Wear and corrosion resistance of laser-cladded Fe-based composite coatings on AISI 4130 steel

The wear and corrosion resistance of Fe_72.2Cr_16.8Ni_7.3Mo_1.6Mn_0.7C_0.2Si_1.2 and Fe_77.3Cr_15.8Ni_3.9Mo_1.1Mn_0.5C_0.2Si_1.2 coatings laser-cladded on AISI 4130 steel were studied. The coatings possess excellent wear and corrosion resistance despite the absence of expensive yttrium, tungsten, and cobalt and very little molybdenum. The microstructure mainly consists of dendrites and eutectic phases, such as duplex (γ+α)-Fe and the Fe–Cr (Ni) solid solution, confirmed via energy dispersive spectrometry and X-ray diffraction. The cladded Fe-based coatings have lower coefficients of friction, and narrower and shallower wear tracks than the substrate without the cladding, and the main wear mechanism is mild abrasive wear. Electrochemical test results suggest that the soft Fe_72.2Cr_16.8Ni_7.3Mo_1.6Mn_0.7C_0.2Si_1.2 coating with high Cr and Ni concentrations has high passivation resistance, low corrosion current, and positive corrosion potential, providing a better protective barrier layer to the AISI 4130 steel against corrosion.     

Effects of yttrium on the formation and magnetic properties of bulk metallic glassy (Fe,Co)-B-Si-Nb alloys

The bulk metallic glassy (BMG) rods of [(Fe_0.5Co_0.5)_0.72B_0.192Si_0.048Nb_0.04]_100-xY_x (x=0-6) and [(Fe_xCo_1-x)_0.72B_0.192Si_0.048Nb_0.04]₉₆Y₄ (x=0.5-0.8) were prepared by copper mold casting. The structure, thermal stability, and magnetic properties of the samples were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and vibrating sample magnetometer (VSM). Adding 1at% to 6at% of yttrium, the bulk glassy alloy rods of [(Fe_0.5Co_0.5)_0.72B_0.192Si_0.048Nb_0.04]_100-xY_x(x=0-6) with the diameter of 3 mm were not formed, and the sample with 4at% of yttrium showed less crystalline phase than others. When the Fe/Co atomic ratio was between 5:5 and 7:3, the bulk glassy alloy rods of [(Fe_1-xCo_x)_0.72B_0.192Si_0.048Nb_0.04]₉₆Y₄ (x=0.5-0.8) with the diameter of 2 mm were fabricated. In the (Fe, Co)-B-Si-Nb-Y BMGs, when the Fe content increased, the thermal stability, the supercooled liquid region, and the glass-forming ability (GFA) decreased, but the saturation magnetization (M_s) increased.     

基于高熵合金中间层的铜/钢TIG焊接头组织与性能

铜/钢复合结构不仅能够满足不同环境对材料性能的要求,还可减少铜材的消耗,将大大降低构件的成本;但铜与钢之间物化性能差异较大,其中极差的相溶性会导致焊后出现液相分离或缺陷。基于焊缝金属固溶-高熵化思路,设计Fe₅Co₃₀Cr₃₀Ni₃₀Cu₅高熵合金作为中间层,对T2紫铜和Q235钢进行TIG焊接,并对中间层及接头的组织与性能进行分析。结果表明：Fe₅Co₃₀Cr₃₀Ni₃₀Cu₅高熵合金为单相FCC固溶体结构,具有良好的强度和塑韧性;采用该中间层材料,利用TIG焊方法可实现T2紫铜和Q235钢的可靠连接,焊缝成形良好且无气孔、裂纹等缺陷;焊缝区组织为单相FCC固溶体结构,具有显著的高熵化特征;焊接接头平均抗拉强度为225 MPa,达到铜母材强度的91%,平均断后延伸率达到44%;接头断裂发生在紫铜侧热影响区,且断口表面呈现有大量的韧窝结构,具有显著的韧性断裂特征。     

