分层采油工艺管柱的研究与应用

为有效降低钻采、开发成本,华庆油田研究应用分层采油技术,在实践中发现,部分井因为封隔器坐封载荷过大造成管柱弯曲,分采泵无法正常抽汲,针对这一问题,研究设计了新型分采工艺管柱,现场试验表明,该分采技术不但能有效控制坐封载荷,还能有效解决层间干扰,提高单井产量。     

异种金属摩擦焊工艺温度场数值模拟研究

基于摩擦焊接过程中热-力学现象,建立摩擦焊接过程中热力耦合模型,对陶瓷/金属焊接过程中温度分布进行数值模拟。所提出的模型能够预测金属陶瓷摩擦焊接过程中随时间增量的温度分布情况;焊接界面区域产生的摩擦热消耗中间层铝,并在氧化铝和低碳钢之间建立焊接层。由于氧化铝和低碳钢具有不同的温度属性,在界面处会产生更多的热应力。数值模拟用来预测氧化铝/低碳钢接口处残余应力的变化情况,进而避免异种金属摩擦焊接过程中不完全联锁、接头强度差的现象。     

Investigation on reactive diffusion bonding of SiCp/6063 MMC by using mixed powders as interlayers

Mixed Al–Si, Al–Cu and Al–Si–SiC powders were used as interlayers to reactive diffusion bond SiCp/6063 MMC. The microstructure and the effects of bonding parameters on the shear strength of SiCp/6063 MMC joints were investigated. The results show that SiCp/6063 MMC joints bonded by using the interlayers of mixed Al–Si, Al–Cu powders have a dense joining layer of high quality. The mass transfer between the bonded materials and the interlayers during bonding leads to the hypoeutectic microstructure of the joining layers. Using mixed Al–Si–SiC powder as an interlayer, SiCp/6063 MMC can be reactive diffusion bonded by a composite joint. Because of the SiC segregation, however, there are a number of porous zones in the joining layer. This is responsible for the low shear strength of the joints, even lower than those reactive diffusion bonded by using the interlayers of mixed Al–Si and Al–Cu powders. Ti added in the interlayer obviously improves the joint strength reactive diffusion bonded by using the mixed Al–Si–SiC powder.     

镁及其合金表面化学镀银工艺的研究

研究了镁合金表面化学镀银的工艺:利用涂膜及化学镀的方法对镁合金进行处理,即先在镁及其合金表面涂覆有机涂膜,然后再进行化学镀.工艺利用有机涂膜充当基体镁合金与镀层之间的中间层,使基体与镀层之间不直接接触,当化学镀进行时,镀层直接在中间层表面形成.虽然镁的化学活性高,但中间层的存在使化学镀银可以在镁及其合金表面实现.以AZ31镁合金轧板为基体,采用该工艺在其表面得到了理想的银镀层.通过SEM和XRD分析了银镀层的生长过程.十字切割法测量结果表明,涂膜与基体之间的结合力能满足使用要求.用极化曲线法研究了化学镀后试样在NaCl溶液中的腐蚀行为,结果表明:化学镀后试样的自腐蚀电位明显正移,腐蚀电流远远小于基体,具有良好的耐蚀性.     

Ta/NiFe/Cu/NiFe/FeMn/Ta自旋阀多层膜的X射线光电子能谱的研究

实验表明：Ta／NiFe／FeMn／Ta多层膜的交换耦合场(Hex)要大于Ta／NiFe／Cu／NiFe／FeMn／Ta自旋阀多层膜中的以Hex。为了寻找其原因，用X射线光电子能谱(XPS)研究了Ta(12nm)／NiFe(7nm)，Ta(12nm)／NiFe(7nm))／Cu(4nm)和Ta(12nm)／NiFe(7nm)／Cu(3nm)／NiFe(5nm)3种样品，研究结果表明，前两种样品表面无任何来自下层的元素偏聚；但在第3种样品最上层的NiFe表面上，探测到从下层偏聚上来的Cu原子。我们认为：Cu在NiFe／FeMn层间的存在是Ta／NiFe／Cu／NiFe／FeMn／Ta自旋阀多层膜的Hex低于Ta／NiFe／FeMn／Ta多层膜Hex的一个重要原因。     

