鳞片石墨对镁合金表面聚苯胺环氧涂层防护性能的影响

目的 针对聚苯胺环氧涂层物理屏蔽性能欠佳的问题,通过引入具有片层结构的鳞片石墨,从而进一步提高涂层对镁合金的腐蚀防护性能.方法 利用化学氧化聚合法在鳞片石墨表面合成聚苯胺,通过X射线衍射仪、扫描电子显微镜、傅里叶变换红外光谱仪,对所得到的聚苯胺/鳞片石墨复合粉末进行表征.将合成的复合粉末均匀分散于环氧树脂中后,在AZ91D镁合金表面制备涂层,通过电化学阻抗测试对涂层在3.5％氯化钠溶液中的腐蚀防护性能进行研究.结果 聚苯胺可以在鳞片石墨的表面聚合,鳞片石墨的加入使聚苯胺环氧涂层的附着力略有降低,涂层硬度、柔韧性及耐冲击性能没有明显改变,但鳞片石墨的加入明显提高了聚苯胺环氧涂层的阻抗值.在浸泡前1488 h,苯胺与鳞片石墨的质量比为1:1时,涂层的阻抗值为1.3×108?·cm2,防护性能最好.但随着浸泡时间的延长,苯胺与鳞片石墨的质量比为4:1时,涂层的阻抗值逐渐高于其他涂层,当浸泡4008 h后,其阻抗值为1.6×108?·cm2,仍具有较优异的防护性能.结论 环氧涂层中添加聚苯胺/鳞片石墨复合粉末后,通过鳞片石墨前期的屏蔽与聚苯胺长期缓蚀的协同作用达到了对镁合金较好的防护效果,而涂层的这一防护效果和苯胺与鳞片石墨比例有关.     

磷化聚苯胺固化含环氧基硅树脂涂层的制备及性能

为了改善有机硅树脂的固化条件及其涂层的防腐蚀性能,以γ-缩水甘油醚氧丙基三甲氧基硅烷（GPTMS）、硅酸乙酯（TEOS）、二甲基二乙氧基硅烷（DMDMS）为硅烷单体,采用溶胶-凝胶法制备了含环氧基的硅树脂（ESiR）,并以磷化聚苯胺（PANI）为固化剂制备了硅树脂防腐蚀涂层,分析了PANI固化含环氧基硅树脂的固化反应。通过测试固化时间、涂层的柔韧性和硬度、热失重曲线等考察了PANI添加量对涂层固化程度的影响;通过附着力、接触角、吸水率、电化学阻抗谱和极化曲线测试了PANI添加量对涂层性能的影响。结果表明：当PANI添加量（质量分数）为3 %时,得到的涂层固化效果较好,涂层既具有良好的柔韧性,又有较高的硬度;且涂层表现出较好的疏水性、附着力和优异的防腐蚀性能,其接触角为103.5°,吸水率为8.91%;涂层的干、湿附着力均为0级;腐蚀电流密度为7.58×10^-8 A/cm²,电化学阻抗值达到3.4×10⁶ Ω·cm²。     

轨腰仿生自分层防腐梯度涂料合成及影响因素和结构探究

目的仿荷藕结构及功能,制备一种自分层防腐涂料。方法合成聚氨酯改性环氧树脂(PU/EP)及氟硅改性丙烯酸树脂(氟硅改性PAA),将两种树脂共混形成自分层涂料。通过铅笔硬度测试、机械性能测试、接触角测试、耐老化测试、划格法附着力测试、电化学阻抗测试等,分别评价两种树脂比例、混合溶剂比例对涂膜自分层行为及性能的影响,并通过SEM-EDS、红外光谱等表征技术分析涂膜分层后的结构。结果当PU/EP∶氟硅改性PAA=1∶1时,接触角达到96.0°,柔韧性为0.5 mm,耐冲击为50 cm,附着力等级为1,失光率降至19%;乙酸丁酯(NBAC)∶正丁醇(NBA)=4∶6时,涂膜分层情况良好,接触角达到107.7°,浸泡水中48 h耐水性无变化,失光率降至17%。SEM-EDS、红外光谱分析表明,自分层涂膜上层为氟硅改性PAA、底层为PU/EP,中间存在过渡涂层,过渡层两种树脂中的─COOH、─OH、环氧基发生反应,使整个涂层更具稳定性。经由EIS分析,在3.5%NaCl溶液中浸泡40天后,腐蚀介质没有渗透涂膜到达基底金属界面。结论制备的轨腰仿生自分层涂膜的机械性能、附着力、疏水性、耐老化、防腐蚀性能优异,涂膜结构稳定。     

