基于腐蚀性能的碳钢管道使役时间评价方法

核电厂管道系统腐蚀程度监测和预测使役时间是核电厂安全性能评估的重要内容之一.文章介绍了采用M（o）ssbauer谱分析碳钢管道腐蚀产物,超声无损检测确定管壁剩余厚度,依据统计学原理,计算各类管道系统管壁腐蚀程度的分布和理论腐蚀速率,用于评估管道在下一生产周期的安全状态和使役寿命.     

溶胶-凝胶法制备掺Er3+:Al2O3/SiO2/Si光波导薄膜

采用溶胶-凝胶(Sol-gel)法在热氧化的SiO2/Si(100)基片上提拉法制备掺EP:A12O3光学薄膜.采用扫描电镜(SEM)、原子力显微镜(ARM),X射线衍射分析(XRD)研究了掺Er3+:Al2O3光学薄膜的形貌、厚度以及结构等特性.结果表明,在氧化的SiO2/Si(100)基片上获得了厚度为1.2 μm,固溶Er3+的面心立方结构γ-(Al,Er)2O3和单斜结构θ-(A1,Er)2O3的薄膜.薄膜表面光滑、平整,无明显的表面缺陷.掺EP:Al2O3薄膜晶粒分布均匀,平均晶粒直径为50～200 m,表面起伏度为10～20 nm.测量了10 K下掺0.1 mo1%～1.5 mo1%Er3+:Al2O3光学薄膜的光致发光(PL)谱,获得了中心波长为1.533μm的发光曲线.PL强度随Er3+掺杂浓度的增加而下降,相应的半峰宽(FWHM)也从45 nm减小到36 nm.Sol-gel法制备掺Er3+:Al2O3/SiO2/Si光学薄膜满足有源光波导放大器基体材料的性能要求.     

Modeling of Inner Surface Modification of a Cylindrical Tube by Plasma-Based Low-Energy Ion Implantation

The inner surface modification process by plasma-based low-energy ion implantation(PBLEII)with an electron cyclotron resonance(ECR)microwave plasma source located at the central axis of a cylindrical tube is modeled to optimize the low-energy ion implantation parameters for industrial applications.In this paper,a magnetized plasma diffusion fluid model has been established to describe the plasma nonuniformity caused by plasma diffusion under an axial magnetic field during the pulse-off time of low pulsed negative bias.Using this plasma density distribution as the initial condition,a sheath collisional fluid model is built up to describe the sheath evolution and ion implantation during the pulse-on time.The plasma nonuniformity at the end of the pulse-off time is more apparent along the radial direction compared with that in the axial direction due to the geometry of the linear plasma source in the center and the difference between perpendicular and parallel plasma diffusion coefficients with respect to the magnetic field.The normalized nitrogen plasma densities on the inner and outer surfaces of the tube are observed to be about 0.39 and 0.24,respectively,of which the value is 1 at the central plasma source.After a 5μs pulse-on time,in the area less than 2 cm from the end of the tube,the nitrogen ion implantation energy decreases from 1.5 keV to 1.3 keV and the ion implantation angle increases from several degrees to more than 40°;both variations reduce the nitrogen ion implantation depth.However,the nitrogen ion implantation dose peaks of about 2×10~(10)-7×10~(10)ions/cm~2 in this area are 2-4 times higher than that of 1.18×10~(10)ions/cm~2 and 1.63×10~(10)ions/cm~2 on the inner and outer surfaces of the tube.The sufficient ion implantation dose ensures an acceptable modification effect near the end of the tube under the low energy and large angle conditions for nitrogen ion implantation,because the modification effect is mainly determined by the ion implantation dose,just as the mass transfer process in PBLEII is dominated by low-energy ion implantation and thermal diffusion.Therefore,a comparatively uniform surface modification by the low-energy nitrogen ion implantation is achieved along the cylindrical tube on both the inner and outer surfaces.     

微米压痕测量TiAlN薄膜断裂韧性的数字孪生方法EI北大核心CSCD

针对高性能表面层制造的薄膜断裂韧性检测,采用扩展有限元法(XFEM)模拟TiAlN薄膜微米压痕行为,基于数字孪生方法优化薄膜最大起始断裂应力(σ_(max))和相应的裂纹分离距离(δc)参数,根据Griffith-Irwin关系测定薄膜断裂韧性。深振荡磁控溅射(DOMS)在AISI 304奥氏体不锈钢基体上沉积具有立方结构的TiAlN薄膜,随着峰值功率由58.7 kW增至129.9kW,薄膜的择优取向由(111)转变为(200)。维氏微米压痕试验在载荷500 mN下压制,聚焦离子束(FIB)结合扫描电子显微镜(SEM)观察薄膜平面和横截面开裂行为,通过3D XFEM建模表征薄膜损伤过程,将模拟的薄膜裂纹形态、数量、分布及总长度与试验值进行交互反馈和融合分析,孪生匹配出薄膜平面开裂的σ_(max)和δc参数,计算出AISI 304奥氏体不锈钢上沉积TiAlN薄膜的断裂韧性。随着DOMS峰值功率提高,TiAlN薄膜断裂韧性先增加后减小。峰值功率为90.2 kW,伴随最高纳米硬度28.3 GPa,断裂韧性最大值为1.88 MPa·m^(1/2),DOMS沉积TiAlN薄膜具有强韧性复合性能。XFEM模拟微米压痕的数字孪生方法,不仅发展了薄膜断裂韧性的测量技术,还为高性能表面层制造反问题提供了一种求解方法。     

