喷雾干燥法制备PS-PVD用8YSZ纳米团聚粉末

目的 通过喷雾干燥法制备用于等离子喷涂-物理气相沉积法（Plasma Spray-Physical Vapor Deposition,PS-PVD）多相沉积柱状/致密涂层的ZrO2-8%Y2O3 (8YSZ)纳米团聚粉末。方法 采用平均粒度为20 nm的8YSZ纳米粉为原料并配制成浆料,球磨后通过喷雾干燥法制备出8YSZ的纳米团聚粉末,并研究不同含量粘结剂（NJ-3）对粉末的影响。利用TEM、SEM表征粉末及涂层的微观结构。通过XRD、激光粒度及拉伸试验对粉末及涂层性能进行表征。结果 纳米8YSZ粉末在添加适当种类及含量的分散剂、粘结剂并通过喷雾干燥加工后,成功制备出球形度高、粒度小且适用于气/液/固多相沉积的PS-PVD用喷涂粉末。当粘结剂含量低于8%时,粉末球形度低,表面存在明显坑孔。而当粘结剂含量高于12%时,PS-PVD气相沉积效率低,涂层质量差。当粘结剂含量为10%时,粉末球形度高,D90=12.24 μm,可气/液/固多相沉积制备形貌良好的柱状涂层及致密涂层。其中气相沉积所制备柱状涂层结合强度可达33 MPa,且原始粉末中的m-ZrO2完全转变为t-ZrO2。结论 当粘结剂含量为10%时,所制备粉末能够流畅送粉,并进行气/液/固多相沉积,且涂层质量最优。粘结剂在粉末内部分布均匀,并主要起粘结和支撑作用,同时可改善粉末表面形貌。喷雾干燥后粉末粒度随着粘结剂含量增加而增大,但非线性变化。     

等离子加工热锻模碳化物涂层的制备

以W6Mo5Cr4V2为基体,采用等离子喷涂-重熔技术和喷焊技术,分别用30％SiC、10％Cr3C2和30％WC粉末制备Ni60-SiC涂层、Ni60-Cr3C2涂层和Ni60-WC涂层.然后对各涂层进行显微组织分析和显微硬度测试,并对涂层的热物性参数进行检测.实验结果表明,采用喷焊的方法,配比为70％Ni60和30％SiC的粉末得到涂层性能最好.从宏观形貌、微观形貌、显微硬度和热物性参数上都满足热锻模表面的使用要求.     

热锻模模膛等离子喷涂-重熔和喷焊制备Ni60-SiC涂层的实验研究

为了制备满足热锻模使用性能要求的模膛表面耐热层,采用等离子喷涂-重熔技术和喷焊技术,以W6Mo5Cr4V2为基体,用SiC含量(质量分数,下同)分别为10%、20%和30%的Ni60-SiC粉末,分别制备Ni基SiC涂层。主要对涂层进行了显微组织分析和显微硬度测试,并对涂层主要热物性参数进行检测。结果表明,采用喷焊的方法,配比为70%Ni60/30%SiC的粉末得的到涂层性能最好,显微硬度可达1100 HV,同时具有很好的热物性能。     

Al_2O_3-SiC复合涂层的制备及性能研究

采用大气等离子喷涂方法制备了不同SiC晶须含量的Al_2O_3-SiC复合涂层,研究了晶须含量对涂层的微观结构、硬度和弹性模量等的影响。结果表明:随着喷涂粉末中SiC晶须的含量增大,Al_2O_3-SiC复合涂层的孔隙率增加,而涂层的显微硬度降低。随着与涂层/基体结合面距离的增加,涂层的显微硬度呈现先增加后降低的趋势。纳米压痕的测试表明,随压痕深度增加,涂层的弹性模量先增大后降低,最后趋于稳定。在现有的研究范围内,SiC晶须含量为10%的复合涂层的韧性优于5%和15%的复合涂层。     

WC-Co复合粉的喷雾造粒及松装密度的影响因素

利用短流程原位反应合成技术制备超细WC-Co复合粉,其平均粒径为300 nm,对此复合粉进行喷雾造粒以制备具有超细结构的热喷涂粉末。采用标准漏斗法测量造粒粉末的松装密度,并利用SEM观察其形貌与结构,结合实验测定结果与理论计算结果研究料浆成分、喷雾干燥温度及初始粉末粒径对造粒粉末松装密度的影响规律。结果表明:料浆固含量最高可达70%(质量分数),此时造粒粉末松装密度达到2.31 g/cm3;随粘结剂含量的增高,造粒粉末松装密度先增高后降低,最佳含量为2.5%(质量分数);分散剂最佳含量为1%~2%(质量分数);干燥温度显著影响造粒粉末形貌结构及松装密度,最佳温度为150℃;喷雾造粒粉末的最高密度实质上取决于初始粉末粒径。     

