ZrO2 加入量对Zr-8Al合金化学复合镀性能的影响

对Zr-8Al合金进行了化学复合镀Ni-P-ZrO_2处理,并研究了不同ZrO_2粒子加入量制备的复合镀层的显微结构、显微硬度、耐磨性和抗蚀性。结果表明,与单纯化学镀Ni-P镀层相比,Ni-P-ZrO_2复合镀层的显微硬度值显著提高,ZrO_2的添加量为4 g/L获得复合镀层显微硬度最高,耐磨性好;在3.5%(质量分数)NaCl溶液中耐蚀性虽有所下降,但腐蚀后镀层完整,仍具有较好的抗蚀性。Zr-8Al合金表面采用4 g/L ZrO_2粒子制备的Ni-P-ZrO_2复合镀层兼具很好的耐磨性和较好的耐蚀性,适用于既要耐磨又要抗蚀的空间活动构件。     

(Ni-P)/（TiO2/ZnO）复合涂层的制备及其在天然海水中的耐蚀性

采用化学镀和溶胶-凝胶技术在碳钢表面制备了(Ni-P)/(TiO2/ZnO)复合涂层。采用光学显微镜、扫面电镜观察涂层表面形貌;采用能谱及X射线衍射技术分析涂层的成分和相组成;采用电化学极化曲线及阻抗谱评价涂层在天然海水中的耐蚀性。结果表明,(Ni-P)/(TiO2/ZnO)复合涂层较之Ni-P涂层具有更好的耐海水腐蚀性能;在Ni-P涂层表面直接制备TiO2/ZnO复合薄膜并进行350℃热处理所获得的复合涂层具有最优的耐天然海水腐蚀性能。     

Ni—P—纳米TiO2化学复合镀层

研究了化学复合镀Ni-P-纳米TiO2粒子涂层的工艺过程和涂层性能。结果显示超声分散再加上表面活性剂可以使TiO2粒子得到充分分散。所获得的Ni-P－纳米TiO2粒子复合涂层和Ni-P合金涂层相比具有更高的硬度和高温抗氧化性能。镀层热处理后,Ni-P纳米TiO2粒子复合涂层的硬化峰值出现在500℃左右。化学镀Ni-P合金涂层的硬化峰值在400℃左右。     

纳米ZrO_2对环保型锌铝合金涂层耐蚀性能的影响

采用锌铝合金粉制备水性锌铝涂层,通过向涂层中添加纳米ZrO_2,制备出纳米复合锌铝涂层。通过电化学测试、中性盐雾试验、扫描电镜观察、能谱分析和X射线衍射分析,研究纳米ZrO_2对锌铝涂层耐蚀性能的影响。结果表明:纳米ZrO_2能增大锌铝粉活化溶解电阻,延缓锌铝合金粉的消耗,提高涂层阴极的保护周期。当纳米ZrO_2的添加量为5%(质量分数)时,涂层的耐蚀性最佳,腐蚀电流密度降低至2.156×10-6 A/cm2。纳米ZrO_2的添加填补了锌铝粉之间的孔隙,使涂层组织均匀致密,增强了涂层阻挡离子渗透能力,阻止涂层表面孔蚀的发生及内部微裂纹的产生,延长涂层的防护时间。     

纳米二氧化钛浓缩浆对硼酚醛环氧涂料性能的影响

目的提高硼酚醛环氧涂料的耐腐蚀性、表面接触角、粘结强度及耐磨性等。方法用纳米二氧化钛浓缩浆改性硼酚醛环氧涂料,制备耐温耐蚀型纳米复合涂料。通过高温高硫原油浸泡试验评价纳米复合涂层的耐腐蚀性能,通过扫描电镜观察、表面接触角测试、粘结强度测试和耐磨性测试等手段分析纳米二氧化钛浓缩浆对涂层性能的影响。结果硼酚醛环氧纳米复合涂层在100℃高硫原油腐蚀浸泡后,微观上没有出现腐蚀坑和裂纹。添加2%纳米二氧化钛浓缩浆的硼酚醛环氧纳米复合涂层与未添加纳米粒子的硼酚醛环氧涂层相比,抗渗性与耐磨性有所提高。720 h腐蚀试验后,纳米复合涂料的粘结强度由试验前的7.7 MPa降低至6.9 MPa。腐蚀过程中,其表面接触角比非纳米涂层高4°~7°。结论高温高硫原油没有破坏硼酚醛环氧纳米复合涂层的形貌结构、粘结强度和耐磨性。添加2%纳米二氧化钛提高了涂层的抗渗透性和表面接触角。     

聚多巴胺修饰六方氮化硼及其环氧复合涂层的腐蚀行为

为了提高六方氮化硼在溶剂和有机涂层中的分散并探究其对环氧涂层耐蚀性能的影响,采用聚多巴胺(PDA)修饰六方氮化硼改善其在溶剂和环氧涂层中分散性的方法,通过SEM、TEM、XPS、Raman、TG表征了改性六方氮化硼的形貌、化学组成和热稳定性;除此之外,采用电化学方法研究了改性六方氮化硼掺入环氧复合涂层在3.5%NaCl溶液中的腐蚀行为。结果表明:与环氧涂层相比,h-BN@PDA/环氧复合涂层在长效腐蚀测试过程中表现出更正的腐蚀电位(-0.1 V)、高的阻抗模值和涂层阻抗值(~10~(10)Ω·cm~2)、低的特征频率值(~0.1 Hz);且金属基底表面无明显腐蚀,显示优异的抗腐蚀性能。这主要是因为纳米层状六方氮化硼的添加可以降低涂层的孔隙率并且能够延缓腐蚀介质的渗入,进而提高了其耐腐蚀性能。     

