耐温耐磨有机硅基复合涂料的冲蚀磨损研究

研究了陶瓷颗粒增强体（ＳｉＣ、Ａｌ２Ｏ３）及不同冲蚀条件对有机硅基复合材料涂料（以下简称有机硅复合涂料）耐冲蚀性能的影响。发现基体组成、陶瓷颗粒种类、含量及冲蚀条件对有机硅复合涂料耐冲蚀性有很大的影响。合适的选择颗粒增强体,复合涂料的冲蚀率较纯有机硅涂料降低了１～２个数量级。ＳＥＭ冲蚀表面形貌分析表明：低速冲蚀时涂层的磨损是因塑性变形和疲劳引起,而高速冲蚀时则由塑性变形、显微犁耕和显微切削造成。传统的耐温耐磨复合涂料多为纤维增强,因此研究开发新型颗粒增强复合涂料有较大的意义。     

氮气钻井过程中的耐冲蚀涂层

将多功能四通制造材料30CrMo钢作为基体材料,使用氩弧焊制备钴基合金HS113,625,Co-112堆焊层,采用喷焊方法制备Ni60涂层,使用超音速火焰喷涂(HVOF)方法制备WC-12Co涂层。对该5种涂层的冲蚀行为使用自制的冲蚀试验机进行了研究,分析了显微组织与显微硬度对冲蚀性能的影响及涂层冲蚀后的表面形貌。结果表明:涂层的冲蚀失重与减薄均随冲蚀时间线性增加,HS113涂层的耐冲蚀性要优于其他4种涂层的耐冲蚀性;显微组织、硬度等均会影响涂层的耐冲蚀性能。     

反应等离子喷涂TiC/ Fe-Ni复合涂层及其耐冲蚀性能

以TiFe粉、Ni粉和蔗糖(碳的前驱体)为原料,通过蔗糖的热分解碳化制备Ti-Fe-Ni-C系反应热喷涂复合粉末,并利用等离子喷涂制备了TiC/Fe-Ni复合涂层。复合涂层主要由TiC颗粒均匀分布于(Fe、Ni)固溶体中形成的复合强化片层构成,片层中TiC颗粒呈球形或近球形,粒度为亚微米级和纳米级。TiC/Fe-Ni复合涂层的耐冲蚀磨损性能研究表明：涂层冲蚀失重率随攻角的增大而增加,表现出脆性材料冲蚀特性,但冲蚀失重率对攻角不敏感,涂层具有较好的塑性与硬度的配合;复合涂层的耐冲蚀磨损性能优于相同工艺条件下制备的C_r2C₃/Ni-Cr复合涂层,约为20G钢的2倍以上。     

氩弧熔覆含Al_2O_3-TiB_2增强颗粒的自熔性镍基合金复合层的冲蚀磨损性能

为了提高Al2O3-Ti B2复相陶瓷涂层的冲蚀磨损性能并降低熔覆成本,以Ni60A自熔性合金粉末、Al2O3粉末以及Al-Ti O2-B2O3体系为原料,在Q235钢表面氩弧熔覆原位合成了Al2O3-Ti B2增强颗粒复合层。采用金相显微镜、X射线衍射仪、显微硬度仪及冲蚀磨损试验对熔覆层的显微组织、物相结构、显微硬度和耐冲蚀磨损性能进行分析。结果表明:熔覆层与基体之间的结合方式为冶金结合,界面无气孔、裂纹;熔覆层中有Al2O3,Ti B2,Fe2B和Fe19Ni3相生成;熔覆层的显微硬度最高可达771.9 HV,较基体提高了3.82倍;熔覆层的冲蚀磨损性能相对基体提高了2.49~4.70倍。     

陶瓷颗粒增强镍合金复合涂层冲蚀磨损的试验研究

以WC,ZrO₂,Cr₂O₃和Al₂O₃陶瓷颗粒为增强相,镍合金粉末为基体,运用等离子喷涂技术制备四种陶瓷/镍合金复合涂层。采用冲蚀磨损试验机和正交试验方法,进行陶瓷颗粒相浓度、磨粒粒度、冲蚀角和速度对陶瓷颗粒/镍合金复合涂层抗冲蚀磨损性能影响的试验研究。采用表面形状测量仪对陶瓷颗粒/镍合金复合涂层磨损表面形貌进行测量和分析。试验结果得到WC,ZrO₂,Cr₂O₃和Al₂O₃四种陶瓷颗粒/镍合金复合涂层冲蚀磨损率的经验关联式。     

