脉冲电沉积Ni-W-P系多元复合镀层性能研究

主要研究了Ni-W-P-SiC，RE-Ni-W-P-SiC，RE-Ni-W-P-SiC-MoS2，RE-Ni-W-P-SiC-PTFE直流及脉冲复合镀层的硬度、磨损率、相结构及形貌．结果表明：脉冲镀层的硬度均高于直流镀层，但RE-Ni-W-P-SiC-PTFE复合镀层的硬度较低．四种复合镀层的硬度随热处理温度的升高而增加，在400℃时达到最大值，此后，热处理温度继续升高，复合镀层硬度反而下降；频率为50Hz，占空比为0．6和0．8时，RE-Ni-W-P-SiC镀层的硬度最高．占空比为0．8时的镀层，其硬度均高于占空比为0．6的镀层；Ni-W-P-SiC，RE-Ni-W-P-SiC，RE-Ni-W-P-SiC-PTFE脉冲镀层的磨损率明显低于直流镀层，且RE-Ni-W-P-SiC-MoS2和RE-Ni-W-P-SiC-PTFE脉冲镀层的磨损率最小；Ni-W-P-SiC，RE-Ni-W-P-SiC脉冲镀层镀态下为非晶态结构，RE-Ni-W-P-SiC-MoS2脉冲镀层镀态下为混晶结构，而RE-Ni-W-P-SiC-PTFE脉冲复合镀镀态下为晶态结构；脉冲镀层的晶粒粒度要小于直流镀层，加入RE有细化晶粒的作用，各种微粒均匀分布在镀层中，镀层表面及断面没有裂纹．     

Co／SiC复合电沉积过程

研究了普通镀钴溶液中碳化硅微粒在质金属钴形成复合镀层的电沉积过程。结果表明,在小的微粒载荷量下,复合电沉积过程由微粒向阴极的传输所控制。而在大的微粒载荷量下,小电流密度时复合电沉积过程由微粒的强吸附所控制,大电流密度时复合电沉积过程由微粒向阴极的传输所控制。     

电沉积Ni-Co-Cr合金镀层及其耐蚀性研究

采用电化学恒电流技术在铜基体上沉积制备了Ni-Co-Cr三元合金镀层,研究了电流密度、温度及pH值对合金镀层成分的影响.利用SEM和EDS研究了Ni-Co-Cr合金镀层的形貌与成分,通过交流阻抗技术研究了镀层的耐蚀性.采用弯曲实验法测定了镀层的结合力.结果表明,在阴极电流密度为100 mA/cm2,镀液温度为25℃,pH为2.5条件下沉积的合金镀层致密均匀,化学组成中Cr含量达到最高(达到10％,该成分为10.22％ Cr,21.61％ Ni,59.86％ Co,质量分数,氧和铜含量未计入),具有优化耐蚀性.     

镍基纳米碳管复合镀层的摩擦磨损性能

利用化学镀方法制备镍基纳米碳管复合镀层,用扫描电镜分析了镀层的表面形貌,并用销-盘式磨损试验机研究了复合镀层在干摩擦条件下的摩擦磨损行为.结果表明:纳米碳管均匀地嵌入在镍基体中,镍基纳米碳管复合镀层具有优良的耐磨性能;由于纳米碳管的自润滑作用,复合镀层的摩擦系数随着纳米碳管体积分数的增加而逐渐降低.     

聚四氟乙烯、石墨等粒子与镍磷化学共沉积复合镀层的研究

由化学镀得到的聚四氟乙稀、石墨、氟化石墨、硫化钼及氟化钙粒子等与镍磷一起沉积的五类自润滑复合镀层。在环块试验机及销盘试验机上研究了其摩擦磨损特性。得出其摩擦系数与抗磨性、试验负荷、粒子含量和镀层的热处理与否有关。与淬火GCr15和氮化过的钢相比,自润滑复合镀层具有低的摩擦系数,比之纯Hi-p镀层其摩擦系数也较低。 由AES和SEM对磨损表面进行分析,当表面的Ni-p逐步磨去时,固相润滑粒子逐步暴露。对细粒子来说(如小于2μm的PTFE)能在对磨件表面形成转移膜,降低摩擦系数,其磨损率略有提高。但如粒子过大(如大于2μm的石墨)则石墨粒子压延并抛光,或碎裂脱落,也能转移并降低摩擦,但使磨损量大为增加。     

