等离子熔覆铁基非晶纳米晶复合涂层及其性能

利用等离子熔覆技术在A3钢表面制备了一层与基体呈冶金结合的、性能良好的非晶纳米晶复合涂层.涂层有非晶相和纳米相组成,根据衍射峰的半高宽,计算出铁基涂层中平均晶粒尺寸为22～24nm.对涂层进行XRD、SEM、EDS、TEM和DSC分析,并利用显微硬度计和电化学工作站研究涂层的硬度和耐蚀性能,研究表明所制备的铁基涂层具有良好的性能.     

等离子熔覆铁基涂层的组织及冲蚀磨损研究

采用等离子熔覆法制备了铁基涂层.研究了涂层的组织结构,测试了涂层的显微硬度及耐冲蚀磨损性能,并利用扫描电镜对涂层显微组织、冲蚀表面形貌进行了分析.结果表明:涂层显微硬度是基体材料不锈钢1Cr18Ni9Ti的2倍,最高达到550,涂层冲蚀后质量损失是不锈钢对比试样1Cr18Ni9Ti和0Cr13Ni5Mo的1/2左右.     

激光熔覆WC增强复合涂层开裂行为分析

研究了激光熔覆WC增强复合涂层的开裂行为。研究结果表明：激光熔覆金属陶瓷涂层开裂是由于熔覆层与金属基体两种材料的热膨胀系数不同所致，同时开裂倾向还受激光工艺参数、涂层合金粉的配比以及强化相的形状、大小等因素的影响。     

激光熔覆玻璃涂层

本文研究在Ａ３钢基材上激光熔覆玻璃涂层的可行性，激光熔覆玻璃涂层的过程是玻璃熔体在基材表面上湿润、铺展，然后冷凝的过程。玻璃熔体在基材表面上铺展，不仅与它们之间的浸润有关，而且与玻璃熔体的流动性有关。玻璃熔体的流动性在熔覆过程中随时间变化；激光处理参数的不同会改变熔体的随时间变化过程。合理选择激光参数能熔覆形成均匀的、光滑的、粘附的、无裂纹的玻璃涂层。在激光熔覆过程中，会在玻璃熔体中出现结晶现象，     

激光熔覆生物陶瓷复合涂层

介绍在奥氏体型不锈钢基材上预置涂覆具有一定梯度的生物陶瓷粉末（ＨＡＰ或ＣａＨＰＯ４．２Ｈ２Ｏ＋ＣａＣＯ３）的激光熔覆，经ＳＥＭ，ＥＤＳ，ＸＲＤ分析表明，低输出功率，高扫描速率是获得激光生物陶瓷涂层的主要控制因素，预置涂覆ＣａＣＯ３与ＣａＨ（ＰＯ４）．２Ｈ２Ｏ混合粉末涂层，在于大常规方法合成ＨＡＰ所需比例下，可激光合成含Ｃａ５（ＰＯ４）３（ＯＨ）等生物活性陶瓷的复合涂层，且存在一定量非晶态的自由表面     

Q235钢表面金属陶瓷涂层熔覆技术的研究进展

综述了近年来Q235钢表面金属陶瓷涂层制备技术的研究进展,重点介绍了常见的金属陶瓷涂层制备方法如氩弧熔覆、感应熔覆、等离子熔覆、激光熔覆等及其存在的问题,展望了今后的发展方向。     

等离子熔覆Cr7C3/γ-Fe金属陶瓷复合材料涂层的组织与耐磨性研究

以Fe-Cr-C合金粉末为原料,采用等离子熔覆技术,在调质C级钢表面制得以原位生成初生相Cr7C3为增强相的新型陶瓷复合材料涂层.利用光子显微镜(OM),扫描电镜(SEM),X射线衍射(XRD)和能量色散谱(EDS)等分析了涂层的显微组织,并在室温干滑动磨损及二体磨料磨损条件下测试了该涂层的耐磨性能.结果表明,涂层组织包括Cr7C3增强相和γ-Fe固溶体与少量Cr7C3构成的共晶;由于Cr7C3/γ-Fe快速凝固复合材料涂层组织细小、均匀,在滑动磨损过程中不易与对偶件黏着、在磨料磨损过程中具有很高的抗切削抗剥落能力,因而在干滑动磨损及二体磨料磨损条件下涂层均具有优良的耐磨性能.     