纳米结构强化无铅焊点的力学性能

新型的无铅钎料不仅要具备含铅钎料的工艺性能,更重要的是要有更高的力学性能,特别是焊接接头的抗蠕变能力。将纳米级多面齐聚倍半硅氧烷(Polyhedral oligomeric silsesquioxanes,POSS)颗粒作为增强相添加到基体钎料中,能够有效地改善Sn-3. 5Ag基复合钎料的性能。研究了不同种类POSS增强颗粒对Sn-3. 5Ag钎料显微组织和力学性能的影响,确定出POSS增强颗粒复合钎料的最佳配比,并对最佳配比复合钎料在不同温度不同载荷条件下的蠕变寿命进行了研究。结果表明：POSS颗粒质量分数小于2%时,可以抑制基板界面处初晶金属间化合物的生长;复合钎料的抗剪切强度明显提高;低温时,最大蠕变寿命明显改善。     

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.     

B_4C增强Fe基活性氩弧熔覆层的冲蚀磨损性能

目前,关于活性氩弧熔覆Fe基B_4C复合陶瓷涂层的研究较少。为了降低弧氩熔覆层的制备成本并提高其性能,同时拓宽固体废物粉煤灰的应用领域,以粉煤灰为活性剂,在Q235钢表面氩弧熔覆Fe基B_4C层。通过研究粉煤灰活性剂对熔覆层成分、金相组织、显微硬度以及耐冲蚀性能的影响,验证粉煤灰作活性剂应用于氩弧熔覆技术的可行性。结果表明:普通氩弧熔覆层中发生了原位反应,生成了Fe_2B、Fe_3B等新相,熔覆层显微硬度300HV左右,在冲蚀介质转速为200,300,400 r/min时,耐冲蚀性能分别为基材的2.17,2.19,2.52倍;粉煤灰活性氩弧熔覆层除生成Fe_2B、Fe_3B外,还生成了Fe_3.5B、Fe_5Si_3、Fe_2Al B_2和Fe_3Al_2Si3等新相,熔覆层显微硬度稍有提高,最高达450 HV,在冲蚀介质转速为200,300,400 r/min时,耐冲蚀性能分别为基材的4.28,4.57,6.46倍。     

CrMoV合金堆焊层组织结构及抗冲蚀磨损性能研究

采用手工电弧焊工艺在20钢基体表面制备CrMoV合金堆焊层进行相组成、显微组织、耐冲蚀磨损性能及冲蚀磨损机理研究。结果表明,堆焊层数增加母材稀释率减小,堆焊层显微组织主要为马氏体、残余奥氏体及合金碳化物。第二、三堆焊层显微硬度最高,堆焊层平均显微硬度达780 HV,为基体硬度的4倍多。在所有冲蚀角度范围内,CrMoV合金堆焊层耐泥沙冲蚀磨损性能优于20钢;冲蚀角度小于30°时冲蚀磨损机制以微切削为主,大于30°时以疲劳损伤及局部塑性变形为主;砂粒粒径增加,堆焊层及20钢的冲蚀磨损率均有所增加,但不与粒径的增加值成正比。     

纯铜材表面煤矸石陶瓷涂层的制备及耐冲蚀磨损性能

纯铜材不耐磨蚀。以阜新热电厂煤矸石为主要原料,添加一定量的铝粉、氧化硼和氧化铈制成涂料;采用热化学反应法在纯铜材表面制备了陶瓷涂层,分别以D/MAX-RB型X射线衍射仪、骤冷骤热法和MSH磨粒磨损试验机,对涂层结构、抗热震性能及耐冲蚀磨损性能进行了研究。结果表明:冲蚀速度为200 r/min时,煤矸石陶瓷涂层和稀土改性陶瓷涂层的耐冲蚀磨损性能分别较纯铜基体提高1.69倍和2.39倍;300 r/min时,分别提高1.79倍和2.50倍。本法具有较好的经济效益和环保性效益。     

n-Al2O3P/Ni复合刷镀层的组织和摩擦磨损特性

研究了镍基纳米Al2O3复合电刷镀层（n-Al2O3^p/Ni）的组织特征及擦磨损特性，并与快镍刷镀（Ni)进行了比较。结果表明：n-Al2O3^p/Ni复合刷镀层表面粗糙度更小，组织更致密，镀层摩擦系数随镀液中纳米粒子含量增加稍有增大；n-Al2O3在复合刷镀层中弥散分布，与基相良好结合；复合镀的耐磨性能明显优于Ni刷镀层，镀液中n-Al2O3含量为20g/L时，复合刷镀层具有最佳耐磨性能。     

