电刷镀Ni-Co-W/Y2O3复合镀层的组织与摩擦磨损特性

采用复合电刷镀工艺在45钢基材上制备了含微米Y2O3颗粒的Ni-Co-W基复合刷镀层,采用扫描电镜、X射线衍射仪、显微硬度计、摩擦磨损试验机等对镀层的表面形貌、截面组织、结构、硬度及耐磨性进行了测定,与Ni-Co-W镀层进行了对比分析。结果表明:Ni-Co-W/Y2O3复合镀层厚度均匀,与基体之间呈凸凹镶嵌,结合紧密;与Ni-Co-W合金镀层相比,Ni-Co-W/Y2O3复合镀层的表面更加平整、光滑,组织更为致密,微裂纹明显减少;硬度较Ni-Co-W合金镀层更高,摩擦系数较低,Y2O3颗粒在镀层与摩擦副相互作用的过程中起支撑作用,减弱了磨损面的犁削效应和黏结效应,耐磨性显著优于Ni-Co-W合金镀层。XRD分析结果表明:此两种镀层均存在非晶态结构,微米Y2O3颗粒的加入促进镀层结构由非晶态向微晶态转变。     

不同Al_2O_3分散对Ni-W复合镀层组织及磨损性能影响

为进一步提高Ni-W-Al_2O_3复合镀层的摩擦磨损性能,采用十二烷基硫酸钠和1.4丁炔二醇两种表面活性剂在不同场下分别对Al_2O_3颗粒进行不同情形化学分散,并通过直流电沉积技术在45#钢基体上成功制备了Ni-W-Al_2O_3复合镀层,运用摩擦磨损实验机、三维表面轮廓仪、扫描电镜(SEM)、能谱仪(EDS)等研究不同Al_2O_3分散方式下所得复合镀层的表面形貌、磨损失重、磨损率与磨痕形貌,并对比其摩擦磨损性能。结果表明,用1.4丁炔二醇分散所得复合镀层表现出优良的磨损性能,耐磨性也最好;与相同情况下Al_2O_3未分散所得镀层相比,其耐磨性提高近4倍,磨损率最小为2.51×10~(-6)mm~3·(N·m)~(-1)。稳恒磁场下用1.4丁炔二醇分散所得镀层磨损率较Al_2O_3未分散所得镀层磨损率降低了24%,超声场下磨损率则相对降低了34.8%。显微组织分析得出:稳恒磁场下用1.4丁炔二醇分散Al_2O_3所得复合镀层表面形貌均匀致密,针孔、缺陷明显减少,超声场下镀层表面形貌致密度加大,针孔、缺陷消失,但晶粒长大较明显。     

Al-Fe2O3-Cr2O3体系SHS制备Al2O3陶瓷复合涂层的研究

以Al粉、Fe2O3粉和Cr2O3粉为主要反应物,采用自蔓延高温合成(SHS)方法在Q235钢基体上制备Al2O3陶瓷复合涂层,研究了反应物成分配比对自蔓延反应过程、涂层的合成产物和涂层性能的影响规律.结果表明:自蔓延反应分两步进行,并且反应不完全.反应物中Al-Fe2O3与Al-Cr2O3体系质量比增加会加快自蔓延反...     

掺杂Nb2O5对RHP合成Al2O3-TiAl复合材料的影响

采用反应热压(RHP)工艺,利用Ti、Al、TiO2及Nb2O5之间的放热反应,在较低温度下制备了Nb2O5强化Al2O3/TiAl复合材料.借助XRD、OM及SEM等手段,考察了Nb2O5对Al2O3/TiAl复合材料的相分布及组织结构的影响.结果表明:材料产物由γ-TiAl、α2-Ti3Al、Al2O3和NbAl3相构成,Al2O3颗粒分布于基体交界处,存在一定的偏聚.Nb2O5的引入,使得γ-TiAl相含量减少,α2-Ti3Al相含量增大;基体晶粒有所细化,且分布逐渐趋于均匀.当Nb2O5的引入量(质量分数)为6%时,组织主要由α2-Ti3Al/γ-TiAl层片状晶团组成,出现了较完整的γ-TiAl晶粒,属于近片层(NL)组织结构,层片状晶团的尺寸小于50μm,γ晶粒尺寸小于5μm.力学性能测试表明,当Nb2O5的引入量(质量分数)为6%时,材料的抗弯强度达到最大值,约为593MPa,硬度为4.77 GPa;断裂韧度达到最大值,为8.93MPa·m1/2,具有可接受的力学性能.     

