超音速激光沉积Cu-Al2O3-石墨复合涂层微观结构及耐磨损性能

目的 研究不同石墨含量对超音速激光沉积Cu-Al2O3-石墨复合涂层的微观组织、显微硬度、耐磨损性能的影响。方法 利用扫描电子显微镜、能量色谱仪、维氏硬度计、激光共聚焦扫描显微系统、X射线衍射仪、摩擦磨损测试对复合涂层的微观组织、显微硬度、耐磨损性能及磨损机制进行分析。结果 随着原始粉末中镀铜石墨质量占比的增加,Cu-Al2O3-石墨复合涂层的沉积效率逐渐降低。基于Al2O3颗粒的原位喷丸效应及激光辐照的加热软化效应,复合涂层具有致密的微观组织,且复合涂层与基体界面结合良好。单一添加Al2O3颗粒可以将Cu涂层的硬度从108.19HV0.2提高至121.82HV0.2。随着石墨含量的增大,涂层的显微硬度逐渐降低,镀铜石墨在原始粉末中的质量分数从5%增至15%,Cu-Al2O3-石墨复合涂层的硬度从116.09HV0.2降至94.17HV0.2。添加石墨能够在复合涂层表面形成固体润滑层,降低复合涂层的摩擦因数,提升涂层的耐磨损性能。CuAlGr10复合涂层具有最优的耐磨损性能,磨损率为0.7×10⁻⁴ mm³/(N.m)。此外,由于激光辐照促进了复合涂层内部颗粒间的界面结合,均匀分散在石墨润滑相中的Al2O3颗粒作为负载支撑和耐磨相,可进一步降低复合涂层的磨损率。结论 Cu-Al2O3-石墨复合涂层优异的耐磨性能是润滑相石墨颗粒和硬质增强相Al2O3颗粒共同作用的结果,石墨的添加能够降低复合涂层的摩擦因数,提升涂层的耐磨损性能,但过量的石墨颗粒会对涂层产生割裂作用,导致增强相Al2O3颗粒脱离涂层,从而加剧涂层的磨损。     

氮化硼纳米片对氧化铝胶黏陶瓷涂层摩擦行为的影响

目的 通过在氧化铝胶黏陶瓷涂层中添加氮化硼纳米片(BNNP),从而改善涂层的摩擦学性能.方法 利用均质机将混合粉末均匀分散,并采用料浆法在304不锈钢表面制得不同含量的BNNP增强氧化铝胶黏陶瓷涂层(BRPCC).通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)和球盘式摩擦磨损试验机,分析了不同含量的BNNP增强氧化铝胶黏陶瓷涂层的显微组织、物相和摩擦学性能.结果 涂层的主要物相为氧化铝、磷酸铝、磷酸锌和氮化硼.BNNP未参与涂层固化反应,但作为黏结相的"成核剂"填补了孔隙或覆盖了孔洞.随着BNNP含量的增加,涂层表面质量得到有效改善,添加1％BNNP的涂层表面孔隙率最低,为4.33％,相比不添加BNNP的涂层,孔隙率下降了55.27％.随着BNNP含量的增加,涂层的摩擦因数和磨损率随之降低,当BNNP添加量为1％时最低,摩擦因数从0.372降到0.242,磨损率从1.512×10-3 mm3/(N·m)降到0.494×10-3 mm3/(N·m).胶黏陶瓷涂层的磨损机理主要为磨粒磨损和粘着磨损.结论 氮化硼纳米片的添加可以有效地提升氧化铝胶黏陶瓷涂层的耐磨减摩性能.     

Ni包石墨对镍基涂层摩擦学性能的影响

用超音速火焰喷涂在45钢表面制备具有Ni包石墨的镍基固体润滑涂层．考察了Ni包石墨对Ni60涂层的摩擦学性能的影响。用SEM观察了喷涂层的磨损表面。探讨了磨损面的形貌与涂层的磨损机理之间的关系。并且分析了速度、载荷对涂层摩擦磨损的影响。结果表明，Ni包石墨喷涂层具有优良的摩擦学性能．明显好于镍基喷涂层，随着Ni包石墨的增加，摩擦系数不断降低，而磨损率呈先下降后上升的变化趋势。Ni包石墨含量为30wt%的涂层磨损性能最优。     

