异质金属丝电弧喷涂工艺的试验研究

本文主要介绍利用电弧做热源,通过电弧喷涂的工艺方法,使不锈钢丝和铝丝瞬间同时熔化后喷射粘附在基体金属表面上,得到一种复合材质涂层。试验中通过改变送丝速度和电弧电压等参数,制备一些涂层试样,并对涂层进行了宏观和微观组织结构检测、X射线衍射分析和显微硬度测量。由试验分析结果可以得到以下结论: (1)通过调节送丝速度和电弧电压等参数,铝和钢的异丝喷涂是可以实现的;(2)涂层的颗粒大小可以通过改变工艺参数来控制;(3)铝和钢异丝喷涂层中有Fe-Al化合物生成,其硬度高于铁、铝纯金属;(4)利用电弧喷涂装置有望使异质金属丝同时熔化并发生冶金反应,从而制备具有特殊性能的金属化合物涂层。     

电弧喷涂粉末管状丝材的工艺参数优化

电弧喷涂工艺参数主要包括喷涂电流、喷涂空气压力、送丝速度、喷涂电压、喷涂距离和喷涂材料成分等。它们各自对涂层的性能有着不同的影响,探求它们的最佳组合,使涂层性能达到最佳,一直是热喷涂领域的热门话题。国外也曾进行过一些工艺参数优化试验,但都采用普通碳钢材料。本文对这一新型喷涂丝材的工艺参数优化试验研究进行了描述。该研究采用二次回归旋转组合设计安排试验方案,并对得出的试验数据进行了计算机分析,建立了各因素和目标函数之间关系的数学模型,得出了各因素对目标函数影响的重要度,并在数学模型的基础上分析了各因素对目标函数的影响规律。最后,给出了电弧喷涂粉末管状丝材的最佳工艺参数。     

电弧喷涂送丝电机的选择

送丝系统是电弧喷涂的丝材进给系统,能否保证丝材以连续、稳定的速度送入电弧区是其关键。而送丝电机是送丝系统的核心,也是整个电弧喷涂系统的动力源泉,是获得优质、高效涂层的保证,所以送丝电机的选择将是电弧喷涂系统的一个重要环节,为此本文将针对送丝电机的选择问题进行讨论。     

电弧喷涂粉芯丝材的研究与应用

简述了电弧喷涂技术的特点和发展。将电弧喷涂与其他热喷涂技术在涂层性能等方面做了对比。概述了电弧喷涂用粉芯丝材的研究和发展现状。展望了这种粉芯丝材在制备金属/陶瓷复合涂层、纳米结构涂层和非晶涂层等方面的应用前景。     

金属喷涂工艺与设备

20091200锆涂层对钛/瓷结合强度的影响[英]/段珍珍…//China Welding.-2008,17(3):10~14采用磁控溅射法在钛表面溅射一层锆涂层,研究了锆涂层对钛/瓷界面微观组织和力学性能的影响。结果表明,在烤瓷过程中,钛/瓷界面发生了原子相互扩散,锆涂层能有效的防止钛表面过度氧化。当溅射锆涂层时间为1h,钛/瓷结合强度达到29.7MPa,与没有溅射涂层的钛/瓷结合强度23.5MPa相比,提高了26.4%。图8表2参920091201可送粉末复合式电弧喷涂枪的设计/蒋湘云…//电焊机.-2008,38(8):65~67基于针对电弧喷涂应用的局限性,设计了一种能有效结合电弧喷涂和火焰喷涂优点的复合式电弧喷涂枪。该喷涂枪设有一个送粉装置,可同时实现电弧喷涂和粉末喷涂,扩大了电弧喷涂的应用范围。通过改变合金粉末的种类和送入量,实现不同性能要求的复合涂层的制备。图5参620091202高速电弧喷涂铁基Cr3C2复合涂层的显微组织/贾焕丽…//机械工程材料.-2008,32(9):45~48采用高速电弧喷涂技术将自制的铁基Cr3C2粉芯丝材在20钢上制备复合涂层,采用SEM、TEM、XRD等研究了涂层...     