表面活性剂对电沉积纳米WO3-Cu复合镀层组织及其性能的影响

为了解不同表面活性剂对纳米复合电沉积过程的作用,研究常用的阴离子、阳离子和非离子表面活性剂对WO_3-Cu复合镀层电沉积过程的影响。采用扫描电子显微镜和能谱分析仪分析添加表面活性剂前后镀层表面微观形貌和镀层成分的变化,通过润湿性试验、自清洁试验、耐磨性试验和光催化试验分别评价表面活性剂对WO_3-Cu复合镀层润湿性能、自清洁性能、耐磨性能和光催化性能的影响。结果表明:表面活性剂可有效改变WO_3纳米颗粒在镀层中的沉积和镀层的表面形貌,其中阳离子和非离子表面活性剂联合添加时制备的复合镀层中WO_3含量达到最高值25.9%;经氟化处理后,其镀层表面接触角可达155°;与纯铜相比,复合镀层有良好的自清洁性、耐磨性和光催化性。     

电沉积Ni-Co-Cr合金镀层的电化学性能

采用电化学恒电流技术在铜基体上沉积制备了Ni-Co-Cr三元合金镀层,研究了柠檬酸钠、硼酸及十二烷基硫酸钠对合金镀层的耐蚀性能影响.结果表明：在柠檬酸钠的浓度为200 g/L,糖精的浓度为1.4 g/L,硼酸的浓度为40 g/L,十二烷基硫酸钠的浓度为0.18 g/L,在此条件下沉积的合金镀层耐蚀性能最佳.     

金属镍和聚四氟乙烯微粒复合电沉积的研究（Ⅲ）：———复合膜 …

由电沉积法得到的金属镍和高分子聚四氟乙烯（ＰＴＦＥ）复合膜层具有优良的减摩、自润滑性能。对所研制的金属镍和高分子聚四氟乙烯复合膜层的硬度、摩擦性能、形貌观察等进行了测试。实验结果表明镍－聚四氟乙烯镀层有较低的滑动摩擦系数，在同样条件下，与镍镀层相比，其滑动摩擦系数下降三分之一左右。     

电沉积Ni基台金及其复合镀层在10％H2SO4中的腐蚀磨损特性研究

采用电刷镀技术制取了Ni-W-Co合金镀层和Ni-W-Co／SiCp复合镀层，利用扫描电镜、能谱仪、X射线衍射仪分别对镀层原始状态及其腐蚀磨损过程中的组织形貌、成分、和相组成进行了观察、分析．研究了在不同的载荷和速度条件下两种镀层的腐蚀磨损特性及腐蚀磨损的协同作用．结果表明：本实验条件下，在较低的载荷和速度下，复合镀层的耐腐蚀磨损性能优于合金镀层，随着载荷和摩擦速度的增大，复合镀层的耐腐蚀磨损性能下降较合金镀层快．     

电沉积Ni—WC 合镀层特性的研究

研究了Ni-WC复合材料镀层的电沉积工艺及热处理和WC微粒对Ni复合镀层的影响 ,同时对其组织结构、硬度、结合强度、孔隙率等也作了测定和讨论 .结果表明 :本文的试验工艺 ,可成功地电沉积出结合力好和孔隙率低的Ni-WC复合镀层 ;随着WC含量的增加 ,镀层的硬度也得到提高 .镀层经适当的热处理后 ,硬度可得到进一步提高     

Dry wear behaviors of wear resistant composite coatings produced by laser cladding

Using different proportional mixtures of Ni-coated MoS2, TiC and pure Ni powders, new typical wear resistant and selflubricant coatings were formed on low carbon steel by laser cladding process. The microstructures and phase composition of the composite coatings were studied by SEM and XRD. The typical microstructure of the composite coating is composed of multisulfide phases including binary element sulfide and ternary element sulfide, γ-Ni, TiC and Mo2C. Wear tests were carried out using an FALEX-6 type pin-on-disc machine. The friction coefficient and mass loss of three kinds of MoS2/TiC/Ni laser clad coatings are lower than those of quenched 45 steel, and the worn surfaces of the laser cladding coatings are very smooth. Because of high hardness combined with low friction, the laser cladding composite coating with a mixture of 70% Ni-coated MoS2, 20%TiC and 10% pure Ni powder presents better wear behaviors than the composite coating with other powder blends. The composition analysis of the worn surface of GCr15 bearing steel shows that the transferred film from the laser cladding coating to the opposite surface of GCr15 bearing steel contains an amount of sulfide, which can change the micro-friction mechanism and lead to a reduced friction coefficient.     

