NiFe2O4基铝用惰性阳极的试制

在实验中合成了镍铁尖晶石，以此为原料，采用冷压烧结的方法制成了Ｎｉ－Ｆｅ－Ｃｕ－Ｏ系铝用惰性阳极，并测定了这种阳极在４７０￣９７０℃下的高温电阻率及其在９７０℃下铝电解质熔体中的抗腐蚀性，然后分别在微型石墨电解槽和石英透明电解槽中对这种阳极的铝电解电极行为进行了定性考察，证明了这种电极的实际应用前景。     

烧结压力对Ti(CN)基金属陶瓷微观结构及力学性能的影响

采用气氛加压烧结法制备Ti(CN)基金属陶瓷,探索以较小的烧结压力制备出较高致密度的Ti(CN)基金属陶瓷刀具材料,同时能够克服传统的热等静压(HIP)所带来的一些组织缺陷.研究结果表明,随着烧结压力的提高,Ti(CN)基金属陶瓷的孔隙率明显降低,硬质相之间的粘连程度加大;为了提高烧结压力而充入更多的氩气,导致冷却阶段延长,从而延长了烧结时间,使环形相变厚,粘结相平均自由程增大.这些微观结构的变化使得随着烧结温度的提高,材料的抗弯强度上升,而硬度降低;快冷处理使环形相变薄,粘结相固溶强化程度加强,孔隙率下降,从而材料的强度和硬度同时得到提高;在烧结压力为2 MPa,烧结末期经过快冷处理,得到了孔隙率为A04B00,微观结构中没有"粘结相池",抗弯强度为2278 MPa,洛氏硬度91.9的高性能金属陶瓷材料.     

微观结构对Ni-SDC阳极电化学性能的影响

用甘氨酸-硝酸盐法制备了具有高比表面积的纳米粒子NiO和Ce0．85Sm0.15O2—8（SDC）,用固相合成法制备了Ni—SDC复合阳极材料,通过测量过电位和电导率对其性能进行比较,研究微结构对复合阳极电化学性能的影响．结果表明,由于阳极组成和制备条件不同导致的微结构的变化,对阳极性能有很大影响．通过调整微结构,可以使阳极过电位和电导率明显改善．用甘氨酸-硝酸盐法制备SDC与NiO初始粉末,将2种初始粉末在600℃预烧,混合后得到的复合阳极具有优异的电化学性能．在600℃时,样品在氢气气氛下的电导率达到了3534S／cm,电流密度为0．5A／cm。时样品过电位是0．18V．     

N含量对Ti(C, N)基金属陶瓷微观组织结构和性能的影响

针对Ti(C, N)基金属陶瓷在烧结过程中存在明显脱氮行为的问题,采用氮分压烧结方法是实现微观组织结构可控和获得优异性能的关键之一。制备了3种不同氮含量的Ti(C, N)基金属陶瓷,研究了氮含量和烧结温度对合金芯部和表面梯度层微观组织结构和性能的影响。结果表明：随着氮含量增加,合金芯部Ti(C, N)黑芯数量越多,黑芯外环的厚度越薄,同时硬质相晶粒越细;随着烧结温度升高,样品氮分解压力逐渐增大,由开始的渗氮现象转变为脱氮现象。当烧结温度为1 470 ℃时,合金表面发生了渗氮反应,形成一层无环黑芯聚集层,且其厚度随着合金氮含量的增加而减少;当烧结温度增加至1 530 ℃时,合金表面发生了脱氮反应,形成了一层灰色固溶体层,且随着合金中氮含量的增加,脱氮反应加剧,固溶体层厚度也越厚。研究发现,在1 470 ℃和0.8 kPa氮分压下烧结的样品,为含氮量最高的合金,具有最薄的黑芯聚集层和最细的硬质相晶粒,表现出较佳的综合性能。     

镁合金阳极氧化膜的微观结构与耐蚀性能研究

为了提高镁合金的耐蚀性能，采用扫描电镜(SEM)、电化学测试和盐雾试验等技术，对不同阳极氧化液中得到的镁合金AZ91D阳极氧化膜层的微观结构及其耐蚀性能进行了评价.所有工艺采用交流电源、氧化液无氟、铬和无磷，有利环境保护.先后对外加交流电压、Na2SiO3浓度、NaAlO2浓度，以及Na2SiO3和NaAlO2的协同作用对膜层腐蚀性能的影响规律进行了考察.结果表明，外加电压和氧化液组成对氧化膜的微观结构及其性能有着至关重要的影响.在碱性溶液中，NaAlO2和Na2SiO3的协同作用下，得到的阳极氧化膜的综合耐蚀性能优异，自腐蚀电流密度达到1.87×10-7A/cm2，耐中性盐雾大于500 h（氧化膜未封孔）.     

