热处理对喷涂Mo涂层微观组织和性能的影响

在纯铌基体上等离子喷涂Mo涂层,将试样在1750~1950℃进行真空热处理,研究了不同温度、不同保温时间对涂层微观组织、孔隙率和硬度的影响规律以及Mo涂层的最佳热处理工艺。结果表明,适当的热处理可以增加Mo涂层的致密性,在Mo涂层与铌基体之间生成了扩散层,增强了涂层与基体的结合力。喷涂态Mo涂层最佳热处理工艺为1850℃保温1 h,此工艺下获得Mo涂层的孔隙率为0.9%,显微硬度113 HV0.5。在热处理后Mo涂层的表面成功制备了MoSi2涂层。     

添加Mo对TiC金属陶瓷涂层组织和磨损性能的影响

采用Praxair 3710型等离子喷涂成套设备,在Q235钢表面制备了两种TiC金属陶瓷涂层TiC-NiCr涂层和TiC-NiCrMo涂层.通过X射线衍射、扫描电镜、电子探针等手段分析了两种涂层的相组成和涂层表面、截面组织结构及元素分布,并进行了磨损试验对比.结果显示,两种涂层均比较致密,与基体结合良好,孔隙率较低,但喷涂过程中均存在氧化现象.由于Mo的加入,在TiC-NiCrMo涂层中出现MoO2和Mo2C,在TiC颗粒周围还形成了(Ti,Mo)C固溶体包覆结构,增强了涂层内部结合强度;干摩擦条件下,TiC-NiCrMo涂层耐滑动磨损性能优于TiC-NiCr涂层.     

电热定向爆炸制备高速钢涂层的试验研究

采用电热爆炸定向喷涂工艺在45钢基体上制备W6Mo5Cr4V2(M2)高速钢涂层。借助扫描电镜、显微硬度计分别对涂层显微组织、孔隙率、涂层基体界面结合以及涂层的硬度进行了测试。结果表明,电热爆炸定向喷涂制备的涂层组织晶粒明显细化,涂层孔隙率低;涂层与基体界面为冶金结合,且结合良好,存在一个熔合区;涂层硬度均明显高于W6MoSCr4V2喷涂材料原始硬度,最高达到954HV。     

反应火焰喷涂工艺对复相陶瓷涂层孔隙率和硬度的影响

以Ti粉、B4C粉和蔗糖(碳的前驱体)为原料,采用反应火焰喷涂技术在钢基体表面制备了TiC-TiB2复相陶瓷涂层,研究了反应火焰喷涂工艺参数(喷涂距离、送粉气压力和喷涂团聚粉的预热温度)对涂层孔隙率和显微硬度的影响.结果表明,在一定条件下,随喷涂距离增加、送粉气压力增大、喷涂粉体预热温度升高,涂层的孔隙率和显微硬度均分别表现出减少和增加的趋势.正交试验结果表明,Ti-B4C-蔗糖体系制备TiC-TiB2涂层最佳工艺条件是喷涂距离为220 mm,送粉气压力为0.3 MPa,团聚粉预热温度为240℃.涂层主要由TiC0.3N0.7、TiB2与TiO2相及孔隙组成,其中TiC0.3N0.7-TiB2为涂层的主相,TiO2为副产物相.涂层与基体之间既有机械结合,又有冶金结合.     

