热喷涂纳米涂层制备方法及材料研究现状和展望

综述了热喷涂纳米涂层的制备方法现状及所用材料的发展情况,介绍了溶液等离子喷涂(SPS)、冷气动力喷涂(CGDS)、高速火焰喷涂(HVOF)技术制备纳米涂层的优势、纳米粉末材料的制备方法及发展趋势,指出纳米涂层制备的主要关键在于解决纳米粉末的输送技术和涂层制备过程中抑制纳米颗粒的长大趋势.纳米涂层的研究对推动热喷涂技术应用有着十分重要的作用.     

热喷涂纳米陶瓷涂层的制备及性能

热喷涂纳米陶瓷涂层的研究是目前陶瓷涂层领域研究热点之一.介绍了国内外热喷涂纳米陶瓷涂层的主要制备方法及涂层性能,重点介绍了可喷涂纳米结构喂料的主要制备方法和工艺路线.与传统微米级陶瓷涂层相比,纳米陶瓷涂层具有更为优异的性能和广阔的发展前景.     

热喷涂纳米结构涂层的研究现状

介绍了国内外喷涂用纳米结构喂料的制备方法以及在应用热喷涂技术制备纳米结构涂层方面的研究进展.与传统材料的热喷涂涂层相比,纳米结构涂层在力学、摩擦学以及耐磨防腐蚀性能方面有了较大的提高.     

热喷涂纳米涂层制备方法及材料的研究现状和展望

综述了热喷涂纳米涂层的制备方法现状及所用材料的发展情况，介绍了溶液等离子喷涂（SPS）、冷气动力喷涂（CGDS）、高速火焰喷涂（HVOF）技术制备纳米涂层的优势、纳米粉末材料的制备方法及发展趋势，指出纳米涂层制备的主要关键在于解决纳米粉末的输送技术和涂层制备过程中抑制纳米颗粒的长大趋势。纳米涂层的研究对推动热喷涂技术应用有着十分重要的作用。     

热喷涂纳米粉体材料及其涂层制备

介绍了国外喷涂用纳米结构喂料的制备方法，以及采用几种先进的热喷涂技术制备的纳米结构涂层，并指出非晶/纳米晶涂层是该领域研究的重中之重。与传统喷涂层相比，纳米结构涂层在耐磨、防腐性能方面呈现出优异性能和良好的发展前景。     

热喷涂专用纳米材料及其涂层制备的研究现状

热喷涂纳米涂层的研究是目前纳米涂层领域研究热点之一.综述了国内外热喷涂专用纳米材料的制备方法以及采用几种先进的热喷涂技术制备的纳米涂层,指出了目前用热喷涂技术制备纳米涂层所面临的难题.展望了热喷涂技术在制备纳米涂层方面的发展前景.     

热喷涂纳米结构涂层技术的研究进展

与传统材料的热喷涂涂层相比,纳米结构涂层在力学和摩擦学等方面的性能有了一定的提高.作者综述了国内外在应用热喷涂技术制备纳米结构涂层方面的研究进展.介绍了纳米结构喂料的制备、热喷涂纳米结构涂层的构筑方法、涂层的特殊性能以及应用情况.从目前国内外的情况来看,热喷涂纳米结构涂层技术的研究取得了较大的进展.随着技术、工艺的不断完善,其必将在很多领域取代传统的涂层.     

热喷涂Zn-Al合金防腐涂层技术的研究进展

热喷涂Zn-Al合金涂层技术是一项新发展起来的防腐技术.介绍了近年来分别利用火焰喷涂技术和电弧喷涂技术制备Zn-Al合金涂层及其喷涂材料的研究应用现状,分析了涂层的形成及其耐蚀机理,并展望了热喷涂Zn-Al合金涂层技术的发展趋势.     

热喷涂技术制备功能梯度材料涂层的发展状况

介绍了热喷涂技术制备功能梯度材料涂层的研究与发展状况,分析了各种热喷涂方法制备功能梯度涂层的技术与工艺特点,指出了各自的优势与不足;同时还介绍了20世纪90年代末发展起来的自蔓延高温合成技术与热喷涂技术相融合而形成的反应热喷涂技术制备功能梯度材料涂层的最新研究动态,并展望了热喷涂制备功能梯度材料涂层的发展前景.     

