Materials Science Forum Vols. 475-479

Abstract: Four Sol-Gel films were developed by dip-coating electroless nickel-plated samples in different Sols, followed by heat treatment. The effects of the coating times and heat treatment temperature on the corrosion, oxidation resistance and wearing quality of the modified coating were examined. Results show that, after six coating, Sol-Gel films obtained can provide good corrosion and oxidation resistance, and their anti-corrosion quality remains high even after being oxidized at 500 °C for 60 hours. Addition of inorganic molybdenum salt or chromate into the Ti Sol also makes the wearing quality of the Sol-Gel film better.

Abstract: Ferromagnetic layer and dielectric layer of nanometer thickness were deposited alternatively on quartz glass plates to compose nanometer multiple-layers with microwave absorbing function by electrostatic self-assembly. The thickness of a double-layer composed of a ferromagnetic layer and a dielectric layer is 6~8 nm measured by UV-VS spectrophotometer. The nanometer multi-layer with total thickness of 100~200 nm exhibits obvious microwave-absorbing effect in the wave range of 8~18 GHz and the maximum attenuation reaches -16.85 dB. The wave-absorbing mechanism of nanometer multiple-layers was discussed based on the quantum theory

Abstract: The irradiation of a Nd-YAG pulsed laser on the CeO2 target in water was investigated. The CeO2 nanoparticles sized of 20-80 nm were formed in water, while the power density was larger than 32 kJ/cm2. The nanocrystalline films with grain sized of 50-150 nm were formed on the target with the energy density of 20 kJ/cm2-25 kJ/cm2. Finally, the amorphous films were formed with the energy density of 6 kJ/cm2-15 kJ/cm2. The formation mechanisms of the nanoparticles and the films were discussed.

Abstract: The elastic modulus in the region of a grain boundary for a commercial 2.6Ni-Cr-Mo-V steel has been obtained from Misra’s observation of grain-boundary segregation of sulphur under a tensile stress. The result is in agreement with the theoretical estimation.

Abstract: The influence of the content of rare-earth La on the microstructure and corrosion-resistance of hot-dipped aluminum was studied in this paper .The results show that ,under the same technology conditions, the thickness of hot-dipped aluminizing layer by adding the appropriate content of rare-earth La is about 2～3 times as much as that without rare-earth La, and the microstructure of hot-dipped aluminizing layer has also greatly changed ,and a great deal of phase Fe3Al was precipitated along the boundary of a phase. The corrosion resistance of the hot-dipped layer with rare-earth La is greatly increased.

Abstract: Microstructure in anchoring site of Pt/Ti explosive clad Plate was observed, tested and analyzed by analytical and high resolution transmission electron microscope, X-ray diffractometer, scanning electron microscope and energy-dispersive spectrometer. An intermittent micro-crystal layer was observed in anchoring area, with thickness of 2 um. The inner crystal size was from some nanometer. to hundreds of nanometer. Some crystal had defects in it, such as staggered layer. The layer was composed of metal compound, like PtTi，Pt5Ti3，Pt3Ti，Ti3Pt and etc. The direct Pt—Ti anchoring area, hexagonal Ti variation-orthorhombic crystal system, α″-Ti metastable martensite phase and bicrystals with partial deformation were also observed. The research of microstructure in anchoring area revealed the nature of explosive compound in metallurgical anchoring.

Abstract: Interfacial atomic and electronic structures of Cu/Al2O3(0001) and Cu/Al2O3(11 ＿ ,20) prepared by a pulsed-laser deposition technique were characterized by high-resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS). It was found that both systems have O-terminated interfaces, irrespective of different substrate orientations. This indicates that Cu-O interactions across the interface play an important role for the Cu/Al2O3 systems.

Abstract: The effect of grain boundary character distribution (GBCD) on intergranular stress corrosion cracking (IGSCC) in austenitic stainless steels in high temperature water was verified experimentally. GBCD control using the strain annealing method increased the fraction of low- S coincidence site lattice (CSL) boundaries and the segmentalized network of random grain boundaries in austenitic stainless steels. The fractions of low- S CSL boundaries of GBCD controlled steels were 75–85%, while those of uncontrolled steels were 60–70%. Creviced bent beam tests were conducted at 561 K in pure water containing 8 ppm dissolved oxygen for stress corrosion cracking (SCC) evaluation. The tests revealed that GBCD control suppressed IGSCC initiation or propagation and that cracks were predominantly propagated along random grain boundaries. It is considered that induced lower- S CSL boundaries result in high resistance to IGSCC.

Abstract: Our recent studies on current-voltage characteristic and grain boundary structure in ZnO bicrystals are reviewed in this paper. All types of undoped ZnO bicrystals showed Ohmic characteristics. This indicates that nonlinear current-voltage characteristic cannot be generated solely by the atomic disarrangement in undoped ZnO. On the other hand, co-doped ZnO bicrystals showed nonlinear current-voltage characteristics, which depended on the types of grain boundary. It is considered that the nonlinearity depends on the Pr concentrations at the respective grain boundaries.

Abstract: The stability of the plane matching boundary is discussed in connection with the deviation from the exact plane matching orientation and the atomic density per unit area of the lattice plane. The statistic calculation of the plane matching boundary distribution in the different types and sharpness of texture revealed that the coverage by plane matching boundaries (>80%) is much higher than the coverage by CSL boundaries (~60%). The sharpness of texture strongly affects the distribution of plane matching boundaries.