儿茶酚–(胺)表面化学介导的一氧化氮催化释放涂层研究

目的 在316L不锈钢(SS)表面构建原位一氧化氮(NO)催化释放涂层,使其能特异选择性地抗凝血、抑制平滑肌细胞(SMCs)增生,从而促进内皮细胞(ECs)生长。方法 在弱碱性水溶液中,选用多巴胺(DA)和己二胺(HD)为前驱体,利用多巴胺邻二苯酚结构自聚合沉膜的能力、多巴胺与己二胺的酚–(胺)表面化学,通过简单的一锅法在316L SS表面构建富氨基粘附涂层DA/HD。再通过碳二亚胺化学交联反应,共价接枝螯合Cu²⁺的1,4,7,10–四氮杂环十二烷–1,4,7,10–四羧酸(DOTA),最后获得均匀且稳定的NO催化释放涂层(命名为Cu-DOTA@DA/HD)。结果 DA/HD涂层表面的氨基密度高达22 nmol/cm²,实现了Cu-DOTA的有效固定,其NO催化释放速率可达5.2×10^–10 mol/(cm²·min)。Cu-DOTA@DA/HD涂层显著地抑制了血小板的粘附和激活,也能有效抑制血栓的形成,其表面血栓总质量由316L SS的(40.3±10.3) mg降低至(3.0±0.4) mg。...     

冷喷涂IN718涂层组织及性能研究

目的 针对Ti6Al4V耐磨性能较差的问题,利用高压冷喷涂技术在Ti6Al4V基体表面以不同的工艺参数制备了IN718涂层,为在Ti6Al4V基体表面制备高性能IN718涂层提供基础理论依据。方法 采用光学显微镜和扫描电子显微镜对涂层组织、断口形貌进行观察分析,以便更好地了解不同的工艺参数和工作气体类型(He/N₂)对IN718涂层组织形貌、力学性能和摩擦磨损性能的影响。结果 以N₂为推进气体制备的IN718涂层,其结合强度为115 MPa,硬度为557HV0.3,孔隙率约为0.24%,涂层磨损率为5.34×10^–4 mm³/(N·m);以He为推进气体制备的IN718涂层,其结合强度可高达256 MPa,是以N₂为推进气体制备涂层的2倍多,硬度为602HV0.3,明显高于以N₂为推进气体制备的涂层,涂层孔隙率和缺陷明显减少,孔隙率测试结果约为0.1%,涂层更加耐磨,磨损率为3.51×10^–4 mm³/(N·m)...     

(Ti,Al)N涂层应力沿层深分布的调整及大厚度涂层的制备

利用电弧离子镀技术在不锈钢基体上制备了（Ti,Al）N涂层,研究了N₂分压改变对涂层残余应力沿层深分布及相关力学性能的影响.结果表明,低N₂分压下,（Ti,Al）N涂层残余应力沿层深分布较均匀,随N₂分压的增加,涂层应力沿层深呈"钟罩型"分布,且全膜厚的应力值也明显增大;通过对涂层生长结构及微观成分分析,初步探讨了应力分布机理.随N₂分压的增加,涂层硬度会显著增加,而膜/基结合力则大幅下降;采用改变N₂分压工艺制备（Ti,Al）N涂层,可有效调整涂层残余应力沿层深分布趋势,改善其力学性能,并可成功制备厚度在130μm以上的硬质涂层.     

离子束活化对GF/PEEK金属化涂层结合强度的影响

为了解决玻纤/聚醚醚酮复合材料(GF/PEEK)因界面惰性导致的金属化涂层结合强度弱的问题,采用低能离子束对基材进行表面活化处理,再以磁控溅射和电镀技术制备Cu膜,从而实现复合材料表面大厚度、高性能金属化层的制备。分别采用Ar、H₂、O₂和H₂+N₂混合气体进行离子束活化,通过对比活化前后基材的润湿性能、微观形貌和表面特性变化,对离子束活化的作用机理展开研究,制备Cu膜并对Cu膜的结合强度进行判定,探讨不同气体活化对结合强度的影响规律。结果表明,经离子束活化后,复合材料的表面润湿性得到显著改善,极性官能团的相对含量明显提高,表面和浅表面玻纤的结构完整性受到破坏,采用Ar、H₂、O₂和H₂+N₂离子束活化处理后,Cu膜的结合强度由未经活化的0.1MPa逐渐提高至0.4 MPa、1.49 MPa、7.97 MPa和11.51MPa。离子束活化技术能够有效改善复合材料的表面活性,显著提高金属化涂层的结合强度,延长金属化...     

基于贻贝仿生构建高效抗菌及良好血液相容性的聚胺-酚表面

目的 赋予血液接触类材料优异的表面抗菌性能。方法 受天然贻贝黏附现象的启发,通过多巴胺（Dopamine,DA）、ε-聚赖氨酸（ε-Poly-L-lysine,ε-PL）、高碘酸钠（SodiumPeriodate,NaIO4）构建一种简易、快速的聚胺-酚涂层（ε-PL@PDA）,同时利用ε-PL丰富的氨基质子化形成的阳离子,实现表面高效抗菌的目的。其中DA和ε-PL通过共价交联形成酚胺聚合物,酚胺共同介导基底材料黏附形成涂层。通过傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）、场发射扫描电镜（SEM）、椭圆偏光、氨基定量、水接触角（WCA）等材料学表征评价ε-PL@PDA涂层的理化性能;通过菌落计数法、细菌活/死染、液体法等细菌实验评价涂层抗菌性能;通过内皮细胞黏附与增殖实验评价其细胞相容性;通过血小板黏附与激活及半体内血液循环实验验证其血液相容性。结果 材料学表征结果证明,ε-PL@PDA富氨基涂层成功制备,同时ε-PL的浓度大小会影响涂层的沉积过程;细菌实验表明,ε-PL@PDA涂层具备优异的抗菌性能,当ε-PL质量浓度为3 mg/mL时,对大肠杆菌和表皮葡萄球菌的抑制...     

