高速电弧喷涂Fe-TiB2/Al2O3复合涂层的组织及性能

采用低碳钢包覆0～70%TiB2/Al2O3硬质相的粉芯丝材和高速电弧喷涂(HVAS)原位合成MMC涂层,分析和测试了涂层的组织、相组成及耐磨粒磨损性能.结果表明:涂层的性能由其组织和相组成决定,HVAS的非平衡制造过程在涂层中形成多种相:在Fe基固溶体上存在TiB2、Al2O3、FexB及少量的金属间化合物AlFe3和NiAl;随着TiB2及Al2O3在涂层中体积分数的增加,涂层的耐磨粒磨损性能明显提高,磨损质量损失随陶瓷相体积分数的增加呈线性减少;添加合金元素Ni和Al可降低孔隙率,增加涂层耐磨性.使用HVAS方法制备了含TiB2的高性能耐磨复合陶瓷涂层.     

SHS反应喷涂TiC-TiB2复相陶瓷涂层的热力学分析与实验

基于SHS反应火焰喷涂技术,在钢基表面制备了TiC-TiB2复相陶瓷涂层.通过对SHS火焰喷涂陶瓷涂层反应体系的设计和其热力学计算,给出了SHS反应火焰喷涂TiC-TiB2复相陶瓷涂层的最佳配系.研究得出,当Ti,B4C和C组成的反应体系按1435摩尔比配制时,SHS反应易实现点火,反应绝热温度高,反应速度快,反应产物为TiC0.7N0 3与TiB2二相构成的共晶体,但其特有的共晶层状结构不明显,为交叉复相结构,陶瓷涂层较致密,机械性能较好,陶瓷与钢基体的结合强度可达27.5 MPa,显微硬度HV达15 270 MPa,耐磨性良好.     

激光熔覆B4C-TiO2-Al粉末制备原位TiB2+TiC/Fe复合涂层（英文）

采用B4C、TiO2、Al以及Fe基自熔合金粉末为前驱体,利用激光熔覆技术在钢基体上制备TiB2+TiC颗粒增强Fe基复合涂层。结果表明,激光熔覆过程通过B4C-TiO2-Al反应生成了均匀分布于基体的TiB2-TiC复合陶瓷相。TiB2颗粒呈长条块状,TiC以不规则形状分布于基体中。涂层具有比基材1045钢更好的耐磨性能,但涂层的摩擦因数小。     

Al2O3复相陶瓷涂层的SHS反应火焰喷涂过程

基于自蔓延高温台成技术(SHS)的反应火焰喷椽技术，用氧-乙炔火焰引燃Al-Cuo团聚粉，使之发生自蔓延反应．在钢基表面制备了Al2O3复相陶瓷涂层。通过水淬熄试验截取飞行粒子的中间状态，对经水拎后的粒子及喷涂涂层进行物相与组执分析，从而给出了SHS反应火焰喷涂Al2O3复相陶瓷椽层的基本过程．即各团聚颗粒构成独立的徽小反应单元，经历Al熔化和Cuo分解的反应孕育、Al与Cu2O的飞行反应燃饶、与基体碰撞并继续反应、结构转变与凝固4个阶段，最终形喊Al2O3复相陶瓷馀层。     

Al_2O_3/TiB_2复相陶瓷涂层和基体相的价电子计算

应用"固体分子的经验电子理论(EET)"处理异相界面结合的分析方法,分析了复相陶瓷涂层中的相Al2O3,TiB2与基体Fe的一些晶面上的电子密度,结果表明:某些晶面电子密度保持连续,与事实相符合,从定量角度证明了该陶瓷涂层的可制备性。     

Al对反应火焰喷涂Al2O3基复相涂层性能的影响

以Al-CuO为主反应体系,利用反应火焰喷涂技术制备了Al2O3基复相涂层.测试了不同Al含量团聚粉喷涂所得涂层与基体的结合强度、显微硬度、孔隙率及耐磨损性能,分析了Al含量对反应火焰喷涂Al2O3基复相涂层性能的影响规律.研究发现,当团聚粉中Al过量6%(质量分数)时,涂层与基体结合强度为24.6 MPa,显微硬度5149 MPa孔隙率为10.5%,磨损量14.9 mg/h,均较Al不过量时明显提高,具有良好的综合性能.     

