陶瓷二次金属化镀镍层厚度的无损检测

本文分析了陶瓷-金属封接中二次金属化镀层厚度对陶瓷-金属封接质量的影响，提出采用X射线荧光光谱法（XRF）对二次金属化镀层厚度进行无损检测，分析了二次金属化镀层成分与含量，对二次金属化镀层的底材进行SEM分析，进行了检测用标准片的设计和标定，建立了XRF无损检测厚度方法的应用程序和校准方法。研究结果表明：采用X射线荧光光谱法，对二次金属化镀层厚度进行无损检测是可行的和可靠的；在试验的范围内（2．48-10．5μm），测量误差小于2％，RSD（相对标准偏差）小于2％。     

影响电真空陶瓷金属化质量的因素分析

本文就一般文献资料中很少见到的关于陶瓷金属化过程中不同的工艺及其条件、材料使用方法等方面引起的产品异常现象进行了深入分析，并提出了相应的解决措施。     

电真空器件用陶瓷三次金属化钎料层烧结工艺的研究

通过扫描电镜SEM与EDS等分析工具研究氧化铝陶瓷表面三次金属化的烧结工艺。结果表明,陶瓷表面三次金属化的烧结温度与烧结气氛对钎料层的结合状况与表面形貌产生重要的影响。820℃与干氢的烧结工艺适合钎料层与镍层的结合。过高的烧结温度与湿氢烧结条件易在钎料层与镍层之间产生缝隙,甚至凸起或凹坑,严重影响三次金属化的烧结质量。     

利用熔盐热析出反应法对AlN陶瓷表面金属化研究

研究了利用熔盐热析出反应法对AlN陶瓷的表面金属化. Ti金属化涂层呈现TiO/TiO_1-x/TiN层状结构,在涂层与AlN陶瓷结合处,存在TiN和AlN的梯度复合结构.研究表明,金属化处理显著改善了AlN陶瓷表面与金属Al的润湿性能,在1000℃下,润湿角从114.4°降至49.7°.     

金属化温度对掺锰铬陶瓷封接性能影响的研究

研究了金属化烧结温度对掺锰铬陶瓷的封接性能的影响,初步分析了其影响原因与机理.结果表明:掺锰铬高氧化铝陶瓷对于MoMnSi配方的金属化反应活性高,1300℃是其最佳金属化温度,温度降低和升高都会导致封接性能降低.在最佳温度,金属化层烧结致密,金属化层与陶瓷间形成了主要由锰尖晶石(MnO·Al2O3)和少量硅氧化物构成的过渡层结构,从而将金属化层与陶瓷有效地连接在一起.温度升高使金属化层过度收缩会形成大量孔洞,元素氧化加剧,不利于过渡层的形成,导致封接性能大大降低.     

端面金属化陶瓷真空管的制备方法与发展方向

介绍了陶瓷真空管的主要用途,重点对实现陶瓷真空管端面金属化的真空离子镀、真空蒸镀、磁控溅射、烧结被金属、烧结金属粉末以及均匀沉淀、电镀、化学镀等制备方法进行了综述,提出了光催化化学镀实现陶瓷真空管端面金属化的制备新方法,并对端面金属化陶瓷真空管的发展方向进行了思考。     

Mo含量对Mo-Mn法陶瓷金属化层性能的影响

采用丝网印刷法在氧化铝陶瓷表面制备了活性Mo-Mn金属化层,研究了Mo含量对烧结后金属化层的微观结构、元素成分以及钎焊后抗拉强度的影响。研究结果表明,Mo-Mn法陶瓷金属化层以Mo为骨架结构,玻璃相填充于骨架结构内部,随着膏剂中Mo含量的增加,烧结后的金属化层中Mo骨架与玻璃相成分并无较大变化,而Mo骨架体积占比增加,玻璃相体积占比相应减少。烧结过程中陶瓷和金属化层二者玻璃相之间相互迁移,陶瓷玻璃相向金属化层中迁移深度可达20μm以上,玻璃相中Si元素在金属化层表面存在一定程度的偏析现象。50wt%、70wt%和85wt% Mo含量膏剂制备的金属化层平均抗拉强度分别为110 MPa、120 MPa和111 MPa,表明Mo含量为70wt%时封接性能最佳。     

半球谐振子金属化镀膜残余应力的测量方法及影响因素研究

半球谐振子金属化镀膜是半球谐振陀螺制造的重要工艺环节.镀膜过程所产生的薄膜残余应力对谐振子Q值有较大影响,决定着半球谐振陀螺零偏稳定性等最终性能.本文采用X射线衍射法测量薄膜残余应力,研究了镀膜工艺参数和膜层厚度对残余应力的影响,结果表明:薄膜残余应力均呈压应力状态;随着沉积速率的增大,薄膜应力先增大后减小,有转化为拉...     

丙烷溶剂罐鼓泡裂纹成因分析与对策

介绍了丙烷脱沥青装置--丙烷溶剂罐检测过程中发现的鼓泡开裂情况,通过金相组织分析,确定低合金高强度16MnR钢的鼓泡开裂原因是设备在工艺介质H2S含量超标情况下发生了典型的湿硫化氢环境下的氢鼓泡(HB)、氢致开裂(HIC)和应力导向氢致开裂(SOHIC),并从设备选材、工艺防腐蚀、设备防腐蚀等方面提出了改进措施.     