La2O3, Ce2O3掺杂对原位合成Al2O3(p)/TiAl复合材料显微组织与性能的影响

借助XRD, SEM分析及力学性能测试, 分析了La2O3, Ce2O3掺杂对原位合成Al2O3颗粒强化钛铝基复合材料组织与性能的影响, 探讨了稀土氧化物（La2O3, Ce2O3）的细化机制. 研究结果表明： 掺杂稀土氧化物后产物由γ-TiAl/α2-Ti3Al双相、 Al2O3及Al4La或Al4Ce相组成;Al2O3颗粒分布于晶界处, 使基体晶粒得以细化;引入稀土元素后材料的密度明显增强, 氧化铝的团聚现象减弱. 力学性能测试表明, La2O3, Ce2O3的引入, 有效改善了复合材料的力学性能, 尤其是掺杂Ce2O3后, 材料的抗弯强度比未掺杂时提高了160%以上.     

化学镀Al2O3/Cu复合粉烧结体的组织研究

采用化学镀法制备了Al2O3/Cu复合粉体,将复合粉体在160MPa的压力下保压5nin压制,在1 000℃保温1h、N2保护烧结,得到体积分数为50％的Al2O3p/Cu复合材料.通过SEM对复合粉体的形貌和复合材料的断口进行观察,通过光学显微镜对复合材料组织进行观察,通过能谱仪对复合材料中颗粒和基体的界面进行成分分析,并对其密度和热膨胀系数进行测定,结果表明:复合材料中Al2O3颗粒分布均匀,与Cu基体结合良好;复合材料相对密度为88.6％,100 ～ 300°C的热膨胀系数在(8.7～14.3) ×10-6/K之间.     

真空原位氧化工艺参数对析出Al2O3显微形貌的影响

采用一种新型的真空原位氧化工艺制备了Al2O3/Cu复合材料。本文主要讨论新工艺参数对原位氧化析出的Al2O3颗粒的数量、分布、粒度的影响。结果表明：在真空环境下，原位氧化工艺更易于控制，析出的Al2O3颗粒为椭球形，粒径、颗粒间距均小于1μm，均匀、弥散分布在基体上。升温速率、反应温度、原始粉末中Al的含量均对Al2O3颗粒的析出及分布有显著的影响。由于Al氧化的强放热效应，三者必须合理匹配，才能制备出组织性能优越的复合材料。     

纳米NiAl2O4圈层包覆Al2O3复合粉末的制备

采用高温氧化的方法制备出纳米NiAl2O4圈层包覆Al2O3粉体.在纳米Al2O3粉体表面包覆一层金属Ni,在1 350℃高温下焙烧Ni/Al2O3复合粉体得到纳米NiAl2O4圈层包覆Al2O3粉体.利用TEM对Ni/Al2O3复合粉体进行观察,发现Ni/Al2O3复合粉体颗粒呈球形,大小为50～60 nm;Ni/Al2O3复合粉体的DTA分析结果表明,Ni/Al2O3复合粉体在900和1 300℃时有新相生成,经XRD检测,新相分别为NiO和NiAl2O4.     

TiAl合金表面阴极微弧制备的Al_2O_3膜结构与性能

以Al(NO3)3乙醇溶液为电解液,采用阴极微弧放电沉积方法,在TiAl合金表面制备连续的Al2O3薄膜,并对膜的结构与性能进行研究.利朋扫描电镜(SEM)观察到样品表面分布着熔融状颗粒,颗粒的平均直径约20μm,颗粒中间有小孔存在.X射线衍射(XRD)分析表明氧化膜的相成分主要为α-Al2O3和γ-Al2O3相,还有少量的ε-Al2O3相;氧化膜中α-Al2O3和γ-Al2O3的相对含量随着制备电压改变而变化.显微划痕实验测得膜与TiAl基体之间结合力大于20 N,表明制得的氧化膜与基体有良好的结合力.900℃的高温氧化实验表明氧化膜能够有效地提高基体的抗氧化性能.     

Al2O3-Cr2O3复合添加剂对镁质复合材料性能的影响

通过在镁质复合材料的骨料中加入镁铝尖晶石,尝试α-Al2O3微粉与Cr2O3复合添加,来研究其对制品性能的影响。借助偏光显微镜手段对复合添加剂在镁质复合材料内的作用机理进行分析。实验结果表明:Al2O3-Cr2O3复合添加时,随着Cr2O3含量的增加,镁质复合材料的各项性能指标变化明显,加入比例为5%Al2O3、3%Cr2O3的性能最优。     

Preparation and tribological performance of electrodeposited Ni-TiB2-Dy2O3 composite coatings

