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L.j. Yang - One of the best experts on this subject based on the ideXlab platform.
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The effect of solidification time in squeeze casting of aluminium and Zinc Alloys
Journal of Materials Processing Technology, 2007Co-Authors: L.j. YangAbstract:Abstract Both gravity casting and squeeze casting were carried out previously on an aluminium alloy (LM6) and a Zinc alloy (ZA3) with different casting temperatures. Tensile, impact and density measurement were conducted. It was found that generally, samples taken from the bottom of the squeeze casting mould gave higher tensile strength, higher impact strength and higher density values. This study was carried out to determine the effect of solidification time on the mechanical properties of the castings. Two analytical methods were used: a steady-state heat flow model and Garcia's virtual model. It was found that similar results were obtained with both analytical methods. Casting samples taken from the lower part of the squeeze casting mould were found to have a significantly shorter solidification time. For both types of Alloys, it was found that generally the shorter the solidification time of the casting, the higher is its density, impact energy, yield strength and ultimate tensile strength (UTS). This study had therefore contributed to a better understanding of the mechanical properties obtained previously from different casting processes.
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the effect of casting temperature on the properties of squeeze cast aluminium and Zinc Alloys
Journal of Materials Processing Technology, 2003Co-Authors: L.j. YangAbstract:Abstract Gravity casting and squeeze casting were carried out on an aluminium alloy with 13.5% silicon and a Zinc alloy with 4.6% aluminium with different temperatures, 660, 690 and 720 °C for the former and 440, 460 and 480 °C for the latter. A top-loading crucible furnace was used to melt the Alloys. The die-preheat temperatures used were 200–220 °C for the aluminium alloy and 150–165 °C for the Zinc alloy. A K-type thermocouples with digital indicator were used to measure the die surface temperature and the molten metal temperature; while a 25 t hydraulic press with a die-set containing a steel mould was used to perform the squeeze casting with a pressure of 62 MPa. Tensile, impact and density tests were carried out on the specimens. It was found that casting temperature had an effect on the mechanical properties of both gravity cast and squeeze cast aluminium and Zinc Alloys. The best temperatures to gravity cast the aluminium alloy and the Zinc alloy were 720 and 460 °C, respectively. For the squeeze casting of the aluminium alloy, the best temperature to use was either 690 or 660 °C; the former would give a better property at the top of the casting while the latter, at the bottom of the casting. However, for the squeeze casting of the Zinc alloy, the best temperature was again 460 °C.
Yufeng Zheng - One of the best experts on this subject based on the ideXlab platform.
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in vitro and in vivo studies to evaluate the feasibility of zn 0 1li and zn 0 8mg application in the uterine cavity microenvironment compared to pure Zinc
Acta Biomaterialia, 2021Co-Authors: Guo Bao, Yufeng Zheng, Qianqian Fan, Kun Wang, Mingming Sun, Zechuan Zhang, Hui Guo, Hongtao YangAbstract:Abstract Significant advances have been achieved in the research evaluating Zn and its Alloys as degradable metallic biomaterials mainly for application in bone and blood vessels. In the present study, the degradation behaviors of Zn-0.1Li and Zn-0.8Mg Alloys in simulated uterine fluid (SUF) were systematically investigated for 300 days. In vitro viability assays were conducted in different uterine cells (HUSMCs, HEECs, and HESCs), and histological examination after the in vivo implantation into the uterine cavity was performed using pure Zn as control. The immersion test results indicated that both Zn-0.1Li and Zn-0.8Mg Alloys exhibited better corrosion resistance than pure Zn, with Zn3(PO4)2⋅4H2O and CaZn2(PO4)2⋅2H2O being the main corrosion products detected in the SUF in addition to ZnO. The cell cytotoxicity assays revealed that Zn-0.1Li and Zn-0.8Mg exhibited better cytocompatibility than Zn. Moreover, the in vivo experiments demonstrated that the Zn-0.1Li and Zn-0.8Mg Alloys induced less inflammation in the uterine tissue than pure Zn, with CaCO3 and Zn(HPO4)⋅3H2O being the major biocorrosion products in addition to ZnO. According to these results, Zinc Alloys appear to be suitable potential candidate materials for future intrauterine biomedical devices.
