氩弧熔覆铁基合金 TiB2-Al2 O3涂层冲蚀磨损性能研究

为提高Q255的冲蚀磨损性能,利用氩弧熔覆方法制备了铁基合金TiB2-Al2 O3涂层。熔覆层显微硬度最高为913．5 Hv0．2是基体硬度的5．9倍;熔覆层的冲蚀磨损性能较基体提高了1．77～4．22倍。熔池组织均匀细小,XRD分析显示,熔覆层由Fe、Al、TiO2、TiB2、Fe2 B、Al2 O3相组成。     

大型颚式破碎机偏心轴激光熔覆再制造技术研究

为了实现对大型颚式破碎机偏心轴的激光熔覆再制造修复,采用激光熔覆技术在偏心轴材料40CrMnMo试验轴段上制备铁基熔覆层。通过正交试验选择最佳的工艺参数,研究了最佳工艺参数下的熔覆层组织性能,利用金相显微镜、显微硬度计对熔覆层的金相组织、显微硬度进行了研究,最后成功对偏心轴进行了激光熔覆再制造修复,恢复了尺寸公差,并提高了表面使用性能。经激光熔覆再制造后零件在使用性能和产品质量上都能达到甚至超越新品的水平,但成本仅为新品的三分之一,给客户带来较大的经济效益,为水泥行业的再制造发展提供一种新的先进技术,为循环经济的可持续发展提供动力。     

大型颚式破碎机偏心轴激光熔覆再制造技术研究

为了实现对大型颚式破碎机偏心轴的激光熔覆再制造修复，采用激光熔覆技术在偏心轴材料40CrMnMo试验轴段上制备铁基熔覆层。通过正交试验选择最佳的工艺参数，研究了最佳工艺参数下的熔覆层组织性能，利用金相显微镜、显微硬度计对熔覆层的金相组织、显微硬度进行了研究，最后成功对偏心轴进行了激光熔覆再制造修复，恢复了尺寸公差，并提高了表面使用性能。经激光熔覆再制造后零件在使用性能和产品质量上都能达到甚至超越新品的水平，但成本仅为新品的三分之一，给客户带来较大的经济效益，为水泥行业的再制造发展提供一种新的先进技术，为循环经济的可持续发展提供动力。     

TiC添加量对等离子熔覆Ni60–WC复合涂层性能的影响

在45钢上通过等离子熔覆制备了WC?TiC?Ni涂层,对其物相、显微硬度和滑动摩擦磨损行为进行了分析.结果表明:熔覆层与基体材料之间为冶金结合,熔覆层表面无裂纹和气孔.TiWC2的形成使得熔覆层的显微硬度和耐磨性得到提高.当TiC的添加量为20％(质量分数)时,涂层的平均显微硬度高达1072.5 HV,较WC/Ni熔覆层高了128 HV,此时涂层的耐磨性最好.     

不同等离子熔覆铁基合金涂层在阀门密封面上的应用

在阀门密封面上用等离子熔覆技术制备了Fe45、Fe313和Fe316三种铁基合金涂层.利用光学显微镜、扫描电镜、能谱仪和X射线衍射仪表征了熔覆层的显微组织和物相组成.采用维氏硬度计测试了熔覆层的显微硬度,并使用电化学工作站和全浸腐蚀试验测试了它们的耐蚀性.结果表明,Fe45熔覆层呈现均匀的等轴晶组织,Fe313和Fe316熔覆层在与基体接触的区域形成了细晶粒区,而在熔覆层的中部出现了柱状晶组织.3种熔覆层的主要硬质相均为M7C3型碳化物,其中存在固溶相(Fe,Cr).3种熔覆层的显微硬度都高于基体,Fe45、Fe313和Fe316熔覆层的平均显微硬度为629.76、550.51和408.91 HV.Fe316熔覆层的耐蚀性最佳,Fe45熔覆层的耐蚀性最差.     