TiB_2增强Ni/Al冷喷涂层的组织结构

在不同的冷喷温度条件下,采用冷喷涂技术制备含不同TiB_2陶瓷含量的Ni/Al-TiB_2涂层,其中Ni/Al-TiB_2喷涂粉末为机械混合制成。采用扫描电镜(SEM)表征Ni/Al-TiB_2粉末、冷喷涂层及热处理后涂层的形貌,通过X射线衍射技术(XRD)分析Ni/Al-TiB_2粉末和冷喷涂层物相结构,采用能谱分析仪对热处理后涂层成分元素进行分析。结果表明,冷喷涂层截面组织结构致密,孔隙率低,尤其是在冷喷温度为450℃条件下涂层孔隙率更低。冷喷涂层的物相与粉末相同,主要为TiB_2、Ni和Al三相。在650℃热处理10 h后涂层中孔隙率增加,涂层中原位生成了Ni Al3和Ni Al金属间化合物,并且涂层与基体界面之间生成了Fe Al3金属间化合物,从而提高了涂层与基体之间的结合力。     

超音速大气等离子喷涂TiB_2-SiC涂层的抗氧化性及耐熔盐腐蚀性能（英文）

采用超音速大气等离子喷涂制备全包覆TiB_2-SiC涂层,研究了TiB_2-SiC涂层在400和800℃的氧化性能,并探究其氧化机理。对TiB_2-SiC涂层在900℃下的抗铝熔盐腐蚀性能进行研究,并探讨其耐熔盐腐蚀机理。结果表明,超音速大气等离子喷涂制备的TiB_2-SiC涂层具有良好的抗氧化性,在400℃的氧化速率常数为1.92×10~(-5) mg~2·cm~(-4)·s~(-1),在800℃的氧化速率常数为1.82×10~(-4) mg~2·cm~(-4)·s~(-1)。超音速大气等离子喷涂制备的TiB_2-SiC涂层在900℃下具有良好的抗熔盐腐蚀性能,熔盐腐蚀后TiB_2-SiC涂层都保持致密结构,未发生涂层的开裂及剥落。     

热锻模等离子喷焊制备Ni60基陶瓷覆层的试验研究

使用等离子喷焊技术,在以W6Mo5Cr4V2为基体的热锻模模膛表面,用SiC、Cr3C2和WC含量分别为10%、20%、30%的镍基粉末制备涂层。主要对涂层进行了显微组织分析和显微硬度测试,并对涂层主要热物性参数进行检测。实验结果表明,配比为70%Ni60和30%SiC的粉末得到等离子喷焊层的性能最好。微观组织、显微硬度(可达到1100 HV)和热物参数均能达到热锻模的工作要求。     

Cf/SiC表面等离子喷涂金属过渡层及其界面结合特征

目的采用等离子喷涂工艺(APS)在C_f/SiC复合材料表面制备金属涂层。方法在对比等离子喷涂Mo粉、NiCrBSi粉以及自制的Ti70Ni20Cu10复合粉末三种涂层的组织形貌和界面结合的基础上,制备了Mo-10%Ti复合涂层,喷涂用粉为通过低速球磨方法在大颗粒的Mo粉表面包覆TiH_2粉末而得,喷涂时将基体预热至700℃,在氩气保护气氛下进行喷涂。结果 APS制备的Mo-10Ti涂层,组织致密均匀,孔隙率较低,无明显裂纹。涂层与基体结合紧密,没有发生剥离现象,结合强度超过6.3 MPa,断裂发生于基体侧。结论材料的热膨胀系数和润湿性是影响等离子喷涂金属涂层与C_f/SiC复合材料结合的关键因素,所设计的Mo-Ti复合涂层较好地兼顾了这两点。     

超音速大气等离子喷涂TiB2−SiC涂层的制备与性能

将喷雾造粒制备的TiB2?SiC粉末进行真空煅烧,采用超音速大气等离子喷涂制备TiB2?SiC涂层,研究喷涂功率和喷涂距离对TiB2?SiC涂层性能的影响,并对超音速等离子喷涂制备TiB2?SiC涂层的工艺进行优化.结果表明:煅烧后的喷涂粉末粒径分布均匀,球形度良好,流动性增强.煅烧粉末制备的涂层结构致密、沉积效率高....     