纳米粉末对轴向等离子喷涂TiB2-Al2O3复合涂层的影响

采用三阴极轴向送粉等离子喷涂制备TiB2/Al2O3陶瓷复合涂层,其中一种喷涂粉末是自蔓延高温合成的常规微米级TiB2/Al2O3复合粉末,另一种是由TiB2/Al2O3复合粉掺杂质量分数10%的纳米Al2O3粉经喷雾干燥造粒制备的纳微米结构喂料.比较研究两种涂层的微观组织、耐磨性能,探讨纳米粉末对涂层的影响:扫描电镜、X射线衍射分析涂层微观结构和物相组成;转盘磨损试验测试涂层的耐磨性能.结果显示两种涂层表面洛氏硬度相当,纳米掺杂涂层组织致密性、耐磨性明显高于常规粉末涂层,以及TiB2的氧化产物TiO2含量低于常规粉末涂层.     

曲轴表面改性用金属陶瓷电弧喷涂药芯丝材的研制

采用Al2O3和NiCr-Cr3C2复合粉末两种材料作为填充材料制备了曲轴表面改性用金属陶瓷喷涂药芯丝.分析了涂层显微组织,测试了涂层结合强度和耐磨性能.结果表明,采用Al2O3作为填充材料的药芯丝制备出的涂层中陶瓷相含量高,涂层和基体结合良好.涂层和基体结合强度达到21.23 MPa,抗剪强度达到31.27 MPa.涂层耐磨性好,相同摩擦磨损条件下,磨损失重仅为灰口铸铁试样的1/4.Ni3Al和石墨的加入是涂层结合强度高的主要原因.     

Al对反应火焰喷涂Al2O3基复相涂层性能的影响

以Al-CuO为主反应体系，利用反应火焰喷涂技术制备了Al2O3基复相涂层。测试了不同Al含量团聚粉喷涂所得涂层与基体的结合强度、显微硬度、孔隙率及耐磨损性能，分析了Al含量对反应火焰喷涂Al2O3基复相涂层性能的影响规律。研究发现，当团聚粉中Al过量6％（质量分数）时，涂层与基体结合强度为24．6MPa，显微硬度5149MPa孔隙率为10．5％，磨损量14．9mg／h，均较Al不过量时明显提高，具有良好的综合性能。     

一般问题/焊接科学和技术的发展及前景

纳米材料具有许多优异的特性，利用热喷涂技术制备纳米结构涂层是一种应用纳米材料的有效办法。介绍了纳米结构涂层喷涂材料的制备，包括液体喂料制备纳米材料、纳米粉末材料和纳米药芯丝材的制备，以及热喷涂制备纳米结构涂层的种类，其中包括纳米结构陶瓷涂层、金属一陶瓷纳米复合涂层和金属纳米结构涂层。[第一段]     

TiB2陶瓷颗粒增强的金属基复合涂层

采用电弧喷涂制备TiB2陶瓷颗粒增强的NiCr-TiB2,NiCr-TiB2/Al2O3和304L-TiB2及304L-TiB2/Al2O3四种金属基复合涂层.采用光学显微镜、扫描电子显微镜(SEM)结合透射电子显微镜(TEM)观察和详细分析了TiB2陶瓷颗粒增强复合涂层的显微组织及微观结构,探讨涂层的形成机理.结果表...     

Oxidation behavior of arc-sprayed FeMnCrAl/Cr3C2-Ni9Al coatings deposited on low-carbon steel substrates

