NiCrFe金属上涂覆玻璃陶瓷涂层的结构和性能

以硝酸铝Al(NO3)3·9H2O和正硅酸四乙酯(TEOS)为主要原料,采用溶胶-凝胶法在镍铬铁合金(NiCrFe)载体上制备不同硅铝摩尔比的玻璃陶瓷涂层,研究不同制备条件对涂层形貌、结晶质量及结合强度的影响。XRD、SEM及热冲击、超声振荡、拉伸试验结果表明,与传统涂层相比,该涂层可以提高比表面积,增强柴油车金属基(NiCrFe)后处理器与催化剂的结合强度,且焙烧温度较低,制备工艺简单。其中,载体经900℃预处理,硅铝摩尔比为5:1的涂层经70℃烘干2h,650℃焙烧2h后得到最佳样品。     

金属表面溶胶-凝胶防腐蚀涂层的研究进展

在各种防腐蚀的方法中,溶胶-凝胶法是一种操作简单、环境友好、成本低廉的表面涂层制备技术,被广泛应用于许多金属材料表面的腐蚀防护上。简单地介绍了溶胶-凝胶法的基本原理以及易改性、易控温、无污染的优点,重点阐述了影响涂层耐腐蚀性能的相关工艺参数,包括水解温度、p H值、陈化时间、反应物浓度、热处理温度等。详细综述了溶胶-凝胶法制备防腐蚀涂层工艺的特点与研究现状,经过单一无机氧化涂层到多元复合涂层的发展,涂层的性能得到提升,应用范围更加广泛。介绍了溶胶-凝胶涂层的3个防腐蚀机理,包括屏蔽作用、缓蚀钝化作用、牺牲阳极保护作用,阐述了涂层的防腐蚀机制,为研究新的防腐蚀工艺提供理论基础。最后,总结了目前防腐蚀涂层研究过程中所遇到的困难,并展望了可能的解决方法,为未来的研究提供了发展方向。     

用溶胶—凝胶法制备金属材料表面非晶态涂层

为了保护钢铁和其它金属材料免于腐蚀破坏或为赋予它表面特殊性质,可以在它表面进行涂装。采用溶胶—凝胶法在金属材料上制备涂层是近年来材料科技领域的新成就。该法可在金属材料上涂覆微晶玻璃及非晶态涂层。这种涂层是一种非常致密牢固的气密性薄膜,与金属材料有很高的粘结强度,它本身有很高的显微硬度、化学稳定性和耐腐蚀性。采用溶胶—凝胶法可以制取多种元素和成份的涂层。涂层薄、韧性好,既可以涂一层,也可以涂二层、三层……。涂装的工艺、设备简单,并且可在比较低的温度下完成,获得的涂层具有高的纯度。目前该工艺在材料保护、表面技术上正渐获得应用与推广。     

先进的溶胶-凝胶涂层的实际应用

溶胶-凝胶技术的特点之一是密切结合工业应用。另一个特点是所得材料有块状、纤维状、薄膜涂层和粉末等各种形状。作者集中研究了能实际应用的在各种基体上的溶胶一凝胶涂层,以及结合工业应用的基础研究。在此评述中将提供此项研究的结果。包括：（1）在金属板材上的防护涂层;     

氧化锆溶胶-凝胶涂层对化学钢化玻璃强度的影响（英文）

以氧氯化锆为前驱物,双氧水为催化剂,在乙醇中水解得到稳定的氧化锆溶胶。通过提拉法在化学钢化玻璃表面制备了0.1-0.3μm厚度的均匀无裂纹、孔洞的致密氧化锆涂层。三点抗弯强度测试结果表明:涂膜钢化玻璃的抗弯强度比相应的末涂膜样品高。这是由于化学钢化玻璃表面裂纹尖端被涂层有效地填充,减少了表断裂纹有效长度。此外,当热处理温度在:400℃至5(0(0℃区间范围内时,随着温度的升高,所有样品的抗弯强度均有下降趋势,处理温度越高,下降得越严重。研究认为这主要是由于在此较高温度下钢化层中钾离子向玻璃内部迁移而引起的表面压应力松弛所致。     

金刚石表面涂覆玻璃涂层的研究

本文应用ＩＲ光谱和ＳＥＭ等技术，探讨了２０Ｎａ２Ｏ．１０ＺｎＯ．１０Ｂ２Ｏ３６０ＳｉＯ２玻璃与金刚石之间的作用。     

Sol-gel法镁合金表面制备SiO2涂层及其腐蚀性能研究

利用有机醇盐水解法制备了SiO2溶胶,采用溶胶-凝胶法在AZ91D镁合金表面制备了SiO2涂层.通过SEM、XRD等分析技术对涂层表面结构和组织进行表征,并探讨了该涂层的耐腐蚀性能及涂覆次数对腐蚀性能的影响.结果表明:以正硅酸乙酯为原料、无水乙醇为溶剂、盐酸为催化剂,可制备出均匀透明的SiO2溶胶;3.5％NaCl水溶液浸泡腐蚀试验表明,SiO2涂层显著提高了镁合金表面的耐腐蚀性能.     