机械加工刀具的切削形貌与性能研究

以SKD12冷作模具钢为工件材料,对比分析了Al Ti N+Si3N4(M01)、Ti Si N(M02)和Al Ti N(M03)3种涂层刀具的切削性能,并用扫描电镜观察了不同涂层刀具的磨损形貌以及局部区域能谱分析。结果表明,3种涂层材料都可以提高机械加工刀具的抗磨损性能;M01涂层刀具耐磨损性能提高的关键是改善基体材料的性能以及对刀刃进行强韧化处理;M02涂层刀具的耐磨损性能的改善主要需要改善抗粘结性能、摩擦和润滑性能;对于M03涂层刀具而言,改善涂层的冲击韧度以及与基体的结合强度是提高耐磨损性能的关键。     

聚酰胺酰亚胺涂层添加润滑剂对其摩擦性能的影响

目的研究固体润滑剂对聚酰胺酰亚胺(PAI)涂层摩擦磨损性能的影响。方法由偏苯三酸酐(TMA)和4,4-二苯甲烷二异氰酸酯(MDI)合成并添加二硫化钼、二硫化钨、石墨制备自润滑PAI涂层,并对其用HSR-2M型高速往复摩擦试验机进行磨损实验。结合ATR-FTIR、TA-TG热重、磨痕形貌等表征手段,对自润滑PAI涂层摩擦性能进行表征,探究了固体润滑剂的种类与含量对聚酰胺酰亚胺涂层摩擦性能的影响。结果载荷与PAI涂层的摩擦系数呈反比例关系,当Mo S2含量达到30%时,PAI涂层的摩擦系数降至0.1744。添加固体润滑剂后,PAI涂层的摩擦系数减小,磨痕宽度变窄,磨痕变浅,表面粗糙度相对较低。结论具备最佳摩擦性能的涂层添加了30%Mo S2,添加10%石墨的涂层次之,添加10%WS2的涂层较好。添加固体润滑剂可明显提高PAI涂层的摩擦磨损性能,增加其使用时长。     

磷酸铝铬封孔处理对热喷涂WC-12Co涂层耐蚀性的影响

以磷酸铝铬溶液和Cr_2O_3粉末为原料制备了一种封孔剂,并对WC-12Co热喷涂涂层进行封孔处理。利用XRD、SEM、EDS以及TG-DSC分别对磷酸铝铬的物相、封孔前后涂层表面形貌、固化特性和耐热性能进行检测分析。利用动电位极化电化学测试和热震试验分别对封孔前后涂层的抗腐蚀性和固化后的磷酸铝铬层的抗热震性能进行研究。结果表明:磷酸铝铬的固化温度在250℃左右,在700℃内体系无任何热效应发生,材料具有良好的耐热性能。固化后涂层表面致密,磷酸铝铬对涂层孔隙具有良好的填充作用,明显降低了涂层的孔隙率。封孔后的涂层具有较高的自腐蚀电位和较小的腐蚀电流密度,涂层耐蚀性显著提高。在450℃下进行热震试验,当热震次数一定时(热循环100次),添加填料的磷酸铝铬层的剥落面积低于未添加填料的磷酸铝铬层,表现出较高的抗热震性能。     

Si对新型Fe3Al基-石墨合金组织和力学性能的影响

采用熔炼法制备出新型Fe3Al基-石墨固体自润滑材料,研究Si含量对Fe3Al基-石墨固体自润滑材料的显微组织、力学性能以及干摩擦磨损性能的影响。结果表明：Si可以促进C原子在Fe-Al-C液态合金中熔入及凝固过程中的石墨化,对Fe3Al基体有固溶强化作用。随着Si含量增加,C原子的石墨化作用增强,合金的硬度逐渐降低,抗弯强度逐渐增大;但Si合金超过3.5%（质量分数）时,由于Si在Fe3Al基体中的过多固溶,三点弯曲强度明显降低。研究表明,Fe3Al基-石墨合金具有高的耐磨性能和良好的润滑性能,摩擦因数随着合金中石墨面密度的增大而降低,磨损率随Si含量的增加而减小,其中Si含量为3.5%的合金经过900℃、15 h退火处理后,综合力学性能好,其磨损率仅为QT-500球墨铸铁的1/20。     