镍磷化学复合镀碳纳米管的摩擦磨损性能研究

利用碳纳米管作为增强相制备镍磷基复合镀层,并对其表面形貌和耐摩擦磨损性能进行了测试分析.结果表明,碳纳米管均匀地嵌镶于基体中,且端头露出,覆盖于基体表面;镀层具有优良的耐磨性和自润滑性.这是由于碳纳米管具有较高的强度和一定的自润滑性,加之以网络和缠绕形态分布于基体中,增大了复合相的粘结力,使碳纳米管在磨损时不易拨出而脱落.     

Modified zirconia abradable seal coating for high temperature gas turbine applications

The results and development of a new full ceramic abradable turbine seal coating material prepared by thermal spraying are presented. The main objective was to achieve high temperature abradability and low mating part wear using an erosion-resistant coating with high temperature stability and thermal shock resistance. The new coating was successfully laboratory tested at temperatures of at least 1100°C (2012°F). Commercial metal-based abradable coatings which are currently available are limited to lower operating temperatures. Typical plasma- sprayed ceramic coatings, because of inherent high particle velocities, are normally to dense to permit abrading without experiencing high turbine blade tip wear damage. In contrast, lower velocity combustion-sprayed ceramic coatings frequently have lower toughness and cohesive particle strength for resistance to abrasive erosion. The new coating material is designed to react exothermically, during combustion spraying, to produce a coating both with high interparticle cohesive strength for resistance to abrasive particle erosion and with controlled porosity for low turbine blade tip wear and effective abradability. Adjustment of spraying conditions gives flexibility to alter the coating hardness and porosity and permits the tailoring of abradability and erosion resistance properties for specific operating requirements.Based on specially developed test methods for high temperature abradability, high temperature particle erosion and thermal cycling, the modified zirconia coating showed superior performance to high performance baseline materials tested in the program. Industrial evaluation of this coating is presently being conducted.     

三种NiAl材料的室温摩擦磨损性能

测试二元NiAl合金、NiAl-Al2O3-TiC原位内生复合材料以及NiAl-Cr(Mo)-Hf共晶合金的室温摩擦磨损性能,研究了磨损机制.结果表明:NiAl材料的抗磨损性能与材料的硬度和断裂韧性成正比,在磨损过程中硬质陶瓷颗粒能有效地传递应力和起到支撑作用,减轻材料的磨损.因此NiAl-Al2O3-TiC复合材料的抗磨损性能最好,在相同工况下其磨损率为NiAl-Cr(Mo)-Hf共晶合金的1/4-3/4和二元NiAl合金的1/20-1/10.摩擦系数随着三种NiAl材料硬度的提高而降低.三种NiAl材料的室温干摩擦磨损过程受控于塑性变形,其磨损机制主要是磨粒磨损机制,随着载荷的增加,磨损表面依次呈现出塑性变形、显微剥落和粘着磨损特征,磨损机制的改变对磨损率和摩擦系数具有重要的影响.     

Surface modification of an aluminium 2124 composite by eutectic alloying

The incorporation of a hard particular dispersion in a metal matrix results in a composite material with unique mechanical and tribological properties. However, once the composite has been fabricated the particular dispersion cannot be rearranged or modified. In this study, the surface of a 2124 aluminium metal matrix composite is modified by eutectic alloying with copper. The results show that by heat treating the composite at a temperature above the eutectic temperature for the Al-Cu system, the distribution of SiC particles can be altered. There is a significant movement of particles towards the surface of the composite and abrasive wear tests show better wear resistance than the unmodified surfaces. This change in wear behaviour is attributed to the absence of severe plastic deformation due to the increase in concentration of hard SiC particles within the surface.     