指尖密封用炭-炭复合材料摩擦磨损性能

为确定指尖密封用炭-炭(炭纤维增强炭基体)复合材料的摩擦学性能,针对指尖密封的轻载使用条件,应用UMT-2摩擦磨损测试仪进行炭-炭复合材料摩擦磨损性能试验,测量摩擦系数与磨损率,并采用扫描电子显微镜(SEM)分析材料的摩擦磨损机理.结果表明,无纬布层垂直于摩擦平面时,材料的摩擦系数和磨损率较低.载荷增加,较高密度材料的磨损率增加缓慢,摩擦系数减小.与载荷相比,材料磨损率受频率的影响较小,且随频率升高摩擦磨损性能越好.磨损表面的SEM分析表明:低频、低载条件下材料发生磨粒磨损;频率的提高加快磨屑膜的成形,自润滑能力增强;载荷的增加虽使磨屑快速被挤压形成磨屑膜,但磨屑膜被不断挤出剥落,纤维裸露断裂产生严重磨损,这一点在材料密度较低时表现更为显著.选用较高密度的材料以及布置无纬布层垂直于摩擦平面可以有效缓解密封材料的磨损.     

Effect of electromagnetic stirring on the microstructure and wear behavior of iron-based composite coatings

The effect of electromagnetic stirring on the microstructure and wear behavior of coatings has been investigated. A series of iron-based coatings were fabricated by the plasma-transferred arc cladding process by applying different magnetic field currents. The microstructure and wear resistance of the composite coatings were characterized by scanning electron microscope (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), and wet sand rubber wheel abrasion tester. The experimental re- sults showed that the microstructure of the coatings was mainly the γ-Fe matrix and (Cr, Fe)7C3 carbide reinforced phase. The coatings were metallurgically bonded to the substrate. With increasing magnetic field current, the amount of the block-like (Cr, Fe)7C3 carbide reinforced phase increased at first, reached a local maximum, and then decreased sharply. When the magnetic field current reached 3 A, the block-like (Cr, Fe)7C3 carbides with high volume fraction were uniformly distributed in the matrix and the coating displayed a high microhardness and an excellent wear resistance under the wear test condition.     

粘结石墨基固体润滑涂层的微动摩擦磨损性能

为了探讨粘结石墨基固体润滑涂层的微动摩擦磨损性能的作用机理,使用SRV微动摩擦磨损试验机对粘结石墨基固体润滑涂层在微动试验条件下的摩擦学性能以及抗承载能力进行研究,对其磨痕形貌和对偶转移膜进行分析。研究结果表明：粘结石墨基固体润滑涂层的磨损率随着试验载荷和摩擦速度的增大而减小;而摩擦因数随着试验载荷增大而减小,随摩擦速度增大而缓慢增大;在微动摩擦过程中,高载高速可以促进高质量转移膜在对偶表面形成,从而使得粘结石墨基固体润滑涂层具有良好的抗承载能力和优异的抗磨减摩性能。     

Abrasive wear behaviors of high velocity arc sprayed iron aluminum composite coatings

The High Velocity Arc Spraying （HVAS） technology was used to prepare Fe-Al composite coatings by the adding of different elements into cored wires to obtain different Fe-Al coatings. The added compounds do great effect on the properties of the composite coatings. The microstructures and abrasive wear performances of the coatings were assessed by transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, and THT07-135 high temperature wear equipment. It was found that the adding of Cr3C2 can greatly increase the room temperature wear behavior, and Fe-Al/WC coatings have adapting periods at the beginning of wear experiment. With the rise of temperature, the wear resistance of Fe-AI/Cr3C2 coatings becomes bad from room temperature to 250℃, and then stable from 250℃ to 550℃; the wear resistance of Fe-Al/WC becomes well with the rise of temperature. The adding of Cr and Ni can also improve wear performances of Fe-Al composite coatings.     

真空条件下GCr15钢摩擦磨损性能研究

为研究登月车轴承内部摩擦磨损机理,研制了真空球盘式摩擦磨损试验机,并在常压和真空(真空度为6×10~(-3)Pa)条件下试验研究了GCr15钢球/GCr15钢盘配副的摩擦磨损性能。结果表明:真空条件下摩擦面之间的高温使得试件剪切强度和粘着力降低,从而摩擦系数低于常压下。而真空条件下配副更易发生粘着,产生的磨屑更多,磨损量更大。     

2738模具钢表面激光熔覆Ni基WC复合涂层的摩擦磨损性能

在2738模具钢表面通过CO2激光熔覆制备Ni基WC复合涂层。分别对2738钢基体和Ni-WC激光熔覆层进行干摩擦试验。用三维表面形貌仪测量磨损体积,用扫描电镜观察磨痕的表面形貌。试验结果表明,Ni-WC复合涂层试样的硬度显著提高,表面硬度超过1200HV,保证了Ni-WC熔覆层的耐磨性。熔覆层的平均摩擦因数约为0.24,与2738钢基体的摩擦因数0.43相比,降低了约44%。熔覆试样的比磨损率比基体试样的比磨损率下降了96.7%,WC硬质相提高了摩擦副表面的承载能力。磨粒磨损为Ni-WC复合涂层的主要磨损机理。