陶瓷涂层热喷涂制备工艺

热喷涂陶瓷涂层将陶瓷材料耐高温、耐磨、耐腐蚀及隔热、绝缘等性能与金属材料的特点有机地结合起来。本文介绍了陶瓷涂层的热喷涂方法及工艺。     

HVAF一超音速火焰喷涂的最新发展

空气超音速火焰喷涂又称为ＨＶＡＦ（Ｈｙｐｅｒｓｏｎｉｃ Ｖｅｌｏｃｉｔｙ Ａｉｒ－Ｆｕｅｌ的简称）,是八十末九十年代初美国的Ｂｒｏｗｉｎｇ先生开发的新型超音速火焰喷涂工艺,它是利用压缩空气代替氧气,溶液２燃料代替气体燃料,在燃烧室内或在特殊的喷嘴中燃烧膨胀产生的高温燃烧焰流,并使其沿喷嘴喷出,获得超音速火焰射流。由于ＨＶＡＦ自身特点和良好的涂层性能使其成为超音速火焰喷涂新的发展趋势,本文对空气超音     

热喷涂系列综述之一:等离子喷涂

热喷涂技术是随着现代航空、航天技术的发展而发展起来的。由于涂层特别是陶瓷涂层具有耐磨、抗蚀、抗热冲击等优异性能,已广泛应用于航空、航天、军事、纺织、机械、电力、化工、生物工程等各个领域,是一项具有广阔应用前景的技术。本文简要概述了热喷涂技术,重点介绍等离子喷涂技术以及现状。     

热喷涂技术在我厂的应用

热喷涂技术是近几年来发展起来的表面处理技术,它在机械、化工、冶金、电力、石化等工业领域及国民经济各部门诸如耐磨、耐蚀、绝缘、隔热等功能涂层及设备维修与加工件尺寸超差的恢复方面得到广泛的应用。 1992年我厂将热喷涂这一新技术运用到设备零件的维修和设备搪瓷釜的修复工程     

热喷涂技术及工业上应用

热喷涂技术及工业上应用黎明（中科热喷涂有限责任公司,７２３０００）热喷涂是国外５０年代发展起来的一项机械零件修复和预保护的新技术。它可以使各种机械设备、车辆的零部件使用寿命延长。使报废的零部件“起死回生”。近３０多年来,热喷涂从简单的手工操作发展到自...     

中国热喷涂技术近期发展概况

叙述了热喷涂技术（包括设备、工艺、材料、科研等方面）在中国的近期发展概况、应用特点和最新成就、展望了该技术的推广应用前景。     

热喷涂技术在DMF储罐制作中的应用

在DMF储罐制作过程中 ,采用了热喷涂技术 ,既节约了大量资金 ,又取得了良好的使用效果 ,在制作类似的罐体时很具有借鉴价值     

油漆热喷涂技术应推广

<正> 一、油漆热喷涂技术可行依据油漆的粘度是其涂装的主要参数之一,且油漆的粘度随着温度的升高而降低。油性漆的粘度与温度的关系如图一。     

Crystalline ytterbium disilicate environmental barrier coatings made by high velocity oxygen fuel spraying

Dense environmental barrier coatings (EBCs) are an essential prerequisite to exploit the advantages offered by SiC-based fiber reinforced ceramic matrix composites (CMCs) to increase efficiency in gas turbines. Today's state-of-the art materials for application as EBCs are rare-earth (RE) silicates which, however, form amorphous phases upon rapid quenching from the melt. This makes their processing by thermal spray a challenge. Recently, high velocity oxygen fuel (HVOF) spraying was proposed as potential solution since the melting degree of the feedstock can be controlled effectively. This work studies the deposition of ytterbium disilicate (YbDS) at short stand-off distances and variant total feed rates and oxy-fuel ratios of the working gas. It was found that the overall degree of crystallinity could be kept at high level above 90%. The kinetic energy transferred by impinging particles was found to be an effective parameter to control the densification of the coatings. Porosities well below 10% were achieved while fully dense coatings were impeded due to the progressive accumulation of stresses in the coatings.     