纳米Al2O3对电刷镀Ni-P复合镀层耐蚀性能的影响

目的为延长油墨刮刀的使用寿命,提高刮刀的耐蚀性能。方法采用电刷镀方法在高碳钢基体表面制备了Ni-P镀层和共沉积纳米Al_2O_3的Ni-P/Al_2O_3复合镀层。通过动电位极化曲线、腐蚀失重曲线和交流阻抗谱等方法研究了Ni-P镀层和Ni-P/Al_2O_3复合镀层在3.5%NaCl溶液中的腐蚀行为,采用扫描电子显微镜和能谱仪对两种镀层腐蚀前后的显微组织和成分进行分析。结果纳米Al_2O_3在Ni-P镀层中的共沉积,使镀层的腐蚀电位由-0.318 V正移到-0.237 V,自腐蚀电流密度由6.04μA下降到5.75μA,这是因为纳米Al_2O_3标准电位比Ni更正,在镀层中的均匀分布能使腐蚀电位正移,在腐蚀过程中形成Ni-P合金作为阳极、Al_2O_3粒子作为阴极的腐蚀微电池,促进阳极极化。共沉积纳米Al_2O_3后,Ni-P/Al_2O_3复合镀层的电化学反应电阻Rct值由1.066×104?·cm~2增大至2.864×104?·cm~2,双层电容Cd I值由43.45μF/cm~2下降到27.36μF/cm~2。与Ni-P镀层相比,Ni-P/Al_2O_3复合镀层表面结构更致密,缺陷更少,在腐蚀过程中,P和O元素在Ni-P镀层表面富集形成钝化膜,抑制腐蚀的进行。结论共沉积Al_2O_3纳米颗粒能有效改善Ni-P镀层的耐蚀性能。     

超高分子量聚乙烯/石墨烯复合涂层制备及其在海洋装备防护中的应用

目的采用热喷涂技术制备涂层,通过材料选择和结构设计,有效延缓海水对金属基底的腐蚀和冲蚀,并抑制海洋材料表面生物污损等对海洋材料的严重破坏。方法采用高能球磨法制备了聚乙烯-石墨烯(UHMWPE-graphene)复合粉末,用火焰喷涂技术在E235B碳钢基底表面制备UHMWPE和UHMWPE-graphene复合涂层。通过扫描电子显微镜和透射电子显微镜对原始粉末和涂层微观组织进行表征,并通过摩擦磨损实验、电化学测试、生物污损检测,分别评价涂层耐海水冲刷性能、耐腐蚀性能以及抗生物污损特性。结果相对于碳钢和UHMWPE涂层,UHMWPE-graphene复合涂层的腐蚀电位提高和腐蚀电流减小,预示着样品的耐腐蚀特性增强。由于UHMWPE-graphene复合涂层呈现疏水性以及更低的表面能,使其表现出优异的抵抗海藻贴附的能力。添加石墨烯的复合涂层的摩擦系数和磨损率比纯UHMWPE涂层均有一定程度的降低。添加石墨烯质量分数为0.5%时,涂层的摩擦系数由0.236降低到0.195,且磨损率下降了约26%。结论利用火焰热喷涂技术在碳钢表面成功制备了组织致密的UHMWPE涂层、UHMWPE-0.2%graphene和UHMWPE-0.5%graphene复合涂层。石墨烯的添加,能够有效提高涂层在模拟海洋环境中的耐蚀性、抗生物污损性及耐磨性。     

新型PEO/纳米结构ZrO_2镁合金涂层的抗菌活性及腐蚀行为（英文）

为了增强镁合金的耐腐蚀性和抗菌活性,先采用等离子体电解氧化(PEO)在镁合金上制备一层结合层,再用空气等离子喷涂(APS)制备纳米结构ZrO_2表面涂层。采用电化学试验研究涂层样品的腐蚀行为,采用琼脂扩散法对其进行大肠杆菌病原菌抑菌活性评价,并与无涂层样品进行对比。与PEO涂层和无涂层镁合金相比,PEO/纳米ZrO_2涂层样品的腐蚀电流密度最低,电荷传递阻力最高,相位角和阻抗模量最高。PEO结合涂层被纳米ZrO_2表面涂层完全密封,能够显著延缓侵蚀性离子向镁合金表面迁移,显著提高镁合金在模拟体液(SBF)中的耐蚀性。此外,PEO/纳米ZrO_2涂层的抗菌活性也高于PEO涂层和无涂层镁合金,这是由于ZrO_2纳米颗粒通过作用于细胞膜而降低了大肠杆菌的生长速率。     

等离子喷涂制备Al_2O_3,ZrO_2,Al_2O_3/ZrO_2和ZrO_2/Al_2O_3涂层的腐蚀性能（英文）

采用大气等离子喷涂技术在低碳钢表面制备Al_2O_3、ZrO_2、ZrO_2/Al_2O_3和Al_2O_3/ZrO_2涂层。利用扫描电镜(SEM)和X射线衍射(XRD)技术对涂层的显微组织和相组成进行分析,采用极化、盐雾和浸泡等实验手段对涂层在3.5%NaCl溶液中的腐蚀行为进行研究。结果表明,双层Al_2O_3/ZrO_2涂层比另外三种涂层具有更好的抗腐蚀性能,这主要归因于该涂层中非常少的内联孔洞和稳定的相组成。     

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。