Using a thermogravimetric analyzer (TGA), Fe–10Cr steel was oxidized in dry air and in a mixed atmosphere of air and water vapor at a relative humidity of 50% and a temperature of 800–1200 °C for 1 h. The oxidation weight gain curves under the two atmospheres were drawn, the oxidation activation energy was calculated, and the phase and cross-sectional morphology of the iron oxide scales were analyzed and observed by X-ray diffractometry (XRD) and optical microscopy (OM). The results showed that when the oxidation temperature was 800 °C, the spheroidization of Fe–10Cr steel occurred, and the oxidation kinetics conformed to the linear law. At 900–1200 °C, the oxidation kinetics followed a linear law in the preliminary stage and a parabolic law in the middle and late stages. In an air atmosphere, when the oxidation temperature reached 1200 °C, Cr2O3 in the inner oxide layer was partially ruptured. In an atmosphere with a water vapor content of 50%, Cr2O3 at the interface reacted with H2O to generate volatile CrO2(OH)2, resulting in a large consumption of Cr at the interface. At the same time, a large number of voids and microcracks appeared in the iron oxide layer, which accelerated the entry of water molecules into the substrate, as well as the oxidation of Fe–10Cr steel, and caused the iron oxide scales to fall off. Due to the volatilization of Cr2O3 and the conversion from internal oxidation to external oxidation, the internal oxidation zone (IOZ) of Fe–10Cr steel under water vapor atmosphere decreased or even disappeared.

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Finite element (FE) simulation is adopted as a fundamental tool to evaluate the mechanical reliability of packaging structures for electronic devices. Nevertheless, the determination of mechanical properties of sintered silver nanoparticles (AgNP) remains challenging as the traditional tensile test is difficult to be performed at a limited size. In the current study, spherical nanoindentation is utilized to measure the applied load-penetration depth responses of sintered AgNP reinforced by SiC microparticles at various weight ratios (0.0, 0.5, 1.0 and 1.5 wt.%). To describe the elasto-plastic behavior of this heterogeneous material, FE analysis is performed to simulate the indentation behavior and determine the parameters in the modified power-law model by fitting the average applied load-penetration depth responses. To overcome the uniqueness problem, the Young’s modulus is directly determined by continuous stiffness measurement technique and the proposed constitutive model can provide a reasonably accurate mechanical estimation of sintered AgNP. The effect of SiC content on sintered AgNP is discussed by correlating the morphology observed by scanning electron microscope (SEM) and the constitutive parameters obtained from the FE simulations.

The atmospheric corrosion behavior of a hot-rolled strip with four types (I–IV) of oxide scale was investigated using the accelerated wet–dry cycle corrosion test. Corrosion resistance and porosity of oxide scale were studied by potentiometric polarization measurements. Characterization of samples after 80 cycles of the wet–dry corrosion test showed that scale comprised wüstite and magnetite had strongest corrosion resistance. Oxide scale composed of inner magnetite/iron (>70%) and an outer magnetite layer had the weakest corrosion resistance. The corrosion kinetics (weight gain) of each type of oxide scale followed an initial linear and then parabolic (at middle to late corrosion) relationship. This could be predicted by a simple kinetic model which showed good agreement with the experimental results. Analysis of the potentiometric polarization curves, obtained from oxide coated steel electrodes, revealed that the type I oxide scale had the highest porosity, and the corrosion mechanism resulted from the joint effects of electrochemical behavior and the porosity of the oxide scale. In the initial stage of corrosion, the corrosion product nucleated and an outer rust layer formed. As the thickness of outer rust layer increased, the corrosion product developed on the scale defects. An inner rust layer then formed in the localized pits as crack growth of the scale. This attacked the scale and expanded into the substrate during the later stage of corrosion. At this stage, the protective effect of the oxide scale was lost.

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