预热温度对自蔓延TiC/Ni功能梯度涂层的影响

为了研究预热温度对TiC/Ni功能梯度涂层的影响,利用自蔓延高温合成结合准热等静压技术(SHS/PHIP),在H13钢表面制备了TiC/Ni梯度功能涂层,采用XRD和SEM-EDS对涂层的物相结构进行分析,采用显微硬度计测定涂层的表面硬度及界面结合性能。结果表明,涂层的主要物相为颗粒状TiC和包裹在TiC周围的Ni基固溶体;涂层为多孔骨架结构;随着预热温度升高,涂层表面孔隙率降低,致密度、TiC晶粒尺寸和表面硬度值增大,涂层与基体之间元素扩散增强,冶金结合强度提高。     

TC4合金氩弧熔覆Ni60+B4C复合涂层组织及耐磨性

利用氩弧熔覆技术在TC4合金表面成功制备出TiC、TiB、TiB2增强Ti基复合涂层.利用SEM、XRD和EDS分析了熔覆涂层的显微组织;利用显微硬度仪测试了复合涂层的显微硬度;利用摩擦磨损试验机测试了涂层在室温干滑动磨损条件下的耐磨性能.结果表明:氩弧熔覆涂层组织均匀致密,熔覆层与基体呈冶金结合,TC4合金表面有颗粒状TiC、粗大棒状相TiB2、细小棒状相TiB生成;复合涂层明显改善了TC4合金的表面硬度,涂层的最高显微硬度可达1300 HV0.2;复合涂层在室温干滑动磨损试验条件下具有优异的耐磨性,磨损机制主要是魔力磨损,其耐磨性较TC4合金基体提高近10倍.     

电热爆炸喷涂法制备TiC-NiAl复合涂层的试验研究

利用自制的电热爆炸超高速喷涂装置在GH3039高温合金基体上制备了NiAl-TiC复合涂层,采用X射线衍射仪(XRD)、扫描电镜(SEM)及能谱分析仪(EDS)对涂层的相组成、形貌和组织成分进行了分析,对涂层与基体的结合强度进行了测定,并利用显微硬度计测定了涂层硬度.结果表明,涂层仅由NiAl和TiC两相组成,没有新的相和氧化物生成;涂层致密均匀,没有分层现象,基体与涂层间发生了元素扩散现象,为扩散-冶金结合.涂层与基体的结合强度大于112.25 MPa,涂层的硬度平均在900 HV0.5左右.     

TiC-Mo2FeB2系复合涂层的组织与性能

用真空液相烧结法在钢基体表面制备了TiC-Mo2FeB2系复合涂层,测定了TiC-Mo2FeB2系复合涂层-钢基体界面结合强度及界面结合区的显微硬度变化,研究了复合涂层的显微组织与界面微观结构和界面区元素分布。结果表明,涂层与钢基体之间具有较高的结合强度,当TiC含量为8%时结合强度最高为820.66 MPa,显微维氏硬度为12.06 GPa,在复合涂层-钢基体结合界面处,存在一个由涂层高硬度到钢基体低硬度的狭窄过渡区,并且两相之间形成了良好的冶金结合。     

超音速等离子喷涂WC-17Co纳米涂层的性能研究

采用超音速等离子喷涂在0Cr13Ni5Mo不锈钢表面制备了纳米和微米WC-Co涂层,并对比了两种涂层的孔隙率、结合强度、硬度和耐磨性。结果表明,纳米涂层的致密性和结合强度均高于微米涂层,其孔隙率仅为0.56%,结合强度大于69.2 MPa;纳米涂层和微米涂层的硬度是基体的3.9和3.8倍,硬度值从涂层的表面到底部逐渐增加;基体磨损为磨粒磨损 粘着磨损 层状剥落,两种涂层磨损均为磨粒磨损。纳米涂层的孔隙率低、硬度高、表面抗压性强使其表现出更优的耐磨性。     

SHS/PHIP法压铸模表面制备TiC/Ni功能梯度涂层研究

利用自蔓延高温合成结合准热等静压技术(SHS/PHIP),在H13钢表面成功制备了TiC/Ni梯度功能涂层,采用XRD和SEM-EDS对涂层进行物相分析和微观组织观察,采用显微硬度测定和冲击试验对涂层性能进行检测。结果表明,涂层的主要物相为TiC和Ni基固溶体,原位生成的TiC颗粒细小且分布均匀,与Ni结合成紧密的TiC/Ni金属陶瓷结构。表面涂层显微硬度(HV_(0.05))为857.94,涂层与基体结合良好。     