Ti-6Al-4V合金表面激光熔覆NiCrBSi＋5%BN涂层组织和性能

Ti-6Al-4V合金具有比强度高、耐蚀性能好等优点,在航天、航空、石油和化工等新科技工业部门广泛使用。在表面激光熔覆金属-陶瓷复合涂层是改善钛合金性能的重要方式,利用XRD、SEM和EDS等分析手段对NiCrBSi＋5%（质量分数）BN熔覆层的微观组织进行分析。利用HV-1000型显微维氏硬度计测试激光熔覆试样的硬度。     

激光熔覆法制备ZrO2-Y2O3涂层的显微组织与性能研究

采用预制粉末式激光熔覆法在钛合金(Ti-6Al-4V)表面制备了纳米ZrO2-8％ Y2O3涂层,利用X射线衍射仪(XRD)、扫描电镜(SEM)和光学显微镜(OM)对涂层的相组成及组织结构进行分析,同时分析了涂层的显微硬度分布情况.结果表明:在一定功率范围内,涂层气孔随激光功率增大而逐渐减少,裂纹随激光功率增大而增多;ZrO2陶瓷涂层与基体间结合良好,熔覆层微观组织结构主要以细小的树枝晶形态存在.在不同区域表现出不同的组织特征,靠近表面处晶体尺寸相对较小,呈柱状整齐排列在熔覆层表层区域;熔覆层中部主要包含块状晶及少量树枝晶;熔覆层底部主要为树枝晶,其一次品轴方向沿垂直于涂层截面方向生长;熔覆层主要由四方相(t相)ZrO2和立方相(c相)ZrO2组成;熔覆层平均硬度达到1000～ 1300 HV0.2,约为基材硬度的3.5倍.     

汽车用AZ91镁合金的表面激光改性研究

为了解决压铸AZ91镁合金耐蚀和耐磨性能较差的问题,采用激光熔覆的方法在汽车用压铸AZ91镁合金表面制备了激光熔覆层,研究了激光功率和激光扫描速度对熔覆层成型、截面和表面形貌、物相组成、耐蚀和耐磨性能的影响。结果表明,过小/过大激光功率或者过大扫描速度会使得熔覆层中产生气孔、熔坑等缺陷;不同激光功率和扫描速度下,熔覆层与AZ91镁合金基体结合良好,AZ91镁合金表面激光熔覆层都主要由α-Mg、Mg₁₇Al₁₂、AlCu₄、Al₄MgY和MgAl相组成;随着激光功率增加,熔覆层表面晶界间距离和晶粒尺寸增大,熔覆层平均维氏硬度会逐渐减小;随着激光扫描速度增加,熔覆层厚度和熔覆层晶粒尺寸逐渐减小。激光熔覆层的耐蚀性和耐磨性都优于AZ91镁合金基体,Al-Cu/Y₂O₃熔覆层适宜的激光熔覆工艺为：激光功率1100 W、扫描速度500 mm/min,此时激光熔覆层与基体结合良好,熔覆层致密、晶粒细小、硬度较高,具有良好的耐蚀性和耐磨性。     

45钢表面激光熔覆WC／Co金属陶瓷

研究了45钢表面WC／Co金属陶瓷激光熔覆层的组织、界面特征及其形成机制,分析了激光熔覆层中涂层元素和硬度的分布特征。结果表明,激光熔覆使WC／Co等离子喷涂层的片层状组织特征消除,形成了连续致密的熔覆层;由于涂层中不同部位的成分。温度分布及冷速不同使初生相呈树枝状、多边形块状、花瓣状、条状及颗粒状等几种形态;实现了涂层与基体间的冶金结合,结合带宽度约3-5μp;涂层硬度达1794HV0.1。     

激光熔覆Ni包WC复合涂层的组织、耐磨和耐蚀性分析及应用

对45钢基体进行激光熔覆Ni包WC金属陶瓷涂层强化处理,通过X射线衍射(XRD)、扫描电子显微镜-能谱分析(SEM-EDX)和透射电子显微镜(TEM),研究了激光熔履Ni包WC涂层的显微组织和物相组成,并采用摩擦磨损试验和电化学测试系统研究了Ni包WC涂层的摩擦磨损性能和耐蚀性能.结果表明,在激光熔覆Ni包WC金属陶瓷...     

镁合金激光表面处理技术

镁合金激光表面处理能改变表面合金成分,细化表面晶粒,从而提高合金的耐腐蚀和耐磨擦性能.本文介绍了镁合金激光熔融、镁合金激光表面合金化和激光熔覆技术,总结了镁合金激光表面处理技术的基本原则,指出了激光表面处理技术的发展前景.     