热喷涂设备的发展

热喷涂技术作为一种重要的表面处理技术,近年来发展很快.本文综述了热喷涂设备(包括等离子喷涂、高速火焰喷涂、爆炸喷涂等)近年来的发展情况.     

粘结剂对超音速火焰喷涂碳化钨涂层磨粒磨损性能的影响

采用超音速火焰喷涂(HVOF)工艺在35钢基体上制备了WC-10Ni涂层和WC-12Co涂层,研究了镍、钴这两种粘结剂对WC涂层的显微硬度、摩擦系数和抗磨粒磨损性能的影响,采用扫描电子显微镜观察涂层磨损前后的表面形貌,探讨了WC涂层的磨粒磨损机理。结果表明,以HVOF方法制备的2种WC涂层均有较高的显微硬度,WC-10Ni涂层和WC-12Co涂层与SiC砂纸摩擦副之间的干摩擦系数相差不大。2种涂层在低载荷下均有较好的抗磨粒磨损性能,但在较高载荷下WC-12Co涂层的抗磨性明显优于WC-10Ni涂层。2种涂层的磨粒磨损形式主要为均匀磨耗磨损,磨损机理以微切削和微剥落为主。WC-12Co涂层的磨损表面损伤较轻微,综合性能优于WC-10Ni涂层。     

Properties of TiN-matrix coating deposited by reactive HVOF spraying

TiN-matrix coating was prepared by reactive high velocity oxygen fuel (HVOF) spraying on carbon steel based on the self-propagating high temperature synthesis (SHS) technique in air. The phase composition, structures, and properties of TiN-matrix coating were analyzed using XRD, EDS, SEM and Vickers microhardness equipment. The anti-corrosion property in nearly neutral 3.5 wt% NaCl electrolytic solution was measured. The Weibull distribution of Vickers microhardness at different loads and their linear fitting were analyzed. The apparent fracture toughness of the coating was also calculated. The coating is composed of main phases (TiN, TiN_0.3), minor phases (Ti₂O₃, TiO₂), and porosity. The anti-corrosion property of an HVOF-sprayed TiN-matrix coating in electrolytic solution is superior to that of AISI 316L stainless steel. The microhardness values from 1137HV_0.05 to 825HV₁ are relatively high and have indentation size effect (ISE). With the increment of m, which increases with the increment of applied load, the microhardness values are more concentrated. The average value of apparent fracture toughness K _IC is . It is higher than that of reactive plasma sprayed (RPS) TiN coating, which reflects the good toughness of a TiN-matrix coating deposited by reactive HVOF spraying.     

电弧喷涂技术及其在不同行业中的应用

介绍了电弧喷涂技术特点及其在煤炭、水利、火力发电等行业和在钢结构桥梁、大型轴件修复等方面的应用状况,并指出其不足.电弧喷涂在防腐工程中具有重要的应用价值,为了扬长避短,应加强对新材料、新工艺和新设备的研究开发,以实现电弧喷涂技术质的飞跃.     

Visualisation of the local electrochemical activity of thermal sprayed anti-corrosion coatings using scanning electrochemical microscopy

Scanning electrochemical microscopy was used to study the electrochemical activity of anti-corrosion coatings formed from Inconel 625, a Ni-Cr-Mo alloy commonly used in engineering applications. The coatings were formed using a high velocity oxygen fuel thermal spraying technique. Upon spraying the alloy onto mild steel substrates, clear splat boundaries were formed at the interface between adjacent droplets as they cooled on the substrate surface. Scanning electrochemical microscopy in the feedback mode, employing ferrocenemethanol as redox mediator, was used to study the local electrochemical activity of samples of the wrought alloy, the sintered alloy and the thermal sprayed coating. The wrought and sintered materials showed responses typical of that expected for a purely insulating material. However, SECM approach curve data showed that the electrochemical activity of the thermal sprayed material was higher than that of the bulk alloy. Local variations in the coating's electrochemical activity were then visualised using SECM imaging, which appear to be related to the splat boundaries formed during the thermal spray process.     

