Formation of a Corrosion-Resistant Layer on Steel by Reaction with a Si3N 4 ― Al2O3 Composite under the Conditions of Light-Thermal Treatment

The formation of a surface layer on low-alloyed steel during light-thermal treatment with a composite material based on Si₃N₄ Al₂O₃ was investigated. The working surfaces were studied using metallographic, x-ray diffraction, and electron-probe microanalysis. It was found that the corrosion-resistant phases Al₂SiO₅, (Fe, Cr)₂O₃, (Cr, Al) ₂O₃, and NiCrO₄ formed in the alloyed layer, increasing its microhardness by 2-5 times and its corrosion resistance in sea water by more than two orders of magnitude.     

Effect of Cryogenic Temperature Deposition of Various Metal Contacts on Bulk Single-Crystal <Emphasis Type="Italic">n</Emphasis>-Type ZnO

The effect of cryogenic temperatures during metal deposition on the contact properties of Pd, Pt, Ti, and Ni on bulk single-crystal n-type ZnO has been investigated. Deposition at both room and low temperature produced contacts with Ohmic characteristics for Ti and Ni metallizations. By sharp contrast, both Pd and Pt contacts showed rectifying characteristics after deposition with barrier heights between 0.37 eV and 0.69 eV. Changes in contact behavior were measured on Pd to anneal temperatures of ∼300 °C, showing an increase in barrier height along with a decrease in ideality factor with increasing annealing temperature. This difference with annealing temperature is in sharp contrast to previous results for Au contacts to ZnO. There were no differences in near-surface stoichiometry for the different deposition temperatures; however, low temperature contacts demonstrated some peeling/cracking for Pt and Pd.     

限流BaTiO3陶瓷PTCR元件化学沉积欧姆电极的研究

本文对程控交换机用过流保护ＢａＴｉＯ３陶瓷ＰＴＣＲ元件不同化学沉积镍和铜电极的耐工频电流冲击性能和稳定性进行了比较研究，对所得结果进行了充分的讨论。     

Dislocation multiplication inside contact holes

Ion implantation into contact holes has been widely used to dope the specific contact area and to reduce the contact resistance. In this study, mask edge defects were observed at the edge area of small contact holes with high aspect ratio, which resulted in multiplied dislocations penetrating into Si substrate for more than 0.3 μm after back-end processings. Those dislocations were identified to be Schockley partial dislocations and stair rod dislocations lying on 4 sets of inclined {111}Si planes.     

Nb微合金化H型钢控制轧制技术研究

用热模拟试验方法确定了Nb微合金化H型钢生产工艺参数，介绍了马钢Nb微合金化H型钢生产工艺和Nb微合金化H型钢达到的实物质量水平，同时对马钢生产的H型钢和国外同类产品的性能做了对比，马钢Nb微合金化H型钢具有良好的强韧性。     

Lubrication properties of non-adsorbing polymer solutions in soft elastohydrodynamic (EHD) contacts

The in-use performance and processing of many consumer products in the food, home and personal care industries are dependent on their tribological properties. A major component of these products is often a high molecular weight polymer, which is typically used to thicken aqueous systems. Polymer solutions tend to be non-Newtonian, and in particular their viscosity varies with shear rate, such that it is difficult to predict their friction or hydrodynamic film-forming behaviour. The present work relates the tribology of aqueous polymer solutions to their rheological properties in thin films in ‘soft’ contacts at high shear rates. The friction properties of three types of polymers in aqueous solution, polyethylene oxide, PEO; xanthan gum, XG; and guar gum, GG, have been studied as a function of polymer concentration over a wide range of entrainment speeds in a point contact formed between silicone rubber and steel. This has enabled the boundary lubrication and isoviscous-elastic lubrication properties of the solutions to be investigated using both hydrophilic and hydrophobic silicone surfaces.It is found that the friction vs. entrainment speed dependence follows the shape of a classical Stribeck curve. In general, a lower friction is observed with increasing polymer concentration in the mixed-regime. Using scaling factors for the entrainment speed, we have shown that this decrease in friction is likely to be due to viscous effects and that the scaling factors represent effective high shear rate viscosities. In the case of PEO and XG, and GG at low concentrations, a good correlation is found between this effective viscosity and the apparent viscosity measured at the highest shear rates attainable with the available rheometer. However, for GG at concentrations above 0.2%, the effective viscosity decreases with increasing polymer content.The three polymers do not significantly reduce friction in the boundary regime and in general give essentially the same response as water when an effective viscosity is taken into account. However, a slight increase in friction in comparison to pure water has been observed for XG and GG on hydrophobic surfaces. It is suspected that this may be due to a blocking of fluid entrainment, or possibly exclusion of polymer from the contact, due to the large hydrodynamic volume and rigid nature of the two biopolymers. Finally, for PEO solutions with full-film elastohydrodynamic conditions were reached, the measured friction coefficient of the film correlated quite well with the value calculated from the effective viscosity.     

The effect of composition on the barrier height and contact resistance of Tixw1-x/si contacts

Barrier height is an important parameter for metal/silicon rectifying contacts. In this paper the barrier heights of Ti_xW{1-x}/Si contacts have been studied and found to range from 0.54 eV for high Ti content to 0.66 eV for pureW. Interpretation is made in terms of the parallel Schottky diode model of Tu. Ohmic contact measurements of Ti_xW_1-x/ Si metallization after heat treatment at 500° C have also been made and specific contact resistances of less than 10⁻⁶ ohm-cm² obtained in shallow implanted junction devices.     

Capacitance theory of open quantum systems with classical contacts

We consider semiconductor devices composed of a small quantum structure as the active device region and two classical environments constituting the source- and the drain contact. The contacts are taken as free electron gases with infinite conductivity defining the chemical potentials in the contacts. The transport through the quantum structure is described in the Landauer–Büttiker formalism using electronic scattering wave functions which determine the electron density in the quantum system. In our Hartree approximation these charges and the induced charges in the contacts are the sources of the self-consistent Coulomb field. As a particular quantum structure we study a GaAs heterostructure device consisting of a two-dimensional electron gas sandwiched between a gate contact and an AlGaAs blocking barrier [see V.T. Dolgopolov et al., Phys. Low-Dim. Struct. 6 (1996) 1]. We demonstrate the quantitative agreement of our theory with the experimental results.     

A model for micro-slip between flat surfaces based on deformation of ellipsoidal elastic asperities—parametric study and experimental investigation

Micro-slip is a phenomenon that occurs between contacting surfaces when a frictional load, less than that necessary to produce macro-slip, is applied to the contacting surfaces. A model is evaluated for micro-slip between a flat smooth surface and a flat rough surface. The rough surface is covered with uniformly distributed ellipsoidal elastic asperities. The results from simulations of the model show that anisotropy, material combination and number of contacts of the contacting surfaces influence the tangential stiffness at zero displacement, the length of the micro-slip zone and the energy dissipated in the contact. An experimental investigation verifies the results computed by the model.     

Placement of Substrate Contacts to Minimize Substrate Noise in Mixed-Signal Integrated Circuits

The placement of substrate contacts in epi and non-epi technologies is analyzed in order to control and reduce the substrate noise amplitude and spreading. The choice of small or large substrate contacts or rings for each of the two major technologies is highlighted. Design guidelines for placing substrate contacts so as to improve the noise immunity of digital circuits in mixed-signal smart-power systems are also presented.