风机叶片用涂层的抗冲蚀性能的研究

针对风机叶片用涂层的抗冲蚀性能进行了研究,从磨损原理入手,分析研究了等离子喷涂涂层和表面粘涂涂层的抗冲蚀性能。采用NIWC35涂层和陶瓷耐磨修补剂（11680）涂层,对涂层结合强度、硬度、显微结构及抗冲蚀性能进行了研究。试验结果表明,等离子喷涂涂层在低角度下的冲蚀明显低于高角度下的冲蚀;而耐磨修补剂（11680）涂层从冲蚀情况看,Al1O3与树脂的粘结状况是良好的,在冲蚀率上,高角度下耐剖蚀性能比低角度下好。     

PPS/SiO2纳米复合涂层的制备和性能测试

用乳化剂、分散剂和稳定剂制备了聚苯硫醚(PPS)、纳米SiO2超细粉体的水基涂料，成功地解决了纳米SiO2粉体的团聚问题。通过烧结的方法在试样表面制备了PPS／SiO2纳米复合涂层，涂层中SiO2的粒度在200nm以下。纳米涂层在硬度、耐磨性、耐冲击性和附着力等方面明显高于普通涂层，其耐冲蚀磨损性是普通涂层的50倍。     

等离子喷涂Al_2O_3/ZrO_2涂层耐磨性能研究

采用溶胶-凝胶方法将微米级颗粒团聚成含纳米粒子的颗粒,利用等离子喷涂技术制备出了含有纳米结构的A1_2O_3/ZrO_2涂层,并在MM—200摩擦磨损试验机上进行了干摩擦试验,对纳米结构涂层和常规涂层的耐磨损性能进行了对比。通过对磨损后的磨痕形貌分析可知,纳米涂层的耐磨损性能明显好于传统陶瓷涂层。传统涂层的磨损机理主要是微裂纹和颗粒的剥落,而相同条件下纳米涂层则由于涂层韧性的提高,几乎不存在微裂纹,因而涂层具有较高的耐磨性。     

超音速火焰喷涂Cr_3C_2/NiCr、Stellite6、Inconel625、Inconel718涂层耐冲蚀性能研究

采用超音速火焰喷涂技术,在15Cr_2Mo合金钢上制备了Cr_3C_2/NiCr、Stellite6、Inconel625、Inconel718涂层。测定了涂层的显微组织、结合力、显微硬度、孔隙率。研究了涂层耐固体颗粒冲蚀性能。结果表明,Cr_3C_2/NiCr涂层在结合力、显微硬度和孔隙率方面均优于其他涂层。同时,Cr_3C_2/NiCr耐固体颗粒冲刷性能最好,其冲蚀试验失重量仅为基体15Cr_2Mo的20%左右。Cr_3C_2/NiCr涂层显微组织中,高硬度的碳化物Cr_3C_2陶瓷相以多边形弥散分布在较软的基体NiCr合金相上。固体颗粒冲刷试验后,Cr_3C_2/NiCr涂层表面磨痕比较明显,但是没有发生明显的涂层分层剥落现象。优异的微观结构、细小的硬质颗粒以及较低的孔隙率等因素对涂层耐冲蚀性的显著提高起着关键作用。Cr_3C_2/NiCr涂层应用于冲蚀磨损环境,可有效提高部件寿命。     

激光熔覆制备纳米陶瓷涂层的研究进展

介绍了激光熔覆工艺纳米陶瓷粉末的供给方式、工艺参数的选择;对比分析了激光熔覆和其他主要的纳米陶瓷涂层制备方法的优缺点;着重分析介绍了激光熔覆制备的几种主要纳米陶瓷涂层的组织和性能特征,尤其是纳米抗裂的最新研究成果以及抗裂机理,分析表明,增加纳米颗粒将明显地改善陶瓷涂层的抗裂性能。另外,涂层的强度、致密度、耐磨性也随着纳米颗粒的增加而相应增加。阐述了激光熔覆制备纳米陶瓷涂层存在的主要问题,并对该技术发展前景和应用进行了展望。     