金属喷涂工艺与设备

20091200锆涂层对钛/瓷结合强度的影响[英]/段珍珍…//China Welding.-2008,17(3):10~14采用磁控溅射法在钛表面溅射一层锆涂层,研究了锆涂层对钛/瓷界面微观组织和力学性能的影响。结果表明,在烤瓷过程中,钛/瓷界面发生了原子相互扩散,锆涂层能有效的防止钛表面过度氧化。当溅射锆涂层时间为1h,钛/瓷结合强度达到29.7MPa,与没有溅射涂层的钛/瓷结合强度23.5MPa相比,提高了26.4%。图8表2参920091201可送粉末复合式电弧喷涂枪的设计/蒋湘云…//电焊机.-2008,38(8):65~67基于针对电弧喷涂应用的局限性,设计了一种能有效结合电弧喷涂和火焰喷涂优点的复合式电弧喷涂枪。该喷涂枪设有一个送粉装置,可同时实现电弧喷涂和粉末喷涂,扩大了电弧喷涂的应用范围。通过改变合金粉末的种类和送入量,实现不同性能要求的复合涂层的制备。图5参620091202高速电弧喷涂铁基Cr3C2复合涂层的显微组织/贾焕丽…//机械工程材料.-2008,32(9):45~48采用高速电弧喷涂技术将自制的铁基Cr3C2粉芯丝材在20钢上制备复合涂层,采用SEM、TEM、XRD等研究了涂层...     

电弧喷涂技术的现状与发展

介绍了电弧喷涂技术的发展历程、特点及应用，重点阐述了电弧喷涂材料及设备的研究现状与发展。指出粉芯丝材作为电弧喷涂材料新的发展方向，可以用其尝试获得非晶涂层、金属陶瓷涂层及纳米涂层。电源和喷枪是电弧喷涂设备的关键部件，逆变技术的应用是电弧喷涂电源的发展方向，而喷枪则向着高速、高效和稳定送丝的方向发展。     

电弧喷涂自熔性药芯丝材填充成分及性能的研究

1　介　　绍电弧喷涂在各种热喷涂方法中具有最高的工艺效率及沉积率。然而 ,早期却以ＨＶＯＦ工艺的开发为主要的研究方向。现在电弧喷涂再次成为人们感兴趣的焦点 ,其原因是采用电弧喷涂取代其它喷涂方法在降低喷涂成本方面存在较大的潜力。从喷涂材料方面来说 ,由于电弧喷涂受到导电丝材的限制 ,也就是说用于喷涂的材料需能制作成丝材且导电 ,为了使送丝稳定 ,丝材又必须有足够的柔韧性 ,并不是每种合金均能达到这种要求。药芯丝材的运用扩展了电弧喷涂材料应用的新领域 ,即可以采用将不导电的非金属粉末作为填充材料与金属导体包敷层结…     

丝-粉电弧喷涂Cu-Sn复合涂层的结合强度研究

研究了丝-粉电弧喷涂工艺参数对Cu-Sn复合涂层结合强度的影响。试验结果表明,在其他条件不变的情况下,电弧电压、工作电流和空气压力是影响Cu-Sn复合涂层结合强度的主要因素。     

电弧喷涂管状丝材新发展及应用

介绍了电弧喷涂管丝的国内外发展状况,及管状丝材较之粉末、线材等热喷涂材料的独特优势。提出了电弧喷涂用管状丝材开发研究方向。指出高耐磨耐蚀集成涂层将是电弧管状丝材的应用方向。     

碳钢高速电弧喷涂的电弧特征及材料过渡行为

高速电弧喷涂过程中两根丝材交汇处电弧的形成、丝材受热熔化与熔滴过渡等过程具有高度动态性,直接影响喷涂涂层的组织与性能.使用Hispec 5高速摄像机观测了高速电弧喷涂碳钢丝材时弧区的动态冶金过程.发现喷涂过程中阴极上的电弧收缩,阳极上的电弧发散;而且电弧的燃烧是不连续的,不断经历引弧、燃弧、熄弧、再引弧的循环过程.电弧的这些特点导致了阴、阳极丝材的非对称加热和熔化,并且熔化金属脱离丝材形成熔滴的雾化形式、大小等特征差异显著.基于高速摄像的试验结果,系统分析了喷涂过程中电弧和熔滴的形成与过渡机理.     

