Structure and Tribological Properties of CrTiAlN Coatings Deposited by Multi-Arc Ion Plating

CrTiAlN coatings were prepared by using a home-made industrial scale multi-arc ion plating system. The coatings were found to be composites of face-center-cubic CrN and TiN. The surface roughness, microhardness, and tribological properties of the films were significantly affected by the nitrogen pressure and dc-pulsed bias voltage applied to the substrate. The CrTiAlN coatings with the smoothest surfaces were obtained at optimum conditions of nitrogen pressure of 5.0 Pa and bias voltage of -200 V. The samples were found to exhibit a hardness of 2900 HV0.05 with an average friction coefficient of 0.16 and wear rate of 1.5×10-16 m3/N?m against cemented carbide.     

离子镀膜法制备铀薄膜的表征

研究了离子镀膜法制备铀薄膜的性质,可为改善薄膜性能、完善过程模型、优化制备参数和提高制备效率提供依据。本工作通过扫描电子显微镜和X射线衍射分别测量了离子镀膜法制备铀薄膜的表面形貌和物相结构,通过俄歇电子能谱和X射线光电子能谱结合Ar+溅射深度剖析,对离子镀膜法制备铀薄膜的元素成分、化学形态及纵深方向的分布进行了分析。分析结果表明:制备的铀薄膜在基体上分布连续,主要物相为CaF2类型面心结构UO2,主要形态为UO2、金属U和FeUO4化合物。     

Study on the Properties of TiN Coatings on Previously Ion-Implanted Pure Magnesium Surface by MEVVA Ion Implantation

A metal vapor vacuum arc （MEVVA） is used in ion implantation for substrate preparation before the deposition process which would ensure the improvement of mechanical properties of the coating. Ti ion is implanted into pure magnesium surface by MEVVA implanter operated with a modified cathode. Implanting energy is kept at 45 keV and dose is set at 3 ×10^17 cm^-2. TiN coatings are deposited by magnetically filtered vacuum-arc plasma source on unimplanted and previously implanted substrates. Microstructure and phase composition are analysed using scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The property of corrosion resistance of TiN coatings was studied by CS300P electrochemistry-corrosion workstation, and the main impact factor of the corrosion resistance was also analyzed.     

偏压对铀表面多弧离子镀Ti/TiN多层膜的结构及抗腐蚀性能影响研究

在不同偏压下,利用多弧离子镀技术在U和Si基体上制备了Ti/TiN多层薄膜。利用X射线衍射仪和扫描电镜对多层膜的组织结构和薄膜界面形貌进行了分析。研究表明：脉冲偏压不但影响多层膜物相各衍射峰的强度,还诱导新相Ti₂N的出现。制备的多层膜呈“犬牙”交错的层状、柱状结构生长。随脉冲偏压的增加,柱状晶结构细化,薄膜变得更加致密。通过50μg/gCl^－溶液腐蚀研究表明：Ti/TiN多层膜提高抗腐蚀性能源于层状失效,使得腐蚀介质到达基体更加困难,抗腐蚀性能优良。     

Linear Coefficient of Thermal Expansion and Mechanical Property of Pb/B4C/BPR Composite

Lead/boron carbide/boron phenolic resin (Pb/B₄C/BPR) is a new kind of shielding composite with high temperature resistance and high shielding performance for radiations. In this paper, the effects of lead powder content, particle size and surface treatment (SiO₂ coating) on the linear coefficient of thermal expansion (CTE) and mechanical properties of the composites were systematically studied. The results show that the composites have the smallest linear CTE and excellent comprehensive mechanical properties when the lead powder content is 36% (volume fraction) and the particle size is 38 μm. Proper coating of SiO₂ on the surface of lead powder effectively reduces the density difference between lead powder and B₄C powder, which not only significantly reduces the linear CTE of the composites, but also improves the tensile, flexural strength and impact toughness. However, too much SiO₂ coating content will result in the linear CTE of the composites increasing and the tensile, flexural strength and impact toughness reducing.     