正极材料Li(Ni1/3Co1/3Mn1/3)1-xCrxO2的合成与表征

采用草酸盐共沉淀法合成一系列的Li(Ni_1/3Co_1/3Mn_1/3)_1-xCr_xO₂正极材料(0 ≤x ≤0.1),用X射线衍射仪（XRD）和扫描电子显微镜（SEM）分析合成产物的晶体结构及表面形貌;利用充放电仪测定了产物的电化学性能.结果表明,合成的Li(Ni_1/3Co_1/3Mn_1/3)_1-xCr_xO₂( x = 0.01,0.03,0.05,0.07) 均保持α-2NaFeO₂ 层状结构相,属于空间R3m点群.Li(Ni_1/3Co_1/3Mn_1/3)_0.95Cr_0.05O₂的电化学性能最佳,首次放电容量达158.6 mAh/g,在2.5～4.5 V区间30次循环后比容量衰竭率仅为3.92%.Li(Ni_1/3Co_1/3Mn_1/3)_0.95Cr_0.05O₂和Li(Ni_1/3Co_1/3Mn_1/3)CrO₂ 的电极阻抗变化不同,进而影响其电化学性能.     

Synthesis,structure and mechanical properties of Zr-Cu-based bulk metallic glass composites

The unusual glass-forming ability (GFA) of the Zr₄₈Cu₃₆Ag₈Al₈ alloy and the high ductility of the Zr₄₈Cu₃₆Ag₈Al₈ metallic glass-matrix composites containing Ta powder were reported. The bulk metallic glass rod with a diameter of 25 mm was successfully synthesized using copper mold casting for the Zr₄₈Cu₃₆Ag₈Al₈ alloy. High GFA of this alloy was found to be related to a large supercooled liquid region and a quaternary eutectic point with low melting temperature. The bulk metallic glass matrix composites were prepared by introducing extra Ta particles into the Zr₄₈Cu₃₆Ag₈Al₈ melt. The composites consist of Ta particles homogenously distributed in the Zr₄₈Cu₃₆Al₈Ag₈ metallic glass matrix. The optimum content of Ta powder is 10at% for the composite with the highest plasticity, which shows a plastic strain of 31%.     

Crystallization behavior of Fe78Si13B9 metallic glass under high magnetic field

The effects of high magnetic field on the crystallization behavior of the Fe₇₈Si₁₃B₉ metallic glass ribbon were studied. The samples were isothermal annealed for 30 min under high magnetic field and no field,respectively. Microstructure transformation during crystallization was identified by X-ray diffraction and transmission electron microscopy. It was found that the crystallizations of Fe₇₈Si₁₃B₉ metallic glass processed under different conditions were that the precipitation of dendrite α-Fe(Si) and spherulite (Fe,Si)₃B phases forms amorphous matrix and then the metastable (Fe,Si)₃B phase transforms into the stable Fe₂B phase. The grain size of the crystals is smaller and more homogeneous for the isothermal annealed samples under high magnetic field in comparison with that under no field indicating that the crystallization behavior of Fe₇₈Si₁₃B₉ metallic glass is suppressed by high magnetic field.     

Preparation of Al-Cu-Fe-(Sn,Si) quasicrystalline bulks by laser multilayer cladding

(Al₆₅Cul₂₀Fe₁₅)_100-x Sn_x (x=0, 12, 20, 30) and Al₅₇Si₁₀Cu₁₈Fe₁₅ powders were cladded on a medium carbon steel (45# steel) substrate by laser multilayer cladding, respectively. The phases and properties of the produced quasicrystalline bulks were investigated. It was found that the main phases in the Al₆₅Cul₂₀Fe₁₅ sample were crystalline λ-Al₁₃Fe₄ and icosahedral quasicrystal together with a small volume fraction of θ-Al₂Cu phase. The volume fraction of icosahedral phase decreased as the Sn content in the (Al₆₅Cul₂₀Fe₁₅)_100-x Sn_x samples increased owing to the formation of β-CuSn phase. The increase of Sn content improved the brittleness of the quasicrystal samples. The morphology of the solidification microstructure in the Al₅₇Si₁₀Cu₁₈Fe₁₅ sample changed from elongated shape to spherical shape due to the addition of Si. The nanohardness of the laser multilayer cladded quasicrystal samples was equal to that of the as-cast sample prepared by vacuum quenching. In terms of hardness, the laser cladded Al₅₇Si₁₀Cu₁₈Fe₁₅ quasicrystalline alloy has the highest value among all the investigated samples.     