添加剂对铝用碳素阳极消耗的影响

铝电解生产中，碳素阳极两组分（石油焦和沥青结焦）的活性差异带来阳极的选择性氧化，是造成碳素阳极过量消耗的主要原因之一。基于阳极中杂质或添加剂时对阳极活性产生的影响，作者采用分别测定石油焦和沥青结焦与ＣＯ２反应活性的实验方法，研究了Ａ１Ｆ３及其它５种添加剂（分别用Ａ，Ｂ，Ｃ，Ａ１Ｆ３＋Ｃ，Ａ１Ｆ３＋Ｄ代替）对二者活性的影响。结果表明，添加剂Ｃ提高了沥青结焦和石油焦的ＣＯ２反应性；添加剂Ａ１Ｆ３，Ａ，     

稀土氧化物对金属陶瓷刀具材料性能的影响

通过添加2种不同的稀土氧化物，利用热压液相烧结法烧结，研究了2种工艺条件下稀土氧化物对Ti（C0.7N0.3）基金属陶瓷刀具材料显微结构和力学性能的影响。结果表明，稀土氧化物的添加使材料的力学性能受工艺影响很大，在烧结温度1400℃压力25MPa，保温时间为30min的工艺条件下，稀土氧化物的添加会大幅度的降低材料的力学性能；在温度1450℃压力25MPa，保温时间为30min的工艺条件下，稀土氧化物会提高材料的断裂韧性。     

铝合金基体微观组织对阳极氧化膜层形貌和性能的影响

本文着重讨论ＬＤ２、ＬＣ４、ＺＬ１０８等不同铝合 基体微观组织对阳极氧化膜层组织形貌、硬度、耐磨性等性能的影响。试验结果表明：基体的微观组织直接影响阳极氧化支的形成和成长,膜层的硬度与附磨性呈非线性关系,最佳匹配受基体微观组织及氧化工艺等多种因素影响。     

稀土氧化物对金属陶瓷刀具材料性能的影响

通过添加2种不同的稀土氧化物,利用热压液相烧结法烧结,研究了2种工艺条件下稀土氧化物对Ti(C0.7N0.3)基金属陶瓷刀具材料显微结构和力学性能的影响.结果表明,稀土氧化物的添加使材料的力学性能受工艺影响很大,在烧结温度1400℃压力25 MPa,保温时间为30 min的工艺条件下,稀土氧化物的添加会大幅度的降低材料的力学性能;在温度1450℃压力25 MPa,保温时间为30 min的工艺条件下,稀土氧化物会提高材料的断裂韧性.     

Effect of sintering atmosphere on microstructure and properties of TiC based cermets

The effect of the sintering atmospheres （vacuum, N2, Ar） on the microstructures and properties of the TiC based cermets was studied using XRD, SEM/BSE and energy dispersive spectrometer. Compared with the alloy sintered in vacuum, the carbon content of the specimen sintered in N2 and Ar is lower by 0.5%; and the nitrogen content is higher by 0.3% when sintered in nitrogen. The central part of the ring structure may be carbide with either a high W or Ti content. The ring structures are （Ti, W, Ta, Mo, Co, Ni）C solid solutions with different metallic elements and distributions. The composition of the binder phase is （Co, Ni） solid solution with different Ti, W, Ta, Mo, C contents. The structures are uniform for the cermets sintered in vacuum and the properties are the best. When sintered in Ar or N2, the O2 and N2 in the atmosphere take part in the sintering reaction to break the carbon balance in the cermets to form a shell structure and defects, which results in poor density, microhardness （HV） and transverse rupture strength （TRS）.     