等离子喷涂 NiCoCrAlY / Al2 O3 涂层的制备及摩擦性能研究

目的制备等离子喷涂NiCoCrAlY/Al2O3高温固体润滑耐磨涂层,并研究该涂层的摩擦性能和磨损机理。方法采用喷雾造粒、化工冶金包覆和固相合金化技术制备NiCoCrAlY/Al2O3复合粉体,用等离子喷涂技术在45#钢表面制备NiCoCrAlY/Al2O3复合涂层。用SEM和XRD等手段分析粉体和涂层的显微结构和物相组成,研究涂层从室温到800℃的摩擦磨损性能,探讨NiCoCrAlY/Al2O3复合涂层在室温和高温下的磨损机理。结果 Al2O3颗粒表面均匀包覆着一层致密的NiCoCrAlY合金,包覆层厚度大约为3~5μm;等离子喷涂NiCoCrAlY/Al2O3复合涂层呈典型的层状结构,涂层各层间结合良好,涂层中孔隙率约为2.84%,主晶相为Ni Cr Al合金相和Al2O3相。涂层的摩擦系数随温度的升高逐渐降低,在室温下约为0.64,800℃时在0.4以下。高温下,金属氧化物的形成是摩擦系数降低的主要原因。涂层的磨损率随温度的升高先升高后降低。涂层在低温下为脆性断裂和磨粒磨损,高温下为氧化磨损、磨粒磨损、塑性变形和金属氧化物的转移。结论等离子喷涂NiCoCrAlY/Al2O3复合涂层是一种性能优良的高温固体润滑耐磨涂层。     

石墨对镍基固体润滑涂层组织与性能的影响

采用超音速火焰喷涂技术在45钢表面制备了含石墨和MoS2双组元润滑剂的Ni基固体润滑涂层,研究加入石墨(含量0%～9wt%)对涂层组织和性能的影响及双组元润滑剂在涂层中的相互作用.结果表明,随着石墨含量的增加,涂层中的孔隙增加,结合强度降低,摩擦系数和磨损率先下降后上升.石墨含量为3.0%时,石墨与MoS2的协调作用有利于保障涂层摩擦表面润滑相的连续形成,涂层摩擦系数为0.26,磨损率为0.82×10-3 mg·s-1,减磨性最优.     

等离子喷涂制备NiCoCrAlY/BaF2/CaF2/C/Y自润滑涂层及其高温摩擦性能

通过等离子喷涂技术制备润滑相BaF2∶CaF2∶C比分别为3.1∶1.9∶7和15.5∶9.5∶4.9的两种NiCoCrAlY/BaF2/CaF2/C/Y复合涂层,研究了所选固体润滑剂在高温摩擦中对涂层润滑性能和机械性能的影响,分析BaF2/CaF2/C的综合作用,在500℃和800℃时分别对涂层进行高温摩擦试验。结果表明:500℃时,摩擦面比较粗糙,涂层的摩擦因数较高,磨损较为严重,表现出明显的剥落现象;800℃时,涂层表面没有BaF2/CaF2/C等润滑相的存在,发生了摩擦化学反应,摩擦表面生成了一层光滑致密的氧化膜,并存在一定程度的材料转移现象。经过X射线衍射(XRD)分析表明,在高温和摩擦的共同作用下,涂层表面有BaCrO4生成,摩擦因数最低可达0.268,对应的磨损量为0.351 6mm3,有效降低了涂层的摩擦和磨损。在涂层的性能测试中,各润滑相之间的协同作用较好。     

乙烯基酯树脂粘结固体润滑涂层的制备及摩擦学性能

以双酚A型环氧树脂E-51和丙烯酸(AA)为原料合成了乙烯基酯树脂(VER),用红外光谱(FTIR)表征了不同反应时间反应体系中基团的变化情况.用过氧化苯甲酰(BPO)为催化剂,N,N-二甲基苯胺(DMA)为促进剂实现了该树脂的室温固化,并制备了以该乙烯基酯树脂为粘结剂,聚四氟乙烯(PTFE)为固体润滑剂的粘结固体润滑涂层.在CSM栓-盘摩擦试验机上考察了不同聚四氟乙烯添加量对涂层摩擦学性能的影响,分别采用扫描电子显微镜(SEM)和光学电子显微镜分析了润滑涂层和对偶钢球的磨损表面形貌.结果表明:以乙烯基酯树脂为粘结剂的聚四氟乙烯固体润滑涂层具有优异的减摩抗磨性能.     

