of SiO2 was better than TiO2 and TiO2-SiO2 composite film. The ban-gap of the TiO2, SiO2 and TiO2-SiO2 thin films were 3.79, 4.01 and 3.91.