FeMnCr/Cr₃C₂ and FeMnCrAl/Cr₃C₂ coatings, using Ni9Al arc-sprayed coating as an interlayer on low-carbon steel substrates, were deposited by high velocity arc spraying (HVAS) on the cored wires. The high temperature oxidation behavior of the arc-sprayed FeMnCrAl/Cr₃C₂-Ni9Al and FeMnCr/Cr₃C₂ coatings on the low-carbon steel substrates was studied during isothermal exposures to air at 800 °C. The surface and interface morphologies of the coatings after isothermal oxidation after 100 h were observed and characterized by optical microscopy, field emission scanning electron microscope, energy dispersion spectrum, and X-ray diffraction. The results showed that the oxidation weight gains of the coatings were significantly lower than that of the low-carbon steel substrate. Moreover, the FeMnCrAl/Cr₃C₂-Ni9Al coating registered the lowest oxidation rate. This favorable oxidation resistance is due to the Al and Cr contents of the aforementioned coating that inhibits the generation of Fe and Mn oxides. This is attributed to the interdiffusion between the substrates and the Ni9Al arc-sprayed coating, which can convert the mechanical bonding between substrates and coatings into a metallurgical one, thereby inhibiting the oxidation of interface between the low-carbon steel and the coating.     

Y2O3对原位自生TiC增强Ni基涂层组织和性能影响

采用氩弧熔覆的方法,以Ni60A自熔性合金粉末为粘结相,添加Ti粉、C粉和不同含量的稀土氧化物Y₂O₃,在16Mn钢基体上制备出TiC陶瓷颗粒增强金属基熔覆涂层. 运用XRD, SEM等手段对复合涂层的显微组织进行表征和分析,并对熔覆涂层的硬度及耐磨性进行了测试. 结果表明,适量添加Y₂O₃可以使涂层组织中枝晶的方向性减弱、同时细化涂层组织,使涂层组织更加均匀,涂层的硬度和耐磨性有显著提高. 添加2% Y₂O₃熔覆涂层的组织为最细,涂层具有较高的显微硬度和良好的耐磨性能.     

过渡材料对等离子喷涂Al2O3梯度陶瓷涂层性能影响

针对Al2O3陶瓷涂层结合强度低、孔隙率高的实际,选择NiAl金属间化合物和金属铜粉作为过渡材料,利用等离子喷涂制备Al2O3梯度陶瓷涂层,并对梯度涂层进行组织形貌观察,测试结合强度和孔隙率.结果表明,梯度涂层的组织表现出宏观的不均匀性和微观连续性的分布特征,NiAl和Cu是金属基体与Al2O3涂层之间过渡层的理想材料,可以有效地提高涂层的结合强度,而Cu-Al2O3梯度涂层又比NiAl-Al2O3梯度涂层结合强度高;梯度涂层的孔隙率远低于双涂层的孔隙率,在Cu-Al2O3梯度涂层中随Al2O3含量的增加,涂层的孔隙率降低,而且孔隙率低于NiAl-Al2O3梯度涂层.     

NiTi-Cr_3C_2/纳米TiC涂层制备及其性能的研究

设计了两种不同含量Ni包覆纳米TiC陶瓷颗粒组分的粉芯丝材,采用超音速电弧喷涂方法在20钢表面制备耐高温冲蚀涂层,结合金相显微镜、显微硬度计、X射线衍射仪、扫描电镜和能谱仪等分析方法对涂层进行高温冲蚀性能研究.结果表明,涂层的组织结构由Fe-Ni基固溶体、Cr3C2、TiC和氧化物相组成,涂层硬度明显高于20钢;涂层表现出了较好的抗热震性能;无论是低冲击角还是高冲击角,涂层的冲蚀率变化不大,且明显小于20钢的冲蚀率.     

碳化硼对电弧喷涂涂层性能的影响

将碳化硼(B4C)陶瓷粉末和其它合金元素与304L不锈钢带轧制成粉芯丝材,采用电弧喷涂技术制备金属陶瓷复合涂层.研究了B4C在电弧喷涂中的应用.利用XRD,SEM对涂层的形貌、相组成和磨损表面进行了分析.利用自行设计的高温磨粒磨损装置和高温冲蚀设备分别评价了B4C对涂层耐高温磨粒磨损性能和耐高温冲蚀性能的影响.结果表明,粉芯丝材喷涂工艺良好,B4C陶瓷与粉芯中其它组分反应,可以形成含Fe3B,CrB,FexN i23-xB6,Fe23(C,B)6,(Cr,Fe)7C3和Fe3C等硬质相的复合涂层,大幅度提高了涂层的硬度和耐磨耐冲蚀性能.     