Preparation and electrochemical properties of Pb-0.3wt%Ag/Pb-WC composite inert anodes

We prepared Pb-0.3wt%Ag/Pb-WC(WC stands for tungsten carbide,the same below) composite inert anodes by double-pulse electrodeposition on the surface of Pb-0.3wt%Ag substrates,and investigated the electrochemical properties of the composite inert anodes,which were obtained under different forward pulse average current densities from 2 A/dm~2 to 5 A/dm~2 and WC concentrations from 0 g/L to 40 g/L in bath.The kinetic parameters of oxygen evolution,corrosion potential and corrosion current of the composite inert anodes were obtained in a synthetic zinc electrowinning electrolyte of 50 g/L Zn~(2+) and 150 g/L H_2SO_4 at 35 ℃,by measuring the anodic polarization curves,Tafel polarization curves and cyclic voltammetry curves.The results show that Pb-0.3wt% Ag/Pb-WC composite inert anodes obtained under forward pulse average current density of 3 A/dm~2 and WC concentration of 30 g/L in an original acid plating bath,possess higher electrocatalytic activity of oxygen evolution,lower overpotential of oxygen evolution,better reversibility of electrode reaction and corrosion resistance in [ZnSO_4+H_2SO_4] solution.The overpotential of oxygen evolution of the composite inert anode is 0.926 V under 500 A/m~2 in [ZnSO_4+H_2SO_4] solution,and 245 mV lower than that of Pb-1% Ag alloy;the corrosion current of the composite inert anode is 0.95×10~(-4)A which is distinctly lower than that of Pb-1%Ag alloy,showing the excellent corrosion resistance.     

Effects of polydopamine modification on self-grown CuO cube anodes in lithium-ion batteries

We report the synthesis of Cu O cubes with well-defined size and shape by thermal treatments of Cu2O cubes.Polydopamine(PDA)is introduced to modify the Cu O cubes by the in-situ polymerization of the dopamine precursor.The initial specific capacity of the lithium-ion batteries using the Cu O cubes as anodes increases about 10 times at a 0.5 C rate as a result of the modification of PDA.The overall specific capacity for 100 cycles also increases effectively due to the introduction of PDA.So PDA as surface modifying agent significantly improves the electrochemical performance of the Cu O anodes.     

热处理对Mg-Y-Gd-Nd-Zr显微组织及力学性能的影响

以快速凝固Mg-Y-Gd-Nd-Zr镁合金为研究对象,采用金相显微镜、扫描电镜和能谱仪等研究了热处理工艺对镁合金组织和性能的影响.结果表明,铸态镁合金内部存在严重的成分偏析,Mg12Nd和Mg24(Y,Gd)5共晶相在晶界处聚集.在525℃固溶处理温度下,随着固溶处理时间(6,8,10 h)延长,合金中非平衡共晶相发生溶解,晶粒不断长大.在525℃/8 h工艺时,Mg5Y第二相分布均匀且合金晶平均尺寸最为理想,成分偏析基本消除.525℃/8h+250℃/16 h热处理后合金晶粒内部析出细小弥散的β析出相,能够阻碍晶粒长大改善镁合金组织及力学性能,因此该工艺是Mg-Y-Gd-Nd-Zr铸态合金最优热处理方案.     

石墨烯对水泥净浆力学性能及微观结构的影响

为改善石墨烯纳米材料疏水性,采用硝酸氧化和超声波法制备石墨烯分散悬浮液,考察石墨烯质量分数对水泥净浆力学性能及其微观结构的影响,探讨石墨烯的增强增韧作用机制,结果表明,水泥基复合材料的抗压、抗折强度随着石墨烯质量分数的增加呈先增大后减小的趋势,且最佳质量分数为水泥质量的0.02%.通过SEM和FT-IR对硬化水泥石的结构进行表征,发现石墨烯能够促进水泥水化产物的生长,改变水化晶体的形状、尺寸,使其有形成完整、簇状的趋势,但并未与水泥发生化学反应,改变其生成物类型.     

