有机硅和环氧树脂复合改性聚氨酯涂料的研制

通过单因素实验和正交实验,以涂膜的拉伸强度为依据,确定了用有机硅和环氧树脂复合改性聚氨酯涂料时,制备聚氨酯预聚体的单体甲苯二异氰酸酯(TDI)和聚醚二元醇(DL2000)的恰当配比,有机硅、环氧树脂和增塑剂的恰当添加量.以及恰当的反应时间和反应温度.对复合改性涂膜进行了红外光谱分析和热重分析,对比检测了未改性涂料,有机硅改性涂料、有机硅和环氧树脂复合改性涂料的各方面性能.结果表明,有机硅和环氧树脂复合改性的聚氨酯涂料各方面性能良好,涂膜具有较高的力学强度、良好的附着力、较低的吸水率、较好的热稳定性和耐酸碱性能.     

水性聚氨酯的合成及可剥涂料的性能研究

目的以水性聚氨酯为主要成膜物质,制备一种耐水性良好且涂层整体可剥的保护涂料。方法首先采用正交法分析水性聚氨酯的合成工艺,并通过测试红外图谱、存储时间、外观及耐水性,分析三乙胺和H2O含量对产物性能的影响。再以合成产物为基料,加入固化剂聚碳化二亚胺及其他助剂制备水性涂料,通过测试邵氏硬度、附着力、拉伸强度、断裂伸长率、剥离强度及耐水性,分析该水性涂料的可保护性和可剥性。结果红外图谱表明成功合成了水性聚氨酯,得出了自乳化型水性聚氨酯的最佳合成工艺。涂料工艺性和涂层的综合性能良好,涂层可以一次性整体剥离。该涂层附着力为4B,具有良好的耐水性,在室温水中浸泡48 h后,质量基本不变,拉伸强度由37.7 MPa变为33.6 MPa,断裂伸长率由540%变为510%,邵氏硬度仍为82HA。结论聚碳化二亚胺和其他助剂的加入使得涂层具有良好的可剥性和耐水性,且涂层硬度为82HA,对基材能起到一定的保护作用。     

仿生自修复环氧树脂涂层制备及性能

采用一步原位聚合法制备了脲醛树脂包覆E-51/711微胶囊,观察微胶囊形貌呈球形,为单核结构,表面致密,粒径大小分布为25～375μm。模仿生物组织损伤自愈合原理,将微胶囊引入环氧树脂涂层结构中,设计了潜伏型微胶囊自修复环氧涂层。对不同微胶囊质量分数(5%,10%,15%,20%)的环氧自修复涂层的力学性能进行测试分析,结果表明:随着微胶囊的添加量增大,涂层的冲击强度、附着力级别和巴尔霍兹硬度不断降低,而适量添加微胶囊可提高涂层的附着力。对微胶囊环氧树脂涂料块体试样进行拉伸断裂测试试验,并对涂层进行预置划痕修复试验,结果表明:少量添加微胶囊对涂层起到了一定增韧作用,含微胶囊自修复体系的涂层在受到损伤时能够释放修复剂,填充修复损伤部位。     

不同腐蚀环境中几种典型涂层在玻璃钢表面的附着力研究

利用加速腐蚀实验、附着力测试、红外光谱分析等手段,研究了几种典型涂层与环氧玻璃钢底材的附着力及其影响因素。玻璃钢与环氧涂层的附着力与玻璃钢表面的粗糙度和润湿性能有关,当玻璃纤维布外露时,涂层附着力最高;240#砂纸打磨底材后涂层附着力高于60#及600#砂纸打磨底材的涂层附着力。不同涂层在玻璃钢表面的附着力与涂层中主要官能团的极性有关,含有极性较强的多卤素键的氟碳树脂漆表现出较强的附着力;与环氧涂层相比,聚氨酯涂层和聚硅氧烷涂层除含有与环氧涂层相同的酯键、醚键外,还因含有氨酯键、硅氧键等极性键,显示出较高的附着力。对比40 ℃浸泡实验、盐雾实验和湿热实验的结果,40 ℃浸泡实验对涂层附着力降低的影响更大;红外光谱分析表明,40 ℃浸泡与盐雾实验相比涂层内部的分子降解程度更明显。     

聚氨酯涂层球墨铸铁管的研制

研制了一种专用于球墨铸铁管的聚氨酯涂层,研究了涂料配比对粘度、流平性、固化速度、附着力、硬度等涂料性能的影响,分析了工艺参数如温度、压力对涂层质量的影响.     