Plasma spray coating of spray-dried Cr2O3/wt.% TiO2 powder

An agglomerated Cr₂O₃/wt.%TiO₂ powder has been fabricated by the spray drying process under different parameters. The spray-dried powder has well-agglomerated particles of spherical shape. In the conditions of the high slurry feed rate and low binder concentration in the slurry, the powder has large cavities inside some particles and ruggedness over their surface. The optimum plasma spray feed rate has been found by examining the spraying behavior of the powder and melted state of particles. The plasma spray coating has been performed under different process variables such as spraying distance and plasma power. These parameters strongly affect the characteristics of the coated layer: microstructure, hardness, and bond strength.     

等离子喷涂铝电解可湿润TiB2阴极涂层研究进展

铝电解工业越来越多的采用石墨阴极,石墨阴极具有良好的导电性能,但石墨不被铝液湿润且和铝液形成Al4 C3,导致铝电解槽运行寿命短.可湿润TiB2涂层阴极因节能和延长槽寿命能够给铝电解工业带来显著效益.等离子喷涂是一种高效、灵活的沉积涂层的方法 ,能够在形状复杂或大表面积的基体上沉积金属间化合物、陶瓷或复合材料,涂层厚度可从数微米到数毫米.等离子喷涂制备可湿润性TiB2涂层阴极是可行有效的方法 ,本文评述了等离子喷涂制备可湿润TiB2阴极涂层的研究进展,简述了等离子喷涂工艺受到的影响因素(包括粉末性质、基体表面形貌和焰流性质)和涂层与基体材料结合的机制(包括机械结合、冶金结合和物理结合),分析和讨论了TiB2粉末制备、基体预处理、等离子喷涂工艺参数、涂层显微结构和性能等.最后,指出了等离子喷涂制备可湿润性TiB2涂层阴极工艺将来研究需要解决的几个关键问题.     

Fabrication and Wear Behavior of Nanostructured Plasma-Sprayed 6061Al-SiCp Composite Coating

6061Al powder with 15 wt.% SiC particulate (SiC_p) reinforcement was mechanically alloyed (MA) in a high-energy attrition mill. The MA powder was then plasma sprayed onto weathering steel (Cor-Ten A242) substrate using an atmospheric plasma spray process. Results of particle size analysis and scanning electron microscopy show that the addition of SiC particles as the reinforcement influences on the matrix grain size and morphology. XRD studies revealed embedment of SiC_p in the MA-processed composite powder, and nanocrystals in the MA powder and the coating. Microstructural studies showed a uniform distribution of reinforced SiC particles in the coating. The porosity level in the coating was as low as 2% while the coating hardness was increased to 232VHN. The adhesion strength of the coatings was high and this was attributed to higher degree of diffusion at the interface. The wear rate in the coatings was evaluated using a pin-on-disk type tribometer and found to decrease by 50% compared to the 6061Al matrix coating. The wear mechanism in the coating was delamination and oxidative type.     

Plasma Spray Coatings of Ni-Al-SiC Composite

Ni-Al-SiC powder mixture containing 12 wt.% SiC was prepared by conventional ball milling. Morphological and microstructural investigations showed that powder particles after 15 h of milling time had the optimum characteristics with respect to their size and microstructure. X-ray diffraction patterns of powder particles included only the elemental Ni, Al, and SiC peaks without any traces of oxides or intermetallic phases. The powder mixture was then deposited onto a steel substrate by atmospheric plasma spray (APS) process under different conditions. The results showed that under APS conditions used here, the coatings were composed of various intermetallics including Ni-Al and Ni₂Al₃. The mean hardness of coating was found to be about 567 HV. It was also found that by increasing current density of APS, the coating/substrate adhesive strength was increased.     