静电喷涂高附着力疏水涂层及其性能

目的提高静电喷涂疏水涂层的附着力。方法采用硅烷偶联剂和聚二甲基硅氧烷制备了表面改性疏水二氧化硅粉末。将一定比例的聚偏氟乙烯粉末、超高分子量聚乙烯粉末与疏水二氧化硅粉末混合,制备了复合型疏水粉末。使用环氧树脂、固化剂、活性剂等配制了导电环氧树脂。通过静电喷涂工艺将复合疏水粉末喷涂到已用导电环氧树脂覆盖的铝基板表面,经过中温固化,制得了铝合金疏水复合涂层。采用扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FTIR)、接触角测量仪(CA)、百格刀附着力测试仪等,对疏水复合涂层进行测试表征。结果 SEM结果表明涂层表面构建了微米-纳米的阶层粗糙结构,经CA测试,该表面具有较好的疏水性。当混合粉末中聚二甲基硅氧烷改性二氧化硅的比例占到20%时,环氧基疏水涂层的接触角最高可达到140°,滚动角最低可达5°,附着力的等级为0级,同时疏水涂层的耐磨性和耐腐蚀性良好。结论采用简单、易于工业化的静电喷涂工艺制备了高附着力的疏水涂层,具有广泛的应用前景。     

鳞片状锌粉防腐蚀涂料的研制

以鳞片状锌粉为牺牲阳极材料,环氧树脂为成膜物质,制备了鳞片状锌粉防腐蚀涂料。采用渗透率法测定了涂层的临界颜料体积,通过对硬度、耐磨性、附着力、抗冲击性、柔韧性以及耐盐雾性能的测试,表征了涂层的各项力学性能和腐蚀性能,阐述了鳞片状锌粉填料与涂层腐蚀性能优劣之间的关系。结果表明:以鳞片状锌粉为填料的环氧树脂防腐蚀涂料颜料体积浓度(PVC)在30%~35%之间时,制得的涂层综合性能较好,防腐蚀性能最佳。     

水性环氧防腐涂料研究

目的研制具有优异防腐性能的水性环氧类防腐蚀涂料。方法采用水性环氧树脂乳液与水性环氧固化剂聚酰胺作为成膜树脂,异丙醇、丙二醇甲醚作为助成膜剂,湿法绢云母、重晶石粉、滑石粉作为填料,防锈颜料体系采用氧化铁红、三聚磷酸铝、磷酸锌,并在涂料体系中添加防闪锈剂、去离子水、分散剂、消泡剂、防沉剂,经过高速分散、研磨制成水性环氧防腐涂料。通过物理机械性能试验,耐酸、碱、盐溶液浸泡和耐中性盐雾试验,测试涂层的综合性能。结果涂层的附着力、柔韧性和耐冲击性能分别达到1级、1 mm和50 cm。涂层的耐酸性(5%H_2SO_4,168 h)、耐碱性(5%NaOH,168 h)、耐盐水性(3%NaCl,30 d)和耐盐雾性能(按GB/T 1771—2007,1000 h)良好,各试样完成后,涂层完好。结论成膜树脂采用环氧当量为500±50的水性环氧树脂乳液与聚酰胺类水性环氧固化剂,控制环氧基与活泼氢当量配比为1:1,颜料体积浓度为30%,并使用三聚磷酸铝、磷酸锌与氧化铁红复配作为防锈颜料,所制备的涂层有优良的物理机械性能和防腐性能。     

碳纳米管复合水性丙烯酸涂层的腐蚀性能研究

目的制备碳纳米管复合水性丙烯酸涂层,探索分析碳纳米管含量对涂层力学和防腐性能的影响规律。方法采用高速球磨方式制备3%,1%,0.5%三种含量(以质量分数计)的碳纳米管复合涂层,对涂层附着力、耐冲击性、耐弯曲性等力学性能进行测试,以电化学阻抗技术来评价碳纳米管复合涂层的防腐性能。结果添加碳纳米管显著提高了涂层的附着力,并且随着碳纳米管含量的增加,附着力上升;其他力学性能,如耐冲击性、耐弯曲性,在不同含量下均保持良好。对改性和未改性的涂层进行了电化学阻抗测试,其中1%的碳纳米管涂层电化学性能最优,在浸泡36 h后,未改性涂层低频区阻抗模值|Z|0.01为2.5×103Ω·cm2,0.5%的碳纳米管涂层为1.1×106Ω·cm2,1%的为1.4×108Ω·cm2,3%的为7×102Ω·cm2。结论由于碳纳米管本身的纳米效应,在较低含量时即可提高涂层的性能,并存在最优含量,超过此含量后性能有所下降。     