Effect of homogenization treatment on microstrucmre and properties of Al-Mg-Mn-Sc-Zr alloy

The effect of homogenization on the hardness, tensile properties, electrical conductivity and microstructure of as-cast Al-6Mg-0.4Mn-0.25Sc-0.12Zr alloy was studied. The results show that during homogenization as-cast studied alloy has obviously hardening effect that is similar to aging hardening behavior in traditional Al alloys. The precipitates are mainly Al3（Sc,Zr） and Al6Mn When homogenization temperature increases the hardness peak value is declined and the time corresponding to hardness peak value is shortened. The electrical conductivity of the alloy monotonously increases with increasing homogenization temperature and time. The decomposition of the supersaturated solid solution containing Sc and Zr which is formed during direct chilling casting and the precipitation of Al3（Sc, Zr） cause hardness increasing. The depletion of the matrix solid solubility decreases the ability of electron scattering in the alloy, resulting in the electrical conductivity increased. Tensile property result at hot rolling state shows that the optimal homogenization treatment processing is holding at 300-350℃ for 6-8 h.     

Effect of homogenization treatment on microstructure and properties of Al-Mg-Mn-Sc-Zr alloy

The effect of homogenization on the hardness,tensile properties,electrical conductivity and microstructure of as-cast Al-6Mg-0.4Mn-0.25Sc-0.12Zr alloy was studied.The results show that during homogenization as-cast studied alloy has obviously hardening effect that is similar to aging hardening behavior in traditional Al alloys.The precipitates are mainly Al3(Sc,Zr)and Al6Mn.When homogenization temperature increases the hardness peak value is declined and the time corresponding to hardness peak value is shortened.The electrical conductivity of the alloy monotonously increases with increasing homogenization temperature and time.The decomposition of the supersaturated solid solution containing Sc and Zr which is formed during direct chilling casting and the precipitation of Al3(Sc,Zr)cause hardness increasing.The depletion of the matrix solid solubility decreases the ability of electron scattering in the alloy,resulting in the electrical conductivity increased.Tensile property result at hot rolling state shows that the optimal homogenization treatment processing is holding at 300-350 ℃ for 6-8 h.     

Ce对Al-Zn-Mg-Cu-Sc合金组织和力学性能的影响

为了研究Ce元素对T6态Al-7.5Zn-2Mg-2.3Cu-0.1Sc合金显微组织和力学性能的影响,通过改变合金中Ce元素的添加量,采用光学显微镜、扫描电子显微镜和电子万能实验机对合金的显微组织、拉伸断口形貌和力学性能进行了研究.结果表明,加入质量分数为0.2%的Ce元素可以显著细化Al-7.5Zn-2Mg-2.3Cu-0.1Sc合金的铸态和T6态显微组织.在合金的T6处理过程中随着时效时间的增加,合金硬度和抗拉强度均先增加后降低,合金的硬度和抗拉强度峰值分别为216 HB和681.7 MPa,合金最高屈服强度为638.2 MPa.合金拉伸断口呈韧脆混合断裂特征.     

短流程等温淬火初始温度对组织及性能的影响

为了研究短流程等温淬火的初始温度对铸件组织和性能的影响,采用消失模铸造工艺制备铸件.当铸件分别冷却到1 173和1 223 K初始温度时,放入50%KNO₃+50%NaNO₂淬火介质进行等温处理,然后空冷至室温.结果表明,铸件中出现了珠光体,ADI-1223和ADI-1173的硬度分别为381和366 HV.当载荷为10 N时,ADI-1223的摩擦系数为0. 289,磨损体积为71. 3×10^-5 mm³;ADI-1173的摩擦系数为0. 273,磨损体积为83. 7×10^-5 mm³.当载荷为12 N时,ADI-1223的摩擦系数为0. 242,磨损体积为114. 1×10^-5 mm³; ADI-1173的摩擦系数为0. 213,磨损体积为136. 5×10^-5 mm³.因此,ADI-1223的硬度高于ADI-1173,摩擦系数大于ADI-1173,磨损量小于ADI...     

Effect of Na concentrations on microstructure and optical properties of ZnO films

Na-doped ZnO thin films were deposited on the glass substrates using sol-gel method. The effect of Na concentrations on the structural and optical properties of ZnO films was studied. As Na concentration increases from 0.0 at% to 16.0 at%, preferential c-axis orientation becomes more and more obvious, and the intensity of the diffraction peaks from (103) increases. The optical band gap Eg value increases from 3.261 to 3.286 eV first and then decreases as Na concentration increases from 0.0 to 2.0 at% and th...