不同工艺下镁合金MAO/GO/SA复合涂层的耐蚀性

为提高AZ91D镁合金基体的耐蚀性，采用微弧氧化、电沉积和自组装工艺在AZ91D镁合金表面制备了微弧氧化/氧化石墨烯/硬脂酸(MAO/GO/SA)复合涂层。通过SEM对复合涂层的微观组织结构进行了分析，利用电化学阻抗谱、极化曲线测试了复合涂层的耐蚀性能。结果表明，最佳电沉积电压为4 V,此时，MAO/GO复合涂层的电荷转移电阻(R_ct)为4.41×10⁵Ω·cm²,腐蚀电流密度(J_corr)为3.88×10^-7 A/cm²。醇水比为7∶3时，MAO/GO/SA复合涂层的R_ct值为3.07×10⁶Ω·cm²,J_corr为3.02×10^-8 A/cm²,达到超疏水状态，涂层耐蚀性最好。     

电场辅助镁锰超疏水类水滑石膜的制备及耐蚀性研究

为了进一步提升镁合金作为生物医用材料的临床应用，本研究采用电场辅助法在ZK60镁合金表面制备了超疏水类水滑石膜(SH)以提高耐蚀性，并用X射线衍射仪(XRD)、扫描电镜(SEM)分析了膜层的表面成分和形貌，实验结果表明膜层表面主要成分为肉豆蔻酸钙(Ca[CH₃(CH₂)₁₂COO]₂)和镁锰类水滑石膜(Mg₆Mn₂(OH)₁₆CO₃·4H₂O)。用电化学测试和接触角测试表征了膜层的耐蚀性，最佳制备工艺下超疏水膜层试样接触角达到152.5°，腐蚀电流密度(4.73×10^-7A·cm^-2)与基体(6.53×10^-5 A·cm^-2)相比下降了约2个数量级，显著减缓了镁合金基体在模拟体液(SBF)中的降解速率。     

激光辅助热喷涂NiCoCrAlYTa-Cr2O3-Cu-Mo涂层高温静态氧化行为

为探究高温润滑耐磨涂层抗高温氧化行为,采用激光辅助等离子喷涂技术(LPHS)在GH4065A镍基高温合金上制备NiCoCrAlYTa-Cr₂O₃-Cu-Mo涂层,研究了该涂层在(850～1000)℃×220 h的抗高温氧化行为。计算得出氧化激活能约为128.5 kJ·mol^-1,850、900、1000℃氧化速率常数分别为1.44×10^-2、3.61×10^-2、7.71×10^-2 mg²·cm^-4·h^-1。结果表明,850℃×220 h氧化后表面生成Al₂O₃为主的连续致密氧化膜,阻碍涂层内部的进一步氧化;1000℃×220 h氧化后表面生成疏松NiO为主,致密Cr₂O₃·NiO为辅的氧化膜。致密氧化膜的生成阻止了涂层及基体的进一步氧化。     

硫醇改性超疏水铜表面的耐候性及失效机理

目的 探究户外环境中导致硫醇改性超疏水铜表面失效的因素及其超疏水性失效的机制。方法 通过化学刻蚀法在铜表面构筑纳米结构，利用正十二硫醇进行表面改性，得到具有超疏水性的铜表面。将该表面置于户外进行耐候性研究，并通过4种模拟户外环境实验探究超疏水性失效的原因，包括组合循环实验（循环条件含紫外辐射、淋雨和凝露）、紫外辐射实验、水环境实验和温度实验。结果 超疏水铜表面经过10 d的户外实验后，其接触角由初始状态的158.5°降至131.1°，表明该表面的超疏水性能已失效。经过2次组合循环实验（每次循环的时间为12 h）、20 d紫外辐射实验及30 d水环境实验后，该表面的接触角分别降至130.3°、124.5°、131.7°，表明该表面均已失去超疏水性；经过40 d高温实验后，表面的超疏水性开始失效。XPS谱图表明，在超疏水性失效后该表面不存在硫元素，即正十二硫醇已经脱离表面。结论 超疏水铜表面的硫醇分子脱落是超疏水性失效的根本原因。紫外辐射、水和高温是导致超疏水铜表面超疏水性失效的主要因素。其中，紫外辐射或水对超疏水性的破坏速度比高温快。相较于单一因素（紫外辐射、水或高温），三者的协同作用更...     

