Q235钢表面氩弧熔覆MoNiSi/Ni_3Si金属硅化物复合涂层组织与性能研究

以Mo粉、Si粉、Ni粉为原料,采用氩弧熔覆技术在Q235钢基材表面原位合成了MoNiSi/Ni3Si金属硅化物复合涂层,分析和测试了涂层的显微组织、显微硬度和耐磨性.结果表明:在Q235钢表面成功制备了以MoNiSi/Ni3Si为基体,以金属硅化物MoNiSi为增强相的复合涂层.性能分析结果表明:涂层的显微硬度可达1 000HV,涂层耐磨性较基体提高12倍.     

Q235钢表面氩弧熔覆B4C-Ti复合涂层组织与性能的研究

以B4C粉、Ti粉和Fe粉末为原料,采用氩弧熔覆技术在Q235钢基体表面制备出增强复合涂层。利用扫描电镜,X射线衍射仪,显微硬度仪和摩擦磨损试验机等对复合涂层的组织,相组成,硬度和耐磨性能进行了研究。结果表明:熔覆层相由α-Fe、颗粒状Ti C和Ti B构成,Ti C颗粒弥散分布在基体上,涂层显微硬度高达700HV0.2,耐磨性能比Q235钢基体提高约6倍。     

氩弧熔覆原位自生(Ti,Nb)C增强镍基复合涂层的抗磨性能

以Ti、C、Nb粉和Ni60A合金粉末为原料,采用氩弧熔覆技术在16Mn钢基材表面分别制备(Ti,Nb)C颗粒增强Ni60A复合涂层(C-Ti-Nb-Ni60A涂层)和Ni60A涂层。应用金相显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)对2种涂层的显微组织和物相进行观察与分析,测试涂层的显微硬度和不同载荷下的磨损性能,分析磨损机制。结果表明:C-Ti-Nb-Ni60A复合涂层与基体间呈冶金结合,界面间无气孔和裂纹;C-Ti-Nb-Ni60A复合涂层的显微硬度较基体16Mn钢提高近5倍,较Ni60A涂层提高0.45倍;常温干滑动200 N载荷条件下,CTi-Nb-Ni60A复合涂层的耐磨性能较基体16Mn钢提高6倍,较Ni60A涂层提高近2倍。16Mn钢表面发生严重的磨粒磨损和粘着磨损,Ni60A涂层表面以磨粒磨损为主,C-Ti-Nb-Ni60A复合涂层的磨损机理为显微檫伤磨损。     

激光熔覆Fe基TiC涂层的组织与性能

采用激光熔覆方法在45#钢基体上制备含TiC质量分数为20%~50%的Fe基TiC复合涂层。分别用扫描电镜(SEM)、能谱仪(EDS)、X线衍射(XRD)、显微硬度计、摩擦磨损机对熔覆层的微观组织、物相、硬度及耐磨性进行研究。结果表明:当TiC质量分数为30%时,涂层组织致密,TiC颗粒分布均匀、部分溶解、尺寸减小;涂层主要是由α-Fe固溶体,Fe C,Fe B,B4C,B4Si,Cr5B3,Ti B以及未溶解的TiC等组成;当TiC质量分数为30%时,熔覆层平均维氏硬度为783.8,磨损率为45#钢基体的1/38。     

氩弧熔覆Ni60+WC合金层的组织与性能

研究了氩弧熔覆Ni60 WC合金层的组织和耐磨性。对不同WC含量的熔覆层：W6MoSCr4V2,4CrB,Cr12MoV和lCr18Ni9Ti进行了磨损试验。结果表明：Ni60 WC合金层具最好的耐磨性,并且随WC含量的增加,耐磨性随之提高,且熔覆层组织进一步细化。     

等离子熔覆(Cr,Fe)7C3/γ-Fe复合涂层的组织与耐磨性

以Fe-Cr-C合金粉末为原料,利用等离子熔覆技术在45号钢表面制备了(Cr,Fe)7C3/γ-Fe复合涂层.并对涂层的显微组织、显微硬度和室温干滑动实验进行了具体分析.结果表明涂层组织包括初生相(Cr,Fe)7C3以及γ-Fe与(Cr,Fe)7C3组成的共晶;其组织有明显的由基材到涂层外延生长的特征,结构均匀,与基材之间为完全冶金结合;且具有较高的硬度及合理的硬度梯度.该涂层在室温干滑动磨损实验条件下具有优异的耐磨性.     

