Advanced Materials Research Vol. 531

Abstract: This paper mainly introduced the causations of deep-sea submersible (DS) surface material damage and some methods of research on corrosion and fatigue. It is suggested that investigating the mechanisms and effects of corrosion and fatigue damage on DS steel structure and coating, and the mapping relation for the origin and accumulation of cross scale damage should be established. In addition, organic coating, metallic coating, steel matrix and their interaction could be detected and analysed using the methods of SEM, XRD, TEM, EIS, EN, CV, Kelvin probe and so on. At last, mathematical model of service life for the steel structure and coating should be established for the quantification study

Abstract: A three-dimensional analytical calculation model of GMAW heat transfer was established, and the weld temperature field of JG590 with different welding parameters was analyzed by numerical simulation. The phase transformation in CGHAZ of JG590 steel was studied by physical simulation. SH-CCT diagrams, the effects of weld thermal cycle on microstructure, impact toughness and hardness were obtained. The results show that the critical cooling time of bainite, ferrite and pearlite appeared are respectively 8s, 110s and 150s. The critical cooling time that martensite takes to finish transferring is 35s. When t8/5 is below 10s, CGHAZ has a better toughness and when t8/5 is beyond 15s, there is a wide range decrease on the toughness. In this paper prediction of CGHAZ microstructure and property of JG590 steel was realized based on the analytical calculation model of GMAW heat transfer and physical simulated results mentioned above

Abstract: The mode-locking phenomenon of a passively Q-switched Raman laser with a ceramic Nd:YAG as the gain medium, an SrWO4 crystal as the Raman medium and a Cr4+:YAG crystal as the saturable absorber had been investigated. From the investigation, the author found that the study on Nd:YAG ceramic material will be helpful for the Laser Technology and Application.

Abstract: A diode-pumped actively Q-switched eye-safe intracavity Raman laser with ceramic Nd:YAG gain medium and BaWO4 Raman crystal is demonstrated for the first time. The highest average output power of 0.76 W is obtained at a pulse repetition frequency of 30 kHz and a pump power of 11.3 W. The corresponding conversion efficiency from the diode pump power to Raman output power is 6.7%. The highest pulse energy of 38.1 µJ is obtained at a pulse repetition frequency of 15 kHz and a pump power of 7.8 W, and the corresponding peak power is 4.9 kW.

Abstract: We consider a bulk silicon crystal as a Mid-IR Raman amplifier and study its Raman amplification. A Raman amplifier is established when an intense pump laser pulse and a Raman laser pulse pass through one silicon simultaneously, with good spatial and temporal overlap. Considering the situation of pumping wavelength at 2.94 μm achievable by using an Er:YAG laser and Raman laser wavelength at 3.47 μm with the 521 cm-1 Raman shift, the properties of the output amplified Raman laser are investigated by numerically solving the coupled transfer equations.

Abstract: Spraying wire was widely used in remanufacturing work piece for worn failure. With the demand of high abrasion resistant wire, new type alloy was developed. The solidification structures of the new high abrasion resistant alloy (HARA) containing Mn, Cr, Si, C and the structure was studied after tension by scanning electron microscopy (SEM). The phase evolution was analyzed by X-ray diffraction and Rockwell hardness evaluated on the hardness testing. The abrasion behavior of HARA alloy used in the liner of wet-grinding machine in metallurgical industry is investigated under impacted energy of 0.5-3 J in acid-ironstone slurry; the test was carried out by a modified MLD-10 tester. The result show that the solidification structures of HARA alloy consist of austenitic Fe and the hardness neared to HRC60. Under the high energy, the wear resistance of HARA alloy is three times more than Mn13. Therefore, the new material has better abrasive wear resistance and lower environmental impact

Abstract: This paper reports on a new clad technology that is protective coating cladding. The method is that the Ni60 alloy was prepared on 0.45%C steel and high temperature powder paste brushed on the outside. Then the sample after being dried was heated in the high temperature resistance electric furnace. The Ni60 alloy powder on the substrate steel was melted at the appropriate temperature, and a uniform, adherent and non-dilution clad coating was obtained after optimizing the cladding parameters. The coating microstructures, compositions and microhardness were analyzed by OPM, XRD, EPMA, and microhardness testing. The experimental results show that the protective coating cladding is an efficient and economic method in cladding technologies

Abstract: Highly photoactive ZnO thin films have been prepared by sol-gel process on glass substrates. The influence of annealing temperatures on degradation rates has been studied, the inactivation and regeneration of photocatalytic properties of ZnO thin films have also been further discussed. The results show that the best annealing temperature is 300oC, surface active sites of new prepared thin films will be passive after the first photocatalytic reactions, photocatalytic performance successively reduced. H2O2 processed films can make the photocatalytic activity basically return to the level of new prepared films, can satisfy the need of repetitive use.

Abstract: TiO₂ thin films with good performance have been prepared by R.F. magnetron sputtering method on glass substrates. Surface morphology and UV absorption spectrum have been studied by XRD, SEM and UV-Vis scanning spectrophotometer. The influence of annealing temperature has also been discussed. The results show that, the films without annealing process present amorphous structure, the defects density of interior fiber is high and the structure is loose. With the rise of annealing temperature, the grain size increases, porosity decreases, and compactness is enhanced, at the same time, the film turns from anatase phase to rutile phase, quantum size effect is significant, surface energy reduces and absorb edge has red shift.

Abstract: A simple theoretical model to predict the size control of carbon-encapsulated metal nanoparticles is developed using heat transfer and carbon diffusion theories. Taking carbon-encapsulated nickel nanoparticles as an example, the minimum size of carbon-encapsulated structure that can be formed as a function of the ambient temperature is calculated and the effect of activation energies for carbon diffusion on the size of carbon-encapsulated nickel nanoparticles is examined. The theoretical results are in good agreement with the experiment, suggesting that our model can be used to guide the size-controlled synthesis of carbon-encapsulated metal nanoparticles.