氮气流量对(Ti,Al,Si,Cr)N超硬薄膜的结构与性能的影响

采用等离子增强磁控溅射技术（PEMC）在YG8硬质合金表面制备了(Ti, Al, Si, Cr)N超硬膜,研究了N₂流量对膜层结构、成分、形态特征与性能的影响。试验结果表明,所得薄膜为面心立方结构,随N₂流量增加,薄膜的晶体学取向由（111）晶面向（200）晶面转变。薄膜表面呈现柱状晶形态,N₂流量为70 sccm时,柱状晶尺寸最小,粗糙度最低。所得薄膜的硬度随N₂流量的增加先增大后减小,N₂流量为70 sccm时,达到最大值35.70 GPa。     

氢传感器用铂电极的制备及性能研究

采用浆料涂覆烧结法制备铂电极,对比了基材处理方式(磁控溅射/喷砂)、铂黑(Ptb)和氧化铂(PtO₂)粒径差异对电极形貌、附着力、方阻及电催化性能的影响。结果表明,基材采用磁控溅射法制备的涂层表面结构优于喷砂法的涂层,使其剥离强度均略高于喷砂处理的样品;针对于粉末粒度,需控制在一定范围内(即Ptb(350nm)和PtO₂(350nm)),其制备的涂层表面易形成蜂窝状或絮状的微连接结构,可显著降低方阻,提高其附着力。对结构和附着力较好的Ptb/Pt电极和PtO₂/Pt电极进行CV曲线分析,PtO₂/Pt电极的电催化性能优于Ptb/Pt电极。     

超音速等离子喷涂ZrO2涂层的缺陷分析与力学性能

采用超音速等离子喷涂技术(SAPS)在Q235钢基体表面制备了ZrO₂涂层。利用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)分别对ZrO₂涂层微观形貌、物相组成、元素分布进行了检测和分析,同时利用维氏硬度计对ZrO₂涂层硬度进行了测量,分别得出了涂层、涂层与基体连接处、基体的硬度值。结果表明:利用超音速等离子喷涂技术所制备的ZrO₂涂层表面存在大量颗粒凸起和孔洞。涂层截面存在形状为“马蹄形”、“弯月形”、“椭球形”以及“不规则多边形”的孔洞和横向裂纹缺陷,孔隙率为13%。在高温作用下,涂层中Zr元素发生扩散,由涂层顶部至底部Zr元素含量上升,且基体表面出现少量Zr元素。涂层材料在喷涂过程中发生相变,由单斜相转为四方相。涂层、涂层与基体连接处、基体显微硬度分别为740.51、205.79、189.33 HV0.2,涂层与基体连接处相比于基体材料表面的显微硬度提高。     

Ti-B-N纳米复合涂层的设计、制备及性能

利用脉冲直流磁控溅射技术研制Ti-B-N涂层,通过降低反应气体N₂流量,减少涂层中a-BN (a代表非晶)软质相的含量,增大TiB₂靶溅射功率,提高硬质相TiB₂的含量,形成nc-(Ti₂N, TiB₂)/a-BN (nc代表纳米晶)纳米复合结构,实现涂层增韧和强化。系统研究了TiB₂靶溅射功率对Ti-B-N涂层成分、微观结构和性能的影响,利用EDS、HRTEM、SEM、XRD、纳米压痕仪和划痕测试仪对涂层进行表征和测试,利用球-盘式摩擦磨损试验机测试涂层摩擦学性能。结果表明,随着TiB₂靶溅射功率增加,Ti-B-N涂层结构逐渐由nc-Ti₂N/a-BN演变成hcp-TiB₂/a-BN;Ti-B-N涂层的纳米硬度也逐渐增加,当TiB₂靶溅射功率为2.4 kW时,涂层硬度最高,约为33.8 GPa;此时Ti-B-N涂层的摩擦系数和磨损率也最低,分别为0.55和2.1×10...     

等离子喷涂Ag/(Sn0.8La0.2)O2涂层的组织及电性能

采用等离子喷涂技术在纯Cu表面制备了Ag/(Sn_0.8La_0.2)O₂涂层,利用XRD和SEM对涂层的相结构和微观组织进行了分析,用拉伸法测定了涂层与基体的结合强度,通过电弧侵蚀实验测试了涂层的耐电压强度以及耐电弧侵蚀性能.结果表明,所得涂层结构均匀致密,与基体结合强度为18.8 MPa,涂层内纳米级(Sn_0.8La_0.2)O₂颗粒均匀分布在Ag基体中;涂层的耐电压强度以及电弧烧蚀速率与块体合金接近,分别为3.76×10⁷V/m和37.7μg/C;电弧侵蚀实验后,涂层表面阴极斑点分散,烧蚀轻微,其电弧侵蚀机制有从液态喷溅向蒸发侵蚀转变的趋势.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。