Effect of scandia content on the thermal shock behavior of SYSZ thermal sprayed barrier coatings

Nanostructured 4SYSZ (scandia (3.5 mol%) yttria (0.5 mol%) stabilized zirconia) and 5.5 SYSZ (5 mol% scandia and 0.5 mol% yttria) thermal barrier coatings (TBCs) were deposited on nickel-based superalloy using NiCrAlY as the bond coat by plasma spraying process. The thermal shock response of both as-sprayed TBCs was investigated at 1000 °C. Experimental results indicated that the nanostructured 5.5SYSZ TBCs have better thermal shock performance in contrast to 4SYSZ TBCs due to their higher tetragonal phase content and higher fracture toughness of this coating     

Experimental visualization of microstructure evolution during suspension plasma spraying of thermal barrier coatings

This paper investigates the evolution of microstructure of thermal barrier coatings (TBCs) produced by suspension plasma spraying (SPS) through a careful experimental study. Understanding the influence of different suspension characteristics such as type of solvent, solid load content and median particle size on the ensuing TBC microstructure, as well as visualizing the early stages of coating build-up leading to formation of a columnar microstructure or otherwise, was of specific interest. Several SPS TBCs with different suspensions were deposited under identical conditions (same substrate, bond coat and plasma spray parameters). The experimental study clearly revealed the important role of suspension characteristics, namely surface tension, density and viscosity, on the final microstructure, with study of its progressive evolution providing invaluable insights. Variations in suspension properties manifest in the form of differences in droplet momentum and trajectory, which are found to be key determinants governing the resulting microstructure (e.g., lamellar/vertically cracked or columnar).     

Laser thermal gradient testing of air plasma sprayed multilayered,multi-material thermal barrier coatings

Air plasma sprayed (APS) thermal barrier coatings (TBCs) are a widely used technology in the gas turbine industry to thermally insulate and protect underlying metallic superalloy components. These TBCs are designed to have intrinsically low thermal conductivity while also being structurally compliant to withstand cyclic thermal excursions in a turbine environment. This study examines yttria-stabilized zirconia (YSZ) TBCs of varying architecture: porous and dense vertically cracked (DVC), which were deposited onto bond-coated superalloys and tested in a novel CO₂ laser rig. Additionally, multilayered TBCs: a two-layered YSZ (dense + porous) and a multi-material YSZ/GZO TBC were evaluated using the same laser rig. Cyclic exposure under simulative thermal gradients was carried out using the laser rig to evaluate the microstructural change of these different TBCs over time. During the test, real-time calculations of the normalized thermal conductivity of the TBCs were also evaluated to elucidate information about the nature of the microstructural change in relation to the starting microstructure and composition. It was determined that porous TBCs undergo steady increases in conductivity, whereas DVC and YSZ/GZO systems experience an initial increase followed by a monotonic decrease in conductivity. Microstructural studies confirmed the difference in coating evolution due to the cycling.     

A highly strain and damage‐tolerant thermal barrier coating fabricated by electro‐sprayed zirconia hollow spheres

An approach to make air plasma sprayed (APS) thermal barrier coatings (TBCs) with the enhanced strain and damage tolerance was reported, using a novel hollow spheres produced by electro‐spraying (ESP) technique. Compared with agglomerated & sintered (A&S) and hollow spherical (HOSP) yttria‐stabilized zirconia (YSZ) powders, the ESP powder showed a unique network microstructure and the TBCs exhibited a 2‐3 times longer thermal cycling lifetime. The splat morphology and the top coats microstructure were investigated. Some semi‐melted ESP particles were observed in the as‐sprayed top coat. The indentation coupled with the Raman mapping technique was employed to evaluate the strain and damage tolerance of the TBCs. The coatings deposited by the ESP powder show a lower in‐plane stiffness determined by three‐point bending tests. It is proposed that the superior performance is attributed to the lower amount of the short microcracks (0.5‐4 μm) with low angle (<45°) and the semi‐melted ESP particles remained in the YSZ top coat.