Ni-P-nano Al2O3 composite coatings were deposited by electroless plating,and their microstructures were observed by SEM（scanning electron microscope）.The microhardness and the wear resistance of the Ni-P-nano Al2O3 ...Ni-P-nano Al2O3 composite coatings were deposited by electroless plating,and their microstructures were observed by SEM（scanning electron microscope）.The microhardness and the wear resistance of the Ni-P-nano Al2O3 composite coatings were measured using microhardness tester and block-on-ring tribometer,respectively,and the comparison with those of Ni-P coatings or Ni-P-micro Al2O3 coating was given.The influences of aging temperature on their hardness and wear resistance were analyzed.The results showed that the nano Al2O3 particles were distributed uniformly in the Ni-P-Al2O3 coatings.Among three kinds of Ni-P based coatings,the hardness and wear resistance of Ni-P-nano Al2O3 coatings were largest,and the maximum values could be obtained at 400 ℃.This indicated that the precipitation of nano Al2O3 particles would improve the hardness and wear resistance of the Ni-P coatings.展开更多
The transformation of MgO· Al2O based inclusions in alloy steel during refining has been studied by in- dustrial trials. Besides Factsage software is used to sttidy the formation and modification of spinel inclus...The transformation of MgO· Al2O based inclusions in alloy steel during refining has been studied by in- dustrial trials. Besides Factsage software is used to sttidy the formation and modification of spinel inclusions in alloy steel using calcium treatment during refining process. The results show that the transformation sequence of inclu- sions is：MgO· Al2O→CaO-Al2O3-MgO complex inclusions--→MgO· Al2O, and under present experimental con- dition, in order to avoid forming MgO· Al2O inclusions the content of dissolved Ca in the molten steel has to reach 1 × 10-6. Also the results show that when more calcium was added to molten steel, the content of Alz 03 and MgO will be lower. Besides, increasing the content of CaO in the inclusions will increase even if tlae content of SiO2 changes little.展开更多
The feasibility study of the AlCl(g) generated by Al_2O-AlCl_2-C system under vacuum was carried out by thermodynamic analysis and CASTEP package of the Material Studio program which was based on density functional th...The feasibility study of the AlCl(g) generated by Al_2O-AlCl_2-C system under vacuum was carried out by thermodynamic analysis and CASTEP package of the Material Studio program which was based on density functional theory(DFT) formalism. Thermodynamic calculations indicate that Al Cl and CO molecules can be formed under conditions of temperature 1760 K and the pressure of 60 Pa. The interaction of Al_2O and AlCl_2 with C shows that the chemical adsorption of Al_2O and AlCl_2 does take place on C(001) crystal plane, and at the same time, new chemical bond is formed between Al atom in Al_2O and Cl atoms from one of the Al—Cl bonds in AlCl_2. The results, after 1.25 ps dynamics simulation, indicate that adsorbed Al Cl molecules are generated and CO molecule will be formed in this system, and they will escape from C(001) surface after a longer period of dynamic simulation time. It means that the reaction of Al_2O and AlCl_2 with C can be carried out under given constraint condition.展开更多
Based on the experimental and theoretical analysis, the tensile elastic modulus, strength and fracture characteristics of squeeze casting δ-Al2O3/Al alloy composites were studied. The fracture characteristics of com...Based on the experimental and theoretical analysis, the tensile elastic modulus, strength and fracture characteristics of squeeze casting δ-Al2O3/Al alloy composites were studied. The fracture characteristics of composites were observed by SEM. The elastic modulus was predicted by the finite element method based on the energy equivalence principle, and the strength was predicted by the statistical integration average method using the maximum energy criterion of composite strength. In the prediction, the distribution density functions of the fiber's. orientation and length were considered. These functions were gained by experimental measurement. It is shown that the predicted results are in agreement with the experimental values well and the microstructure feature of composites controls the fracture characteristics.展开更多
综述了稀土元素在镁合金溶液中去氧化夹杂、除氢和与熔剂的相互作用,以及稀土元素对镁及镁合金的组织、性能、起燃温度、耐蚀性等方面的影响。阐述了 RE 在镁合金显微组织中细化晶粒、强化晶粒和晶界、提高合金力学性能的机理,以及与氧...综述了稀土元素在镁合金溶液中去氧化夹杂、除氢和与熔剂的相互作用,以及稀土元素对镁及镁合金的组织、性能、起燃温度、耐蚀性等方面的影响。阐述了 RE 在镁合金显微组织中细化晶粒、强化晶粒和晶界、提高合金力学性能的机理,以及与氧等元素反应在镁合金表面生成 MgO、Al_2O_3、RE_2O_3、Mg_(17)Al_(12)组成的致密保护膜和由于Ce、Y、Le 等元素的加入形成稀土转化膜对镁合金起燃温度、耐蚀性的作用。并对含稀土镁合金进行了评价与展望。展开更多
基金Item Sponsored by Jiangsu Natural Science Foundation of China(04KJB430013)Jiangsu Key Laboratory of Friction Wear Opening Foundation
文摘Ni-P-nano Al2O3 composite coatings were deposited by electroless plating,and their microstructures were observed by SEM（scanning electron microscope）.The microhardness and the wear resistance of the Ni-P-nano Al2O3 composite coatings were measured using microhardness tester and block-on-ring tribometer,respectively,and the comparison with those of Ni-P coatings or Ni-P-micro Al2O3 coating was given.The influences of aging temperature on their hardness and wear resistance were analyzed.The results showed that the nano Al2O3 particles were distributed uniformly in the Ni-P-Al2O3 coatings.Among three kinds of Ni-P based coatings,the hardness and wear resistance of Ni-P-nano Al2O3 coatings were largest,and the maximum values could be obtained at 400 ℃.This indicated that the precipitation of nano Al2O3 particles would improve the hardness and wear resistance of the Ni-P coatings.