YPSZ纳米结构热喷涂粉末材料工艺优化研究

热等离子体喷涂制备YPSZ纳米结构涂层必须首先进行YPSZ纳米结构粉末材料的研究.本文采用浆料分散、喷雾干燥、热处理的方法制备适于热等离子体喷涂纳米结构涂层的球形、致密YPSZ纳米结构粉末材料.测定浆料的粘度、沉降高度曲线表征浆料的均匀性和稳定性,利用扫描电子显微镜、x射线衍射分析对粉末材料的微观组织及相结构进行分析,利用热重/差热分析对热处理工艺过程进行分析.结果表明:采用优化的工艺成功制备出球形、结构均匀、致密的YPSZ纳米结构粉末材料,适于热喷涂制备YPSZ纳米结构涂层.     

Prozessüberwachung beim thermischen Spritzen durch die Analyse akustischer Emissionen verifiziert durch die Methoden der CFD zur Berechnung der Schallemission beim HVOF‐Verfahren

Refining of thermal spray process conditions by acoustic emission analysis verified by computed fluid dynamic Modern thermal spray technology requires process diagnostic in order to achieve high quality coating production. Common diagnostic systems used for observing optical emissions of spraying processes analyse the geometry of the spray jet or the in‐flight particle parameters. Such optical systems are expensive and complex. More economic and easier to apply is the analysis of the acoustic emissions of the spraying process. Depending on the method of thermal spraying, acoustic signals contain extremely useful information that can be used for detecting critical spraying conditions. Application of microphones and vibration pick‐ups is tested for HVOF and electric arc spraying. Finally the correlation between the acoustics of real processes and results from computer simulations are investigated.     

低压等离子喷涂技术及研究现状

低压等离子喷涂作为一种热喷涂技术,相比于传统的大气等离子喷涂技术以及气相物理沉积,可制备更加纯净、更为致密、结合强度更高的涂层。主要介绍了低压等离子喷涂的原理、分类及特征,回顾了低压等离子喷涂的产生及发展历程,并与等离子喷涂、超低压等离子喷涂和等离子喷射沉积相比较,分析了其在涂层制备上的独特优势。进一步叙述了低压等离子喷涂技术在制备热障涂层、燃料电池、太阳能、半导体等领域的国内外研究及应用情况,并对其发展进行了展望,指出低压等离子喷涂技术未来的重点发展方向在于对等离子喷涂焰流与材料基板作用机理进行深入研究,以及与其他前沿技术进行复合。     

喷涂距离对Fe基非晶涂层孔隙影响的研究

热喷涂涂层中孔隙的存在会降低涂层的耐蚀性,减少涂层寿命,而热喷涂工艺参数很大程度上影响涂层的孔隙率。本文采用计算机数值模拟和设计验证实验的分析方法,重点研究了JP-8000超音速火焰喷涂系统(HVOF)制备Fe基非晶涂层工艺参数中喷涂距离与涂层孔隙的关联性。利用商用计算软件Fluent计算平台,研究加入粉末粒子前,喷枪内火焰温度和速度的变化规律,以及加入非晶粉末后,不同喷涂距离条件下颗粒飞行过程的温度和速度的变化规律。仿真结果表明,喷涂距离为360~380 mm时,非晶粉末颗粒在撞击基板时处于半融化状态,颗粒在基板上具有良好的流动性,可获得孔隙率较低的涂层。验证实验结果与仿真结果一致。X射线衍射结果表明,粉末、不同喷涂距离所制备的涂层以及同成分的非晶条带均为完全非晶态结构。SEM和孔隙率统计结果表明,喷涂距离为370 mm时,涂层截面的孔隙较少,且孔隙率最低,为0.57%,验证了计算模拟优化的最佳喷涂距离范围。     

Spray Dried Polylactide Microsphere Preparation: Influence of the Technological Parameters

Spray drying technique has been widely used in the pharmaceutical technological field with different applications. Recently it has been also successfully employed in the preparation of microparticulate drug delivery systems. The structure of the microparticles obtained is different according whether the drug is dispersed or dissolved in the polymeric solution to be spray dried.

Microcapsules are obtained by spraying a drug suspension in a solution of the polymeric coating, while polymeric matrices (microspheres), in which the drug is embedded, are obtained by spraying a solution of the drug and of the polymer.

The aim of this work is the investigation of several technological parameters that can affect the preparation and therefore the characteristics of the microparticles obtained by spray drying method. The effect of the inlet/outlet temperatures, spray rate of feed and of concentration of the starting polymeric solution on the characteristics of diazepam loaded poly-D, L-lactide microparticles are studied and evaluated with respect to yield of production, shape, size, and in vitro drug release behaviours.     