纳米Fe-Al/Cr_3C_2复合涂层及其抗高温腐蚀性能

制备纳米金属间化合物Fe-Al/Cr_3C_2复合涂层并测试其抗腐蚀性能,为利用热喷涂技术治理火电站易损部件腐蚀问题提供有效手段。运用自主研发的造粒系统,成功对高活性的纳米Fe-Al/Cr_3C_2复合喷涂粉体实施团聚造粒;运用高速火焰喷涂方法,在结构材料表面制备出了纳米Fe-Al/Cr_3C_2复合涂层,对比测试了微米、纳米Fe-Al/Cr_3C_2复合涂层的抗高温腐蚀性能,分别采用抛物线型和幂函数型对腐蚀动力学曲线进行拟合。纳米Fe-Al/Cr_3C_2复合喷涂材料的粒径由原始的50nm团聚到最终的114~178μm,团聚后的纳米颗粒呈圆形或椭圆形,各成分比例保持原始比例,团聚颗粒内部仍然保持纳米粉体状态;纳米Fe-Al/Cr_3C_2复合涂层表面致密、铺展均匀,截面元素过渡平缓、层片细小;运用幂函数方程对腐蚀动力学曲线的拟合效果更好。通过对腐蚀动力学拟合方程进行求导运算可推算出各复合涂层的腐蚀速率。团聚后的纳米颗粒满足热喷涂材料的相关要求,纳米Fe-Al/Cr_3C_2复合涂层的抗高温腐蚀性能显著高于微米Fe-Al/Cr_3C_2复合涂层。纳米Al、Cr优先氧化生成具有保护作用的氧化膜机理解释了纳米涂层抗高温腐蚀性能优异的原因。     

聚氨酯/TiO2纳米复合材料冲蚀磨损特性研究

以纳米TiO2作为填料,制备耐磨蚀聚氨酯纳米复合材料.用相对抗磨损性法评价了聚氨酯纳米复合材料的冲蚀磨损性,通过扫描电镜观察聚氨酯纳米复合材料的磨损形貌,尝试解释纳米TiO2增强聚氨酯复合材料抗含沙冲蚀磨损性能的机理.试验结果表明,纳米粒子均匀分散于聚氨酯中,使聚氨酯弹性体耐磨蚀性得以提高.聚氨酯/TiO2纳米复合材料的抗冲蚀磨损性能分别是45#钢的10.67倍,2Cr13钢的6倍,纯聚氨酯的1.28倍,TiN/聚氨酯复合材料的1.09倍.     

热喷涂纳米结构Al2O3／TiO2涂层断裂韧性的统计性质

采用压痕裂纹法测定了等离子喷涂纳米结构Al2O3／TiO2涂层的断裂韧性及其统计离散度。研究表明,采用不同载荷获得的压痕韧性呈现出较大的离散性,其分布符合韦伯分布类型。通过分析指出,随着载荷的增大压痕韧性的数值趋于集中,而导致压痕韧性产生较大波动性的根本原因在于涂层之中显微结构的不均匀性。     

Sb-SnO2掺杂量对Al2O3-13%TiO2复合陶瓷涂层抗结垢性能的影响

以Al₂O₃-13%TiO₂(AT13)和纳米掺锑SnO₂(Sb-SnO₂)粉体为原料,采用等离子喷涂工艺在4145H合金钢基体表面制备了掺杂不同质量分数(0～16%)Sb-SnO₂的AT13复合陶瓷涂层,研究了复合陶瓷涂层的表面性能、微观形貌、显微硬度、结合强度以及在地层采出水中的抗结垢性能,并与电镀铬层和未处理4145H合金钢进行对比。结果表明：与电镀铬层和未处理4145H合金钢相比,复合陶瓷涂层的水接触角较大,表面能较低,随着Sb-SnO₂掺杂量的增加,水接触角基本呈先增大后减小的趋势,表面能先减小后增大;复合陶瓷涂层具有大量的孔隙;随着Sb-SnO₂掺杂量的增加,硬度整体呈降低趋势,但均高于4145H合金钢和电镀铬层,单位面积结垢质量先减小后增大;掺杂质量分数10%Sb-SnO₂的复合陶瓷涂层具有最大的水接触角、最小的表面能、最小的单位面积结垢质量,平均结合强度为25.7 MPa。     

