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101.
铜及其合金抗氧化工艺研究现状与前景 总被引:2,自引:0,他引:2
综述了铜及其合金在广泛应用中亟待解决的的问题-变色过程及机理;分别论述目前防变色工艺中的各种方法及评价抑制变色效果的方法,并对其防变色工艺的发展趋势进行展望. 相似文献
102.
通过添加不同量的钛铁到药芯焊丝中,并在不同保护气焊接的条件下,研究其对熔敷金属扩散氢的逸出和含量的影响.结果表明,保护气体氧化性的增加可以降低熔敷金属扩散氢,而保护气还原性的增加,则熔敷金属扩散氢含量也会相应增加;在药芯焊丝中加入一定量的钛铁,一方面TiO,Ti(C,N)颗粒会在熔敷金属中形成的不可逆氢陷阱,对氢产生捕获作用,可以降低熔敷金属扩散氢;同时,加入的钛铁会提高电弧气氛的还原性,这样会增加熔敷金属的扩散氢,所以适量的添加钛铁,使钛铁对焊接气氛的氧化性的影响和形成不可逆氢陷阱的作用之间合理的结合,能达到理想的降氢效果.Abstract: The effects of Ti content on diffusible hydrogen escape characteristic of deposited metal of flux cored wire were investigated by adding different quantities of Ti-Fe and in different protecting gas conditions. The results show that the oxidative susceptibility of protecting gas can decrease the diffusible hydrogen of deposited metal, and the grains of Ti and Ti(C,N) which exhibit irreversible hydrogen traps can also decrease the diffusible hydrogen of deposited metal. The rational adding Ti-Fe, which harmonized the oxidative susceptibility of welding atmosphere and formed the irreversible hydrogen traps, could obviously decrease the diffusible hydrogen of deposited metal. 相似文献
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104.
浅析壬基酚的产品质量中色泽的控制 总被引:1,自引:0,他引:1
通过对壬基酚的生产过程、生产工艺以及其变色因素的分析,为壬基酚的国产化和工艺改造提供了大量实践数据。 相似文献
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Ultraviolet (UV) weathering performance of unpigmented and rutile titanium dioxide pigmented rigid polyvinyl chloride (PVC)/wood‐fiber composites has been studied. The composite samples were manufactured by dry‐blending PVC, wood fibers, and other processing additives in a high‐intensity mixer. The dry‐blended compounds were extruded and compression molded into panel samples. The manufactured samples were artificially weathered using laboratory accelerated UV tests. Composite samples were exposed to 340‐nm fluorescent UV lamps and assessed every 200 h, for a total of 1200 h of accelerated weathering. Each assessment consisted of a visual examination of surface roughness or erosion, a contact angle measurement, a FTIR collection, and a color measurement. The experimental results indicated that wood fibers are effective sensitizers and that their incorporation into a rigid PVC matrix has a deleterious effect on the ability of the matrix to resist degradation caused ultraviolet irradiation. The light stability of these composites could be improved quite efficiently with the addition of rutile titanium dioxide photoactive pigment during formulation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1943–1950, 2001 相似文献
108.
Tone P. D'Amico Connor Barrett Joseph Presing Roshni Patnayakuni Masoumeh Pourali Amy M. Peterson 《应用聚合物科学杂志》2019,136(47):48239
Shape transformation upon annealing of fused filament fabrication additively manufacturing structures is investigated as a one-way shape memory strategy using commodity thermoplastics. Irreversible thermal strain, which is a measurement of shape transformation upon annealing, is shown to depend on both raster angle and layer thickness, both of which are parameters than can be easily adjusted on most FFF printers. We present an algorithm based on our understanding of the underlying micromechanics of the system that allows for input of desired final dimensions and output the necessary print parameters. We also demonstrate that this approach is extensible to other materials and report more complex shape memory geometries. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48239. 相似文献
109.
Chong Wang Yongjie Liu Alexander Nikitin Qingyuan Wang Min Zhou 《Fatigue & Fracture of Engineering Materials & Structures》2019,42(9):2183-2194
When high‐strength steels are subjected to very high‐cycle fatigue loading, crack initiation site shifts from surfaces to the interior, and a fish‐eye forms on the fracture surface. Majority of the fatigue life is estimated to be associated with the formation of this internal crack morphology. In the present work, features of such internal cracks in two high‐strength steels are studied. Specifically, three initiation patterns are investigated. A general internal crack initiating scenario is proposed base on an understanding of dislocation slip in the materials. A simplified threshold is calculated from Young's modulus and interatomic spacing, defining the transition from the initiation stage to the crack propagation. The relationship between internal crack initiation and slower descending S‐N curves is discussed. 相似文献
110.