Pb/B4C/BPR复合材料的线膨胀系数与力学性能

铅/碳化硼/硼酚醛树脂(Pb/B4C/BPR)是一种新型屏蔽复合材料,具有较好的耐高温性能,在辐射屏蔽领域有重要应用。本文系统研究了该复合材料中Pb粉添加量（体积分数）、Pb粉粒径、Pb粉表面处理(SiO₂包覆)对其线膨胀系数和力学性能的影响规律。结果表明：Pb粉添加量为36%、粒径为38 μm时,复合材料具有最小的线膨胀系数与优异的综合力学性能;Pb粉表面包覆适量的SiO₂可有效减小Pb粉颗粒和B₄C颗粒之间的密度差异,不仅显著降低了复合材料的线膨胀系数,还提高了其拉伸强度、弯曲强度和冲击韧性,但Pb粉表面包覆过多SiO₂将导致复合材料的线膨胀系数增加,拉伸强度、弯曲强度和冲击韧性降低。     

Mechanical Properties and Uniformity of Nanocrystalline Diamond Coating Deposited Around a Sphere by MPCVD

Nanocrystalline diamond coatings were deposited by MPCVD on the spheres used for a ball bearing.The nanocrystalline coatings with a grain size of 50 nm were confirmed by the surface morphology and composition analysis.The hardness of the coating is 20-40 GPa tested by nanoindentation,which is higher than that of tungsten carbide and silicon nitride substrates.The coating around the sphere observed from the Micro CT images is uniform with a thickness of12 μm.     

反应熔渗法制备C/C-SiC材料的组织结构及性能

采用液相气化热梯度CVI法制备C/C材料,并通过反应熔渗法制备出密度为2.13～2.28g/cm3的C/C-SiC复合材料.用X射线衍射仪和光学显微镜分析C/C-SiC的显微组织结构,并对其力学性能(弯曲强度、压缩强度、硬度、断裂韧性)和摩擦磨损性能进行了研究.结果表明:反应熔渗法制备的C/C-SiC材料由C、SiC和Si组成;C/C多孔体的密度越低,得到的C/C-SiC材料密度越高.石墨化处理使C/C-SiC材料的弯曲强度由203～275 MPa降低到150～210 MPa,压缩强度由463～607 MPa降低到403～536 MPa,但材料的断裂韧性由6.6～8.5 MPa·m1/2提高到7.3～9.2 MPa·m1/2.在C/C-SiC盘与SiC销配对的滑动摩擦试验中,摩擦系数为0.19;石墨化处理可使摩擦系数降低到0.14～0.15,但平均体积磨损速率由3.4×10-3～5.0×10-3 mm3/h增大到7.9×10-3～9.8×10-3mm3/h.     

Influences of Bias Voltage and Target Current on Structure,Microhardness and Friction Coefficient of Multilayered TiAlN/CrN Coatings Synthesized by Cathodic Arc Plasma Deposition

Multilayered TiAlN/CrN coatings have been synthesized on stainless steel substrates by cathodic arc plasma deposition using TiAl and Cr targets.Influences of the bias voltage,cathode current ratio ITiAl/ICr,and deposition pressure on the hardness and friction coefficient of the coatings were investigated.The measurement revealed existence of two cubic phases,face-centercubic (Cr,Al)N and(Ti,Al)N,in the coatings deposited under various bias voltages except for the coating deposited at -400 V,which is amorphous.The hardness of the coatings was strongly dependent on the Itial/Icr ratio and deposition pressure,and reached a maximum of 33 GPa at an ITiAl/ICr ratio of 1.0 and a pressure of 1.0 Pa.The incorporation of the element chromium can reduce the density of pinholes in the coatings and assist the optimization of deposition conditions for high quality TiAlN/CrN coatings.     

Texture Evolution and Mechanical Properties of Mg/Al Multilayered Composite Sheets Processed by Accumulative Roll Bonding

正Mg and its alloys are regarded as potential candidates to replace steel and other heavier materials in some applications due to low density and high specific strength.However,the application of Mg alloys is limited because of their low strength,poor formability and corrosion resistance.Grain refinement and Mg-Al composite     

Microstructure and Mechanical Properties of CrN Films Deposited by Inductively Coupled Plasma Enhanced Radio Frequency Magnetron Sputtering

CrN films have been synthesized on Si（100） wafer by inductively coupled plasma （ICP）-enhanced radio frequency （RF） magnetron sputtering. The effects of ICP power on microstructure, crystal orientation, nanohardness and stress of the CrN films have been investigated. With the increase of ICP power, the current density at substrate increases and the films exhibit denser structure, while the DC self-bias of target and the deposition rate of films decrease. The films change from crystal structure to amorphous structure with the increase of ICP power. The measured nanohardness and the compressive stress of films reach the topmost at ICP power of 150 W and 200 W, respectively. The mechanical properties of films show strong dependence on the crystalline structure and the density influenced by the ICP power.     