TiB2 and Dy2O3 were used as codeposited particles in the preparation of Ni-TiB2-Dy2O3 composite coatings to improve its per-formance. Ni-TiB2-Dy2O3 composite coatings were prepared by electrodeposition method with a nickel cetyltrimethylanunonium bromide and hexadecylpyridinium bromide solution containing TiB2 and Dy2O3 particles. The content of codeposited TiB2 and Dy2O3 in the compos-ite coatings was controlled by adding TiB2 and Dy2O3 particles of different concentrations into the solution, respectively. The effects of TiB2 and Dy2O3 content on microhardness, wear mass loss and friction coefficients of composite coatings were investigated. The composite coat-ings were characterized by X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometer (ICP-AES) and scanning electron microscopy (SEM) techniques. Ni-TiB2-Dy2O3 composite coatings showed higher microhardness, lower wear mass loss and friction coefficient compared with those of the pure Ni coating and Ni-TiB2 composite coatings. The wear mass loss of Ni-TiB2-Dy2O3 composite coatings was 9 and 1.57 times lower than that of the pure Ni coating and Ni-TiB2 composite coatings, respectively. The friction coefficient of pure Ni coating, Ni-TiB2 and Ni-TiB2-Dy2O3 composite coatings were 0.723, 0.815 and 0.619, respectively. Ni-TiB2-Dy2O3 composite coat-ings displayed the least friction coefficient among the three coatings. DY2O3 particles in composite coatings might serve as a solid lubricant between contact surfaces to decrease the friction coefficient and abate the wear of the composite coatings. The loading-bearing capacity and the wear-reducing effect of the Dy2O3 particles were closely related to the content of Dy2O3 particles in the composite coatings.     

Structure and Mechanical Properties of Ni-P-Nano Al2O3 Composite Coatings Synthesized by Electroless Plating

Ni-P-nano Al2O3 composite coatings were deposited by electroless plating,and their microstructures were observed by SEM（scanning electron microscope）.The microhardness and the wear resistance of the Ni-P-nano Al2O3 composite coatings were measured using microhardness tester and block-on-ring tribometer,respectively,and the comparison with those of Ni-P coatings or Ni-P-micro Al2O3 coating was given.The influences of aging temperature on their hardness and wear resistance were analyzed.The results showed that the nano Al2O3 particles were distributed uniformly in the Ni-P-Al2O3 coatings.Among three kinds of Ni-P based coatings,the hardness and wear resistance of Ni-P-nano Al2O3 coatings were largest,and the maximum values could be obtained at 400 ℃.This indicated that the precipitation of nano Al2O3 particles would improve the hardness and wear resistance of the Ni-P coatings.     

等离子喷涂Al_2O_3-TiO_2陶瓷涂层的显微组织及摩擦学性能

以Al_2O_3-TiO_2(x=0%,3%,13%,20%,40%,质量分数)复合陶瓷粉末为原料,采用等离子喷涂工艺在316L不锈钢基体表面制备5种陶瓷涂层。利用扫描电镜(SEM)、能谱仪(EDS)和X线衍射仪(XRD)、荧光金相显微镜分析粉末和涂层形貌、微观结构、物相组成及涂层孔隙率;利用显微硬度计及摩擦磨损试验机测试涂层力学及摩擦学性能,观察试样磨损形貌,分析磨损机理。结果表明:涂层呈典型的等离子喷涂层状堆积特征,涂层与基体结合良好。随TiO_2含量增加,涂层主相由γ-Al_2O_3向Al_2TiO_5相过渡,涂层韧性升高,硬度和孔隙率降低。在大气环境下,低TiO_2含量的涂层(Al_2O_3、AT3)发生应力疲劳磨损,高TiO_2含量的涂层(AT13、AT20和AT40)发生应变疲劳磨损;而在水环境下,5种涂层均发生应力疲劳磨损。     

铁基Cr3C2复合涂层的组织及性能研究

利用空气燃料超音速火焰喷涂技术(HVAF)在D2钢表面制得Cr3C2-FeCrBSi复合涂层.借用光学显微镜(OM)、维氏硬度计、扫描电镜(SEM)、拉伸试验机及摩擦磨损试验机对复合涂层的显微结构、力学性能及摩擦磨损性能进行表征与测试,研究了不同比例纳米-微米Cr3C2陶瓷增强相对复合涂层组织结构及性能的影响.试验结果...     