氩弧熔覆Ni35B+Co-WC层的组织、性能及强化机制

采用氩弧熔覆工艺在Ｑ２３５ 基材上熔覆Ｎｉ３５Ｂ＋ Ｃｏ－ＷＣ,获得了具有较高硬度和耐磨性的熔覆层。分析了熔覆层的显微组织、硬度和耐磨性及物相形貌和相结构等,证明熔覆层的强化机制是：①形成细小的Ｍ６Ｃ型合金化合物网架;②高度弥散的粒状Ｍ６Ｃ型合金化合物颗粒和极细小的Ｃｒ２Ｎｉ３ Ｂ及ＷＣ颗粒的弥散强化;③Ｃ、Ｃｒ及Ｂ等合金元素溶入α－Ｆｅ（Ｍｅ）和γ－Ｎｉ（Ｍｅ）中产生的固溶强化。     

La2O3对激光熔覆TiC/Ni基复合涂层的组织和性能的影响

用5kWCO2激光器在A3钢表面激光熔覆添加有La2O3的TiC/Ni基复合涂层，研究了稀土对激光熔覆金属陶瓷复合涂层的组织，耐蚀性和耐磨性的影响。研究结果表明：复合合金粉末中添加0.4%的La2O3能够减少熔覆层的气孔，疏松，使熔覆层的组织致密。熔覆层中TiC分布均匀且细小圆滑，熔覆层的耐蚀性和耐磨性得到提高。     

TiC含量对激光熔覆Fe基复合涂层组分和性能的影响

采用激光熔覆技术在高锰钢基材上制备了不同TiC含量的Fe基复合涂层,研究了TiC含量对熔覆层组分和性能的影响.试验结果表明,熔覆层化学组分包含奥氏体、M7C3碳化物、TiC析出相和未熔TiC颗粒.随着TiC含量的增加,熔覆层硬度逐步增加,耐磨性能先增加后降低.     

感应熔覆Co基涂层工艺

感应熔覆技术是一种高效的表面防护技术,能有效提高钢件表面的硬度、耐磨性和耐蚀性,延长工件使用寿命等。其中Co基合金具备很高的红硬性,可有效改善基体的耐磨损性能。因此感应熔覆Co基复合涂层能够更有效的提高钢件表面的硬度、耐磨性和耐蚀性等。文章就感应熔覆Co基复合涂层的工艺进行了论述。     

基于激光熔覆TiC/TiB2的钛合金表面组织及性能研究

在钛合金表面激光熔覆制备TiC/TiB₂复合涂层,分别采用SEM、显微硬度计和摩擦磨损设备分析了TiB₂+15%TiC复合涂层的微观组织和硬度、摩擦磨损性能。实验结果表明：涂层上部组织主要由粗大的TiB₂树枝晶和少量白色颗粒状的TiC/TiB共晶组织组成,涂层中部组织主要由棒状型、细针状型的TiB₂相和小块状的TiC相组成,涂层下部则由树枝型、块状TiB₂相、较大的片状TiC相和少量的小层片状金属间化合物TiAl组成。由测试结果可知,涂层硬度(960HV_0.2)约为基体的(350HV_0.2)的2.7倍。涂层的耐磨性能显著提高,涂层出现较少的剥落、细小磨痕和颗粒碎屑,基体表面主要是犁沟式的磨损。涂层的磨损量为1.132 mg是基体(5.342 mg)的20%。     

宏观颗粒增强铁基复合材料的制备与性能

颗粒与基体之间难以均匀稳定的混合以及二者的界面结合强度较差是限制颗粒增强金属基复合材料制备以及推广应用的共性关键问题,而目前的主要解决措施\     

超高速激光熔覆316L涂层的组织与性能

采用超高速激光熔覆技术,在45钢轴上制备了316L涂层;利用扫描电镜(SEM)观察了涂层的显微组织,用能谱仪(EDS)和X-射线衍射(XRD)进行元素及物相分析,并测试了涂层的显微硬度和耐磨性。结果表明,超高速激光熔覆技术的光斑直径小、搭接率高,故涂层的平整度高;能量密度高(约9×10⁴W/cm²),粉末完全熔化,故涂层的致密度高;熔体的体量小,冷热转换速度快,过冷度△T大,晶粒细化明显;涂层中下部由快速凝固产生的细小枝晶以及枝晶间共晶相组成,中上部的晶粒逐渐向等轴晶粒转变;搭接分界处和熔覆层/基材界面处,两边的晶粒尺寸差异较大;激光对基材有一定的稀释作用;涂层厚度不均匀,与基材结合良好,为冶金结合;316L涂层物相由γ-Fe、Cr_0.19Fe_0.7Ni_0.11、Fe₆₃Mo₃₇组成;由于细晶强化和第二相强化机制,316L涂层的平均硬度(634.12HV_0.5)是45钢基体的3.07倍;耐磨性提高了31.8%,其...     

激光熔覆无碳Fe-Co-Mo高速钢涂层的组织结构与性能

用水雾化合金粉末为原料,通过同步送粉式激光熔覆技术在40Cr基材上制备无碳高速钢涂层,对涂层的显微硬度、红硬性和抗回火稳定性进行测试和分析,研究工艺参数对涂层形貌及硬度的影响。结果表明,在适宜的参数下能够在基材表面获得无宏观裂纹和气孔的无碳高速钢涂层。涂层致密度高、稀释率低,与基体呈现出良好的冶金结合。涂层熔覆态下显微硬度(HV0.2)达到700,经过600℃下1 h时效后,涂层硬度(HV0.2)明显提升至900。经过4次600℃保温1 h的时效后,涂层硬度(HV0.2)保持在800。此外在600℃保温30 h的长时间回火后,涂层仍然可以保持硬度(HV0.2)达750,相较于常规高速钢ASP2030以及热作模具钢H13具有更加出色的抗回火能力。     