纳米钛基杂化材料对水性环氧涂层组织结构和耐蚀性能的影响

目的 研究不同纳米钛基杂化材料含量对水性环氧树脂涂层组织结构和耐腐蚀性能的影响。方法 以纳米钛基杂化材料为填料,采用物理共混法对水性环氧涂料进行改进,通过铅笔硬度测试、十字划格附着力测试、扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、电化学测试以及盐雾试验等方法对涂层的力学性能、微观形貌、组织结构及耐蚀性能进行检测。结果 随着纳米钛基杂化材料含量的增加,涂层硬度逐渐上升,由HB变为3H,并且涂层的附着力保持为0级,同时涂层的防腐性能随纳米钛基杂化材料含量的增加先增强后减弱。当纳米钛基杂化材料质量分数为10%时,涂层最为致密,涂层的腐蚀电位最高,为-1.024 9 V,腐蚀电流密度最小,为8.09×10^-8A/cm²,涂层低频部分的阻抗模值最大,为7.6×10⁵?·cm²,较纯水性环氧树脂涂层提升了3倍,并且在60d的盐雾试验后涂层表面状况最佳,表现出良好的防腐性能。结论 纳米钛基杂化材料可以明显改善环氧树脂乳胶颗粒团聚的现象,提升涂层的致密性,增加涂层的铅笔硬度,增强涂层的防腐性能。     

快干型高固体分环氧防腐底漆的研究

目的研制高性能快干型高固体分环氧防腐底漆。方法将低黏度高活性环氧树脂和普通环氧树脂进行复配,得到可用于高固含涂料的树脂基料;通过分子结构优化设计,合成制备了以酚醛胺改性聚酰胺树脂为主体并结合柔性长链改性胺树脂复配的固化剂体系;利用复配的环氧树脂基料、自制的固化剂体系和无铬防锈颜料等组分研制了快干型高固体分环氧底漆。根据国家标准,进行了力学性能(包括柔韧性、耐冲击性和附着力)、耐环境性能(包括耐湿热、耐盐雾性能)和耐液体介质等涂层性能测试;通过考核涂层耐丁酮擦拭100次是否露底,来表征涂层的固化,采用FTIR手段,动态跟踪环氧固化过程。结果新研制的环氧涂料具有优良的力学性能和防腐性能,涂料的固含量73%,表干时间40 min,适用期8 h,耐盐雾和湿热均能达到5000 h,全面性能已达到国外现役先进材料水平,且工艺性能良好。结论以低黏度高活性环氧树脂为基体,采用酚醛与柔性长链二聚酸改性的聚酰胺固化剂,可制备高性能快干高固体分环氧防腐底漆,在飞机的防护底漆领域具有良好的应用前景。     

有机硅自润滑组分对自抛光涂层防污、减阻性能的影响

目的 制备一种兼具海洋防污和流体减阻功能的绿色海洋装备防护涂层。方法 将长链线型有机硅自润滑组分化学键合到自抛光黏结树脂中,与一定的无机填料复配,通过喷涂的方法制备了具有自润滑特性的自抛光防污减阻涂层。通过铅笔硬度测试、抗冲击测试、划格法附着力测试、涂层柔韧性测试、三维轮廓测试、表面接触角表征和固–液摩擦测试,分别评价了涂层的硬度、抗冲击性、附着力、黏弹性、表面粗糙度、表面润湿性能和自润滑特性,并通过抗蛋白和海藻黏附、海洋挂片试验和旋转流变仪分别表征了涂层的防污、流体减阻性能。结果 随着涂层黏结树脂中有机硅自润滑组分含量增多,涂层的硬度由2H变为4B,结合力由0级变为2级,涂层的抗冲击性能略有下降,接触角由65°上升至92°,涂层的表面粗糙度均小于500nm,但涂层的自润滑性质、防污性能和减阻性能却不断增强,摩擦因数（干磨）由0.119下降为0.075。当有机硅质量分数超过20%时,涂层的防海藻黏附效率达到97%,减阻率达到10%以上。海洋挂片进一步证明涂层具有优异的综合防护性能。结论 长链线型有机硅虽然一定程度上降低了涂层的硬度和附着力,但由于其特殊的性质,可在满足实际工况需求的前提...     

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.