Advanced Materials Research Vol. 716

Abstract: The paper aims to compare the hardness and corrosion behavior of carburized and borided Iron-Based Austenitic Steels (IBAS) which were treated at the same temperature and time under vacuum conditions. Boronizing was performed by pack cementation in Ekabor II powder and carburization was carried out by annealing under vacuum conditions using glucose as a carburizing medium. Both boronizing and carburizing procedures were performed at 900°C for 3h. The characterization of the treated materials was assessed by using X-Ray Diffraction (XRD) analysis, optical observations, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS) measurements and micro-Vickers hardness tests. Potentiodynamic polarization curves were also used to determine electrochemical characteristics such as the corrosion potential (mV), corrosion current density (μΑ/cm²) and corrosion rate (μm/year). The results showed that borided samples with a single phase layer, exclusively Fe₂B strongly toothed, exhibited better hardness behavior towards carburized samples but lesser corrosion resistance instead.

Abstract: The work deals with attribute ratings of chosen hard thin coatings on substratum C60E. The work contains their tribological properties and based on critics review, hard thin coating applicable to material used for the manufacture of gear wheels of type C60E is designed aiming to increase surface carrying capacity of gear wheels made from C60E material.

Abstract: In this study, a novel type of corona-resistance polyimide/spherical SiO₂ hybrid films based on 3,3,4,4-biphenyltetracarboxylic dianhydride (s-BPDA) and 1,3-bis (4-aminophenoxy) benzene (1,3,4-APB) was synthesized by incorporation with different loadings of spherical SiO₂ particles via in-situ polymerization. All the films were prepared by a so called two-step procedure and finally cured at 300°C. TEM images showed the SiO₂ particles were homogeneously dispersed in the polyimide matrix by means of ultrasonic method and the addition of coupling agent. Experimental results indicated that the hybrid films with much higher inorganic content exhibited good thermal and mechanical properties as well as low water absorption. Especially, the dielectric strength and electric aging time of the hybrid films were obviously enhanced, which was attributed to the highly dispersed spherical SiO₂. The morphology changes of the film surface caused by the electric field were also studied by scanning electron microscope (SEM).

Abstract: In this work, fifteen polymers have been studied to test their potential as donors for polymer solar cells by density functional theory. Those polymers contained five homopolymers based on pyridazine, [1,2,thiadiazolo [3,4-pyridazine, [1,2,oxadiazole [3,4-pyridazine, isothiazolo [3,4-pyridazine and isoxazolo [3,4-pyridazine, and ten copolymers composed of the above compounds and thiophene incorporated with 1:1 and 1:2 ratios. The fifteen polymers have been examined in terms of the abilities of absorbing sunlight, stabilities in the environment, and photovoltaic properties. The results suggest that the copolymes DTHP, DTHTP, DTHOP, DTHITP, and DTHIXP are good material candidates of polymer donor for polymer solar cells.

Abstract: This paper aimed at that titanium alloy grinding is easy to appear surface burn, crack, then carry out the titanium alloy TC4 abrasive belt grinding experiment, focus on the effect of grinding parameters on the titanium alloy TC4 surface integrity (surface roughness, microstructure and surface residual stress) . The results of the study show that the use of zircon corundum belt and cutting speed velocity range from 18 to 26 meter per second, the surface integrity of titanium alloy TC4 is better.

Abstract: According to the KF-CsF-AlF₃ ternary phase diagram, 25 samples (named group A) near the region around the E₄ and E₅ (ternary eutectics points), and 22 samples (named group B) near another region around the e₅ (binary eutectic point) and m₂ (ternary eutectics point) were prepared by the wet synthesis method. The melting curves of these samples were measured by differential scanning calorimetry (DSC). Based on the DSC data, the effects of the fluxs compositions on the melting characteristics were analyzed and summarized. The results indicated that the lowest solidus of group A samples was about 480°C, meanwhile, their liquidus was about 520~530°C, and the melting range was approximately 40°C. Furthermore, when the content of CsF was lower than 18mol%, the solidus of group A samples apparently rose to about 510°C, but the liquidus did not change greatly. The lowest solidus of group B samples was about 420°C, meanwhile, their liquidus was below 450°C, and the melting range was approximately 20~30°C. So, with this profile of melting characteristics, some of the samples of group B flux would be good substrates for aluminum alloy middle temperature brazing, with good prospects for application.

Abstract: Hydrophilic Fe₃O₄ nanoparticles (NPs) were prepared by reverse micro-emulsion, in which OP-10 as surfactant, n-butanol as co-surfactant, cyclohexane as oil phase, FeSO₄·7H₂O and FeCl₃·6H₂O aqueous solution as water phase. The as-prepared Fe₃O₄ NPs were functionalized by using of silane coupling agent 3-glycidoxypropyltrimethoxysilane (KH-570) to promote adhesion at the inorganic and organic interface (s). From the experimental results, it was found that the modified Fe₃O₄ NPs were of inverse spinel crystalline structure, and both Fe₃O₄ and modified Fe₃O₄ NPs exhibited super-paramagnetic behavior due to it near zero coercivity value.

Abstract: This study utilized electroless nickel (EN) and cathodic arc evaporation (CAE) technologies, with the known advantage of low processing temperature, to treat the austempered ductile iron (ADI) substrates. The eligibility of applying the EN and CAE-TiN duplex coatings on ADI, along with the coating properties, such as structure, roughness, adhesion, and surface hardness were evaluated and analyzed. Moreover, erosion tests were performed to further understand the effect of both the coatings on the erosive behavior of ADI. The results showed that the unique microstructure of ADI did not deteriorate after EN and CAE treatments. By the way of TiN/EN duplex coatings, surface hardness of ADI largely increased from 398 to 2243 HV_5g. Moreover, the duplex coated ADI had a noticeable performance on erosion protection under a specific erosive environment with Al₂O₃ particles.

Abstract: Taiwan Shi-Men Reservoir sediments were used to investigate the expansion mechanism of lightweight aggregate under high temperature sintering processes. The fundamental properties of reservoir sediment and the effects of temperature and time during the sintering process are obtained. Experimental results show that the Shi-Men Reservoir sediment is a very good raw material to be the production of lightweight aggregate. The controlling of the temperature and time during the sintering processes has significant effect on the particle density and absorption of the lightweight aggregate. The feasibility of the major expanded material in reservoir sediments may be due to the decomposition of the carbonate, the organic matter and crystallization water.

Abstract: 15CrMo steel is widely used in engineering. In order to evaluate the fatigue performance of 15CrMo, axial loading for 15CrMo specimen has applied by high frequency fatigue testing machine under stress ratio R=0.1 at room temperature, the linear S-N relationship has obtained by grouping fatigue test, the fatigue limit has obtained and compared by two different fatigue limit analysis method. The consequences of this test could provide a theoretical support for the use of 15CrMo in engineering and the research of fatigue limit theory.