等离子束熔覆技术在缸体缺陷修复中的研究

针对液压支架缸体的使用条件,采用等离子熔覆技术修复其表面缺陷,在27SiMn钢基体上熔覆合金粉末,形成金属基复合材料熔覆层.该熔覆层硬度可达1433 HV.该熔覆层与基体形成的冶金结合体具有较高的耐磨性能.应用结果表明,经熔覆处理,缸体使用寿命提高3～5倍,达到了良好的效果.     

熔覆技术的发展与展望

熔覆技术具有诸多优点,已经大量应用于工业生产中.近年来,在传统熔覆技术基础上发展而来的复合熔覆技术,可以显著提高涂层的综合性能,给表面强化技术注入了新的动力.本文在概述了激光熔覆、等离子熔覆和感应熔覆等传统熔覆技术的基础上,对近年来国内外不同热源间的复合熔覆技术、辅助技术复合熔覆技术及其应用现状进行了综述,总结了现有技...     

等离子熔覆ZrB_2-ZrC/Fe复合涂层组织及耐磨性

采用等离子熔覆技术,以Zr、Fe、B_4C混合粉末为原料,在Q235低碳钢表面原位反应合成了ZrB_2和ZrC增强的Fe基复合涂层,分析了ZrB_2-ZrC/Fe涂层的物相组成和组织结构,并进行了硬度、耐磨性对比试验,探讨了物相和组织结构的形成过程及磨损机制。结果表明:涂层主要物相为ZrB_2、α-Fe、ZrC、Fe_2B和Fe_3C,其中ZrB_2呈现针棒状、花瓣状,ZrC呈现规则的颗粒状;随着原始粉末中(Zr+B_4C)含量的增加,增强相ZrB_2和ZrC含量增多,尺寸变大,ZrB_2-ZrC/Fe涂层与Q235钢基体之间结合紧密,呈冶金结合;与Q235钢基体相比,ZrB_2-ZrC/Fe涂层耐磨性显著提高,最高可达基体的5.45倍,ZrB_2-ZrC/Fe涂层的磨损方式以磨粒磨损为主,断裂方式以穿晶断裂为主。     

Microstructure evolution of Fe-based nanostructured bainite coating by laser cladding

A Fe-based coating with nano-scale bainitic microstructure was fabricated using laser cladding and subsequent isothermal heat treatment. The microstructure of the coating was observed and analyzed using optical microscope (OM), field-emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results showed that nanostructured bainitic ferrite and carbon-enriched retained austenite distributed uniformly in the coating. Blocky retained austenite was confined to the prior austenite grain boundaries resulting from the elements segregation. The bainitic microstructure obtained at 250 °C had a finer scale compared with that obtained at 300 °C. The volume fraction of austenite increased with increasing transformation temperature for the fully transformed bainitic coating. The bainitic transformation was accelerated as a result of the fine prior austenite generated during the laser cladding. The evolution of the carbon contents in bainitic ferrite and retained austenite revealed the diffusionless mechanism of the bainitic transformation.     

等离子原位合成TiC颗粒增强Ni基复合涂层

采用等离子熔覆技术,选择合适的工艺参数,在碳钢表面原位合成了TiC/Ni基复合材料涂层.借助金相显微镜、扫描电镜、X射线仪、透射电镜对复合涂层的组织、结构进行了测试,并利用热力学原理对TiC形成进行了分析.结果表明:熔覆层的组织由γ-Ni、M23C6、CrB及原位合成的TiC组成,TiC以颗粒状为主,少量呈块状,尺寸为1～2μm,弥散分布于熔覆层中;TiC的形成遵循形核与长大方式进行,等离子快速加热、快速冷却的特点决定了原位合成的TiC颗粒尺寸细小;TiC的不同形态可由共晶过程得到解释.     

Effect of re-melting on the cladding coating of Fe-based composite powder

The aim of this paper is to investigate the influence of laser re-melting on the geometry and overlapping pores of cladding coating. In this study, Fe-based alloy mixed with 5 wt.% Cr₃C₂ powder was used as cladding material to obtain high hardness and strength coating. However, this coating has overlapping pores and a rough surface. Therefore, re-melting process is explored systematically. The geometry, microhardness and microstructure of the coatings have been analyzed and compared subsequently. Besides, a 3D finite element model has been built to provide a thermal field analysis for laser re-melting. Finally, it is found that re-melting process is an effective method to improve the surface smoothness of cladding layer, which could reduce the process cycle and cost of secondary operations. More importantly, it could remove the overlapping pores easily.     