Electroplating of wear-resistant nanocrystalline coatings from a bath containing basic chromium(III) sulfate (chrome tanning agent)

Regularities of the electroplating of chromium-carbon alloy coatings from a bath containing basic chromium(III) sulfate, carbamide, formic acid, sodium sulfate, aluminum sulfate, orthoboric acid, and sodium dodecyl sulfate are studied. Replacement of chromium sulfate as a source of trivalent chromium ions in the solution with basic chromium sulfate (chrome tanning agent) results in a decrease in the current density when metal deposition begins. As a result, the covering power of the bath increases. The effects discovered are determined by changes in the composition of the discharged chromium complexes. A certain excess of OH^? groups in the inner sphere of electroactive chromium complexes results in acceleration of electroplating. The studied electrolyte based on chrome tanning agent enables one to produce thick high-quality nanocrystalline Cr-C alloy coatings with improved tribological characteristics.     

Microstructural study of aluminum phosphate-sealed, plasma-sprayed chromium oxide coating

Microstructural characterization of aluminum phosphate-sealed, plasma-sprayed chromium oxide coating was carried out in order to study the strengthening mechanisms of the aluminum phosphate sealant in the coating. Characterization was performed using x-ray diffractometry, scanning electron microscopy, and analytical transmission electron microscopy. The structure of the sealed coating was lamellar with columnar α-Cr₂O₃ grains extending through the lamella thickness. Amorphous aluminum phosphate sealant had penetrated into the structural defects of the coating such as cracks, gaps, and pores between the lamellae. The relative composition was 25 at.% aluminum and 75 at.% phosphorus for the sealant in the coating, giving the molar ratio P/Al of 3, which corresponds to that of metaphosphates Al(PO₃)₃. There is no indication of reaction products from the chemical reactions between the sealant and the coating. Thus, the aluminum phosphate sealing in the chromium oxide coatings can be explained mainly by adhesive binding resulting from the formation of the condensed phosphates with the appropriate adhesive properties to the coating, and not by chemical bonding resulting from the chemical reactions between the sealant and the coating.     

新型高温磷酸盐胶粘剂的制备和研究

以磷酸、氢氧化铝、氧化铜等为主要原料,拟制备出具有高粘结性且耐高温氧化的胶粘剂。采用正交试验方法优选出配方,讨论了氧化铜粒径、固化温度、固化时间、氢氧化铝对其粘结性能的影响。验证实验表明:开发的新型高温磷酸盐胶粘剂,制备工艺简单,最佳固化温度为120℃,最佳固化时间为4 h;该胶粘剂粘结性能好,耐高温,呈淡黄青色,具有广阔的应用前景。     

Wear and Friction Properties of Electrodeposited Ni-Based Coatings Subject to Nano-enhanced Lubricant and Composite Coating

This paper presents research findings on the tribological performance of electrodeposited coatings subject to nano-lubricants with the addition of nano-Al_2O_3 and graphene and Ni/nano-Al_2O_3 composite coatings. Electrodeposited coatings were produced by using a pulse electrodeposition method. Tribological experiments were conducted by using a linear reciprocating ball on flat sliding tribometer. Experimental results confirmed that the wear and friction resistance properties were significantly enhanced by doping of nano-effects in the lubricating oil and composite coating. The addition of Al_2O_3 nanoparticles in the lubricating oil showed the best tribological properties, followed by Ni–Al_2O_3 composite coatings and nano-oil with graphene. The surface morphology and microstructure of electrodeposited coatings were examined by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. The wear mechanisms of these coatings subjected to tribological testing were investigated by post-test surface analyses. This research provides a novel approach to design durable nano-coatings for tribological applications in various industries such as automotive,aerospace, locomotive and renewable energy technologies.     

Plasma sprayed cast iron coatings containing solid lubricant graphite and h-BN structure

Water-atomized cast iron powder of Fe-2.17 at.%C-9.93at.%Si-3.75at.%Al were deposited onto an aluminum alloy substrate by atmospheric direct current plasma spraying to improve its tribological properties. Preannealing of the cast iron powder allows the precipitation of considerable amounts of graphite structure in the powder. However, significant reduction in graphitized carbon in cast iron coatings is inevitable after plasma spraying in air atmosphere due to the in-flight burning and dissolution into molten iron droplets. Hexagonal boron nitride (h-BN) powders, which have excellent lubricating properties like graphite, were incorporated into the cast iron powder as a solid lubricant by the sintering process (1300°C) to obtain protective coatings with a low friction coefficient. The performance of each coating was evaluated using a ring-on-disk-type wear tester under a paraffin-based oil condition in an air atmosphere. A conventional cast iron liner, which had a flaky graphite embedded in the pearlitic matrix, was also tested under similar conditions for comparison. Sections of worn surfaces and debris were characterized, and the wear behavior of plasma-sprayed coatings was discussed. The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding, Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany.     

