首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
通过单因素实验和正交试验确定了一种合金钢的黑色磷化液的组成和操作条件,并用中性盐雾试验和电化学测试表征了黑色磷化膜的耐腐蚀性。结果表明,最优黑色磷化液的成分为:30 g/L马日夫盐,20 g/L Zn(H2PO4)2·2H2O,8 g/L Zn(NO3)2·6H2O,10 g/L Mn(NO3)2。在最优磷化液中得到的黑色磷化膜耐中性盐雾试验6h未见腐蚀。通过X-射线衍射分析,黑色磷化膜由Mn2Zn(PO4)2·4H2O、Zn2Fe(PO4)2·4H2O和Zn3(PO4)2·4H2O组成。  相似文献   

2.
本文在超声波作用下,对钢铁表面进行常温磷化处理,以提高钢铁表面耐蚀性能。研究以磷化膜外观及耐蚀性为考察指标,通过单因素实验,首先考察了常温磷化液中氧化锌、磷酸、硫酸羟胺(HAS)、硝酸锰、柠檬酸等组分对超声磷化的影响,其次考察了磷化方式对磷化膜性能的影响,最后测试了磷化液使用寿命。结果表明,磷化液组成为氧化锌15 g/L、磷酸80 g/L、硫酸羟胺12 g/L、硝酸锰4 g/L、柠檬酸2 g/L时,超声磷化膜外观及耐蚀性最好,此时磷化膜为灰黑色,膜层连续、均匀、致密,耐蚀时间可达217 s;磷化方式中常温超声磷化比常温静止磷化效果更佳,前者外观及耐蚀性比后者优越;磷化液寿命测试发现,当磷化次数超过9次时,制备的磷化膜耐蚀时间开始低于60 s,此时磷化液已经失效,累计磷化面积为0.3 m~2/L。  相似文献   

3.
在常温工况下,将电化学方法与磷化处理相结合,加速磷化液中各离子的扩散,使磷化时间保持在10 min以内。对电化学磷化方法中的各影响因素进行对比实验后发现,在常温工况下的最优磷化处理条件为马日夫盐浓度30~50 g/L,硝酸锌浓度50~70 g/L,电流密度1.00~1.50 A/dm2,电化学磷化时间5~7 min。在此条件下所制得的结晶型磷化膜综合性能最佳。分析测试表明:磷化膜主要包括O、Zn、P、Mn、Fe元素,且磷化膜耐腐蚀性强,晶体均匀致密,富有层次感,易于涂层材料附着。  相似文献   

4.
AZ31镁合金钙系磷化工艺优化及磷化膜组织结构研究   总被引:1,自引:0,他引:1  
利用正交试验法优选出适用于AZ31镁合金材料的最佳钙系磷化工艺配方及工艺,即NaH2PO4·2H2O 40 g/L,Ca2+40 g/L,六次甲基四胺1 g/L,有机配体D 15 g/L,pH 3.0,温度30°C。扫描电镜观察发现,镁合金表面钙系磷化膜均匀致密,无明显缺陷,呈花瓣状结晶生长。X射线衍射结果表明,膜层的主要成分为CaHPO4·2H2O。  相似文献   

5.
1 前言 钢铁常温发黑-磷化工艺在我国已推广使用十多年了,在广大技术人员的共同努力下,其结合力和耐蚀性能不断提高.我们在2003年研制出一种常温发黑-钝化工艺,其膜层结合力和耐蚀性均高于原常温发黑(磷化)膜层3~5倍.如果在常温发黑钝化后再进行中温磷化,得到的发黑-钝化-磷化膜,其结合力和耐蚀性显著提高,采用磷化膜的点滴试验可达20~30 min.若在该复合化学转化膜上再浸涂防锈油或清漆等后处理,则耐蚀能力更高.本文从膜层性质和结构等方面探讨钢铁复合化学转化膜高耐蚀性的原因.  相似文献   

