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邓思娟 《合成材料老化与应用》2022,(3):181-182
<正>一种检测汽车外饰件塑料制品虎皮纹缺陷的加速老化方法本发明公开了一种检测汽车外饰件塑料制品虎皮纹缺陷的加速老化方法,包括以下步骤:(1)选取汽车外饰材料,制备试验样品;(2)建立太阳跟踪聚光加速老化法试验条件,(3)根据材料光效应,计算有效总紫外辐照量;(4)将试验样品采用太阳跟踪聚光加速老化法进行老化试验,当试验样品出现明暗相间的虎皮纹现象,则样品存在虎皮纹缺陷,若无明暗相间的虎皮纹现象,则样品不存在虎皮纹缺陷;(5)相关性验证,设置自然老化对照组,验证太阳跟踪聚光加速老化法的准确性。该方法具有试验成本低、操作简便、能源消耗少、结果准确性高等优点,具有很高的应用价值。(CN112051206B中国电器科学研究院股份有限公司) 相似文献
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3.2涂膜酸蚀失重与野外实际曝露试验的相关性将上述5种汽车清面漆按天然曝晒要求制成样板,分别在美国Boston、Atlanta和Jacksonville3个曝露点进行野外实际曝露试验16周,在16周内对曝露板不检验、不冲洗,曝露16周结束后,冲洗试验样板,按10级目测:0级无变化,10级最差。具体是0~3级腐蚀不易察觉;4~6级可明显觉察出腐蚀现象,但可通过抛光修复;7~10级腐蚀锈点明显看出,只有通过重涂才可修复。3个曝露点的pH之差不大于0.5。所得试验结果如表1所列。Boston点的腐蚀最严重,Jack-sonville点腐蚀最轻… 相似文献
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研究了高密度聚乙烯在海南自然曝露和氙灯人工老化后的结构和力学性能变化。结果表明:相比于自然曝露,高密度聚乙烯主要力学性能的氙灯人工老化加速倍率大约为4;老化期间,高密度聚乙烯分子间存在着交联和降解二种竞争反应,老化早期以交联为主,后期以降解为主;氙灯老化试验相比于自然曝露,老化主要集中在材料表层。 相似文献
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氯碱厂有许多贮存各种浓度Na0H的贮槽,这些设备由于施焊产生的残余应力而经常出现焊缝开裂,经补焊有时更容易开裂。原因是由于NaOH已经渗入气孔或微裂纹中,会与金属铁发生电化腐蚀;补焊时所产生大量的氢又会形成气孔且由于扩散而形成富红地带,使氢压力增高,导致原微观缺陷不断扩大至再形成裂纹。再补焊时,按如下方法效果较好:1.开裂处的NaOH处理干净(l)先用水将补焊处的碱液冲洗干净(2)将补焊处焊缝区烘干后,用手提砂轮机进行打磨,消除肉眼可见的裂纹和气孔,将之磨成带60被口的长条状槽c(3)用毛刷沾上3%的医用硼酸溶… 相似文献
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CePO4/Ce-ZrO2可加工陶瓷加工机理的研究 总被引:10,自引:2,他引:10
以CePO4/Ce-ZrO2为基体,通过复合不同加入量的第二相CePO4颗粒,并借助扫描电子显微镜对材料压痕、磨削及切削表面进行分析,研究了CePO4/Ce-ZrO2陶瓷材料的可加工机理。单相CePO4材料的弯曲断口显示出层片状断裂机制;而复相CePO4/Ce-ZrO2陶瓷由于两相之间弱结合界面的存在,压痕裂纹扩展形式发生明显变化,由连续扩展机制过渡为不连续扩展。基于上述两种重要机制形成的大量微裂纹是赋予材料可加工性的主要原因,材料加工去除是以微裂纹的连接来实现的。同时,大量微裂纹起到耗散主裂纹扩展能量的作用,有效阻止了较大裂纹的形成,使材料加工损伤大大降低。最后,给出了CePO4/Ce-ZrO2陶瓷加工机理的简单模型。 相似文献
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某沉降-再生器在运行中发生了泄漏,检验后发现筒体的环焊缝存在大量垂直于环焊缝的裂纹,研究表明该裂纹为典型的烟气露点腐蚀造成的应力腐蚀焊缝开裂。经过修复,消除了环焊缝上的裂纹缺陷,并提出了避免发生类似问题的方法。 相似文献
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介绍氯气压缩机主轴成分;分析主轴发生裂纹的原因是:淬火前组织中存在缺陷,导致纵向裂纹;提出改进措施:锻件在进行调质处理前再进行一次正火处理。 相似文献
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为验证再生聚丙烯(RPP)应用于汽车保险杠的可行性,研究了不同比例消费后回收聚丙烯(PCR⁃PP)的用量对RPP的冲击、拉伸、弯曲、压缩等力学性能的影响规律,并对RPP的热性能和拉伸断口形貌进行了分析。结果表明,在PCR⁃PP含量占比分别为0、10 %、30 %和50 %的情况下,随着PCR⁃PP添加量的增加,RPP力学性能总体呈现缓慢下降趋势,断裂伸长率从467 %下降至210 %,下降最为明显;当添加10 %PCR⁃PP时,材料的冲击、拉伸、弯曲性能变化较小,均可满足应用于保险杠材料的性能要求。 相似文献
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The effect of test conditions on the work of fracture of Thiokol-based sealants containing different dispersed fillers is studied. Carbon black, titanium dioxide, and hydrophobized natural chalk are used as fillers. The influence of an increase in a single defect is estimated to predict the long-term adhesive strength between the Thiokol-based sealants and different materials. The mechanism and the scale of variations in the fracture strength of sealants in the peel regime are considered. The efficiency of the testing procedure for samples with a central defect is shown. Methods to enhance the fracture strength of Thiokol-based sealants under the conditions of combined stress are discussed. 相似文献
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光稳定剂复配对核壳WPC抗紫外老化性能的影响 总被引:1,自引:0,他引:1
为探索经济、环保且效果更好的木塑复合材料(WPC)表面耐老化处理方法,采用共挤技术,以不同复配方式将纳米白炭黑、HALS–L944及UV327添加于核壳型WPC壳层。对试样进行紫外光加速老化试验,并对其弯曲性能、表面颜色及化学成分结构进行了测试表征与方差分析。研究结果表明,当壳层加入1%纳米白炭黑与1%UV327复配时效果最好,紫外老化2 500 h后,较之空白样,WPC的弯曲强度保留率提高了14.7%,弹性模量保留率提高了17.4%,保护效果最好,具有一定的协同作用;表面颜色变化较为缓慢,色差下降了44.9%,优于单独添加光稳定剂效果;O/C值增长幅度为9.1%,氧化的碳/未氧化的碳比值增加了11.8%,表面氧化程度最低。说明纳米白炭黑与UV327具有一定的协同作用,能够更好地提高核壳WPC的抗紫外老化性能,降低其光氧化降解程度。 相似文献