溅射功率对磁控溅射制备Bi薄膜结构和性能的影响

采用直流磁控溅射方法在不同功率下制备了铋(Bi)薄膜,对薄膜的沉积速率、表面形貌、生长模式、晶体结构进行了研究,并对其晶粒尺寸和应力的变化规律进行了分析。扫描电镜(SEM)图像显示：薄膜均为柱状生长,平均晶粒尺寸随溅射功率先增大后减小,薄膜的致密度随着功率的增加而降低,在60W时又变得较致密。X射线衍射(XRD)结果表明：Bi薄膜均为多晶斜六方结构,薄膜内应力随功率的增加由张应力变为压应力。     

Effects of Annealing on the Structural and Photoluminescent Properties of Ag-Doped ZnO Nanowires Prepared by Ion Implantation

ZnO nanowires deposited on Si substrates were prepared by thermal evaporation of a mixture of ZnO and carbon powder. Ag ions with an energy of 63 keV and a dose of 5×1015 ions/cm-2 were implanted into the as-prepared ZnO nanowires. After ion implantation, the Ag-implanted ZnO nanowires were annealed in air at different temperatures from 600℃ to 1000℃. Effects of ion implantation and thermal annealing on the structural and photoluminescent (PL) properties of the ZnO nanowires were investigated by transmission electron microscopy (TEM), selected area energy dispersive X-ray spectroscopy (SAEDX), X-ray diffraction (XRD), and fluorescence spectrophotometry. TEM, HR-TEM, and SAEDX analyses demonstrated that efficient doping of Ag was achieved by ion implantation and the subsequent annealing process. XRD patterns revealed that the hexagonal wurtzite structure of ZnO nanowires was maintained after ion implantation. Photoluminescent emissions of ZnO nanowires were decreased significantly by Ag implantation but could be recovered by thermal annealing. The mechanism of the influence of ion implantation and annealing on the PL intensity was assessed.     

Cr/CrN Compound Films Prepared by Ion Beam Assisted Deposition for Improving the Performance of Bearing Steel

With the development of industry, much attention has been paid to lengthening the life span of bearings. As reported in this paper, we investigated the Cr/CrN compound films formed on the specimens of W9Cr4V2Mo bearing steel by ion beam assisted deposition for improving the performance of bearing steels. The Vicker＇s microhardness, pin-on-disc, electrochemical measurement, XRD and SEM tests were used to characterize and analyze the treated samples. All results indicated that the mechanical properties of the treated samples were good, with the microhardness greater than that of the uncoated specimen, and the wear resistance, the passivity and pitting corrosion resistance increased considerably, the films possessed alternate Cr and CrN compound phases and produced different effects on the improvement of the performance of W9Cr4V2Mo bearing steels with different composing phases.     

30%TBP/煤油中DBP和MBP的离子色谱分析

采用离子色谱作为检测仪器,建立了简单、快速、灵敏地测定30%TBP/煤油中DBP和MBP的新方法。以去离子水为反萃剂将有机相中DBP和MBP反萃到水相,去除有机相干扰,离子色谱仪进行检测。当DBP浓度在0.01～6.0 mmol/L、MBP浓度在0.02～2.5 mmol/L时,标准曲线均具有良好的线性,相关系数r²均达到0.999,DBP的检出限为5.0 μmol/L,MBP的检出限为4.0 μmol/L。采用建立的方法对模拟30%TBP/煤油生成的辐解产物进行重加回收实验,DBP的重加回收率在92%～96%,模拟样品6次平行测定的s_r=2.1%。     

30％TBP/煤油中DBP和MBP的离子色谱分析

采用离子色谱作为检测仪器,建立了简单、快速、灵敏地测定30%TBP/煤油中DBP和MBP的新方法。以去离子水为反萃剂将有机相中DBP和MBP反萃到水相,去除有机相干扰,离子色谱仪进行检测。当DBP浓度在0.01～6.0 mmol/L、MBP浓度在0.02～2.5 mmol/L时,标准曲线均具有良好的线性,相关系数r²均达到0.999,DBP的检出限为5.0 μmol/L,MBP的检出限为4.0 μmol/L。采用建立的方法对模拟30%TBP/煤油生成的辐解产物进行重加回收实验,DBP的重加回收率在92%～96%,模拟样品6次平行测定的s_r=2.1%。