铁基含TiC陶瓷粉电弧喷涂粉芯丝材的研究

采用电弧喷涂含TiC陶瓷粉末的粉芯丝材，在低碳钢基体上制备了铁基复合涂层。用MLS-225型湿砂橡胶轮磨损试验机测试了涂层的抗磨粒磨损性能。利用光学显微镜、SEM、XRD分析技术对涂层的显微组织结构、磨损表面和相组成进了研究。结果表明：采用电弧喷涂工艺可制备含TiC陶瓷硬质相的复合涂层，在铁基体上弥散分布着一定量的TiC硬质颗粒，使整个涂层得到强化，涂层显微硬度平均值约为1137HV0.1，涂层的抗磨粒磨损性能较好，相对Q235钢提高T6倍。涂层磨损机制主要为犁沟切削和脆性断裂。     

TC4合金表面氩弧熔覆TiCp/Ti基复合涂层组织及耐磨性

利用氩弧熔覆技术在TC4合金表面制备出TiC增强的Ti基复合涂层。利用SEM、XRD和EDS分析了熔覆涂层的显微组织;利用显微硬度仪测试了复合涂层的显微硬度;利用摩擦磨损试验机测试了涂层在室温干滑动磨损条件下的耐磨性能。结果表明:氩弧熔覆涂层组织均匀致密,熔覆层与基体呈冶金结合,涂层中有大量的TiC树枝晶和条块状TiC颗粒;复合涂层明显改善了TC4合金的表面硬度,HV平均硬度可达9GPa;复合涂层室温干滑动磨损机制为磨粒磨损和轻微粘着磨损。     

液氮辅助冷却激光熔覆Al基非晶涂层的组织与耐蚀性

采用激光熔覆加液氮辅助冷却技术在S355海洋钢表面制备Al基非晶涂层,运用SEM、XRD、电化学工作站等技术分析了涂层腐蚀前后表界面形貌及物相组成,研究了液氮辅助冷却对涂层性能的影响以及涂层在5%NaCl溶液中浸泡10、20、40和80 d后的腐蚀性能。结果表明:经过液氮辅助冷却后涂层中存在少量的非晶AlFeNi相;涂层与基体形成了良好的冶金结合;表面组织细小,增强相TiC均匀弥散分布,且裂纹气孔较少。涂层表面显微硬度增加15%;残余应力与自然冷却时基本持平,均为拉应力;其耐蚀性也得到了显著提升。     

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.     

Improvement of a-C:H film adhesion by intermediate layers and sputter cleaning procedures on stainless steel, alumina and cemented carbide

The adhesion of amorphous hydrogenated carbon (a-C:H) films deposited in a radio frequency (r.f.) plasma discharge on stainless steel, alumina and cemented carbide with different intermediate layers (Ni, Ti and TiC) and sputter cleaning procedures was studied. The composition of the carbon films and the intermediate layers as well as the interface between the coating and the substrate was determined by secondary ion mass spectroscopy (SIMS). The adhesion experiments were carried out using a scratch tester. Tested specimens were also studied by scanning electron microscopy (SEM) to reveal the morphology of the coatings and the scratches.

Without any intermediate layer, the a-C:H coatings generally had insufficient adhesion to the substrate materials studied. For stainless steel and cemented carbide substrates, the TiC intermediate layer and, for alumina substrates, the titanium intermediate layer gave the best adhesion values evaluated by the scratch test. Also, the sputter cleaning of the substrates prior to deposition was necessary for sufficient adhesion of the coating. The intermediate layers also change the failure mode of the coating in the scratch test in some cases.     