高功率脉冲磁控溅射轮辐特征等离子体研究综述EI北大核心CSCD

高功率脉冲磁控溅射技术(HiPIMS)是最新一代磁控溅射技术,高度离化的脉冲等离子体是HiPIMS技术的核心特征。针对HiPIMS放电轮辐特征,评述特征放电下HiPIMS等离子体测量、模拟及对薄膜生长作用的最新研究进展。较之常规磁控溅射技术,HiPIMS溅射靶材粒子高度离化,等离子体阻抗显著降低。等离子体在靶材表面形成以千米每秒速度旋转漂移的致密等离子体结构,存在局域化和自组织特征,可显著影响沉积粒子输运行为,为沉积薄膜生长提供一个新的控制维度。HiPIMS放电轮辐一般呈现扩散形和三角形两种形态,通过介绍轮辐变化规律、形成机制的进展,明确靶材溅射产额也对其形态有影响。另一方面,HiPIMS轮辐结构结合其脉冲放电特点,可控制薄膜沉积通量输运特征,进而影响沉积薄膜的微结构、表面粗糙度等表面完整性参数。具有微秒到毫秒跨尺度多级脉冲调节能力的高功率调制脉冲磁控溅射(MPPMS)和高功率深振荡脉冲磁控溅射(DOMS),脉冲控制跨时间尺度特性带来的轮辐特征可剪裁性,为在更大时间和空间维度上薄膜生长控制提供了可能性。     

Ultrasonic characterization of modified Cr_2O_3 coatings by reflection coefficient spectroscopy

Pores,microcracks and density of plasma sprayed Cr2O3 coatings before and after high-intensity pulsed ion beam(HIPIB) irradiation were investigated using the ultrasonic reflection coefficient spectroscopy(URCS).The URCS was analyzed based on an acoustic transmission model for the multi-layered structure.The longitudinal velocity in the coatings was calculated from the experimental URCS,and the attenuation coefficient expression was deduced by comparing the experimental and numerical fitting amplitude spectral lines.The longitudinal velocity of as-sprayed Cr2O3 coating is 2 002 m/s,and increases to 2 099 and 2 148 m/s after being irradiated by HIPIB with 1 and 5 shots.Correspondingly,the factor A changes from 0.046 to 0.026 and 0.020 and n from 1.702 to 1.658 and 1.649 in the attenuation coefficient expression of α=Af n.It is observed that the surface morphology of Cr2O3 coatings changes from rough and porous to smooth and uniform with the increase of shot number,which accords with the ultrasonic analyses reasonably.The URCS seems to provide a convenient and nondestructive method to characterize surface modification of the plasma sprayed coatings.     

基于随机介质理论的热障涂层随机孔隙模型构建

基于随机介质理论、采取统计学方法,将热障涂层(TBCs)中孔隙和裂纹引起的局部密度和弹性模量起伏用空间自相关函数及某些统计参数来描述,借助极值搜索法对连续随机介质模型进行改造,并针对涂层孔隙率及各向异性取向等进行模型参数优化,提出并建立了TBCs随机孔隙模型。将模型模拟结果与ZrO2涂层SEM观察结果进行对比表明,所建立的模型能够较好地描述热障涂层中的孔隙、裂纹形貌特征。本研究对于确定TBCs孔隙特征与涂层性能的理论关系以及涂层性能计算研究具有较大意义。     

强流脉冲离子束辐照WC-Co硬质合金的组织与性能

用扫描电镜（SEM）、表面轮廓仪、X射线衍射仪（XRD）、电子探针（EPMA）和显微硬度计等方法,研究了强流脉冲离子束辐照WC-Co硬质合金的组织与性能。结果表明,HIPIB辐照使硬质合金表面发生快速重熔和Co粘结相的优先烧蚀,导致六方α-WC相向立方β-WC1-x相转变,形成丘状凸起重熔烧蚀形貌;硬质合金表面硬度随束流密度和辐照次数的增加先增加后减小,归因于辐照硬质合金表面重熔致密化、Co粘结相优先烧蚀、β-WC1-x相转变以及表面微裂纹的产生。     

腐蚀电化学方法评价硬质涂层孔隙率

综述了以电化学阻抗理论为基础的一维孔传输线模型、有限扩散模型和以阳极极化理论为基础的多孔涂层电极模型计算金属表面硬质涂层孔隙率的原理及其测量方法.一维孔传输线模型依据涂层体系与涂层、基体间极化电阻的关系计算孔隙率;有限扩散模型则利用孔隙率与扩散系数和频率间的函数关系测定;多孔涂层电极模型利用涂层体系和金属基体间极化电流密度,极化电阻,自腐蚀电位和库仑电量等参数分别确定孔隙率.比较测定的硬质涂层孔隙率,不同工艺条件下孔隙率的测量范围为0.001%～50％;测量精度在80%以上.     

掺Er3+勃姆石(γ-AlOOH)凝胶高温烧结相变

采用溶胶-凝胶法(sol—gel)制备掺0-20mol％Er^3 勃姆石(γ-AlOOH)凝胶，X射线衍射和差热分析法研究掺Er^3 ：γ—AlOOH凝胶在950-1400℃烧结的相变过程．结果表明：Er^3 的掺杂降低α相的生长速度，抑制Al2O3的θ→α相变，推迟相变结束温度50-70℃，Er-Al-O系化合物Al10Er6O24和ErAlO3相的析出取决于掺Er^3 浓度和烧结温度．在较高烧结温度下，ErAlO3相由掺1-5mol％Er^3 ：Al2O3中析出；Al10Er6O24相则在掺5-20mol％Er^3 ：Al2O3中析出，随着烧结温度的升高，在全部掺Er^3 ：Al2O3中析出．ErAlO3相促进θ→α相变的形核，α相形核起始温度可提前30-50℃，但对α相生长影响不大．Al10Er6O24相对θ→α相变没有显著影响．