热处理对非晶Ni-P电镀层结构与性能的影响

为进一步了解Ni-P合金电镀层的结构与性能的关系,利用X射线衍射(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)和显微硬度仪等,研究了P含量12.3%(质量分数)的Ni-P合金电镀层热处理前后结构的变化对性能的影响.结果表明:镀态镍磷镀层呈非晶态结构,270℃恒温10 min镀层开始晶化,析出亚稳相Ni12P5和Ni5P2,360℃亚稳相向Ni3P和Ni稳定相转变,且晶粒长大,420℃时只有Ni3P和Ni相;热处理后镀层的硬度大于非晶态镀层,300℃部分晶化析出的纳米晶弥散分布于非晶相中,镀层的硬度达到极大值,Ni3P硬质相的析出大大提高了镀层的耐磨性能.     

Ni-P-纳米金刚石化学复合镀新技术研究

在Ni-P-化学复合镀工艺的基础上,探索加入纳米金刚石粒子作为硬质点的Ni-P-纳米金刚石共沉积复合镀新工艺技术.进行Ni-P-纳米金刚石非晶态复合镀层的晶化转变过程、及其硬度和耐磨性等的研究,并与Ni-P化学镀层、Ni-P-微米金刚石复合镀层的性能进行比较.结果表明,Ni-P-纳米金刚石共沉积复合镀中,最佳的金刚石添加量为12g/l.复合镀层为非晶态,300℃时镀层开始晶化.随时效温度升高,镀层的显微硬度逐渐升高,到400℃达到峰值,而后因弥散相聚集长大粗化导致硬度下降,复合镀层的耐磨性也随着硬度的变化而变化.     

电刷镀纳米Ni-P-SiC复合镀层性能的研究

纳米微粒加入镀液可提高镀层的性能,用电刷镀方法制备了纳米SiC/ Ni-P复合镀层,测试了纳米SiC微粒添加量对复合镀层的硬度、耐磨性的影响,探讨了纳米SiC微粒复合镀层的强化机制及Ni-P晶化过程中的强化作用.结果表明,采用电刷镀制备工艺,能在一定程度上改善纳米微粒在镀液中的分散均匀性并能提高复合镀层性能.在Ni-P合金镀液中适量添加纳米SiC微粒(7～10 g/L),纳米SiC微粒在形成复合镀层时能起到硬质点的强化作用,同时在Ni-P晶化过程中还能在细化晶粒中起到再强化作用.不仅能使镀层硬度提高1.5～1.8倍,还能提高其耐磨性.     

热处理对Ni-P镀层结构及硬度的影响

采用化学镀的方法,在低碳钢基体上制备了纳米相含量不同的镀层.镀层在氩气保护下,分别经200,400℃保温1h进行热处理.采用电子探针(EPMA)、XRD射线衍射以及维氏硬度计研究了镀层热处理前后结构及硬度的变化.结果表明,随着纳米相含量的增多,镀层由非晶逐渐变为纳米晶,而硬度相应变大.200℃保温1h热处理,非晶与混晶镀层由于少量析出物Ni3P的出现使得硬度增大,而纳米晶镀层由于发生了弛豫使得镀层硬度降低.400℃保温1h热处理时,试样均发生了晶化,析出弥撒的Ni3P金属间化合物以及Ni相,纳米晶镀层的Ni相峰值强度增大最多,而非晶镀层所对应的Ni相峰值强度增大较少.然而,经400℃保温1h热处理后,非晶镀层硬度增大最多,这归因于非晶镀层析出的Ni3P金属间化合物数量多于混晶以及纳米晶镀层.     

热处理对Ni-P合金镀层组织结构、显微硬度与耐蚀性能的影响

目前,有关热处理对Ni-P合金镀层组织结构与性能的影响研究不够深入。采用脉冲电沉积方法在Q235钢表面制备Ni-P合金镀层,并在200～500℃下进行热处理。利用X射线衍射仪分析镀层的相结构,用电化学极化曲线和扫描电子显微镜(SEM)对镀层在3.5%NaCl,10%HCl和10%H2SO4溶液中的腐蚀行为进行了研究。结果表明,提高热处理温度,Ni3P相的析出速度增大,Ni-P合金镀层的晶化时间减少,达到最高硬度所需的热处理时间相应缩短,镀层经300℃和400℃热处理后的最高硬度分别达到862.8 HV2N和887.4HV2 N;Ni-P合金镀层热处理晶化后,其耐蚀性能显著降低,在3种腐蚀介质中均发生点蚀。     