Effect of yttrium on microstructure and mechanical properties of laser clad coatings reinforced by in situ synthesized TiB and TiC

Titanium-based composite coatings with and without Y particles were deposited by laser cladding on Ti6Al4V substrates. Solidification microstructure,phase constituents and distribution of the reinforcements with different morphologies,were investigated by X-ray diffractometer (XRD),scanning electron microscopy (SEM) and electron probe micro analyzer (EPMA). In addition,the effects of the addition of Y on mechanical properties (in terms of microhardness and the cracking susceptibility) were also highlighted. The results showed that the coatings were composed of α-Ti cellular dendrites,coarse needle-shaped TiB phase and an eutectic in which a large number of needle-shaped TiB whiskers and a few equiaxial TiC particles were uniformly embedded. Y was not stable and was transformed into Y2O3 during laser cladding. The addition of Y could refine the microstructure of the coating by hastening the spheroidization of primary phase structure. Moreover,it could also decrease the activity of carbon and prevent solute atoms from traversing the interface and moving into primary phase structure,namely,increase the fraction volume of TiC in the coating. All of there factors made the cracking susceptibility of the coating containing Y reduced on the premise that microhardness of the coating was increased. Microhardness of the coating without Y ranged from HV 875.6 to HV 659.8,the average microhardness was about HV 747.9. For the coating with Y,microhardness changed from HV 876.5 to HV 741.5 and the average michardness was about HV 795.3. Fracture toughness of the upper,middle,bottom and interface of the coating without Y were 6.33,8.91,11.94 and 11.93 MPa.m1/2. Fracture toughness of the similar positions of the coating with Y were 8.58,12.93,13.81,17.11 MPa.m1/2,respectively. The coating with Y presented higher microhardness and fracture toughness in comparison with that without Y. Obviously,the addition of Y had a very positive effect on the microstructure and mechanical properties of the coatings.     

涂覆颗粒增强耐热铝基复合材料的力学及摩擦磨损性能

研究了经真空热压、热挤压工艺制备的涂覆颗粒(化学涂层工艺)增强Al-Fe-V-Si耐热铝合金基复合材料在不同温度下的力学性能与摩擦磨损性能.实验结果表明:涤覆后的SiC_p与基体结合更加牢固,涂覆层(Ni)的加入降低了材料内部颗粒(SiC_p)与基体(Al-Fe-V-Si)之间的孔隙,10％SiC(Ni)/Al-Fe-V-Si(0812)复合材料在室温的断裂强度分别比基体和10％SiC_p/Al-Fe-V-Si(0812)复合材料增加了62.15％和2.82％,在400℃时分别增加了55.3％和28.6％.复合材料耐磨性能比增强体未涂覆复合材料大大提高,在载荷50N,转速0.63 m/s的工况下,经增强体涂覆的铝基复合材料在300℃时为以磨粒磨损为主的磨损机制;高于350℃时,为以粘着磨损为主的磨损机制.     

Tribological properties of FeCoCrNiAlBx high-entropy alloys coating prepared by laser cladding

FeCoCrNiAlBx(x=0, 0.25, 0.50, 0.75) coatings were prepared by laser cladding to study the effects of boron on the structure and properties of high-entropy alloys coatings.The microstructure, microhardness, and wear resistance properties of the samples were investigated by scanning electron microscopy, X-ray diffraction, metallographic micro-hardness test, and friction-wear test, respec-tively, and the mechanism of the wear behavior was also analyzed.The results showed that the high-entropy alloys consisted of BCC phase and eutectic structure, which contained FCC phase and M2 B. With boron addition, the content of BCC phase increased while that of eutectic structure decreased. The wear resistance of the high-entropy coatings was considerably improved with increasing addition of boron, and accordingly, the FeCoCrNiAlB0.75 coating showed the best wear resistance.     

Microstructure and high-temperature properties of Fe-Ti-Cr-Mo-B-C-Y_2O_3 laser cladding coating

Fe-based composite coatings were fabricated on 5 CrNiMo die steel by laser beam melting a precursor mixture of ferrotitanium,ferrochromium,ferromolybdenum,B4 C and Y_2 O_3 powders.Micro structure and properties of the coatings were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectrometer(EDS),resistance furnace and high-temperature tribometer.The results show that(Ti,Mo)C particles with flower-like and(Ti,Mo)B_2 with block-like shapes are in situ formed during laser cladding.Volume faction of multiple ceramic particles increases with the increasing of Y_2 O_3.The cumulative oxidation mass of the coating with 2 wt% Y_2 O_3 is decreased by one-third than that of the coating without Y_2 O_3.The oxidation layer of the coating with Y_2 O_3 is getting smooth.Meanwhile,high temperature wear volume loss of the coating with 2 wt% Y_2 O_3 is about 40% that of the coating without Y_2 O_3.The coating with 2 wt% Y_2 O_3 shows a smoother wear scar and few flat grooves are observed after high temperature wear test.