激光熔覆技术制备新型Al-TiC复合涂层的研究

采用预置激光熔覆技术,将Al-Ti-C混合粉末预置于铝合金基体表面,并在氩气保护下,利用YAG激光器实现了在铝合金表面原位形成Al-TiC复合熔覆层。通过改变激光束能量密度和激光束扫描速度等工艺参数,获得了不同工艺条件下的激光熔覆层,并对其显微组织、物相分布及耐磨性能进行比较研究。结果表明由于激光能量密度和激光束扫描速度不同,所形成的熔覆层中TiC的分布状态有很大差别。随着激光能量密度的增大,TiC分布趋于均匀。当激光束扫描速度为2.5mm/s、激光束能量密度为6.09 J/mm2时,熔覆层具有最高的耐磨性能。     

Microhardness and wear resistance of Al2O3-TiB2-TiC ceramic coatings on carbon steel fabricated by laser cladding

Al₂O₃-TiB₂-TiC ceramic coatings with high microhardness and wear resistance were fabricated on the surfaces of carbon steel substrates by laser cladding using different coating formulations. The microstructures of these ceramic coatings with the different coating formulations were investigated using X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometer. The wear resistance and wear mechanism were analyzed using Vickers microhardness and sliding wear tests. The results showed that when the amount of independent Al₂O₃ was increased to 30%, the ceramic coatings had a favorable surface formation quality and strong metallurgical bond with the steel matrix. The cladding layer was uniformly and densely organized. The black massive Al₂O₃, white granular TiB₂, and TiC distributed on the Fe substrate significantly increased the microhardness and wear resistance. The laser cladding ceramic coating had many hard strengthening phases, and thus resisted the extrusion of rigid particles in frictional contact parts. Therefore, the wear process ended with a “cutting-off” loss mechanism.     

提高发动机铝合金件耐磨性的表面处理工艺

介绍了各种表面处理工艺在提高发动机铝合金件耐磨性能中的研究和应用,包括等离子喷涂、等离子弧焊、等离子扫描、等离子电解、电镀、物理气相沉积和激光熔覆成形工艺,对表面强化铝合金耐磨件的应用前景进行了展望。     

Microstructure and wear resistance of in-situ synthesized Ti(C,N) ceramic reinforced Fe-based coating by laser cladding

In order to enhance the wear resistance of Fe-based cladding layer, TiN, Ti and graphite were added into Fe313 powder and in-situ formation of Ti(C, N) ceramic reinforcement phase was carried out by laser cladding. Firstly, thermodynamic calculations were used to determine the feasibility and favorability of a chemical reaction. Then, the reaction mechanism was investigated by adding five groups of different contents and carrying out EDS and phase analysis. We report that large TiN particles do not completely decompose and in-situ synthesized TiC phase forms around large TiN particles. However, small TiN particles are completely decomposed and directly formed the Ti(C, N) phase. Finally, through the friction and wear tests, it has been observed that the friction coefficient of a sample, with three powders added, was 0.559 times smaller than the substrate and 0.725 times smaller than the initial powder, and the wear volume of the same sample was 0.365 times smaller than the substrate and 0.799 times smaller than the initial powder. Therefore, it can be concluded that the in-situ synthesis of Ti(C, N) ceramic reinforced Fe-based coatings by laser cladding greatly improves the wear resistance of the Fe313 layer.     

粉煤灰活性氩弧熔覆Al2O3-TiB2-TiC复合涂层组织和性能分析

以铁基合金粉末、Al、TiO2和B4 C粉末为涂覆材料,以高铝粉煤灰、SiO2、MgO、CaF2和CeO2为活性剂,采用活性氩弧熔覆技术在Q235钢表面原位合成Al2O3-TiB2-TiC颗粒增强铁基复合涂层.测试熔覆涂层的物相结构、金相组织、显微硬度和耐磨性能,并与未涂覆活性剂的常规熔覆涂层进行对比分析.结果表明,复合涂层由Al2O3、TiB2、TiC、FeSi2 Ti、FeB2和α-Fe相组成,其与基体界面无气孔、裂纹等缺陷,呈良好的冶金结合;复合涂层测试点的最高显微硬度为1283.4 HV0.2,其在室温干滑动磨损条件下耐磨性良好;粉煤灰复合活性剂的加入可以促进熔覆层与母材之间的良好熔合、增加涂层中新相种类和数目、提高氩弧熔覆效率,这对改善复合涂层的综合性能具有重要意义.     