医用可降解Fe30Mn○xCa合金的制备及性能

通过机械合金化、粉末压坯及热挤压的方法制备了医用可降解Fe₃₀Mn_○xCa(x=0，1.5，3.0，4.5)合金棒材，运用金相显微镜、SEM、拉伸测试、电化学测试和SBF浸泡腐蚀等研究了Ca的添加对合金组织及性能的影响.结果发现，Fe₃₀Mn_○xCa合金均由奥氏体组成，且随着Ca质量分数增加，该合金硬度增加，伸长率和强度降低，降解性能显著提高，腐蚀速率从Fe₃₀Mn的0.1130mg/(cm²·d)增至Fe₃₀Mn_4.5Ca的0.2260mg/(cm²·d).细胞毒性实验表明其生物相容性为0～1级.     

改良类Fenton法降解亮绿染料的研究

以亮绿染料为目标污染物，在紫外灯照射下，采用H₂C₂O₄—Fe₂(SO₄)₃—H₂O₂类Fenton体系降解亮绿染料，测定其脱色率，并对试验条件进行了优化。结果表明：亮绿的最大吸收波长为632 nm, 365 nm紫外光下最佳反应时间为15 min;通过正交试验确定最优水平方案为：A₂B₂C₂D₁。即：5.0 g/L Fe₂(SO₄)₃最佳用量为1.0 mL,10.0 g/L草酸最佳用量为0.08 mL,3%(质量分数)H₂O₂最佳用量为0.06 mL,最佳pH为3.0±0.1。在此条件下，亮绿的平均脱色率可达98.68%,降解效果较好。     

放电等离子烧结Al20Cr20Fe25Ni25Mn10高熵合金的硬度和腐蚀性能研究

采用放电等离子烧结(SPS)技术在不同温度（800、900和200°C）下保温不同时间（4、8和12 min）合成了Al₂₀Cr₂₀Fe₂₅Ni₂₅Mn₁₀高熵合金（HEA）。通过扫描电子显微镜、能谱仪（EDS）、维氏显微硬度计、极化曲线等对合金的微观结构、显微硬度和腐蚀进行了实验研究。X-射线衍射（XRD）表征了所制备合金的成分。EDS结果显示不论烧结参数如何变化,合金均由原始合金元素组成。XRD、EDS和扫描电子显微镜的结果说明所制备的合金具有球形微观结构,呈现出面心立方结构相,这是基于固溶机制形成的。这表明SPS合金具有HEAs的特征。在1000°C保温 12 min生产的合金显微硬度最高,为HV 447.97,热处理后其硬度降至HV 329.47。同一合金表现出优异的耐腐蚀性能。烧结温度升高,Al₂₀Cr₂₀Fe₂₅Ni₂₅Mn₁₀合金可具有更高的密度、显微硬度和耐腐蚀性。     

一种高性能铁基纳米晶合金的软磁性能研究

在Finemet合金FeSiNbBCu系列的基础上,设计了Fe75.9Cu1Si13B8Nb1.5Mo0.5Dy0.1合金铁芯,用于研究铁芯的软磁性能.结果表明:Fe75.9Cu1Si13B8Nb1.5Mo0.5Dy0.1的工业化非晶合金带材在铸态下为完全的非晶态结构,真空退火后在非晶基体上析出了α-Fe纳米晶相.Fe...     