Preparation and performance of electrodeposited Ni-TiB₂-Sm₂O₃ composite coatings

Sm2O3 and TiB2 were used as codeposited particles in electrodeposition Ni-TiB2-Sm2O3 composite coatings to improve its performance. Ni-TiB2-Sm2O3 composite coatings were electrodeposited in the nickel sulfate,hexadecylpyridinium bromide and cetyltrimethylammonium bromide solution containing TiB2 and Sm2O3 particles. The content of codeposited Sm2O3 in the composite coating was controlled by changing the concentrations of Sm2O3 particles in the solution. The composite coatings were characterized with X-ray diffraction(XRD) and inductively coupled plasma-atomic emission spectrometer(ICP-AES) . The effects of Sm2O3 content on microhardness,wear weight loss and friction coefficient of composite coatings were investigated,respectively. The microhardness of the Ni-TiB2-Sm2O3 composite coatings was 19.35%,16.58%,2.03% higher than that of the Ni coating,Ni-Sm2O3 and Ni-TiB2 composite coatings,respectively. The wear weight loss of the Ni-TiB2-Sm2O3 composite coatings was 7,2.33,1.22 times lower than that of the Ni coating,Ni-Sm2O3 and Ni-TiB2 composite coatings,respectively. The friction coefficient of the Ni coating,Ni-Sm2O3,Ni-TiB2 and Ni-TiB2-Sm2O3 composite coatings were 0.712,0.649,0.850 and 0.788,respectively. The loading-bearing capacity and the wear-reducing effect of the Sm2O3 particles were closely related to the content of Sm2O3 particles in the composite coatings.     

Al2O3-Y2O3 Nano- and Micro-Composite Coatings on Fe-9Cr-Mo Alloy

Al2O3-Y2O3 nano- and micro-composite coatings were deposited on Fe-9Cr-Mo substrates by using sol-gel composite coating technology. The processing includes dipping samples in a sol-gel solution dispersed with fine ceramic powders, which are prepared by high-energy ball milling. High-resolution microscopy （FE-SEM） analyses show that the coating is composed of composite particle clusters with an average diameter of 1μm, and the coating is relatively dense without cracking during drying and sintering stages. XRD analyses show that the oxide coating is mainly composed of α-Al2O3 and γ-Al2O3. The oxidation tests performed at 600℃ in air show that the coatings are provided with much improved resistance against high temperature oxidation and scale spallation. It is indicated that nano-structured composite particles and reactive elements are integrated into the coatings, which plays an important role in preventing agglomeration of nano-particles and initiation of cracks.     

Al_2O_3含量对铜基粉末冶金摩擦材料摩擦磨损性能的影响

采用粉末冶金方法制备铜基摩擦材料,研究Al_2O_3的添加量对材料的摩擦磨损性能的影响。结果表明:Al_2O_3对材料摩擦磨损性能的影响与摩擦速度密切相关;随着Al_2O_3含量增加,材料的摩擦因数提高,密度降低,硬度增加,磨损量先减小后增大,Al_2O_3质量分数为9%时,复合材料的摩擦因数较高且稳定,磨损量最小。不含Al2O3的材料摩擦表面出现大量凹坑,磨损严重,随着Al_2O_3含量提高,凹坑数量减少,弥散分布的Al_2O_3粒子能强化基体表面强度,从而导致材料磨损量降低。     

Effect of Al2O3 on Structure and Wearability of Composite Coating

Asasurface strengtheningtechnology ,thether malsprayhasevolvedfromearlynormal protectivecoatingtocurrentfunctionalcoating .Thedevelopmentofcompositepowderisanimportantbreakthroughinthisfield .Particularly ,thenewlydevelopedmetal basedceramiccoatings ,such…     

A comparative Study on the Wear Behavior of Al2O3 and SiC Coated Ti-6Al-4V Alloy Developed Using Plasma Spraying Technique

This paper reports the wear characteristics of the ceramic coatings made with Al₂O₃ and also with SiC which were performed using atmospheric plasma spraying technique on the Ti-6Al-4V biomedical alloy with the aim of improving their tribological behavior. The wear behavior of the coatings was evaluated using reciprocatory wear tester with coated substrate as the flat and alumina ball as a friction partner in simulated body fluid (Hank’s solution) environment. The microstructure and phase composition of the ceramic powders and as-sprayed coatings have been characterized using scanning electron microscope and X-ray diffractometer. Porosity, microhardness, adhesion strength and roughness of the coatings were measured as they have a bearing on wear and friction behavior. The results indicate that plasma sprayed Al₂O₃ coating exhibits higher wear resistance compared to that of plasma sprayed SiC coating. The higher wear resistance of Al₂O₃ coating is attributed to the improved melting and spreading of the alumina particles onto the substrate yielding increasingly bonded splats, resulting in compact and dense microstructure with lower porosity and higher microhardness.     

等离子喷涂制备铁基复合陶瓷涂层的研究

以铝粉和氧化铁粉作原料,采用等离子反应合成技术制备出了金属颗粒增韧的FeAl2O4-Al2O3-Fe复合陶瓷涂层。研究分析了复合涂层的组织及其性能。结果表明：等离子反应合成得到了以层状基体相FeAl2O4与硬质相Al2O3为骨架,球状Fe相弥散分布于基体相上的复合涂层。复合涂层的断裂韧性和结合强度明显优于普通Al2O3涂层,特别是复合涂层的具有较高的耐磨性能。