Microstructure and properties of Ni-WC gradient composite coating prepared by laser cladding

In this study, an Ni-based gradient composite coating reinforced with WC was prepared on a Q345R steel substrate by laser cladding. The Ni-WC composite coating was designed as a multilayer structure with gradient composition. The coating started with a layer of C276 alloy with 10 wt% WC on the substrate, and the subsequent layers were composed of Ni60 alloy with different WC contents (10, 30, and 50 wt% WC). The overall morphology, phase composition, and microstructure of the coatings were investigated. The microhardness and the wear properties of each layer of the coatings were also evaluated. The results showed that the gradient composition design was beneficial for reducing the cracking tendency. The coating was composed of an Ni-based matrix, WC, and multiple carbides and borides hard phases. With increasing WC content in the layers, the hard phases exhibited regional distribution characteristics. The WC reinforcement particles underwent different types of dissolution during the cladding process. From the surface to the substrate, the average microhardness of the coating was 1053.5 HV_0.2, 963.4 HV_0.2, 859.0 HV_0.2, 441.7 HV_0.2, and 260.5 HV_0.2. The wear tests revealed that the coefficient of friction and the wear loss values of the four layers were all lower than those of the substrate, demonstrating enhanced wear resistance.     

Effect of laser power on microstructure and tribological performance of WC−10Co4Cr coating

In order to enhance wear resistance of cold work molds, WC−10Co4Cr coating was fabricated on Cr12MoV steel by laser cladding. The morphologies, chemical compositions, and phases of obtained coatings were analyzed using a scanning electron microscopy (SEM), energy disperse spectroscopy, and X−ray diffraction, respectively. The effect of laser power on the tribological performance was analyzed using a ball−on−plate friction machine, and the wear mechanism was also discussed. The results show that the WC−10Co4Cr coating is composed of WC and Co₆W₆C phases, and the average hardness of coating cross−sections fabricated at the laser power of 1200, 1500, and 1800 W was 1296, 1375, and 1262 HV_0.5, respectively, in which that fabricated at the laser power of 1500 W is the highest among the three kinds of coatings. The average coefficients of friction of coatings fabricated at the laser power of 1200, 1500, and 1800 W are 0.61, 0.52, and 0.59, respectively; and the corresponding wear rates are 64.38, 35.38, and 123.92 μm³•N⁻¹•mm⁻¹, respectively, showing that the coating fabricated at the laser power of 1500 W has best friction reduction and wear resistance. The wear mechanism of WC−10Co4Cr coating is fatigue wear and abrasive wear, which is contributed to the increase of hard WC mass fraction.     

Friction and wear performances of Si3N4 ceramic matrix composites: A review from the perspectives of doped phase,layered structure design,and laser surface texturing

Si₃N₄ ceramic matrix composites (SN-CMCs) have been designed and widely used in many engineering fields under externally loading conditions. It is well known that the wear of materials is closely related to components’ mechanical reliability and service life. Understanding of the friction and wear performances is very important to provide insights into how to improve the wear resistance of materials. Coefficient of friction and wear rate, in general, are the most critical parameters of tribological behavior of materials. In this paper, friction and wear performances of SN-CMCs are reviewed from the perspectives of doped phase, layered structure design, and laser surface texturing. The article describes the change of friction and wear performances of SN-CMCs sintered with different additive phases. Tribological behavior of SN-CMCs with engineering designed layered structure is also analyzed from the aspects of surface coating and gradient structure. In addition, friction and wear performances of SN-CMCs under different lubrication conditions are also discussed. As an ideal processing method for hard and brittle ceramic materials, laser surface texturing has been proved to be an effective way to improve the wear resistance of SN-CMCs. Researches have shown that the better wear resistance can be obtained by combining laser surface texture with layered structure. At the end of paper, studies on friction and wear performances of SN-CMCs are summarized and prospected.