Study on the blackening phenomenon of leaded glass during microgroove molding using nickel phosphorous mold

Precision glass molding (PGM) is a recently developed method to fabricate glass microgroove components. Lead glass is commonly used as an optical material due to its high refractive index and low transition temperature. A nickel-phosphorous (Ni–P) plated mold is traditionally employed in the PGM process for microstructures optics. However, leaded glass is subject to color change and can blacken during the PGM process, reducing the light transmittance of microgrooves. In this paper, an equation for the redox reaction between Ni and Pb is proposed, which is based on the diffusion of inner Ni atoms to the surface of the mold and the standard electrode potential of the Pb ions in leaded glass. A viscoelastic constitutive model of the glass is established to simulate the compression stress distribution during molding. Finally, the effects of molding pressure, molding temperature, and mold material on glass blackening are studied. The results show that the blackening of leaded glass is caused by Pb enriching the surface. The rise in molding stress and temperature increases the deformation of Ni–P plating, which promotes the diffusion of Ni atoms. By adding a titanium incorporated diamond-like carbon (Ti-DLC) coating, the deformation of the Ni–P plating during molding is suppressed, and the diffusion of Ni atoms can be prevented. In this way, the blackening of leaded glass can be prevented.     

紧固件的黑化处理

通过集传统的氧化，磷化工艺与一体化的试验研究，确定一种黑化处理的新型工艺，以期应用于紧固件的黑化处理中。     

化学镀后的发黑工艺

开发了一种高质量发黑工艺,它是在低温化学镀镍的基础上进行氧化处理的方法.该方法获得的发黑膜层质量得到了极大的提高.膜层结合力优异,耐磨,色泽纯正.可满足工业生产的高质量发黑的需要.     

应用统计学实验方法优化铜常温发黑剂配方

运用统计学试验设计方法研究了不同的因素对铜常温发黑剂体系的性能影响.通过试验结果的统计分析,揭示了这些因素对体系的多种显著影响.更为重要的是本研究发现了多种因素间的双因素交互作用.而且这些交互作用的影响很难被传统的单因素试验发现.本研究结果可用于设计高性能的铜常温发黑剂.     

引发电控模块短路之PCB孔口发黑原因研究

PCB在使用过程中在经常会出现短路故障,对相关故障电子模块进行分析时发现模块PCB较多孔口存在发黑物质,严重者出现黑色物质连孔,通过测试确认黑色物质具有导电功能。本文通过理论分析及模拟实验论证,确认了黑色物质是引发电子模块故障的根源,同时明确了其产生机理,并提出了针对性的预防措施。     

Failure analysis on reflector blackening between lead frame electrodes in LEDs under WHTOL test

Blackening induced lumen decay in a QFN LED after WHTOL reliability test was reported and analyzed in this paper. A new LED blackening failure mechanism was proposed based on solid experimental results. We concluded that the failure process underwent delamination between lead frame and reflector polymer composites followed by chemical penetration, composite corrosion, silver migration, and finally caused blackening failure. Delamination and corrosive de-flash agent were the key factors for the failure mode. Besides, we also estimated the influence of the failure to the optical performance through simulation. Apart from other reported factors, this study highlighted that both composite corrosion and Ag migration could generate serious illumination decrease as well. The outcome of this study is valuable for LED manufacture and quality control in the future.     

改善Se—Cu系钢铁常温发黑剂的使用效果

论述Se-Cu钢铁常温发黑剂在推广使用中遇到的一些问题，作了理论探讨，提出相应对策，并研制了HD钢铁常温发黑剂和新型防锈钝化水。     

Millennium-long damage to building materials in London

Damage functions from a range of sources are used to estimate deterioration of carbonate stone, iron and copper, in addition to the rate of blackening of stone surfaces in London across the period 1100-2100 CE. Meteorological and pollution input is available for only a relatively short part of this span, so non-instrumental weather records and modelled pollution are utilised for historic values, while future climate is adapted from the HadCM3A2 model output and pollution assessed from likely regulatory trends. The results from the different damage functions compare reasonably well showing comparable changes in damage rates with time. A potential square-root dependence of change in deposition velocity of SO₂ to limestone suggests a possible overestimate of damage when pollution is high. Deterioration is especially intense from the 1700s. It is difficult to be certain whether the corrosion of copper accelerated as early as this or it developed in the 20th century. Nevertheless all the functions predict a decline in copper corrosion from the end of the 20th century. A blackening function was developed to relate elemental carbon concentration and the colour of deposited particulate matter to blackening rate, which suggests that soiling was particularly rapid in the late 19th century. The increase and subsequent decrease in damage to building materials is interpreted in terms of a Kuznets curve. The centuries where pollution controlled damage to durable building material seems to be over. Weathering, in a changing climate may have the greatest impact in the future.     

常温KY型发黑液的研制与性能研究

为了在黄铜基材上常温获得黑色膜层,研究了黄铜酸性氧化发黑工艺,着重对硒-铜-磷系发黑液进行研究.主要讨论了黄铜氧化发黑的前处理、溶液组分和着色时间等因素对着色膜层质量的影响.研究结果表明:溶液组分是影响着色膜颜色的主要因素,使用时要注意控制其含量;适量的添加剂可以提高着色膜质量.最终研制出一种常温KY型发黑液,与传统配方相比,该发黑剂具有发黑时间短、发黑膜耐磨且黑色纯正、光亮性好、生产成本低等优点,具有广阔的推广和应用前景.     

Characterization of black rust staining of unpassivated 55% Al–Zn alloy coatings. Effect of temperature, pH and wet storage

Wet storage staining is a phenomenon that occurs on both zinc coated and 55% Al–Zn coated steel sheets during shipment or storage in damp conditions. Whereas zinc coated sheets form white corrosion products, 55% Al–Zn coated steel sheets form black corrosion products. The effect of temperature, pH and wet storage on the occurrence of black rust staining of unpassivated Aluzink samples has been investigated in the laboratory in terms of corrosion product formation and composition. A characterization of corrosion products formed has been performed mainly based on scanning electron microscopy with X-ray microanalyses (SEM/EDS) for morphological and quantitative analyses and X-ray diffraction techniques (XRD) for crystalline phase identification. Black rust formation is strongly related to alkaline pH regions and is enhanced by the temperature. All black panels show the presence of Bayerite (Al(OH)₃), mainly formed on the aluminum rich dendrite branches and a basic zinc aluminum carbonate (Zn₆Al₂(OH)₁₆CO₃·4H₂O) formed in the zinc rich interdendritic alloy regions in contact with air. Blackening of Aluzink surfaces is connected to differences in optical properties of embedded metallic zinc and/or aluminum particles of different shape and size in the corrosion layer.