Effects of C/B4C ratio on microstructure and property of Fe-based alloy coating reinforced with in situ synthesized TiB2-TiC

The Fe-based alloy coatings reinforced with in situ synthesized TiB₂-TiC were prepared on Q235 steel by reactive plasma cladding using Fe901 alloy, Ti, B₄, and graphite(C) powders as raw materials. The effects of C/B₄C weight percentage ratio(0-1.38) on the microstructure, microhardness, and wet sand abrasion resistance of the coatings were investigated. The results show that the coatings consist of (Fe, Cr) solid solution, TiC, TiB₂, Ti₈C₅, and Fe₃C phases. The decrease of C/B₄C ratio is propitious to the formation of TiB₂ and Ti₈C₅. Increasing the C/B₄C ratio can help to refine the microstructure of the coatings. However, the microhardness of the middle-upper of the coatings and the wet sand abrasion resistance of coatings degenerate with the increase of C/B₄C ratio. The coating exhibits and the wet sand abrasion resistance at C/B₄C=0 and its average mass loss rate per unit wear distance is 0.001 2%/m. The change of the wet sand abrasion resistance of the coatings with C/B₄C ratio can be mainly attributed to the combined action of the changes of microhardness and the volume percentage of the ceramic reinforcements containing titanium in the coatings.     

Effect of applied current on the electrodeposited Ni-Al2O3 composite coatings

Nano-sized Al₂O₃ ceramic particles (50 nm) were co-deposited with nickel using electrodeposition technique to develop composite coatings. The coatings were produced in an aqueous nickel bath at different current densities and the research investigated the effect of applied current on microstructure and thickness of the coatings. The variation in some mechanical properties such as hardness, wear resistance, and the adhesive strength of the composite coatings is influenced by the applied current and this was also studied. The morphology of the coatings was characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. The hardness, wear resistance, and bond strength of the coatings were evaluated by Vickers micro-hardness test, pin-on-disc test, and tensile test, respectively. Results showed that the Al₂O₃ particles were uniformly distributed in the coatings, and the coatings deposited at a current density of 0.01 A/cm² was most favorable in achieving a maximum current efficiency which causes the co-deposition of a maximum amount of Al₂O₃ particles (4.3 wt.%) in the coatings. The increase in Al₂O₃ particles in the coatings increased the mechanical properties of the Ni-Al₂O₃ composite coatings by grain refining and dispersion strengthening mechanisms.     

等离子喷涂Cu-Al2O3梯度涂层的组织与耐磨性分析

针对纯陶瓷涂层由于结合强度低、孔隙率高、影响涂层耐磨性的实际,用等离子喷涂法制备了Cu-Al2O3梯度涂层,用电子扫描显微镜(SEM)、金相显微镜等手段对涂层进行微观组织和成分分析,用自制销盘式固定磨料磨损试验机,检测了Cu-Al2O3梯度涂层的耐磨料磨损性能.结果表明,采用等离子喷涂法制备的Cu-Al2O3梯度涂层无明显的组织突变和宏观层间界面,涂层的组织表现出宏观不均匀性和微观连续性分布特征;梯度涂层中当Al2O3含量(质量分数,%)达到80%时(GC6),涂层的耐磨性最高,约为基体的3倍,随着Al2O3含量继续增大,纯陶瓷涂层(GC7)的耐磨性有所下降.     

Al_2O_3/MoS_2复合涂层的制备及摩擦磨损性能

以大气等离子喷涂工艺制备的Al_2O_3陶瓷涂层为模板,利用陶瓷涂层中存在的孔隙和微裂纹,采用水热反应在其内部原位合成具有润滑特性的MoS_2,制备出Al_2O_3/MoS_2的复合涂层。结果表明,通过水热反应在陶瓷涂层原有的微观缺陷中成功合成了MoS_2,合成的MoS_2固体粉末呈类球形状,并且这球状的粉末是由纳米片层状的MoS_2搭建组成的。摩擦试验结果表明,与纯Al_2O_3涂层相比,复合涂层中由于MoS_2润滑膜的形成,其摩擦因数和磨损率都显著降低,且载荷越大,复合涂层的摩擦性能越好。