热处理非晶态Ni-P合金镀层的晶化过程

运用电沉积的方法在45钢基体上制备Ni-P合金镀层,使用差示扫描量热法(DSC)和热重法(TG)分析非晶态NiP合金镀层在20℃/min加热速率下的热效应和质量变化。在300℃和400℃分别对镀层进行0,15,30,45,60,75min的热处理,采用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、显微硬度计对镀层进行表征。结果表明:Ni-P合金镀层在加热过程中的放热峰出现在284.8℃处,镀层的质量和元素组成稳定;晶化过程经历了非晶态、亚稳态NiP和Ni5P2、稳定态Ni3P的转变;经过热处理后,镀层的显微硬度显著提高,最大值达1036.56HV,约为镀态的2倍;热处理态镀层的耐NaCl溶液腐蚀性能比镀态有所下降,但两者都比45钢基体好。     

非晶态Ni-P电刷镀层晶化过程和动力学的研究

X 射线衍射分析和差热分析结果表明,Ni-P 电刷镀层自约300℃开始晶化,于约400℃晶化结束,最后转变为 Ni 与弥散分布的 Ni_3P 相的混合物组织。采用等温热分析法,利用 Johnsoa-Mehl-Avrami 方程,作出了 Ni-9.3%P 电刷镀层的晶化动力学曲线和 TTT 图;得到的晶化激活能为192kJ/mol,Johnson-Mehl-Avrami 方程转变方式指数 n为2.7。外推的瞬时晶化温度约为440—450℃。经不同温度热处理后,Ni-P 镀层的峰值硬度出现在400℃左右,对应于晶化后硬化相的最佳弥散分布状态。所以,热模具寿命的提高,是非晶态Ni-P 镀层在工作条件下发生晶化和沉淀硬化,使模具表面红硬性提高的结果。     

脉冲电沉积Ni-P/纳米Al2O3复合镀层的性能

Ni-P/纳米Al2O3复合镀层具有良好的耐磨、耐腐蚀性能,但有关脉冲电沉积Ni-P/纳米Al2O3复合镀层的报道较少.采用脉冲电沉积方法制备了Ni-P/纳米Al2O3复合镀层,研究了复合镀层的表面形貌、结构及其在5%NaCl溶液中的耐腐蚀性能,并对300,400,500℃热处理后的复合镀层的显微硬度进行了测试.结果表明:Ni-P/纳米Al2O3复合镀层的耐蚀性优于1Cr18Ni9Ti不锈钢,但比Ni-P合金镀层差;随镀液中纳米Al2O3浓度增大,复合镀层的显微硬度提高,镀液中纳米Al2O3浓度为25.0 g/L时制得的复合镀层的硬度为685.5 HV;Ni-P/纳米Al2O3复合镀层经400℃热处理后硬度最高.     

包装材料用陶瓷表面化学沉积Ni-P镀层研究

为提高包装材料的表面质量,满足工业生产、航空、航天、日常生活等需求。采用化学沉积方法在包装材料用陶瓷表面沉积Ni-P镀层,利用扫描电镜、X射线衍射仪、DSC差热分析仪和摩擦磨损试验机研究Ni-P镀层的表面形貌、物相结构、晶化温度及耐磨性能。结果表明,当镀液中硫酸镍含量30g/L、热处理温度500℃时,Ni-P镀层的磨损质量达到最小22.2mg。当热处理温度达到500℃时,Ni-P镀层磨损机制主要表现为磨粒磨损和黏着磨损。DSC分析可知,Ni-P镀层主放热峰对应的晶化温度为339℃。当热处理温度达到500℃时,Ni-P镀层最终稳定相为Ni+Ni_3P+NiO。     

低温退火对电沉积纳米晶Ni镀层耐蚀性的影响

通过脉冲电沉积方法制备纳米晶Ni镀层。采用浸泡法和电化学方法研究了不同温度低温退火纳米晶Ni镀层在3.5wt.%NaCl和5wt.%HCl溶液中的腐蚀行为。结果表明:150℃以下退火,晶粒未出现明显长大。在3.5wt.%NaCl溶液中,镀层耐蚀性随退火温度的升高而提高;200℃退火后镀层的耐蚀性最好,镀层表面均有钝化现象。在5wt.%HCl溶液中,退火后镀层的耐蚀性有所提高,但退火温度的影响不大,镀层腐蚀过程中未观察到钝化现象。     

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.     

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.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to