FeCrBSiNb粉芯丝材电弧喷涂的弧区动态行为

电弧喷涂粉芯丝材是由金属外皮包覆金属或非金属的复合粉末组成,喷涂过程中在弧区发生冶金反应并雾化成熔滴,大量熔滴沉积在基体表面最终形成涂层。粉芯丝材的电弧喷涂是一个高度动态的传热传质过程,采用高速摄像技术研究了喷涂过程中两根粉芯丝材交汇处的电弧、丝材熔化与熔滴形成等行为。另外,通过高速摄像试验分析了喷涂电流和电压对电弧形态及丝材熔化的影响规律。结果表明:喷涂时间歇出现燃弧、熄弧、再燃弧的循环变化;不同于实心丝材,粉芯丝材在阴阳极上的电弧都发散,这有利于丝材外皮和粉芯间的冶金反应;阴极丝材主要表现为抽吸作用下以细小熔滴或片状挤出物等形式形成熔滴,阳极丝材主要以片状液带的形式脱离并雾化成小熔滴。     

Study of the Splat Microstructure and the Effects of Substrate Heating on the Splat Formation for Ni-Cr Particles Plasma Sprayed onto Stainless Steel Substrates

The plasma spraying process is still poorly understood in term of the processes by which the coating is built up, especially coating interactions with the substrate. This present study enhances this understanding by studying, through a range of electron microscopy techniques, single NiCr splats plasma sprayed onto stainless steel substrates, which were first exposed to different heat treatments. The microstructure of the splats, particularly the splat-substrate interface, was characterized, and the formation of the observed features is discussed. Evidence of localized substrate melting and inter-mixing with the splat material was found, showing metallurgical bonding. The structures observed were also correlated to the treatment of the substrate, demonstrating how such treatments can influence the properties of the fully deposited coating by modifying the splat formation process. Most notably, heating the substrate during spraying was found to significantly modify splat formation by reducing splashing and increasing the extent of substrate melting.     

Particle Size Distribution of the Filling Powder in Cored Wires: Its Effect on Arc Behavior, In-Flight Particle Behavior, and Splat Formation

The filling powder, as a part of the feedstock in cored wires, directly influences the particle formation, in-flight particle behavior, the coating microstructure, and consequently the behavior of the desired coating, produced by twin wire arc spraying (TWAS). In this work, the effect of the particle size distribution of the filling powder in cored wires was studied. The process parameters were changed for different intervals of particle size distributions. Arc fluctuations were measured and found to be higher at smaller particle sizes. The in-flight particles showed a higher velocity when powders with smaller grain sizes were used and higher particle temperature when bigger grain sizes were used. The splats tended to form a regular disk shape in the case of smaller grain sizes. This investigation studied the important effect of using cored wires and the filling powders grain sizes on the TWAS process.     

双丝电弧喷涂中粒子交叉飞行行为的在线测量及分析

采用两根具有不同熔点的材料分别作为双丝电弧喷涂的阳极和阴极丝材,采用SprayWatch-2i热喷涂监测系统,通过对融熔粒子飞行中温度的在线测量分析,直接验证了粒子的＂交叉飞行＂现象.利用能谱仪（EDS）定量研究了两极的材料和氧化物在喷涂沉积丘中的分布,并分析了这些分布特征在不同喷涂距离上的变化规律,结果发现,沿喷涂丘的横截面,来自阴极和阳极的扁平化粒子以接近反对称的方式分布.在所测量的两个喷涂距离上,各种成分（包括氧化物）的含量随喷涂距离变化不大.而且电弧喷涂涂层中具有约10 %左右的氧化物含量.     