稳定超疏水镍基涂层的制备及其耐蚀性

目的 在金属表面制备稳定的超疏水镍基涂层,以提升金属的耐蚀性。方法 通过电沉积方法先后在金属表面获得具有微纳结构的多孔镀镍层和聚硅氧烷层。通过扫描电子显微镜、X射线粉末衍射仪、X射线光电子能谱、傅里叶变换红外光谱仪、接触角测定仪、电化学工作站等对涂层的形貌、成分、疏水性和耐蚀性进行表征。结果 乙二醇的添加能够促进电镀镍时阴极氢气的析出,当乙二醇的添加量为50.0～100.0mg/dm³时,形成了均匀相互连接的多孔镍镀层;在水解后的硅氧烷溶液中、-1.5 V电压下沉积3.0 min,可形成具有自清洁性能的超疏水膜层,其表面水接触角达到(159±1)°。在质量分数为3.5%的氯化钠溶液中,涂层的腐蚀电流密度约为3.6×10^-8A/cm²,与未修饰的镍镀层相比降低了3个数量级;低频阻抗模值|Z|0.01Hz为2.0×10⁶Ω·cm²,与未修饰的镍镀层相比,提升了3个数量级;在磨损实验后,涂层的微纳米结构依旧存在,保持着超疏水能力,其腐蚀电流密度和|Z|0.01 Hz分别为5.3×10...     

氧化时间对7A04铝合金微弧氧化膜层组织与性能的影响

在硅酸盐与铝酸盐混合电解液体系下，在7A04铝合金表面制备了微弧氧化陶瓷膜层，通过对膜层的厚度均匀性、电化学特性、物相组成以及表面形貌进行分析，研究了氧化时间对陶瓷膜层厚度、电化学耐蚀性、物相组成与表面形貌的影响。结果表明，膜层微观表面凹凸不平，呈火山喷口状形貌，微弧氧化时间不会改变膜层物相种类，主要由γ-Al₂O₃和α-Al₂O₃组成；微弧氧化时间是决定微弧氧化膜层性能的关键因素，氧化时间为25 min时，膜层厚度均匀性最好，方差为0.69,腐蚀电位为-0.482 1 V,腐蚀电流密度为3.75×10^-7 A/cm²,极化电阻为4.63×10⁶Ω·cm²;氧化时间为35 min时，交流阻抗性能最好。     

化学刻蚀-阳极氧化复合制备钛合金超疏水表面试验研究

目的 提高TC4钛合金超疏水表面的疏水性、耐腐蚀性与力学性能。方法 首先选择化学刻蚀法对TC4钛合金进行处理制备出微米级结构，再采用阳极氧化法制备出纳米级结构，最终在试样表面制备出了具有微纳分级结构的超疏水表面。通过观察微观结构表面、Tafel测试、线性磨损试验、抗冲击性测试以及防冰性能测试，分别对H₂O₂刻蚀、强酸刻蚀、阳极氧化、H₂O₂刻蚀-阳极氧化和强酸刻蚀-阳极氧化制备的超疏水表面进行性能对比。结果 使用双氧水-碳酸氢钠混合溶液制备出的超疏水表面接触角为156.4°，滚动角为2.7°；硫酸-盐酸混合溶液制备出的超疏水表面接触角为153.1°，滚动角为7.6°；阳极氧化法制备的超疏水表面接触角为156.3°，滚动角为4.2°；双氧水-碳酸氢钠混合溶液刻蚀并阳极氧化处理后，表面接触角为157.6°，使用硫酸-盐酸混合溶液刻蚀并阳极氧化处理后，表面接触角为155.9°，二者滚动角均小于2°。复合方法制备的表面疏水性能优于单一方法制备的超疏水表面。超疏水试样的OCP都高于TC4钛合金，经过强酸刻蚀和...     