Untersuchung der Einflüsse von Substratrauheit und Spritzpartikelgröße auf die Haftung thermisch gespritzter Schichten

About the influence of substrate roughness and spray particle size on the adhesion of thermal spray coatings The influence of substrate roughness and spray particle size on the adhesion of thermal spray coatings was researched systematically. In addition to established spray materials (Cr₂O₃, WCCo, NiCr) and spraying processes (atmospheric plasma spraying (APS), high velocity flame spraying (HVOF)) different substrate materials (steel, stainless steel, aluminum) were included in the research work as well.     

Effects of Feedstock and Laser Post-spray Treatment on Plasma Sprayed Bioceramic Coatings*

Hydroxyapatite (HA) is a bioactive material with Ca to P ratio similar to that of natural bone. This can encourage early bonding between bony tissues and the implant surface. Plasma spraying is efficient in coating HA onto biomedical implants. However, the biocompatibility of hydroxyapatite (HA) changes after plasma spraying. This paper reports the preparation and characterization of HA coatings using different feedstocks; calcined HA (CHA) that has angular geometry, and spray dried HA (SDHA) that is predominantly spherical in shape. The results indicates that the state of the starting powder adversely influences the coating characteristics. Both types of HA, calcined and crushed HA powders and spray dried HA powders, are plasma sprayed on steel substrates to produce HA coatings. The results indicate that particle cohesion, size range and thermal treatment during thermal spray processing alter the phase and structure of the as-sprayed coatings. Post-spray treatment by pulsed lasers is performed on the coatings to modify the surface characteristics and phase composition of the surface layer. This, in addition, may be necessary to produce a dense and well-bonded coating having the desired biocompatible properties. Laser treatments show overall melting of the HAcoating to yield a smooth surface. However, the presence of crack networks is undesirable.     

冷喷涂制备高熵合金的研究进展

高熵合金是近年来一种突破传统合金设计理念的新型多主元合金材料,在抗压强度、硬度、热稳定性、耐磨性、耐腐蚀性等方面具有显著优于常规金属材料的特质.冷喷涂作为一种固态沉积技术,在高性能涂层制备、零件修复与再制造和零构件增材制造等方面受到国内外的广泛关注,为高熵合金的制备提供了一种新的途径.通过分析国内外冷喷涂制备高熵合金的...     

超细NiO粉体的制备及其应用研究进展

综述了超细NiO粉体近年来的制备方法及其特点(主要有固相反应法、沉淀法、微乳液法、喷雾热解法、热分解法和电化学法),介绍了超细NiO粉体的应用现状.     

Thermisches Spritzen neuartiger SiC und TiC Pulver mit oxidischer Binderphase

Processing of newly developed SiC and TiC Powders with Oxide‐Ceramic Matrix by means of Thermal Spraying Intermediate results of an actual project are presented. The investigations concern newly developed SiC and TiC powders, their processing by means of thermal spraying and the characterization of produced coatings. Development and optimization of powders, thermal spray process and spray parameter optimization are carried out on permanent feedback. The powder production line is spray‐drying, sintering and conditioning. The binder matrix phase is aluminum oxide / yttrium oxide. The produced powders SiC – Al₂O₃/Y₂O₃ and TiC – Al₂O₃/Y₂O₃ show different specific chemical compositions and morphologies each. Carbide contents of >65 % are aimed at. Applied thermal spray processes are atmospherical plasma spraying and high velocity oxygen fuel spraying. The results demonstrated characterize feedstock powders as well as produced coatings. The investigations are done by means of light and scanning electron microscopy.     

Characterization of Thermal Spray Coatings

The ability to characterize fully the microstructure of a coating is paramount for understanding the in-service properties and eventual optimization of the coating. This article discusses sample preparation and subsequent analytical techniques (LOM, SEM, XRD, WDS, and QIA) for several cermet thermal spray coatings and provides a detailed analysis of as-sprayed microstructures in addition to processing trends for several FeCrAIY-carbide coatings. It was found that the splats produced in these high velocity oxy-fuel (HVOF) coatings tended to exhibit a predominantly dendritic structure most likely retained from the gas atomization process that produced the original powder. Chemical analysis showed that the carbides tend to breakdown during spraying producing a complex mixture of oxides and various carbides. Finally, image analysis revealed that as the carbides in the pre-sprayed powder were increased, more carbides and oxides with less FeCrAIY and thinner coatings were found. These techniques allow the thorough characterization of thermal spray cermet coatings, which in turn should further the understanding of the thermal spray processes and help provide superior coatings in the future.