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microstructure mechanical properties and creep behaviour of extruded zn xli x 0 1 0 3 and 0 4 Alloys for biodegradable vascular stent applications
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2020Co-Authors: Chengcheng Wu, Guannan Li, Yufeng ZhengAbstract:Abstract Zn–Li Alloys have been shown to be promising for biodegradable vascular stent applications due to their favourable biocompatibility and superior strength. This work presents a thorough evaluation of the microstructure, room temperature mechanical properties and human body temperature creep behaviour of hot-extruded Zn-xLi (x = 0.1, 0.3 and 0.4) Alloys. All Alloys show typical basal texture after the extrusion but the recrystallized grains are much finer with increasing Li content. Consequently, not only the room temperature yield and tensile strengths but also the elongation to fracture is significantly increased with increasing Li content. However, increasing Li content has an adverse effect on the creep resistance at human body temperature. Moreover, there is a transition in the operative creep mechanism from dislocation creep in the Zn-0.1Li alloy to grain boundary sliding in the Zn-0.3Li and Zn-0.4Li Alloys. The observed mechanical behaviour in these Alloys can be well related to the grain size effect, i.e. strengthening to softening by grain boundaries with decreasing strain rate. This work suggests that grain size of biodegradable Zinc Alloys should be optimized in order to achieve a balance between room temperature mechanical properties and human body temperature creep resistance.
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Creep properties of biodegradable Zn-0.1Li alloy at human body temperature: implications for its durability as stents
'Informa UK Limited', 2019Co-Authors: Suming Zhu, Yufeng Zheng, Jian-feng NieAbstract:This is the first report on creep properties of biodegradable Zinc Alloys at human body temperature. The extruded Zn-0.1Li (wt.%) alloy exhibits appreciable creep deformation at 37°C under stresses ranging 80–230 MPa within 500 h. The creep deformation at low stresses (80–155 MPa, about 0.4–0.8 yield strength) is characterized by a stress exponent of about 4 and an activation energy close to that for self-diffusion of Zinc, which are typical of dislocation creep. The implications of creep at human body temperature for durability of biodegradable Zinc Alloys as stents are discussed
Tadeja Kosec - One of the best experts on this subject based on the ideXlab platform.
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Benzotriazole as an inhibitor of brass corrosion in chloride solution
Applied Surface Science, 2016Co-Authors: Ingrid Milosev, Boris Pihlar, Tadeja KosecAbstract:The current research explores the formation of protective layers on copper, Zinc and copper-Zinc (Cu-10Zn and Cu-40Zn) Alloys in chloride solution containing benzotriazole (BTAH), by use of electrochemical techniques, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Electrochemical reactions and surface products formed at the open circuit potential and as a function of the potential range are discussed. The addition of benzotriazole to aerated, near neutral 0.5 M NaCl solution affects the dissolution of copper, Zinc, Cu-10Zn and Cu-40Zn Alloys. The research also compares the inhibition efficiency and Gibbs adsorption energies of the investigated process. Benzotriazole, generally known as an inhibitor of copper corrosion is also shown to be an efficient inhibitor for copper-Zinc Alloys and Zinc metal. The surface layer formed on Alloys in BTAH-inhibited solution comprised both oxide and polymer components, namely Cu2O and ZnO oxides, and Cu(I)-BTA and Zn(II)-BTA polymers. The formation of this mixed copper-Zinc oxide polymer surface film provides an effective barrier against corrosion of both metal components in chloride solution. © 2007 Elsevier B.V. All rights reserved.
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impedance and xps study of benzotriazole films formed on copper copper Zinc Alloys and Zinc in chloride solution
Corrosion Science, 2008Co-Authors: Tadeja Kosec, Darja Kek Merl, Ingrid MilosevAbstract:The formation of protective layers on copper, Zinc and copper–Zinc (Cu–10Zn and Cu–40Zn) Alloys at open circuit potential in aerated, near neutral 0.5 M NaCl solution containing benzotriazole was studied using electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). Benzotriazole (BTAH), generally known as an inhibitor of copper corrosion, also proved to be an efficient inhibitor for copper–Zinc Alloys and Zinc metal. The surface layers formed on Alloys in BTAH-inhibited solution comprised both polymer and oxide components, namely Cu(I)BTA and Zn(II)BTA polymers and Cu2O and ZnO oxides, as proved by the in-depth profiling of the layers formed. A tentative structural model describing the improved corrosion resistance of Cu, Cu–xZn Alloys and Zn in BTAH containing chloride solution is proposed.