纳米结构Al2O3/13TiO2涂层精密磨削的材料去除机理的研究

应用扫描电镜对纳米结构Al2O3/13TiO2(n-Al2O3/13TiO2)涂层精密磨削后的表面/亚表面形貌进行观察和分析,结合对n-Al2O3/13TiO2精密磨削的单颗磨粒磨削力、磨削力分力比和比磨削能的磨削实验结果的分析,揭示了n-Al2O3/13TiO2涂层精密磨削的材料去除机理.研究表明,在大多数磨削条件下,n-Al2O3/13TiO2陶瓷涂层磨削的材料去除机理主要是以材料碎裂和材料压碎等脆性去除方式为主,同时也存在一定的材料粉末化以及极少的显微塑性变形等方式.研究结论对纳米结构陶瓷涂层的工业化应用具有重要的理论和实用价值.     

Tribological Behaviour of Nanostructured Al2O3-3 wt% TiO2 Coating Against Steel in Dry Sliding

Nanostructured and conventional Al₂O₃-3 wt% TiO₂ coatings were deposited by atmospheric plasma spraying. The wear and friction properties of both coatings against a steel ball under dry friction conditions were examined. It was found that the wear resistance of the nanostructured Al₂O₃-3 wt% TiO₂ coating was superior to that of the corresponding conventional counterpart. The improvement in wear resistance of the nanostructured coating was attributed to its higher toughness and cohesion strength between splats. As for the nanostructured coating, the wear mechanism was mainly adhesion with micro-abrasion at low loads (20 N). At high loads (80 N), the wear of the nanostructured coating was controlled by plastic deformation and associated delamination along the splat boundaries, which was similar to that of the conventional coating at low loads. However, the failure of the conventional coating was predominantly brittle fracture within the splats and delamination between splats at high loads.     

超音速火焰喷涂微米和纳米结构WC-12Co涂层及其性能

以纳米和微米级WC-12Co粉末为原料,采用超音速火焰喷涂(HVOF)方法在16Mn基体上制备了两种涂层.利用X射线衍射仪对喷涂粉末及涂层进行了相结构分析,用扫描电镜对喷涂粉末、磨粒磨损前后的涂层表面形貌进行了观察,探讨了粉末结构、涂层的组织和结构以及抗磨粒磨损的性能.结果表明:WC-12Co粉末结构对涂层的组织结构影响非常显著,微米WC-12Co粉末中的WC的分解基本上得到了抑止,而纳米结构的粉末由于出现了WC的部分分解,导致了纳米涂层的抗磨粒磨损性能相对于微米涂层提高不多,但是与基体16Mn相比,两种涂层均表现出优异的抗磨粒磨损性能.     

Evaluation of unlubricated wear properties of plasma-sprayed nanostructured and conventional zirconia coatings by SRV tester

Atmospheric plasma spraying method was used to deposit nanostructured and conventional zirconia coatings using spray-dried nanostructured zirconia powder and conventional zirconia powder as feedstock, respectively. Their wear properties were evaluated comparatively by a sliding, reciprocating and vibrating (SRV) tester under dry conditions. The obtained results show that the wear properties of the plasma sprayed zirconia coatings deposited from spray-dried nanostructured zirconia powder were greatly improved compared with those of plasma sprayed zirconia coatings produced from conventional powder. The wear rates of nanostructured zirconia coatings are approximately half of those of conventional zirconia coatings. Under dry conditions, the wear mechanism for the plasma-sprayed nanostructured zirconia coatings is abrasive wear. Whilst in the case of plasma sprayed conventional zirconia coatings, it is a combination of abrasive wear and brittle fracture, the former is dominant wear mechanism. Their wear properties were explained in terms of their microstructure as well as mechanical properties and compared with the wear properties obtained under distilled-water lubricated conditions. Based on the experimental results, it is concluded that the finer debris is a critical factor for the improvement of wear properties of plasma-sprayed nanostructured zirconia coating under dry conditions. The wear properties of plasma sprayed zirconia coatings can be increased by the presence of water during the SRV testing.     