白铜基体低表面能复合膜的制备及其耐腐蚀性能研究

目的研究混合修饰构筑白铜超疏水表面的可行性及防腐性能。方法以白铜为基体,采用简单的化学刻蚀法,以硝酸银溶液作为刻蚀液,经肉豆蔻酸和十二硫醇的混合乙醇溶液修饰来制备超疏水白铜。采用接触角测量仪、XRD、FTIR、SEM、EDS对超疏水白铜表面性能和结构等进行了表征,并利用Tafel曲线和电化学阻抗谱研究低表面能复合膜的耐蚀性能。结果肉豆蔻酸和十二硫醇的疏水长链都组装到薄银层表面,其中肉豆蔻酸和薄银层的键合形式为双齿桥式复合模式,超疏水白铜表面形貌由微米级枝晶和纳米级乳突状结构组成,同时材料表面与水的接触角达到157.4°,表现出超疏水水平。此外,制备的超疏水白铜表面具有良好的化学稳定性和耐腐蚀性能,在水、有机溶液、3.5%Na Cl溶液中分别浸泡2 d,所有样品表面仍表现为超疏水水平。由Tafel极化曲线拟合参数计算可知,其缓蚀效率达到83.9%。结论以两种低表面能物质混合修饰来制备超疏水白铜表面的方法是可行且有效的,且该复合膜具有优良的耐腐蚀性能。     

气缸套表面耐磨热障涂层制备与性能研究

柴油机气缸套表面热障涂层是协同提升其阻热、耐磨、减摩性能的有效方法。利用超音速高能等离子弧喷涂设备,在38CrMoAlA基体表面制备了厚度为1.5 mm的NiCoCrAlY-YSZ双层结构的热障涂层,并对其微观结构、力学性能与高温摩擦学行为进行了研究。结果发现,涂层孔隙率约为(9.62±2.23)%,与基体结合强度为(30.33±1.89) MPa;当环境温度为200℃时,38CrMoAlA基体的磨损率约为1.96×10^-4 mm³/(N·m),高于250℃油润滑条件下YSZ涂层的1.14×10^-4 mm³/(N·m);涂层在油润滑时的摩擦磨损性能较为优异,无润滑时的摩擦因数与磨损率分别由0.05和0.54×10^-4 mm³/(N·m)增加至0.70和2.97×10^-4 mm³/(N·m),其磨损形式以磨粒磨损为主。该研究为低散热柴油机关键部件的设计与防护提供了理论与技术支撑。     

2024铝合金超疏水表面的制备及其耐蚀性能

目的 在2024铝合金基体上制备超疏水表面,从而提高自清洁性能和耐腐蚀性能。方法 采用硫酸和草酸钛钾混合电解液阳极氧化,用月桂酸乙醇溶液修饰,在铝合金基体上制备超疏水表面,用扫描电子显微镜（SEM）、红外光谱和光学接触角测量仪观察、分析超疏水表面形貌、化学结构和润湿性,用电化学交流阻抗和极化曲线测试研究超疏水表面在3.5%氯化钠中的耐蚀性。结果 20 V恒电位阳极氧化时间小于90 min时,随着时间的增加,接触角增大。铝合金在0.5 mol/L硫酸和0.01 mol/L草酸钛钾混合电解液中阳极氧化90 min,并在5%（质量分数）的月桂酸乙醇溶液中修饰1.5 h,能制备出最优的超疏水表面,接触角为157.99°。在3.5%氯化钠中浸泡14天后,超疏水铝的交流阻抗值高于空白铝4个数量级,Tafel极化曲线解析表明,保护效率为99.92%。结论 在低浓度硫酸中对铝阳极氧化,并用月桂酸修饰能够成功制备出超疏水表面。所得表面展现出良好的耐腐蚀性,并且耐孔蚀性能得到改善。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.