Advanced Materials Research Vol. 549

Abstract: The effect of Al content on the anti-erosion and anti-oxidation performance of high Al steels at 1373K is studied in this paper. By 168-hour heat treating at 1373 K and at oxidation atmosphere, These results show that for comparing non-Al steel and low-Al (w[Al]=1.14%) steel sample there are a more obvious and easily-dropping oxidation layer in surface in 24 h , the average oxidation rate is up to 0.406 mg/(cm2.h), but for high Al steel, there is a thinner gray oxidation layer in surface and a more fast oxidation rate for w[Al]<5% sample , and there is a thin, close and yellow gloss film and the average oxidation rate is only 0.016 mg/(cm2.h) for w[Al]=8.46% sample. The average erosion rate is 0.096 mg/cm2.h in initial 24 h and thereafter the erosion is very slow. But there is a higher erosion rate and the average erosion rate is 0.594 mg/(cm2.h) in 6 % HCl solution for high Al steel sample and comparing non-Al steel. Accordingly high Al steel possesses a good performance of high temperature anti-oxidation and anti-erosion in NaCl solution.

Abstract: The electrical performance of single cell of anode-supported planar solid oxide fuel cell (SOFC) received much concern. In this paper, measurement principle, design method and experimental processes of the electrical performance test device for SOFC single cell were introduced. The fluid system of the device consisted of flowmeters, valves, tubes, furnace, etc. The measurement system of the device consisted of digital direct current voltage meter, chromatography work station, and industrial computer, etc. The operator could aquire the test data by the electronic load and work station operation software in the industrial computer.

Abstract: The cementitious system containing FBC ash is usually associated with volume expansion when cured in the normal temperature, due to its relatively high SO₃ content. This paper presents a further study on the effect of different curing conditions on the flexural and compressive strength of FBC ash-Portland cement clinker mortar and linear expansion ratio of FBC ash-Portland cement clinker paste. The results show that autoclaved curing is more beneficial to increasing mortar strength in early days than standard curing, but with slow strength development in later period. Moreover, autoclaved curing could decrease the expansion of FBC ash greatly. This study confirms that the expansion of FBC ash can be significantly inhibited by autoclaved curing.

Abstract: The study is carried out combing with the production practice in Danjiangkou Hongyuan SiC limited. Si3N4 and SiC were prepared successfully from SiC and Silicon power in nitrogen atmosphere at 1425°C and 1375°C sintering temperature by the serial of techniques, such as ingredients, mixing, molding and drying, respectively. In the actual production, silicon powder content and sintering temperature will directly influence the products of the bending strength and thermal shock resistance. By measuring bending strength, porosities, bulk density, XRD and FESEM, the bending strength and thermal shock resistance of samples were studied mainly by changing sintering temperature and silicon powder content. The results show that bending strength and thermal shock resistance of sample which was added 16% Si powder is best. And bending strength and thermal shock resistance of sample of 1425°C sintering temperature is higher than that of 1375°C sintering temperature.

Abstract: The effect of microconstituents on the corrosion and electrochemical behavior of Mg-Zn-Zr-Nd ZM6 magnesium alloy prepared by die-casting and ingot casting route has been investigated in 3.5Wt%NaCl solution.The experimental techniques used include long term immersion test and potentiodynamic polarization experiments. Surface examination and analytical studies were carried out using optical(OM) and scanning electron microscopy(SEM) and X-ray diffraction(XRD). Die-cast ZM6 magnesium alloy with smaller grain size offered marginally lower corrosion rate. In die-cast and ingot, corrosion attack took place preferentially on α-Mg phase. XRD patterns of non-corroded surface revealed α-Mg and Mg12Nd phases. The corrosion products for ZM6 ingot consisted of Mg(OH)2 together with α-Mg and Mg12Nd phases. The corrosion resistance of ingot is higher than diecast sample.

Abstract: A novel composite, wood-polymer composite, was fabricated by polymerization of functional monomers within wood porous structure. The wood was a fast-growing plant wood, Micheliamacclurel wood, which was rarely reported in previous studies, and two functional monomers, glycidyl methacrylate and ethylene glycol dimethacrylate, were novelly employed. The monomers, added with a few Azo-bis-isobutryonitrile as initiator, and maleic anhydride as catalyst, were first impregnated into wood pores under vacuum/pressure conditions, and then in-situ polymerized into polymers through a catalyst-thermal treatment. After the processes, wood-polymer composite was resulted. SEM and FTIR analysis for the composite indicated that the monomers polymerized into solid polymer, which fully filled up wood pores, and the resulted polymer grafted onto wood matrix, resulting in good interface combination between polymer and wood matrix. Such composite with satisfactory interface can be potentially applied as structural material in construction field.

Abstract: In this paper, a novel carbon/bentonite composite was prepared using sucrose as carbon source and bentonite as raw material. The characterization results shown that plenty of carbon particles distribute on the surface of the composite, and an abundant of functional groups, such as SO₃H, carboxylic and hydroxyl groups, were successfully introduced onto the surface of the prepared composite. The adsorption capacity of the prepared composite for typical heavy metal ions and methylene blue deys also was investigated and compared with activated carbon and bentonite, the results show that the composite shows excellent adsorprion performance for heavy metal ions, and the adsorption capacity for Cu²⁺ and Ni2+ increase by 136% and 591% than natural bentonite, respect^{Superscript text}ively. The prepared composite with excellent adsorption performance could be used as a low-cost alternative to activated carbon for the treatment of heavy metal ions polluted wastewater.

Abstract: Nowadays, the piezoelectric materials are widely used in many areas. The piezoelectric materials will undergo an electrical degradation process during working causes the piezoelectricity and resistance of the piezoelectric materials degrade. The existence of the electrical degradation phenomenon severely limits the applications of the piezoelectric products. During the electrical degradation process, electrical breakdown often occurs and this electrical breakdown has been proposed [1, 2] induces the resistance decrease and local phase changing. In this paper, the electrical breakdown induced current transients are detailed investigated. Three types of current transients are presented and the time durations of current transients are suggested not constant and corresponding to the time duration of the local burn-out process, which is caused by the heat released from the electrical breakdown process.

Abstract: The effect of overheating treatment on the crystal orientation of the Tb0.27Dy0.73Fe1.9 alloy was investigated. The results indicated that different overheating treatment conditions could obtain different crystal orientation. It means that overheating treatment affects the process of Tb0.27Dy0.73Fe1.9 solidification. The conjectural discussions of these results are also presented.

Abstract: In this paper, cement is used to stabilize reclaimed asphalt pavement materials (RAP) and original aggregate with the same gradation. Compressive strength, freezing-thawing resistance and fatigue life of cement recycled RAP mixture (CRAPM) and cement stabilize original aggregate mixture (CSAM) are evaluated. Test results indicate the compressive adhesive strength of cement-RAP is lower than cement-original aggregate. At the same gradation, RAP has negative effect on the freezing-thawing resistance of CRAPM, and can increase the fatigue life sensitive to stress level. Therefore, for using 100% RAP, it is necessary to increase the cement content to properly improve the strength and durability of RAPM in order to satisfy the specification of cement stabilized base materials in china.