Q235钢表面氩弧熔覆TiC复合涂层的组织与性能

以Ti粉、C粉、Fe粉为原料,利用氩弧熔覆技术在Q235钢表面原位合成了TiC增强Fe基复合涂层,分析了涂层的显微组织和物相,测定了涂层的硬度。结果表明:复合涂层与基体界面无气孔、裂纹,呈冶金结合;熔覆层组织由树枝晶、等轴晶组成,TiC主要分布于晶粒内和晶界处;涂层显微硬度随TiC含量的增加而增大。     

A study on reactive braze coating of （TiC＋Cr3C2 ）／Fe composite coatings

0Introduction Inmanycases,itisrequiredthatsurfacesofstructur alcomponentshavegoodpropertiessuchasthewear,cor rosionandoxidationresistancessoastotaketheadvantage ofalongerservicelifeandtheconsequentreductionofto talcost.Tothisend,numeroussurfaceprocesse…     

Electrodeposited Ni-W-TiC Composite Coatings:Effect of TiC Reinforcement on Microstructural and Tribological Properties

Ni-W-TiC composite coatings were prepared via electrodeposition technique by dispersing the different amount of TiC particles into the plating bath.The Ni-W and Ni-W-TiC composite coatings containing different concentrations of TiC particles were characterized by using the scanning electron microscope,X-ray diffraction technique,Vickers microhardness test,surface roughness test,and tribology test.The results show that the Ni-W coatings containing reinforced TiC particles have shown a typical FCC Ni-W crystal structure with significantly higher Vickers microhardness.The amount of dispersed TiC particles into the plating bath considerably affected codeposition weight percent of TiC into the Ni-W matrix,as revealed by the EDS analysis.Ni-W-TiC samples demonstrated the decreased abrasive wear as compared to Ni-W coating and no characteristic features observed for the adhesive wear.Similarly,an improvement in coefficient of friction was observed in Ni-W-TiC composite coating as compared to Ni-W coating.     

Microstructure and wear properties of TiC/FeCrBSi surface composite coating prepared by laser cladding

Titanium carbide particles reinforced Fe-based surface composite coatings were fabricated by laser cladding using a 5 kW CO₂ laser. The microstructure, phase structure and wear properties were investigated by means of scanning electron microscopy, transmission electron microscopy and X-ray diffraction, as well as dry sliding wear test. The results showed that TiC carbides were formed via in situ reaction between ferrotitanium and graphite in the molten pool during the laser-clad process. The morphology of TiC is mainly cubic and dendritic form; and the TiC carbides were distributed uniformly in the composite coating. The TiC/matrix interface was found to be free from cracks and deleterious phases. The coatings reinforced by TiC particles revealed higher wear resistance and lower friction coefficient than that of the substrate and FeCrBSi laser-clad coating.     

Characterization of in situ synthesized TiC particle reinforced Fe-based composite coatings produced by multi-pass overlapping GTAW melting process

In this paper, in situ synthesized TiC particles reinforced Fe-based surface composite coatings by multi-pass overlapping gas tungsten arc welding (GTAW) melting process employing a proper amount of graphite and ferrotitanium (FeTi) on AISI 1020 steel substrate was produced. The microstructure and wear properties of the composite coatings were investigated by means of an electron microprobe microanalysis (EPMA), X-ray diffractometer and wear tester. The results showed that the multi-pass overlapping GTAW melting surface composite coatings can be obtained under suitable welding parameters, and no crack and porosity are found in the tracks. The X-ray and EPMA results confirm that TiC particles can be formed via reaction of FeTi and graphite during multi-pass overlapping GTAW melting process. TiC particles present cubic and dendrite shape in the non-overlapping zone. It is found that there occurred TiC particles coarsening at the overlap regions, which can lead to detrimental effects on the hardness and wear performance. Composite coatings give a high hardness and excellent wear resistance; and the wear friction coefficient of the coating is less than that of the 1020 steel. As a result, multi-pass overlapping GTAW melting process can be used effectively for producing surface composite coatings with a pre-placed powder to improve wear resistance of the AISI 1020 steel.