不同退火温度下a-C:Si涂层的热稳定性研究

目的在碳化硅基底上制备a-C:Si涂层,通过分析涂层在不同退火温度下的热稳定性机制,拓宽其在高温领域的应用。方法采用非平衡磁控溅射法在碳化硅表面沉积a-C:Si涂层,并进行不同温度的退火热处理,通过XPS、SEM、拉曼光谱对涂层进行表征与分析。利用分子动力学对a-C:Si涂层退火过程进行仿真,从涂层与原子结构、原子径向分布函数、配位数、键长及键角等多方面对涂层石墨化行为进行分析。通过仿真与实验数据的交叉分析,探究a-C:Si涂层热稳定性机制。结果a-C:Si涂层主要由C、Si元素组成,且碳原子之间主要形成sp~2和sp~3两种杂化键,其中sp~3键居多,随退火温度的上升,其相对含量下降。a-C:Si涂层的拉曼光谱在400～500℃时出现明显的D峰,I_D/I_G积分强度比和G峰峰值具有相似的变化趋势。退火温度升高时,涂层中键长较长的sp~3-sp~3键最先开始向sp~2-sp~2转化,随着退火温度的升高,键长较短的sp~3-sp~3键才开始变化。石墨化过程中,sp~3-sp~3键转化率最大,Si与C形成高热稳定性的Si—C键。结论退火处理对a-C:Si涂层的热稳定性有重要影响,退火温度为400℃时,a-C:Si涂层开始发生石墨化转变。Si元素能稳定原子结构,与Si成键的C-sp~3杂化原子具有更高的热稳定性,降低了石墨化的速率。     

常温固化耐高温400℃的有机硅-聚硅氮烷涂料

目的实现有机硅树脂的室温固化并提高其耐热性,从而制备室温固化耐高温涂层。方法以硅羟基为活性官能团的有机硅树脂作为主体树脂,选择自制的聚硅氮烷作为固化剂,添加碳化硅和玻璃粉等耐热颜填料,制备一种室温固化的有机硅/聚硅氮烷耐高温涂料。采用红外光谱扫描仪和热失重分析仪分别对树脂的固化过程和耐热性能进行表征。加入填料后,对固化后涂层的铅笔硬度、抗冲击性、柔韧性和耐高温性能进行评价。采用金相显微镜对热处理后的涂层形貌进行观察。结果硅树脂和聚硅氮烷在室温下混合反应72 h后,涂覆层硬化成膜,其红外谱图中N—H的弯曲振动峰消失,归属于Si—N的吸收峰强度呈减弱趋势,证明了二者之间发生了化学反应。随着聚硅氮烷加入量的增加,样品热失重率减小且残重增加,其中加入32.5%聚硅氮烷的固化物样品,400℃的失重率仅为0.76%,失重5%时的温度高达500℃以上。固化后涂层的附着力为0级,柔韧性为1级。热处理后,涂层表面的平整度变好,附着力明显提高。结论聚硅氮烷不仅能常温固化硅树脂,改善其附着力,而且明显提高了有机硅树脂的耐热性。基于聚硅氮烷固化有机硅树脂制备的涂层具有良好的柔韧性和耐高温特性,最高耐温达到400℃以上。     

硬质合金刀具类金刚石涂层及其性能评价

利用磁控溅射技术在硬质合金刀具表面制备了含纯金属过渡层的类金刚石涂层。采用光学轮廓仪、SEM、EDS、拉曼光谱、显微硬度计和多功能表面性能测试仪对制得的涂层进行了成分和性能等表征。结果表明,在类金刚石涂层和基体之间成功沉积了过渡层,过渡层对样品的性能影响程度不同。通过拉曼光谱分析表明过渡层的金属种类对样品涂层的sp~3键含量影响不大,过渡层元素为Cu和Ag的样品涂层中sp~3键含量略高。通过硬度测试表明涂层的硬度受到的影响也较小,其中过渡层元素为Ti和W的样品硬度较高。通过膜/基结合力测试表明过渡层的金属种类对该项性能影响较大,其中过渡层元素为W的样品表现最好。综合各项表征可以看出,过渡层更多地影响涂层与基体之间的关系,而对涂层本身的性能影响并不大。     

涂料防腐蚀工程质量检验与评定方法

本文介绍了在涂料防腐蚀工程质量检验过程中,对于涂装前表面处理、涂层厚度、孔隙率、附着力和硬度的常用检验和评定方法以及常用检测仪器的基本原理.     

氮化钛含量对热塑性涂层光热效应及自修复性能的影响

为了实现涂层破损的高效自修复,将纳米氮化钛与热塑性聚氨酯混合,制备了不同氮化钛含量的复合涂层。 利用扫描电子显微镜(SEM)、X 射线衍射仪(XRD)和紫外可见分光光度计(UV-Vis)分析了氮化钛的结构和光谱吸收特征;利用差示扫描量热仪(DSC)、热电偶、光学显微镜、扫描电子显微镜( SEM)、交流阻抗谱(EIS)等对复合涂层的热力学性能、光热转换性能、自修复性能及防腐性能进行测试。 结果表明:基于纳米氮化钛的表面等离激元特性,在热塑性聚氨酯中添加质量分数为 2%的氮化钛后,复合涂层具有良好的光热转换性能,在近红外激光照射后其表面温度高于聚氨酯的玻璃化转变温度。 当涂层表面有划口时,通过激光照射可以提高涂层的局部温度,使聚合物分子链运动并流向划痕界面,复合涂层的结构和防腐性能均得到恢复,并且修复后涂层中氮化钛仍分布均匀。 此外,氮化钛纳米颗粒还有助于填补涂层的微观孔隙,使复合涂层的防腐性能提高。     

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.