Effect of Process Inputs on Coating Properties in the Twin-Wire Arc Zinc Process

Relationships between process inputs and coating properties were characterized using a twin-wire arc torch spraying zinc. Specifically, standoff distance, primary and secondary atomizing gas pressures, and arc current were varied in order to determine their effects on deposition efficiency, surface roughness, coating porosity, and spray particle size. Process associations were investigated using an analysis of variance with a design of experiments approach with the intent of determining which spray parameters affect each of the aforementioned coating properties. The associations found are consistent with other studies of the twin-wire arc spray process and provide a framework for selecting process operating conditions based on desired coating properties. Such a specific outline has not been previously available.     

An evaluation of the electric arc spray and (HPPS) processes for the manufacturing of high power plasma spraying MCrAIY coatings

The high power plasma torch (PlazJet) can be used to spray refractory ceramics with high spray rates and deposition efficiency. It can provide dense and hard coating with high bond strengths. When manufacturing thermal barrier coatings, the PlazJet gun is well adapted to spraying the ceramic top coat but not the MCrAIY materials that are used as bond coat. Arc spraying can compete with plasma spraying for metallic coatings since cored wires can be used to spray alloys and composites. In addition, the high production rate of arc spraying enables a significant decrease in coating cost. This paper discusses the performances of the PlazJet gun, and a twin-wire are spray system, and compares the properties and cost of MCrAIY coatings made with these two processes. For arc spraying, the use of air or nitrogen as atomizing gas is also investigated.     

Microtomographic Analysis of Splat Formation and Layer Build-Up of a Thermally Sprayed Coating

Thermal spraying is a material processing technique, which is based on the combination of thermal and kinetic energy. The used feedstock is melted in a hot flame. The melt is atomized and accelerated by means of atomization or process gases. As the formed particles hit a pre-treated substrate they are rapidly solidified and consolidate to form splats. The splats pile one-on-top-of-other forming lamellas creating the final coating. In the work presented here a combination of cored wire (WC as filling powder) and massive wire (copper) were simultaneously sprayed using the twin wire arc spraying process. 3D micro tomography was used in order to gain knowledge about splat formation and layer build-up. Due to the high attenuation coefficient of tungsten in comparison with copper and carbon, tungsten-rich particles and splats can easily be spotted in the tomogram of the coating layer. It turns out that besides irregular formed flat splats also ball-shaped particles exist in the coating layer which suggests that the spherical particles impacted on the substrate in an un-molten state. By 3D data processing tungsten-rich particles were visualized to analyze their spatial distributions and to quantify their geometric parameters. This work aims at contributing to the understanding of spraying processes.     

On process–structure–property interconnection in anti-phase synchronised twin-wire GMAW of low carbon steel

The paper investigates process–structure–property interconnection in anti-phase synchronised twin-wire gas metal arc welded low carbon steel samples wherein process variation is achieved by using similar and dissimilar currents and diameters at lead and trail wires. Scanning electron microscopy and microhardness measurements are used as characterisation techniques. The investigation offers new observations on heat generation and distribution in twin-wire welding that affect weld bead and microstructure formation due to changes in arc phenomenon and molten metal flow in weld pool. Use of dissimilar currents facilitates effective utilisation of heat. The two-stage arcing in twin-wire welding facilitates slow heating and cooling that leads to weld metal and heat affected zone softening. A combination of polygonal ferrite, pearlite and bainite with varying compositions is observed across the weldment. A higher current value and larger wire diameter at the lead wire leads to coarsening of the grains thereby reducing the hardness.     

电弧喷涂技术在中国的发展和应用

电弧喷涂虽然不是一项新技术,随着电弧喷涂设备的改造和完善、新型喷涂材料的不断出现以及对电弧喷涂过程和涂层机理研究的深入,特别是电弧喷涂用管状丝材的开发和应用,使电弧喷涂技术得到越来越广泛的应用,成为最具有活力的热喷涂方法之一。在中国,电弧喷涂技术已成为最有效的钢结构长效防腐手段之一,另外,电弧喷涂技术在零部件修复和表面强化、电弧喷涂制模、锅炉水冷壁的抗热腐蚀、制造防滑涂层以及减磨涂层等方面得到了广泛应用。