等离子束熔覆铁基合金涂层的组织与性能研究

利用等离子熔覆技术,在钢基体表面熔覆了一层铁基合金,获得了与基体呈冶金结合的、性能良好的涂层;采用金相显微镜对熔覆层的组织进行观察,发现熔覆层整体组织由柱状树枝晶向等轴晶转变,无气孔、夹杂,其中枝晶组织粗大,等轴晶组织细小;利用显微硬度计分析表明,熔覆层具有较高的硬度,并且由表面到基体呈梯度分布;磨损试验结果表明熔覆层的耐磨性是淬火45钢的2.56倍.     

Epitaxial growth and oxidation behavior of an overlay coating on a Ni-base single-crystal superalloy by laser cladding

An overlay coating material was deposited on a single crystal superalloy SRR99 by laser cladding.The microstructure and oxidation behavior of this coating was investigated through scanning electron microscopy(SEM) and X-ray diffraction(XRD). The results indicated that although the composition of the coating was chosen based on the γ' composition in René N5 superalloy, the primary solidification phase of this coating during laser cladding was γ-Ni. Furthermore, under the laser cladding condition, fine parallel dendrites grew epitaxially in the coating from the substrate, indicating the single crystal structure of the substrate was reproduced. When the single crystal MCrAlY coating was oxidized at 1000?, both Al_2O_3 and Al_2O_3 formed during initial oxidation process. As the oxidation time proceeded, the presence of Al_2O_3 facilitated the formation of NiAl_2O_4 spinel oxide. Once the spinel was observed, it flourished and induced some porosity in the scale. When the scale thickness increased to 6–7 μm, large area spallation of the scale began.     

激光熔覆Fe基合金涂层强化H13热作模具钢

为了解决H13热作模具钢在锻模和热挤压模等领域因发生脱模剂腐蚀而失效的问题,本文通过引入激光熔覆技术来探究Fe基合金粉末对H13钢综合性能的强化效果,并系统研究了扫描速度、搭接率和熔覆层数对涂层的相位组成和显微组织的影响,详细分析了涂层的截面显微硬度和耐腐蚀性能的变化规律.研究表明:涂层主要由α-Fe、γ-Fe、M23...     

钛合金表面宽带激光熔覆梯度生物陶瓷复合涂层

为了减少激光熔覆过程中基材与生物陶瓷涂层之间的热应力,设计了一种梯度生物陶瓷复合涂层并采用宽带激光熔覆技术在Ti-6Al-4V合金上制备了梯度生物陶瓷复合涂层,对其组织和显微硬度进行了研究。结果表明：钙和氧元素主要分布在生物陶瓷涂层中;钛和钒元素主要分布在基材和合金化层内;磷元素分布在合金层与陶瓷层中。合金层中基底组织上分布着白色共晶组织和白色颗粒,基底组织主要为Ti(Al、P、Fe、V)相,白色共晶组织主要为Fe2Ti4O AlV3,白色颗粒为结晶析出的Al3V0.333 Ti0．666;生物陶瓷层中的基底组织为胞状晶,其上分布有灰色相和白色颗粒相,胞状晶主要为CaO、CaTiO3和HA,灰色相为β-TCP及Ca2Ti2O6,白色颗粒相为TiO2。合金层的最高硬度为1600Hv0．2,生物陶瓷涂层显微硬度最大值约为1300Hv0．2。     

Q235低碳钢表面等离子熔覆TiB2-TiC/Fe复合涂层及耐磨性

采用等离子熔覆技术,以Fe55、Ti、B₄C混合粉末为原料,在Q235低碳钢表面获得了TiB₂-TiC/Fe复合涂层,并分析了涂层的物相组成、组织结构,测试了显微硬度和摩擦磨损性能,探讨了其磨损机制。TiB₂-TiC/Fe复合涂层的主要物相为TiB₂、TiC、α-Fe,其中TiB₂呈多边形和矩形,TiC则呈不规则块状;随着原始粉末中Ti、B₄C含量的增加,TiB₂、TiC尺寸逐渐增大,TiB₂-TiC/Fe涂层与基体之间结合紧密,呈冶金结合;随着TiB₂-TiC/Fe复合涂层陶瓷相含量的增加,涂层硬度和耐磨性显著提高,当陶瓷相含量增加到一定程度（35wt%）时,涂层耐磨性能有所降低,TiB₂-TiC/Fe复合涂层的磨损方式主要是磨粒磨损和剥层磨损。Ti+B₄C陶瓷相含量为30wt%的等离子熔覆涂层耐磨性能较好,约为Q235钢基体的7倍,当Ti+B₄C含量持续增加时,TiB₂、TiC尺寸增大、缺陷增多,最终使TiB₂-TiC/Fe复合涂层耐磨性降低。