SiC涂层制备及辐射性能分析（英文）

模板热防护涂层是高超声速飞行器热防护系统(TPS)的重要组成部分,具有高发射率的涂层可以增强TPS系统效率。将SiC、C0_3O_4纳米粉与A1_2O_3溶胶混合球磨后,采用溶胶-凝胶法在镍基高温合金表面制备了SiC涂层。利用扫描电子显微镜观察涂层的微观形貌,测定了涂层的光谱发射率。分析了涂层发射率与厚度的关系。结果显示,涂层具有较高的发射率,厚度在20-30um范围内,发射率具有最高值。     

9-磷钨酸光致变色玻璃涂层的制备与表征(英文)

自制的9-磷钨酸与高聚物如聚乙烯吡咯烷酮、聚乙烯醇等在一定温度下的醇溶液中醇解得到混合溶胶样品,采用喷涂法或浸渍涂布法在玻璃基板上成膜,常温干燥得到具有光效应的涂层。透明的玻璃涂层在日光照射下10s变蓝色。用XRD、SEM、UV-可见分光光度计、红外光谱分析仪等对薄膜以及粉末的特性进行了测试。实验结果表明该涂层具有良好的光致变色消色特性。     

溶胶-凝胶法制备准晶颗粒涂层及其表征

采用常规铸造法和球磨法制备得到单相Al-Ni-Co十次准晶颗粒,并采用溶胶-凝胶法在准晶颗粒表面成功的添加了涂层。分别采用XRD、SEM、FE-SEM和EDS分析了干凝胶以及添加涂层后准晶颗粒的微观组织、形态以及界面情况。实验结果表明,制备得到的干凝胶为非晶态的勃姆石,经高温煅烧后它转化为α-+δ-+θ-Al2O3晶体相。而添加涂层后的准晶颗粒经高温煅烧后,其相组成为DQC+α-+β-+θ-Al2O3,准晶仍然保持较高的热稳定性。FE-SEM分析结果表明,涂层与颗粒的界面结合特性良好,涂层的厚度约为0.71～0.91μm,均匀分布于颗粒表面。     

硬质合金基底表面线缺陷对金刚石涂层膜基界面结合强度的影响

基于密度泛函理论的第一性原理平面波赝势方法,研究了不同硬质合金基底线缺陷率下的金刚石涂层膜基界面结合强度。通过建立[111]、[110]、[100]3种不同晶向的金刚石涂层膜基界面分子模型,研究了硬质合金基底线缺陷率对涂层膜基界面结合强度的影响以及[111]、[110]、[100]3种不同金刚石涂层晶向下的最优膜基界面结合强度。研究结果表明:硬质合金基底的表面能随着基底线缺陷率的增加而逐步增大;当线缺陷率ρ=12.5%时,基底表面能达到最大值;其后,随着基底线缺陷率继续增大,基底表面能逐渐呈减小趋势。进一步研究显示,不同晶向的金刚石涂层膜基界面的最优界面结合能的最优线缺陷率不同,[111]晶向和[110]晶向的金刚石涂层的最优基底线缺陷率均为6.25%,而[100]晶向金刚石涂层的最优基底线缺陷率则为0%。      

Zr基非晶合金与铜的扩散连接研究

利用Gleeble 3500热模拟试验机在添加和未添加扩散连接中间层条件下对Zr41.25Ti13.75Cu12.5Ni10Be22.5块体非晶合金与纯铜的扩散连接性进行了研究。实验结果表明,在两种条件下均获得了无裂纹和空洞的良好的连接界面。通过扫描能谱分析和电子探针分析在连接界面处观察到明显的元素扩散,但元素扩散距离较窄。非晶合金中晶化相的出现促进了界面处元素的扩散。     

涂层结合强度研究现状与发展

综述了近年来国内外针对不同性质涂层所采用的结合强度测定方法,发现涂层结合强度测定方法应根据涂层厚度、涂层硬度、涂层功能等特征来选定。从弹性断裂力学角度分析了相关的结合强度理论模型,得出了结合强度的计算公式,总结了提高涂层结合强度的各种途径,阐明了涂层结合强度的研究现状和发展趋势。     

High strength ductile Cu-base metallic glass

Usually, bulk metallic glasses exhibit strength values superior to conventional crystalline alloys, often combined with a large elastic limit and rather low Young's modulus. This combination of properties renders such alloys quite unique when compared to commercial materials. However, the major drawback for engineering applications is their limited room temperature ductility and toughness due to the localized deformation processes linked to shear banding, where high plastic deformation is accumulated in a very narrow region without contributing to macroscopic deformation, work hardening or yielding. In this work we report on a new class of metallic glass in a simple Cu-base alloy. Addition of 5 at.% Al increases the glass-forming ability of binary Cu₅₀Zr₅₀. The resulting Cu_47.5Zr_47.5Al₅ glass exhibits high strength (2265 MPa) together with large room temperature ductility up to 18%. After yielding a strong increase in the flow stress is observed during deformation. The structure of the metallic glass exhibits atomic-scale heterogeneities that enable easy nucleation and continuous multiplication of shear bands. The interaction and intersection of shear bands increases the flow stress of the material with further deformation, leading to a ‘work hardening’-like behavior and yields a continuous rotation of the shear angle up to fracture resulting in a high compressive ductility.     