Three body abrasive wear characteristics of plasma sprayed conventional and nanostructured Al2O3-13%TiO2 coatings

In this paper, the conventional Metco130 coatings, and two kinds of nanostructured coatings (NP and NS coatings) were fabricated by plasma spray with different feed powders. The coatings were evaluated by indentation, scratch and three body abrasive wear tests. The NP coating sprayed with plasma densified feed powder had the highest hardness, crack growth resistance and scratch resistance. Test results exhibited that the nanostructured coatings had greatly improved three body abrasive wear resistance compared with conventional coatings. The three body abrasive wear resistance of NP coatings was about three times that of conventional coatings. The failure mode in scratch tests and wear mechanism of three coatings were also discussed.     

A study on erosive wear behavior of HVOF sprayed nanostructured WC-CoCr coatings

WC-CoCr cermet coatings were deposited on stainless steel substrate using high-velocity oxy-fuel (HVOF) thermal spray process. The coatings were developed with two different thermal spray powders: one has WC grains of conventional micron size and the other is composed of nanosized (near-nanostructured) grains. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control the process parameters that have resulted in quality coatings. Cavitation erosion testing was performed using a vibratory test apparatus based on ASTM standard G32-98. Surface morphology of powders and coatings was examined using the FESEM images, and phase identification was performed by XRD analysis. The erosion behavior of coatings and mechanism of material removal was discussed by examining the microstructure images of worn-out surfaces. WC-CoCr cermet coating deposited with nanosized WC grains exhibited higher cavitation erosion resistance as compared to conventional coating.     

Tribological behavior of plasma sprayed Cr2O3-3%TiO2 coatings

Tribological behaviors of plasma-sprayed conventional and nanostructured Cr₂O₃-3%TiO₂ ceramic coatings (i.e., CC3T and NC3T, respectively) using pin on disc type dry sliding and pot type slurry erosion test were investigated in the present work. The experimental results indicated that there were two main wear mechanisms, plastic smearing and adhesive tearing, in the worn coatings under dry sliding. Plastic smearing corresponded to a lower average friction coefficient and wear rate, while adhesive tearing corresponded to higher values. The erosive environment selected for the slurry erosion experiments include 10, 20 and 30% of SiO₂ slurry concentrations in water with particle size 75-106 μm. The main damage mechanism observed in all the coatings submitted to slurry erosion were the formation and propagation of brittle cracks resulting in the detachment of coating surface material. Microstructural investigation was also carried to investigate the wear and erosion mechanism of the coatings using FE-SEM and EDS analysis. Properties like microhardness and porosity were also investigated for these coatings. Tribological performance of NC3T was better as compared to CC3T as observed in the present work.     

Structure of Micro-nano WC-10Co4Cr Coating and Cavitation Erosion Resistance in NaCl Solution

Cavitation erosion(CE) is the predominant cause for the failure of overflow components in fluid machinery. Advanced coatings have provided an effective solution to cavitation erosion due to the rapid development of surface engineering techniques. However, the influence of coating structures on CE resistance has not been systematically studied. To better understand their relationship,micro-nano and conventional WC-10Co4 Cr cermet coatings are deposited by high velocity oxygen fuel spraying(HVOF), and their microstructures are analyzed by OM,SEM and XRD. Meanwhile, characterizations of mechanical and electrochemical properties of the coatings are carried out, as well as the coatings' resistance to CE in 3.5 wt % Na Cl solution, and the cavitation mechanisms are explored. Results show that micro-nano WC-10Co4Cr coating possesses dense microstructure, excellent mechanical and electrochemical properties, with very low porosity of 0.26 ± 0.07% and extraordinary fracture toughness of 5.58 ± 0.51 MPaám~(1/2). Moreover, the CE resistance of micro-nano coating is enhanced above 50% than conventional coating at the steady CE period in 3.5 wt % Na Cl solution. The superior CE resistance of micronano WC-10Co4Cr coating may originate from the unique micro-nano structure and properties, which can effectively obstruct the formation and propagation of CE crack. Thus,a new method is proposed to enhance the CE resistance of WC-10Co4Cr coating by manipulating the microstructure.     