6.
为提高磷化膜的装饰效果以满足特殊场合的需要,通过正交试验优化了一种能在常温下获得金黄色磷化膜的磷化液配方,用正交试验极差分析法、目测法和硫酸铜溶液点滴试验分别研究了溶液主要成分、pH、温度及磷化时间等因素对磷化膜外观和耐蚀性的影响。其磷化液组成为:3.0 g/LHO-R-COOH、3.5 g/L促进剂、3.0 g/LNa3PO4.12H2O、4.8 g/LZn2+、1.2 g/LMn(H2PO4)2.2H2O、13.6 mL/L H3PO4。最佳磷化工艺参数:θ=25~31℃,pH=2.34~2.84,t=15~20min。  相似文献   

7.
研究了中温磷化液组分Zn2 、Mn2 、Ni2 、F–对镀锌板磷化膜重和耐碱性的影响。通过正交实验确定了最佳磷化配方:2.5g/LZn2 ,2.0g/LMn2 ,0.8g/LNi2 ,1.5g/LF–,20g/L促进剂。据此配方得到的磷化膜外观呈浅灰色,表面均匀,膜厚30~33μm,膜重5~8g/cm2,硫酸铜点滴时间大于30s,3%(质量分数)NaCl浸泡100h无锈点。  相似文献   

8.
研制了一种以磺基水杨酸为添加剂的常温、高效、耐腐蚀型磷化液。通过正交实验,得到磷化液最佳配方:5.0g/氧化锌,10.0mL/L磷酸,0.20g/L磺基水杨酸,0.50g/L氯酸钾,0.1g/L络合剂,0.20g/L柠檬酸,0.15g/L钼酸盐0.50g/L硝酸镍。分析了磷化膜层的表面形貌及电化学特征测定了该膜层的耐蚀性与膜重,并对磺基水杨酸的作用机理进行了探讨。结果表明,该磷化液性能优良;磺基水杨酸可以与Fe3 配位,加快磷化反应速率,缩短磷化成膜时间,提高磷化膜的耐蚀性。  相似文献   

9.
环保型常温锌钙系磷化工艺   总被引:1,自引:0,他引:1  
研究了(NH4)2MoO4、Ca(NO3)2、硫脲、柠檬酸、温度,时间和pH等工艺条件对磷化膜层的耐蚀性和表面状况的影响.通过正交试验法确定的最佳工艺配方为:氧化锌4.5 g/L,磷酸11.25 mL/L,硝酸钙8 g/L,钼酸铵4.0 g/L,硫脲1.5 g/L,柠檬酸1.4 g/L,温度25~35℃,时间20 min以上,pH 2.5~3.0.该磷化工艺操作简单,清洁环保,常温即可磷化,使用周期较长,易维护.  相似文献   

10.
采用恒电流法在AZ91D镁合金表面制备磷酸盐转化膜,通过计时电位法研究了镁合金在锌锰系磷化液中的电化学磷化过程,结合X射线衍射、扫描电子显微镜以及能谱测试分析了电化学磷化膜不同生长阶段膜层成份及微观形貌的变化规律.结果表明,镁合金在电化学磷化初始阶段,在化学、电化学作用下,α-Mg相首先发生溶解,并在溶解处出现不完整膜层,成分为Mg3(PO4)2,β-Al12Mg17相区域内出现颗粒状晶体,晶体成分为Zn3(PO4)2·(H2O)4、Mn3(PO4)2·7H2O及少量Mg3(PO4)2.随着磷化进行,α-Mg相区域的膜层增厚,β-Al12Mg17相区域内晶体逐渐长大聚集成呈花状球型晶簇.磷化60 s后,磷化膜的生长以β-Al12Mg17相区域内花状球型晶簇为主,形成以Zn3(PO4)2·(H2O)4、Mn3(PO4)2·7H2O和Mg3(PO4)2物质组成的磷化膜.  相似文献   

11.
Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.  相似文献   

12.
It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.  相似文献   

13.
14.
15.
16.
17.
Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.  相似文献   

18.
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.  相似文献   

19.
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。  相似文献   

20.
Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号