Tribological performances of Ti(C,N)-based cermets with different graphite contents in dry sliding condition

Ti(C,N)-based cermets with different graphite (Gr) contents were prepared to solve the problem that the cermets self-mated couples suffer severe wear in dry sliding condition. The microstructure and mechanical properties of cermets with varying graphite contents were observed and evaluated, and the effects of graphite content on the tribological performances of the cermets self-mated rubbing pairs were investigated using a block-on-ring apparatus at room temperature. The results show that the distribution of graphite phase in cermets transforms from segregated floc-like to uniform granular with the increase of graphite content. The hardness and fracture toughness of the cermets self-lubricating materials rise firstly and then fall, whereas the transverse rupture strength decreases gradually with graphite adding. Compared with the cermet without graphite, the tribological properties of the cermets containing graphite are improved significantly. When the graphite addition reaches 0.8 wt%, the cermet exhibits the optimal wear resistance, which is attributed to the formation of a stable lubricating film composed of graphite and metal oxides (TiO₂, MoO₃, NiO) on the tribo-surface. Additionally, results reveal that the wear mechanism of cermets in dry condition is a complicated regime containing abrasion, adhesion and oxidation. After adding graphite, the adhesive wear of cermets is inhibited effectively, however the abrasive wear will be aggravated as the graphite content increases continuously.     

Tribological behaviour of pulsed magnetron sputtered CrB2 coatings examined by reciprocating sliding wear testing against aluminium alloy and steel

Among the number of attractive properties that transition-metal diborides (TiB₂, CrB₂, etc.) possess, high resistance to wear and chemical inertness are the most important when considering diboride coatings for dry machining of nonferrous materials, such as aluminium and its alloys. Due mostly to the problematic deposition of chromium diboride (preparation of targets, target cracking during the deposition process, control of stoichiometry etc.), these coatings remain comparatively less studied than, for example, titanium diborides, regarding their tribological performance.In this paper we report on the tribological behaviour of pulsed magnetron sputtered (PMS), smooth and fully dense, crystalline, 21-38 GPa hard CrB₂ coatings examined by reciprocating sliding wear testing in ambient air (20 ± 2 °C, 20-30% humidity) against EN AW-2017A aluminium alloy and AISI 52100 chrome steel. The results are compared to those of pulsed magnetron sputter deposited TiN and CrN coatings. It is demonstrated that pulsed magnetron sputtered chromium diboride coatings exhibit the best tribological performance, in terms of amount of aluminium adhered on the surface of the wear track, during testing against aluminium alloy. When slid against AISI 52100 steel PMS CrB₂, CrN and TiN coatings exhibited coefficients of friction of 0.6, 0.6-0.7 and 0.43-0.45 respectively. The tribological behaviour of coatings was found to be dependent on the transfer film formation and its properties. Wear rates were up to ten times lower for pulsed magnetron sputtered CrB₂ coatings, compared to DC sputtered Cr-B films.     

The microstructural characteristics and mechanical properties of Ni-Al/h-BN coatings deposited using plasma spraying

Hexagonal boron nitride (h-BN) material was added to a nickel aluminum alloy (Ni-Al), which was deposited as plasma spray coatings, and the resultant enhanced tribological properties of these coatings were investigated. The microstructures of the coatings were analyzed using a scanning electron microscope (SEM) to monitor the morphologies of both the powders and the coatings. After wear testing, the surface morphologies of the scratched coatings were analyzed using an SEM to monitor the fracture mode of the coatings. The results of this study indicate that the addition of h-BN material to Ni-Al results in coatings with enhanced tribological properties.     

锡对铸造铝-石墨颗粒复合材料摩擦性能的影响

采用M-200摩擦磨损试验机,对加入固体润滑剂锡的铸造铝-3%石墨颗粒复合材料的摩擦性能进行试验研究,研究表明:锡和石墨具有优越的协同润滑效应,加锡可极大提高铝-石墨颗粒复合材料的减摩性能,使有润滑的摩擦系数达到0.004～0.005。同时锡和石墨的协同润滑作用存在最佳配合,在本试验条件下,加约7%的锡时,协同润滑效应最佳。加锡不能改善干摩擦时铝-3%石墨颗粒复合材料的耐磨性,但能极大提高有润滑时复合材料的耐磨性。并对加锡的铝-石墨颗粒复合材料的磨损机理进行了初步研究,其在干摩擦时的磨损机理为粘着迁移、粘着磨损和磨料磨损,在半干摩擦时的磨损机理为疲劳磨损和磨料磨损。