红格钒钛磁铁矿氧化物相转变及非等温氧化动力学

在对红格钒钛磁铁矿基础特性研究基础上,探讨了其球团氧化过程物相的存在形式和转变过程,并通过热分析法研究了红格矿非等温氧化动力学.结果表明:红格钒钛磁铁矿属于高铬型钒钛磁铁矿,Cr_2O_3的质量分数为1.48%,连晶强度为625 N;主要物相组成为磁铁矿、钛磁铁矿、钒磁铁矿、铬铁矿;温度低于300℃时其氧化速率缓慢;球团氧化过程有价组元物相迁移变化历程为:Fe_3O_4→Fe_2O_3;Fe_2VO_4→(Cr_(0.15)V_(0.85))_2O_3;Fe_(2.75)Ti_(0.25)O_4→FeTiO_3→Fe_9TiO_(15);FeCr_2O_4→(Fe_(0.6)Cr_(0.4))_2O_4,Fe_(0.7)Cr_(1.3)O_3,(Cr_(0.15)V_(0.85))_2O_3.红格矿非等温氧化动力学研究表明:当升温速率为10℃/min时,温度在220~380℃,380~500℃和500~800℃时,反应活化能分别为47.02,14.95和30.36 kJ·mol~(-1).     

系列Fe(Ⅲ) 草酸配位超分子的合成、 结构及磁性

采用常规方法合成了3种Fe（Ⅲ）配位超分子配合物：  ［Fe(phen)₃］［Fe(ox)₃］·KOH·6H₂O(1), ［Fe(en)₂(ox)］［Fe(en)(ox)₂］·2H₂O(2), K₃(glycol)·(Fe_0.2Cr_0.8)(ox)₃(3)(phen=邻二氮杂菲, en=乙二胺, ox=草酸). 通过X射线单晶衍射、 红外光谱（IR）、 紫外可见吸收光谱（UV-Vis）对配合物进行表征, 并测定了它们在4.5~300 K的变温磁化率. 研究结果表明, 在低温区配合物1~3均表现出弱的反铁磁性质, 其中配合物2的反铁磁性最强.     

稠油硫酸盐热化学还原生成H2S实验研究

为了研究稠油注汽热采过程中生成H₂S机理，以Na₂SO₄，CaSO₄，MgSO₄，Fe₂（SO₄）₃，Al₂（SO₄）₃与稠油硫酸盐热化学还原（TSR）实验为基础，探究稠油TSR生成H₂S机理。实验表明，不同硫酸盐与稠油反应生成H₂S不尽相同，硫酸盐的阳离子所带电荷数决定TSR反应程度的难易，电荷数越多越容易进行反应，且H₂S生成量顺序为Al₂（SO₄）₃>Fe₂（SO₄）₃ > MgSO₄ > CaSO₄ > Na₂SO₄，但生成的烃量顺序为Fe₂（SO₄）₃ > Al₂（SO₄）₃ > MgSO₄ > CaSO₄ > Na₂SO₄。与其他硫酸盐不同的是，由于Fe₂（SO₄）₃的氧化性，Fe³⁺可能与生成的H₂S进一步反应。通过傅里叶红外变换光谱（FT-IR）对固相检测发现，不仅存在金属氧化物（CaO，MgO，Fe₂O₃，Al₂O₃）还存在FeS₂。最后，通过对MgSO₄油相硫含量的检测发现，反应后硫含量高于原油硫含量，证明了无机硫向有机硫的转化。     

共沉淀中热力学耦合对正极材料电化学性能的影响

以共沉淀法制备钠离子层状氧化物正极材料NaNi_0.4Mn_0.4Fe_0.2O₂,采用Al³⁺有效控制和平衡共沉淀反应的过程.考察了加入Al元素带来的热力学耦合效应及对正极材料电化学性能的影响.结果表明,在Mn²⁺,Ni²⁺和Fe²⁺离子共存的环境中,由于Al³⁺更高的过饱和度和更负的吉布斯自由能变(ΔG)所产生的热力学耦合效应,显著改变了溶液离子之间的沉淀驱动力,加速Ni²⁺和Mn²⁺的沉淀并抑制Fe³⁺的沉淀.Na［Ni_0.4Mn_0.4Fe_0.2］_0.995Al_0.005O₂正极材料表现出优异的电化学性能,这归因于引入Al³⁺制备得到高质量的前驱体(［0.4MnCO₃·0.4NiCO₃·0.2Fe(OH)₃］_0.995·0.005Al(OH)₃).     