Ingrid Milosev - One of the best experts on this subject based on the ideXlab platform.
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Benzotriazole as an inhibitor of brass corrosion in chloride solution
Applied Surface Science, 2016Co-Authors: Ingrid Milosev, Boris Pihlar, Tadeja KosecAbstract:The current research explores the formation of protective layers on copper, Zinc and copper-Zinc (Cu-10Zn and Cu-40Zn) Alloys in chloride solution containing benzotriazole (BTAH), by use of electrochemical techniques, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Electrochemical reactions and surface products formed at the open circuit potential and as a function of the potential range are discussed. The addition of benzotriazole to aerated, near neutral 0.5 M NaCl solution affects the dissolution of copper, Zinc, Cu-10Zn and Cu-40Zn Alloys. The research also compares the inhibition efficiency and Gibbs adsorption energies of the investigated process. Benzotriazole, generally known as an inhibitor of copper corrosion is also shown to be an efficient inhibitor for copper-Zinc Alloys and Zinc metal. The surface layer formed on Alloys in BTAH-inhibited solution comprised both oxide and polymer components, namely Cu2O and ZnO oxides, and Cu(I)-BTA and Zn(II)-BTA polymers. The formation of this mixed copper-Zinc oxide polymer surface film provides an effective barrier against corrosion of both metal components in chloride solution. © 2007 Elsevier B.V. All rights reserved.
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impedance and xps study of benzotriazole films formed on copper copper Zinc Alloys and Zinc in chloride solution
Corrosion Science, 2008Co-Authors: Tadeja Kosec, Darja Kek Merl, Ingrid MilosevAbstract:The formation of protective layers on copper, Zinc and copper–Zinc (Cu–10Zn and Cu–40Zn) Alloys at open circuit potential in aerated, near neutral 0.5 M NaCl solution containing benzotriazole was studied using electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). Benzotriazole (BTAH), generally known as an inhibitor of copper corrosion, also proved to be an efficient inhibitor for copper–Zinc Alloys and Zinc metal. The surface layers formed on Alloys in BTAH-inhibited solution comprised both polymer and oxide components, namely Cu(I)BTA and Zn(II)BTA polymers and Cu2O and ZnO oxides, as proved by the in-depth profiling of the layers formed. A tentative structural model describing the improved corrosion resistance of Cu, Cu–xZn Alloys and Zn in BTAH containing chloride solution is proposed.
Juan Torrentburgues - One of the best experts on this subject based on the ideXlab platform.
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tin Zinc electrodeposition from sulphate tartrate baths
Journal of Electroanalytical Chemistry, 2005Co-Authors: E Guaus, Juan TorrentburguesAbstract:Abstract The electrodeposition of tin–Zinc Alloys with 20–30% Zn by weight from sulphate–tartrate baths at pH 4 and 5 and different c L /( c Sn + c Zn ) ratios was studied. The anodic stripping analysis of the deposits was correlated with their morphology, composition and phase structure both on vitreous carbon and on copper electrodes. The use of tartrate anion as a complexing agent allows deposits to be obtained with a uniform composition and morphology under stirred conditions during the electrodeposition process. The deposited tin–Zinc alloy is a mixture of Zn and βSn phases, with a Zn content of around 20% by weight.
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tin Zinc electrodeposition from sulphate gluconate baths
Journal of Electroanalytical Chemistry, 2003Co-Authors: E Guaus, Juan TorrentburguesAbstract:Abstract The electrodeposition of tin–Zinc Alloys with 20–30% Zn by weight from sulphate–gluconate baths at pH 4 and different [Sn(II)], [Zn(II)] and [gluconate]/([Sn(II)]+[Zn(II)]) ratios was studied. The anodic stripping analysis of the deposits was correlated with their morphology, composition and phase structure. When [Zn(II)] is equal to or not much greater than [Sn(II)], a eutectic type Sn–Zn alloy is obtained, with a Zn content of around 20% by weight, which is greater than that of a thermal eutectic alloy. The morphology of the electrodeposited eutectic Sn–Zn alloy tends to disappear at high deposition charges and a second crystalline coating, richer in Sn, is obtained.