A method for determining the bonding strength of a silver coating with a silicon substrate

A method for determining the bonding strength of a silver coating with a silicon substrate is described. Various high-strength adhesives are tested and the optimum adhesive for the determination of the bonding strength of the silver coating with the silicon substrate on the basis of the bonding method is selected.     

钎剂预处理对涂层结合强度的影响

采用预涂Nocolok钎剂的方法对ZL101基材进行等离子喷涂前的表面预处理,结合对基材界面温度的计算,分析了钎剂预处理提高涂层结合强度的作用机理,并通过正交试验研究了喷涂工艺参数对Ni5Al涂层结合强度的影响.结果表明,表面预涂钎剂可显著提高基材与Ni5Al涂层的结合强度,喷涂粒子及基材表面的温度对界面产生冶金结合起到了决定性的作用;当喷涂距离为120mm,钎剂预涂量80mg/cm2,预热温度为573K时,Ni5Al涂层的结合强度最高.     

Microstructure and bonding strength of Ni-based alloy coating

Glass molding dies often fail due to wear, oxidation and crack under the service condition of the melting glass above 1100℃ , existence of thermal shock or sliding contact friction. A repeated phase transformation may occur because the surface temperature of the die cavity exceeds eutectoid temperature during the service once the die is in contact with the hot glass. This, in turn, results in cracking on the die cavity surface, and finally, the service life of the die will be reduced[1]. Aust…     

The effect of zirconium coating on bonding strength of porcelain to titanium

The Zr coating was deposited on titanium surface using the magnetron sputtering technique. Effects of Zr coating on microstructure and mechanical properties of porcelain fired to titanium have been investigated. The results show that interdiffusion of elements occurs during porcelain firing, and the Zr coating can effectively protect titanium surface from excess oxidation. The strength of bond zone with Zr coating deposited for 1 hour reaches 29. 7 MPa, which has increased by 26.4% as compared with that of bond zone without coating （23.5 MPa）.     

Bioactive glass nanopowder and bioglass coating for biocompatibility improvement of metallic implant

Preparation and characterization of bioactive glass nanopowder and development of bioglass coating for biocompatibility improvement of 316L stainless steel (SS) implant was the aim of this work. Bioactive glass nanopowder was made by sol–gel technique and transmission electron microscopy (TEM) technique was utilized to evaluate the powders shape and size. The prepared bioactive glass nanopowder was immersed in the simulated body fluid (SBF) solution at 37 °C for 30 days. Fourier transform infrared spectroscopy (FTIR) was utilized to recognize and confirm the formation of apatite layer on the prepared bioactive glass nanopowder. Bioactive glass coating was performed on SS substrate by sol–gel technique. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques were used to investigate the microstructure and morphology of the coating. Electrochemical polarization tests were performed in physiological solutions at 37 °C in order to determine and compare the corrosion behavior of the coated and uncoated SS specimens. Cyclic polarization tests were performed in order to compare the pitting corrosion resistance of the coated and uncoated SS specimens. The results showed that the size of bioactive glass powder was less than 100 nm. The formation of apatite layer confirmed the bioactivity of bioglass nanopowder. Bioactive glass coating could improve the corrosion resistance of 316L SS substrate. Bioactive glass coated 316L SS showed more pitting corrosion resistance in compare with pristine samples. It was concluded that by using the bioactive glass coated 316L SS as a human body implant, improvement of corrosion resistance as an indication of biocompatibility and bone bonding could be obtained simultaneously.     

Laser surface coating of Fe-Cr-Mo-Y-B-C bulk metallic glass composition on AISI 4140 steel

Fe-based bulk metallic glasses exhibit very high hardness, elastic modulus/limit and wear/corrosion resistance. In the present investigation, an attempt has been made to develop an amorphous coating with Fe₄₈Cr₁₅Mo₁₄Y₂C₁₅B₆ bulk metallic glass on AISI 4140 substrate by laser surface processing. Following coating, the microstructure and phase aggregate were analyzed by scanning electron microscope and X-ray diffraction, respectively. Microhardness and wear resistance were assessed using Vickers microhardness tester and ball-on-plate wear testing machine, respectively. The coating thickness varied directly with incident laser power and interaction time. Despite trials with wide range of process parameters, the present experiments were unable to retain complete amorphous surface microstructure after laser surface coating. Numerical prediction of the thermal profile and related parameters suggest that the cooling rate and thermal gradient experienced by the coated zone were fairly high. Yet failure to retain amorphous/glassy microstructure of an otherwise bulk metallic glassy alloy suggests that compositional changes (solute redistribution) within the coated zone and across the coating-substrate interface are responsible for nucleation and growth of crystalline phases from the melt. However, correlation between coating parameters and surface microstructure and properties allowed determination of the optimum conditions that ensured fine grained uniform microstructure with a significant improvement in hardness and wear resistance.