硫酸铁改性活性氧化铝除氟性能及机理探究

采用浸渍法制备质量分数为1.0%、2.5%的硫酸铁溶液改性活性氧化铝（1.0% Fe₂（SO₄）₃-MGAA、2.5% Fe₂（SO₄）₃-MGAA）,根据吸附等温实验和吸附动力学实验研究其对氟的吸附性能,从BET表征、零质子电荷点（pH_zpc）和pH缓冲强度等角度探讨吸附剂除氟机理。实验结果表明：活性氧化铝GAA、1.0% Fe₂（SO₄）₃-MGAA、2.5% Fe₂（SO₄）₃-MGAA 3种吸附剂除氟的吸附等温线均更好地符合Langmuir吸附,最大吸附量分别为8.78、14.08、16.78 mg/g,对20 mg/L高氟水去除率分别为34.5%、54.5%、66.5%;3种吸附剂对水中氟的吸附动力学符合准二级吸附速率方程;改性活性氧化铝表面存在的SO₄^2-和OH^-与F^-发生离子交换作用,SOFe²⁺与F^-产生配位作用,并存在一定的静电作用。改性后活性氧化铝pH缓冲强度均显著增强,数据分析发现pH缓冲强度与吸附性能呈正相关,因此可以从pH缓冲强度的角度初步预测改性效果。     

新型材料Na_4MnV(PO_4)_3的电化学性质及其改性

用溶胶-凝胶法制备纯相Na_4MnV(PO_4)_3@C材料,对Na_4MnV(PO_4)_3@C进行石墨烯复合,通过降低材料中Mn含量抑制体系的Jahn-Teller效应,并利用恒流充放电方法测试材料的电化学性能.结果表明:Na_4MnV(PO_4)3@C作为钠离子正极材料,在2.5~4.0V下的比容量为105mA·h/g,平均电压为3.6V,30次循环后的容量保持率为63%;复合后的材料在30次循环后,容量保持率为71%;低锰材料Na_(3.5)Mn_(0.5)V_(1.5)(PO_4)_3@C在2.5~4.2V下的比容量为110mA·h/g,50次循环后的容量保持率为90%,材料的容量保持率得到大幅度提高.     

四氮唑配体和Anderson型多酸组装铜配合物的合成及性能

以3-(1H-四氮唑-1-乙酸酰胺)吡啶(TAAP)、 Anderson型多金属氧酸盐和氯化铜为原料, 用水热合成方法制备一种新的基于四氮唑配体(HTrz=1H-四氮唑)和Anderson型多酸的铜配合物{H₂Cu₁₂(Trz)₁₂［CrMo₆(OH)₆O₁₈］₂(OH)₈(H₂O)₄}·12H₂O. 晶体结构解析表明： 该化合物先由去质子化的四氮唑配体Trz通过铜离子连接形成金属 有机二维层, 再通过多酸阴离子［CrMo₆(OH)₆O₁₈］-3-端氧连接二维层上的铜离子形成三维框架结构; 在水热合成过程中配体TAAP原位转化成Trz. 合成的配合物对H₂O₂有良好的电催化还原效果, 在紫外光下对亚甲基蓝和结晶紫有良好的催化降解效果.     

四氮唑配体和Anderson型多酸组装铜配合物的合成及性能

以3-(1H-四氮唑-1-乙酸酰胺)吡啶(TAAP)、 Anderson型多金属氧酸盐和氯化铜为原料, 用水热合成方法制备一种新的基于四氮唑配体(HTrz=1H-四氮唑)和Anderson型多酸的铜配合物{H₂Cu₁₂(Trz)₁₂［CrMo₆(OH)₆O₁₈］₂(OH)₈(H₂O)₄}·12H₂O. 晶体结构解析表明： 该化合物先由去质子化的四氮唑配体Trz通过铜离子连接形成金属 有机二维层, 再通过多酸阴离子［CrMo₆(OH)₆O₁₈］-3-端氧连接二维层上的铜离子形成三维框架结构; 在水热合成过程中配体TAAP原位转化成Trz. 合成的配合物对H₂O₂有良好的电催化还原效果, 在紫外光下对亚甲基蓝和结晶紫有良好的催化降解效果.