Papers by Author: Y. Zhang

Abstract: Formation of a protective scale such as chromia or alumina is a prerequisite for an excellent oxidation performance of high-temperature materials. Based on this principle, a novel concept of designing chromia- or alumina-forming nanocomposites by means of nanocomposite electrodeposition of Ni with Cr or/and Al nanoparticles were proposed. A brief review on the high temperature oxidation performance of such novel electrodeposited nanocomposites like Ni-Cr, Ni-Al and Ni-Cr-Al is presented.

Abstract: Bi3.5Nd0.5Ti3O12 (BNT) ferroelectrics modified with different concentrations of Nb are prepared by a hot-pressing method. XRD diffraction shows that all samples have only a layeredstructured pervoskite phase. Raman spectra confirm that the crystal symmetry change locally when increasing Nb concentration. It is found that the introduction of a suitable amount of Nb can enhance the remnant polarization of BNT. The temperature dependence of dielectric constant is also investigated in BNT ceramics. All samples have high Curie temperature above 530°C.

Abstract: A series of [FePt(4min)/Fe(tFe)]10 multilayers were prepared by RF magnetron sputtering and post annealing. The structures, morphology, composition, and magnetic properties were measured by XRD, SEM, EDX and VSM. X-ray diffraction showed that lattice constants of FePt phase changed with Fe layer thickness and annealing temperature. Both a and c are smaller than the standard values and a decreases as the deposition time of Fe layer increases. The grain sizes of samples annealed at 500°C increase slightly, while those at 600°C increase sharply as Fe layer decreases. The coercivities decrease with the deposition time of Fe layer, and the energy product (BH)max reaches a maximum at Fe layer deposition time of 3 minutes.