铝合金碱性电化学抛光新工艺

为了克服碱性Brytal法抛光铝材的缺点,在NaOH溶液中加入EDTA作光亮剂抛光铝材,可获镜面光亮效果.其中直流抛光的工艺条件为:光亮剂25～40g/L、操作电压7 V、电流密度20 A/dm2、溶液温度45～50℃,抛光20 min后铝材表面反射率为90%,阳极溶解损耗0.018 2g/cm2;采用周期换向抛光时溶液温度可降低至40℃,阳极溶解损耗仅0.010 1g/cm2.两抛光新工艺在生产成本、操作环境和抛光效果等方面均优于传统碱性电化学抛光.     

电化学抛光NiTi合金表面性能的研究

提出了一种改进的电化学抛光液（冰醋酸．高氨酸-A-B），并采用此抛光工艺对NiTi合金伍．50．8％（原子分数）Ni）进行电化学抛光．与机械抛光作对比，研究了两种抛光技术对合金表面光洁度的影响，并利用电化学方法研究了抛光技术对合金在Hanks’溶液中腐蚀性能的影响．研究结果表明，此工艺下的电化学抛光有效降低了NiTi合金的表面粗糙度，光亮度近似镜面状态．与机械抛光相比，电化学抛光更好地提高了NiTi合金在Hanks’溶液中的耐腐蚀性能。     

国内铝制品无铬酸电化学抛光工艺开发现状

传统的铝制品酸性电化学抛光溶液含有严重污染环境的铬酸，综述了80年代以来，我国开发无铬酸电化学抛光工艺的现状和研究成果。     

NiTi合金电化学抛光工艺

为了探索较为理想的NiTi合金电化学抛光工艺,采用一种改进的冰醋酸-高氯酸基抛光液,对其进行了电化学抛光.采用SEM和表面轮廓仪考察了抛光液成分以及各工艺参数对NiTi合金微观形貌和表面粗糙度的影响.试验结果表明,抛光液成分在电化学抛光中起着关键的作用,并且当电流密度为1.0A/cm2、抛光液温度为0 ℃、抛光时间为45 s、阴阳极间距为1.5 cm时,电化学抛光效果比较理想,表面粗糙度降为70 nm左右.与未抛光试样相比,电化学抛光后NiTi合金表面光滑均匀,基本无缺陷.     

氟离子对硅化学机械抛光作用机理研究

研究了氟(F)离子对硅化学机械抛光速率的促进作用。抛光结果显示,加入2.5%(质量比)的氟化钾(KF)到硅溶胶基碱性抛光液中能够使抛光速率提高57.7%。为了揭示其作用机理,通过测试硅在KF碱性溶液中的开路电位和极化曲线分析了电化学反应过程,其结果表明F离子不仅能够溶解硅钝化层还能增加极化电流,当KF浓度为2.5%(质量比),硅的腐蚀电流密度可达44.5μA/cm2。光电子能谱和接触角的进一步测试表明,F离子的加入减少了硅在碱性水溶液中的氧化物生成,并使得抛光后表面接触角达到93.2°,形成强疏水的表面。结合Pietsch提出的无F条件下硅在碱溶液中原子去除模型,分析了在有F条件下硅的抛光机理。这种机理可以给开发硅衬底高速抛光液提供解决思路。     

不同电化学抛光工艺条件下Q235A表面镍镀层的性能

钢件镀镍前的电化学抛光工艺对镀层性能有较大影响。以低碳钢Q235A为基材,研究电化学抛光工艺参数对镍镀层性能的影响规律,探讨了在低碳钢表面制备性能优良的镀镍层的较优工艺。首先选择4组、每组2件样品,研究电化学抛光中有、无磁性搅拌对镍镀层的影响。在此工作基础上,采用正交试验,选择16件样品研究磁性搅拌下抛光工艺参数对镀层的影响。用数显外径千分尺测试镀层厚度、表面轮廓测量仪2302A测量表面粗糙度值Ra、纳米压痕仪Nano Indenter XP测试镍镀层的弹性模量及硬度。结果显示:电化学抛光时加磁性搅拌可以使镀层表面光滑、镀层增厚;电化学抛光电流密度对镀层表面粗糙度影响较小,但对镀层厚度、弹性模量及硬度的影响很大;而电化学抛光温度、抛光时间对镀层表面粗糙度、镀层厚度的影响与抛光电流密度有关。在其他条件相同的情况下,选择抛光时间15 min、电流密度30 A/dm2,抛光温度为65℃时得到的镍镀层弹性模量、硬度可以达到最大值。     

3J1弹性合金的化学抛光工艺

研究了一种用于３Ｊ１弹性合金的化学抛光溶液。介绍了抛光工艺及影响抛光效果的因素。抛光的合金表面几乎可达到镜面光亮度。新溶液用于生产，效果较好。     

铝合金表面碱性化学抛光液组分的最佳浓度

铝合金碱性化学抛光效果较酸性抛光的差,为此,研究了低温下铝合金碱性化学抛光基础液及添加剂的最佳浓度。结果表明:以250g/L氢氧化钠、150g/L硝酸钠、15g/L硅酸钠、13g/L氟化钾为基础组分,分别加入30g/L硫脲、2g/L十二烷基硫酸钠、1.0g/L硫酸铜都可以使抛光效果得到提升,但加入30g/L硫脲效果更好,可以使铝合金抛光后的光泽度达到274 Gs,单位面积消耗量达0.01643kg/m~2。该工艺具有无污染、抛光光泽度高、操作简便等特点。     

医用钛合金超声-电化学抛光工艺

研究了一种对常用的医用钛合金(Ti-6Al-4V)试件进行表面光整加工的新工艺.在试验的基础上,将功率超声波与电化学作用相结合,利用功率超声波的能量特性并结合电化学抛光的特点,实现对常用钛合金试件的超声-电化学抛光处理.分析了功率超声波对电化学抛光过程的促进作用及电流密度对抛光效果的影响,获得了较为合理的工艺参数.结果表明,采用合理的超声-电化学抛光工艺参数,经2 min左右时间,试件表面粗糙度由 3.2 μm降至0.2 μm,这不仅可以改善试件的表面粗糙度,而且还可以增加表面氧化膜中钛的氧化物含量,进一步提高钛合金植入物的生物相容性和耐腐蚀性.     

铝的碱性电解抛光

对碱性环境下铝的电解抛光机理进行了分析，通过实验获得了寿命扫描光效果好的电解液，结果表明，采用碱性电解抛光法特别是碱性脉冲电解抛光法有很大的优点，成本低，操作温度低，抛光液寿命长，污染小，获得的表面反射率高，有较好的应用前景。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.