A vacuum plasma surface pretreatment for refining seeding of Co in electroless copper plating

In this work, various vacuum plasma types, generated by either single gaseous sources (N₂ or H₂) or mixed sources (N₂-H₂) are incorporated into an aqueous-solution electrochemical seeding process to pre-treat the surfaces of SiO₂ dielectric layers. Under the optimal plasma atmosphere (monitored by optical emission spectroscopy), the dielectric surfaces can be modified to terminate by hydrophilic bonds, accelerating the adsorption of a crowd of catalytic seeds as small as 3 nm. Such a seeding refinement allows for the growth of a Co-based barrier layer with thickness as thin as 10 nm using electroless plating. Moreover, the capacity of integrating the plasma surface pretreatment with the seeding and electroless-plating process steps to deposit an ultrathin copper-stacked metallization layer in a selective and sequential manner on blanket wafers will be demonstrated by the fabrication of copper-gated and barrier-interposed capacitors. Finally, a tentative work of filling the seeds and the barrier layer into trenches of a patterned wafer was carried out, demonstrating the potential of the reported technique for advanced technology nodes of 60 nm or less.     

BaTiO3铁电陶瓷的应力腐蚀

研究了BaTiO3铁电陶瓷在恒载荷下的应力腐蚀,环境分别为湿空气、水、硅油和甲酰胺.结果表明,BaTiO3铁电陶瓷在湿空气、硅油、水和甲酰胺中都能发生应力腐蚀,其本质是介质分子吸附降低表面能.在空气中的瞬时断裂为穿晶断裂,滞后断裂大部分为穿晶断裂,局部为沿晶断裂.在这四种环境中,归一化应力腐蚀门槛应力强度因子分别为KIsCC/KIC=0.78(空气),0.63(水),0.66(硅油)和0.82(甲酰胺),其断裂韧性为KIC=1.29±0.14 MPa·m1/2.     

化学镀镍Si3N4陶瓷与金属钎焊接头的分析

利用扫描电镜,能谱仪及射线衍射仪对化学镀镍Ｓｉ３Ｎ－Ｑ２３５钢钎焊接头进行了微观分析,分析表明,接头为多层复合结构,陶瓷／镀镍层间发生了界面反应,但反应区在界面上不连续,机械结合仍为陶瓷与金属界面的主要结合方式。     

Numerical evaluation of inhomogeneity forces in a coating layer due to thermal loading

Abstract

In order to clarify the mechanical state at the interface between substrate and coating material, numerical analyses are implemented on model materials under thermal loads, and the possibilities of debonding are discussed from the configurational mechanics concept. The intensity of the interfacial singularity can be discussed in relation to the inhomogeneity force which is numerically evaluated in the course of thermal loading via finite element analysis. It is shown that interfacial roughness, a small perturbation at the interface, may have a dominant role in the evolution of inhomogeneity. Effects of initial defects, temperature gradient and additional external load are also evaluated. It is confirmed that the inhomogeneity force is a generalisation of the J-integral, i.e. the energy release rate in fracture mechanics, and this is also applicable to interfacial problems. A possible scenario of layer debonding is discussed in terms of the material inhomogeneity and the deformation characteristics of the thin coating layer under thermal loading.     

A Computational Approach to Estimating a Lubricating Layer in Concrete Pumping

When concrete is being pumped, a lubricating layer forms at the interface of the inner concrete and the wall of the pipe. The lubricating layer is one of the most dominant factors in determining the pumping capability, yet no study has endeavored to quantitatively estimate the thickness and rheological properties of the layer. Recently, there has been a growing demand for large-scale construction under extreme conditions, such as high-rise buildings and super-long span bridges. This demand has heightened the need for more accurate predictions of pumpability.
A possible mechanism that contributes to the formation of the lubricating layer is shear-induced particle migration. That is, particles of suspension in the shear flow move from a region with a higher shear rate to a region with a lower shear rate. This study uses computational fluid dynamics to analyze the pipe flow of concrete under conditions of shear-induced particle migration. The analysis shows how the particle distribution as well as the plastic viscosity and yield stress vary throughout a particular cross section. The analysis results are used to estimate the thickness and rheological properties of the layer.     

Analysis of failure criteria applied to wood

This article presents a study on failure criteria applied to wood, specifically the criteria of Hill, Tsai-Hill, Tsai-Wu, Hoffman and Norris. The theoretical basis of the research involves a development from the conventional failure theory with an application to orthotropic materials. Thus, an analysis of failure criteria was performed, in particular the failure envelope curve achievement from the mechanical properties of two Brazilian wood species, Pinus elliotti and Goupia glabra. A comparison between the obtained envelopes curves with experimental results, which were obtained from biaxial compressive tests, shear tests and off-axis uniaxial tests, was performed to evaluate the analyzed criteria. In general, the Hoffman criterion presented the best result for strength evaluation of these wood species.     

Al2O3/Cu/Al扩散连接工艺参数的优化

通过一定范围内的强度实验数据建立了Al2O3/Cu/Al扩散连接工艺规范参数优化的数学模型，得到了评价接头综合性能的回归方程。利用该方程求得最佳接头性能的工艺参数为：T＝777K、t=1226s。对该工艺规范扩散连接的Al2O3/Cu/Al接头进行强度试验，接头抗拉强度为108MPa、剪切强度为45MPa。强度试验结果表明，接头获得最佳综合强度值的工艺规范介于获得最大抗拉强度值时的规范与获得最大剪切值时的规范之间。在最佳综合规范下，接头的抗拉强度和剪切强度值与最大抗拉强度、最大剪切强度值接近，这表明数学模型所计算出来的最佳规范与实际值吻合较好。