AlTiN layer effect on mechanical properties of Ti-doped diamond-like carbon composite coatings

Ti/Ti-doped diamond-like carbon (DLC) and Ti/AlTiN/Ti-DLC composite coatings were deposited by magnetron sputtering on W18Cr4V high speed steel substrates. The effect of the AlTiN support layer on the properties of these composite coatings was investigated through microstructure and mechanical properties characterization, including hardness, elastic modulus, coefficient of friction and wear properties measured by scanning electron microscopy, Raman spectroscopy, scratch and ball-on-disk friction tests. Ti and AlTiN interlayers have a columnar structure with 50-80 nm grains. The hardness and elastic modulus of Ti/Ti-DLC and Ti/AlTiN/Ti-DLC coatings is 25.9 ± 0.4, 222.2 ± 6.3 GPa and 19.3 ± 1, 205.6 ± 6.7 GPa, respectively. Adhesion of Ti-DLC, Ti/AlTiN/Ti-DLC and AlTiN/Ti-DLC coatings expressed as the critical lateral force is 26.5 N, 38.2 N, and 47.8 N, respectively. Substrate coefficient of friction without coatings is 0.44, and it is 0.1 for Ti/Ti-DLC and Ti/AlTiN/Ti-DLC coatings. Wear resistance of Ti/AlTiN/Ti-DLC composite coatings is much higher than Ti/Ti-DLC coatings based on the wear track width of 169.8 and 73.2 μm, respectively, for the same experimental conditions.     

Interfacial effects on the magnetic profiles and interlayer exchange coupling of Co/CoSi multilayers

Density functional calculations are conducted to investigate the interlayer exchange coupling (IEC) between ferromagnetic Co slabs mediated by a CoSi spacer in Co/CoSi(001) multilayers with CsCl crystalline structure. For both sharp and mixed Co-Si interfaces we calculated the magnetic moment distribution and the energy stability for ferromagnetic (F) IEC and antiferromagnetic (AF) IEC between the Co slabs as function of the spacer thickness. We show that mixing near to the interface noticeably modifies the IEC to the extent that this can change from an oscillatory IEC as function of the spacer thickness to an exponentially decaying AF behavior.     

Magnetron sputtered NbN films with electroplated Cr interlayer

NbN films were deposited on SS substrates by reactive DC magnetron sputtering at various N₂ flow rates and substrate biasing. Coatings were studied for their thickness, structure, hardness and adhesion aspects. Process parameters were optimized for deposition of NbN coatings. NbN coatings were then extended on to MS substrates with Cr interlayer in three different thicknesses of 2, 4 and 10 μm. Cr was deposited by electroplating. The duplex coatings have been studied for the improvement with respect to surface hardness by Knoop micro indentation, adhesion by scratch testing and corrosion performance by potentiodynamic polarization technique. Open circuit potentials were also measured.     

Microstructure and mechanical properties of diffusion bonded titanium/304 stainless steel joint with pure Ag interlayer

Abstract

In the present study, diffusion bonding of commercially pure titanium to 304 stainless steel (SS) using a pure Ag interlayer was carried out. It is found that the pure Ag interlayer can effectively block the interdiffusion and interaction between Ti and SS. The resultant joints were composed of Ti substrate, Ti–Ag solid solution, TiAg intermetallic phase, the remnant Ag interlayer and SS. Upon tensile loading, fracture took place through the remnant Ag interlayer, indicating that the TiAg intermetallic phase exhibits no detrimental effect on the strength of the joints. A maximum tensile strength of 421 MPa was achieved, which is notably improved compared with previous results. Furthermore, extensive dimples were observed on the fracture surfaces, clearly indicating that the joints were ductile in nature.     

高频板制作关键技术探讨

高频板涉及的技术相对较高,相关制作、检测设备和技术人员都是企业在跨越的一道难题,所以应充分考虑市场和技术、设备能力等方面的因素尤为重要。通讯基站应用的高频板市场方面,在中国及另一些发展中国家市场需求相对旺盛,值得关注。文章重点介绍高频板内层-压合层间控制和钻孔-电镀孔粗控制两个方式制作关键点,以供参考和建议。