Ti6Al4V合金激光原位合成自润滑复合涂层高温摩擦学性能

为提高Ti6Al4V合金的高温摩擦学性能,采用激光熔覆技术在其表面原位合成多相混杂金属基高温自润滑耐磨复合涂层,熔覆粉末的成分为Ni60-16.8%TiC-23.2%WS_2(质量分数,下同),系统地研究复合涂层的显微组织、物相结构及其在20,300,600,800℃下的摩擦学性能和相关磨损机理。结果表明:复合涂层的显微硬度(701.88HV_0.5)约为基体(350 HV_0.5)的2倍;由于原位合成固体润滑相(Ti_2SC/TiS/NiS/TiO/TiO_2/NiCr_2O_4/Cr_2O_3)和硬质相(W,Ti)C_1-x/TiC/Cr_7C_3的协同作用,复合涂层的耐磨减摩性能明显优于基体。随着温度升高,涂层和基体的摩擦因数和磨损率均呈下降趋势,在800℃时复合涂层和基体的摩擦因数分别为0.32和0.43,磨损率分别为1.80×10^-4,2.92×10^-5mm/Nm。在800℃下塑性变形、分层和氧化磨损为基体主要磨损机理,复合涂层以氧化磨损和轻微的黏着磨损为主。     

Al2O3—TiC—Co与Al2O3—TiC陶瓷冲蚀磨损行为的比较研究

通过特殊的化学处理方法，完成了对Ａｌ２Ｏ３及ＴｉＣ陶瓷粉末的钴包覆，将包覆后的两种粉安７０ｗｔ％Ａｌ２Ｏ３－Ｃｏ和３０ｗｔ％ＴｉＣ－Ｃｏ的比例混合烧结出硬度和韧性都较理想的Ａｌ２Ｏ３－ＴｉＣ－Ｃｏ（ＡＴＣ）精细陶瓷，通过ＳＥＭ观察研究其冲饥蚀磨损行为，并对ＡＴ３０（７０ｗｔ％Ａｌ２Ｏ３－３０ｗｔ％ＴｉＣ）和ＡＴＣ陶瓷的冲蚀行为机制进行了比较研究，与ＡＴ３０陶瓷相比，ＡＴＣ陶瓷良好的综合力学性能和细     

Cemented carbide reinforced nickel-based alloy coating by laser cladding and the wear characteristics

Composite coatings composed of metal matrix and ceramic particles have received particular attention in surface engineering. In this paper nickel base alloy powder and WC-Co cemented carbide particles have been chosen to manufacture composite coatings by use of kW CO₂ laser. Laser processing parameters including output power and scanning speed have been optimized. X-ray diffractor, optical and electron microscopes and energy dispersion spectra have been applied to investigate the phase constituents and microstructures of the coating. Block-on-ring dry sliding wear test and rubber wheel slurry erosive abrasion wear test have been conducted to study the wear properties of the composite coating as well as the reinforcing effect of WC-Co particles. A 50–100 mm wide ring appeared along the particle side of the particle-matrix boundary, showing superior wear and corrosion resistance, higher than even the original central part of the WC-Co particle. The mechanism of its formation has been probed.     

Fabrication of Graded, Spray, and Fused Coatings and Their High Temperature Erosion Performance

Thermally sprayed coatings are often used industrially to protect bulk metal structural and heat exchange surfaces against wear and corrosion at high temperature. Spray and fused coatings of Ni-based alloys are dense, with metallurgical coating adhesion and have provided excellent industrial corrosion resistance. This process allows the addition of hard particles to improve coating wear resistance in a functionally graded manner, and the first such coating is developed. There has been few wear studies of such functionally graded materials (FGMS), particularly as coatings. Because such materials provide a gradation in properties such as hardness and thermal expansion coefficient between the coating and the substrate, it is thought that they may have potential in aggressive environments such as high temperature energy conversion processes (resisting spallation and erosion).

In a low velocity fluidized bed erosion environment the effects of erodent particle size and bed temperature on the erosion rate through the section of a functionally graded spray and fused coating was studied. The coating consisted of a varying fraction of WC particles (0-42 vol.%) in a Ni-Cr-based, self-fluxing matrix. The erodent particle size varied from 200 to 600 μm, testing was between 25 and 600°C, with impact angles of 30° and 90°.