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Mark Carroll Amy Hanlon Tanya Hanlon Arthur R. Zangerl May R. Berenbaum 《Journal of chemical ecology》1997,23(12):2707-2719
The parsnip webwormDepressaria pastinacella, acquires a distinct yellow stripe when it consumes the yellow flowers of its principal host plantPastinaca sativa, the wild parsnip. Caterpillars raised on artificial diet lacking host-plant material lack this yellow coloration. By chemical characterization and comparison of caterpillars raised on parsnip flowers and on artificial diet, we were able to determine that lutein, along with smaller amounts of other xanthophylls from the host plant, is selectively sequestered in the fat body. In bioassays designed to measure avoidance of ultraviolet light, caterpillars raised on parsnip flowers or on artificial diet supplemented with lutein were less likely to avoid exposure to ultraviolet light than caterpillars raised on unaugmented artificial diet and thus lacking sequestered carotenoids. The ability to sequester xanthophylls, which are highly effective antioxidants, may confer a selective advantage on these caterpillars, whose apiaceous host plants produce large quantities of furanocoumarins, natural products that are photoactivated by light wavelengths in the ultraviolet region; such sequestered pigments may reduce not only the oxidative stress associated with ultraviolet light and diurnal foraging but also the photooxidative stress associated with ingestion of photoactive furanocoumarins. 相似文献
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The mechanical properties, heat aging resistance, dynamic properties, and abrasion resistance of fibrillar silicate (FS)/styrene butadiene rubber (SBR) nanocomposites are discussed in detail. Compared with white carbon black (WCB)/SBR composites, FS/SBR composites exhibit higher tensile stress at definite strain, higher tear strength, and lower elongation at break but poor abrasion resistance and tensile strength. Surprisingly, FS/SBR compounds have better flow properties. This is because by rubber melt blending modified FS can be separated into numerous nanosized fibrils under mechanical shear. Moreover, the composites show visible anisotropy due to the orientation of nanofibrils. There is potential for FS to be used to some extent as a reinforcing agent for rubber instead of short microfibers or white carbon black. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2725–2731, 2006 相似文献
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N. M. Ahmed 《Polymer-Plastics Technology and Engineering》2013,52(2):275-283
Incorporation of fillers in rubber results in a profound effect on rheological and mechanical properties of the formed composites. Fillers are customarily classified into organic and inorganic. The latter class includes calcium carbonate, talc, barium sulfate, kaolin, silica, etc. Molybdates are inorganic, nontoxic white pigments combined with reasonable pricing range and controlled solubility. The purpose of this study was to employ white molybdates and study their role as reinforcing fillers that can replace traditional carbon black, or semi-reinforcing furnance black (SRF), with both natural rubber (NR) and a blend of natural rubber-styrene butadiene rubber (NR-SBR), to show the modification of rheometric characteristics, tensile strength, strain at break, hardness, Young's modulus, swelling in toluene, thermal oxidative aging, and calculation of the rubber-filler interaction after the addition of such fillers. 相似文献