不同喷涂工艺制备的Al_2O_3-13%TiO_2涂层表面自由能与冲蚀磨损性能研究

采用接触角测量仪和冲蚀磨损试验机等设备,研究超声速等离子喷涂与普通大气等离子喷涂两种技术制备的Al_2O_3-13%TiO_2涂层的表面自由能和冲蚀磨损性能,并对涂层的显微硬度、孔隙率及成分进行检测分析。研究结果表明,普通大气等离子喷涂技术制备的涂层,其表面和内部结构疏松,孔隙率及显微硬度分别为6.653%和836.93 HV0.1。而超声速等离子喷涂技术制备的涂层,孔隙率及显微硬度分别为3.467%和1 078.68 HV0.1,相比普通大气等离子喷涂而言,超声速等离子喷涂制备的涂层整体性能较为优异。通过对两种涂层的结构和表面自由能分析发现,超声速等离子喷涂Al_2O_3-13%TiO_2涂层由于结构致密、表面自由能较低而具有较为出色的冲蚀磨损性能。     

Microstructure and performance of multi-dimensional WC-CoCr coating sprayed by HVOF

WC-based coatings deposited by high velocity oxy-fuel (HVOF) spraying have been widely used in many industrial fields, where mechanical components are subjected to severe abrasive wear. Much attention has been especially paid to nanostructured and multimodal WC-based coatings due to their excellent abrasive wear resistance. In this study, a new kind of multi-dimensional WC-10Co4Cr coating, composed of nano, submicron, micron WC particles and CoCr alloy, was developed by HVOF. The microstructure, porosity, microhardness, fracture toughness, and electrochemical properties of the coating were investigated in comparison with nanostructured WC-10Co4Cr coating deposited by HVOF. Abrasive wear resistance of both WC-10Co4Cr coatings was evaluated on wet sand rubber wheel abrasion tester. The results show that the multi-dimensional coating possesses low porosity (0.31 ± 0.09%), excellent microhardness (1126 ± 115 HV_0.3), fracture toughness (4.66 ± 0.51 MPa m^1/2), and outstanding electrochemical properties. Moreover, the multi-dimensional coating demonstrates approximately 36% wet abrasive resistance enhancement than the nanostructured coating. The superior abrasive wear resistance originates from the coating’s multi-dimensional structure and excellent mechanical and electrochemical properties.     

真空退火对磁控溅射CuS-MoS2涂层润滑性能的影响

为提高MoS2润滑涂层承载力和抗湿性能,使用磁控溅射技术制备CuS掺杂MoS2复合涂层,并对制备涂层进行220、320和420℃真空退火处理,以发挥CuS与MoS2协同润滑作用。采用场发射扫描电子显微镜、激光拉曼光谱分析涂层结构,通过洛氏硬度压痕试验、摩擦磨损试验和纳米压痕试验对涂层性能进行分析。实验结果表明:随CuS靶溅射功率提高,涂层中出现颗粒长大和CuS结晶化趋势,且CuS掺杂抑制了MoS 2形核长大,涂层膜-基结合力有所下降;真空退火处理后CuS-MoS2复合涂层表面发生分解,厚度明显降低,MoS2(002)相形核长大,摩擦学性能得到提升;320℃退火处理后涂层在常温和RH70%大气环境下获得最低平均摩擦因数0.08,纳米硬度达到5.64 GPa,并具有较好的耐磨损性能。研究认为由于CuS受热分解导致复合涂层结构和成分变化,生成了有利于发挥CuS与MoS2协同润滑效应的微晶相,使得涂层润滑性能得到明显提升。