大气等离子喷涂TiB2-TiC-Co涂层的组织与性能

利用Co-Ti-B4C自蔓延体系合成TiB2-TiC-Co复合陶瓷粉末，并结合大气等离子喷涂技术在Q235 钢基体表面制备TiB2-TiC-Co陶瓷涂层，研究了自蔓延产物和涂层的相组成、显微组织，以及涂层的结合强度和抗磨损性能。结果表明：Co-Ti-B4C体系自蔓延产物的物相中，除了少量剩余的NaCl添加剂衍射峰外，主要由TiB2和TiC陶瓷相的强衍射峰组成；产物断面中，两相陶瓷颗粒细小。随Co含量增加，TiB2-TiC-Co涂层表面盘状组织增多，表面逐渐平滑，截面涂层厚度均匀，组织致密性逐渐增加；结合强度和耐滑动磨损性能呈先升高后降低的变化趋势。Co含量为10wt.%时，涂层的结合强度和耐滑动磨损性能最好，涂层的滑动磨损机制主要为粘着磨损和层状剥落磨损。     

Structural evolution of mechanically alloyed Al-12Si/TiB2/h-BN composite powder coating by atmospheric plasma spraying

In the present study, mechanically alloyed Al-12Si/TiB₂/h-BN composite powder was deposited onto an aluminum substrate by atmospheric plasma spraying. The effect of mechanical alloying (MA) and plasma spray parameters on composite powder and coating structure were investigated. It has been observed that the MA process has a significant effect on the composite powder morphology and reactivity between the selective powders. Results also demonstrate that, at relatively high milling time h-BN decomposes into B and N and forms a solid solution. Also, it has been found that, the relative amount of the in-situ formed AlN through the reaction between h-BN and Al and/or the decomposition of Al-B-N solid solution is independent from the plasma parameters (arc current and secondary gas flow rate). However, spray parameters remarkably affects the coating hardness due to coarsening of Si during the solidification of the coating.     

等离子喷涂TiO2基涂层工艺参数优化研究

目的对TiO_2基涂层的等离子喷涂工艺参数进行优化。方法采用正交实验、基材温度采集并结合涂层微观形貌分析、能谱分析、结合强度试验、显微硬度测试等方法,研究了喷涂电流、喷涂距离、主气流量对涂层组织及性能的影响规律,并获得了优化的喷涂工艺参数。结果涂层分熔融区和部分熔融区,呈现双模结构的混合微观结构特征,截面形貌凹凸不平,并以机械结合为主。拉断后,涂层断裂面呈韧窝状,由陶瓷层到粘结层呈台阶状过渡,陶瓷层整体的内聚结合强度优于陶瓷层与粘结层结合界面的结合强度。涂层条带状夹杂随着粉末流到达基板的温度的增加而减少,对结合强度影响不显著,但对硬度影响较显著。等离子喷涂过程中,粉末流到达基板的温度在一定范围内时,涂层性能随着粉末流到达基板的温度的增加而增加,但粉末流到达基板的温度过大,涂层性能降低。结论获得最优涂层必须采用最优工艺参数,工艺参数对涂层综合性能的影响主次顺序为喷涂电流、喷涂距离、主气流量,得到的优化工艺参数为:喷涂电流350 A,喷涂距离110 mm,主气流量2100 L/h。     

等离子熔-喷WC-17%Co涂层工艺参数对外观形貌的影响

等离子熔-喷技术同时具备等离子喷涂、熔焊技术的综合特点,可以实现各种陶瓷材料涂层与基体的冶金结合。Co基WC具有硬度高、耐磨损、耐腐蚀、耐高温等一系列优点。采用等离子熔-喷技术在Q235钢基体表面制备WC-17％Co涂层,通过研究等离子熔-喷工艺参数（等离子熔枪和喷枪角度、熔枪和喷枪与基材表面的距离、熔-喷速度、喷涂送粉量）对涂层外观形貌的影响,获得最佳的工艺参数,制备出外观形貌良好、无缺陷的熔-喷涂层。     

Cold spray of SiC and Al<Subscript>2</Subscript>O<Subscript>3</Subscript> with soft metal incorporation: A technical contribution

Al + SiC, Al + Al₂O₃ composites as well as pure Al, SiC, and Al₂O₃ coatings were prepared on Si substrates by the cold gas dynamic spray process (CGDS or cold spray). The powder composition of metal (Al) and ceramic (SiC, Al₂O₃) was varied into 1:1 and 10:1 wt.%, respectively. The propellant gas was air heated up to 330 °C and the gas pressure was fixed at 0.7 MPa. SiC and Al₂O₃ have been successfully sprayed producing coatings with more than 50 μm in thickness with the incorporation of Al as a binder. Also, hard ceramic particles showed peening effects on the coating surfaces. In the case of pure Al metal coating, there was no crater formation on hard Si substrates. However, when Al mixed with SiC and Al₂O₃, craters were observed and their quantities and sizes depended on the composition, aggregation and size of raw materials.