基金Item Sponsored by China Postdoctoral Science Foundation(20080430020)
文摘The transformation of MgO· Al2O based inclusions in alloy steel during refining has been studied by in- dustrial trials. Besides Factsage software is used to sttidy the formation and modification of spinel inclusions in alloy steel using calcium treatment during refining process. The results show that the transformation sequence of inclu- sions is：MgO· Al2O→CaO-Al2O3-MgO complex inclusions--→MgO· Al2O, and under present experimental con- dition, in order to avoid forming MgO· Al2O inclusions the content of dissolved Ca in the molten steel has to reach 1 × 10-6. Also the results show that when more calcium was added to molten steel, the content of Alz 03 and MgO will be lower. Besides, increasing the content of CaO in the inclusions will increase even if tlae content of SiO2 changes little.
基金Projects(51104078,51264023)supported by the National Natural Science Foundation of ChinaProject(2010CD022)supported by Yunnan Province Applied Basic Research Fund,China+2 种基金Project(IRT1250)supported by the Program for Innovative Research Team in University of Ministry of Education of ChinaProject(U1202271)supported by the National Natural Science Foundation of China-Yunnan United FundProject(KKZ3201252020)supported by Kunming University of Science and Technology for Talent Training,China
文摘The feasibility study of the AlCl(g) generated by Al_2O-AlCl_2-C system under vacuum was carried out by thermodynamic analysis and CASTEP package of the Material Studio program which was based on density functional theory(DFT) formalism. Thermodynamic calculations indicate that Al Cl and CO molecules can be formed under conditions of temperature 1760 K and the pressure of 60 Pa. The interaction of Al_2O and AlCl_2 with C shows that the chemical adsorption of Al_2O and AlCl_2 does take place on C(001) crystal plane, and at the same time, new chemical bond is formed between Al atom in Al_2O and Cl atoms from one of the Al—Cl bonds in AlCl_2. The results, after 1.25 ps dynamics simulation, indicate that adsorbed Al Cl molecules are generated and CO molecule will be formed in this system, and they will escape from C(001) surface after a longer period of dynamic simulation time. It means that the reaction of Al_2O and AlCl_2 with C can be carried out under given constraint condition.
基金Ac plied Fundamental Research Fund of Sichuan Province 1998(19), P.R.China Fund of Material and Structural Failure Mechanic
文摘Based on the experimental and theoretical analysis, the tensile elastic modulus, strength and fracture characteristics of squeeze casting δ-Al2O3/Al alloy composites were studied. The fracture characteristics of composites were observed by SEM. The elastic modulus was predicted by the finite element method based on the energy equivalence principle, and the strength was predicted by the statistical integration average method using the maximum energy criterion of composite strength. In the prediction, the distribution density functions of the fiber's. orientation and length were considered. These functions were gained by experimental measurement. It is shown that the predicted results are in agreement with the experimental values well and the microstructure feature of composites controls the fracture characteristics.
文摘综述了稀土元素在镁合金溶液中去氧化夹杂、除氢和与熔剂的相互作用,以及稀土元素对镁及镁合金的组织、性能、起燃温度、耐蚀性等方面的影响。阐述了 RE 在镁合金显微组织中细化晶粒、强化晶粒和晶界、提高合金力学性能的机理,以及与氧等元素反应在镁合金表面生成 MgO、Al_2O_3、RE_2O_3、Mg_(17)Al_(12)组成的致密保护膜和由于Ce、Y、Le 等元素的加入形成稀土转化膜对镁合金起燃温度、耐蚀性的作用。并对含稀土镁合金进行了评价与展望。
