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1.
锌系磷化的稀土促进成膜机理研究   总被引:3,自引:0,他引:3  
邝钜炽 《稀土》2006,27(1):26-29
能谱成分分析结果表明,加入稀土硝酸盐(REN)后磷化膜内P元素含量增大,Zn元素含量减小,而对磷化膜耐腐蚀性的贡献为P>Zn。由SEM形貌分析可获知,添加REN后无定形晶体Zn2Fe(PO4)2在磷化膜表面覆盖率有较大幅度提高,从而使得膜的P/(P+H)比率增大,磷化膜的耐蚀性能提高。机理研究则指出,稀土实质是一个有良好载氧能力的催化剂,具有良好的成核促进作用和阴极去极化作用,在磷化过程中同时发挥了表调剂、促进剂与致密剂的作用,加速了磷化过程,并使膜的耐腐蚀性能提高。  相似文献   

2.
采用柠檬酸盐溶胶 凝胶法制备了组成为Li1 2xZn1-xPO4 (x =0 ,0 .1,0 .14,0 .2 ,0 .3,0 .4,0 .5 )的固体粉末和烧结体。对其结构的研究结果表明 ,在这样的组成范围内 ,采用溶胶 凝胶法得到了一系列α LiZnPO4 (x =0 )、Li9Zn6(PO4 ) 7(x =0 .14)、α Li4 Zn(PO4 ) 2 (x=0 .5 )单相以及由α LiZnPO4 Li9Zn6(PO4 ) 7、α Li4 Zn(PO4 ) 2 Li9Zn6(PO4 ) 7两相构成的混合相 ,用这种合成方法得到的样品的生成温度较传统的固相合成样品降低了约 40 0℃。用交流阻抗技术测定了样品的导电性 ,其中α LiZnPO4 、Li9Zn6(PO4 ) 7在室温下不显示导电性 ,而α Li4 Zn(PO4 ) 2 具有较高的导电性 ,t=2 5℃时 ,σ=1.6 6× 10 -6S·cm-1。  相似文献   

3.
钢铁化学法磷化发黑工艺研究   总被引:6,自引:0,他引:6  
介绍了一种钢铁化学法着黑色溶液的组成及工艺参数:K2Cr2O710g/L、MnSO4 4g/L、(NH4)2SO4 20g/L、Zn(H2PO4)2 20g/L、KNO3 12g/L、CuSO4 6g/L、添加剂A(钼酸铵)2~3g/L、添加剂B(柠檬酸盐)3g/L、H3PO4适量、pH值为1.5~2.5、温度为10.25℃(室温)、时间为12~18min。分析了该着色液着色的机理,着重讨论了该配方各组分的作用及其对着黑色膜质量的影响。实验结果表明:该工艺发黑具有着色时间短、环境污染小、黑膜附着力强、光泽性好特点,同时该膜提高了钢铁的耐磨性和耐蚀性。  相似文献   

4.
根据化学位图绘制基本原理和方法,分析了Mg2+-Ca2+-H2CO3-H2O、CaCO3·MgCO3-SO2-4-H2O、Ca2+-F--H3PO4-H2O、Ca5(PO4)3F -SO2-4-H2O和Mg2+-H3PO4-H2O体系在常温下的热力学平衡,研究了Ca-Mg-P-H2SO4体系在常温下的溶液-矿物溶解、沉积条件,形象、直观地描述了该溶液体系化学平衡条件及反应进行的限度,为磷矿选矿和湿法浸出过程提供理论依据.结果表明:硫酸可以促进白云石和氟磷灰石的溶解,溶解产物主要是Mg2+、H3PO4,其次是H2PO-4,固相产物主要是硫酸钙晶体;氟磷灰石溶解过程中产生的磷酸在酸性条件下不与溶出的Mg2+反应形成Mg3(PO4)2.  相似文献   

5.
邝钜炽  朱恒祥 《稀土》2007,28(1):92-95
提出在表面生成磷化膜以提高不锈钢的耐磨与耐蚀性能的工艺方法,讨论了各种促进剂(亚硝酸钠、钼酸钠、硝酸铈和硝酸镧)对磷化膜形成的影响,探讨了稀土对磷化的影响机理.结果表明,稀土元素对磷化的强化作用是明显的,其中Ce(NO3)3对提高不锈钢基的磷化速度与耐磨性能的贡献均较为显著,La(NO3)3对提高不锈钢的耐腐蚀性的贡献则较大.  相似文献   

6.
JP级钢管磷化的研究   总被引:3,自引:0,他引:3  
孙挺  何翊  刘仰硕 《钢铁研究》2004,32(5):40-42
在大量实验的基础上,研究了JP级钢管磷化工艺的优化问题,研究包括磷化液组成和配制工艺的改进。该磷化液主要由ZnO、HNO3、H3PO4和适量的催化剂组成。用Q235、Q345、J-55、N-80、P-110等钢种进行了实验,并对中温条件下不同钢种的磷化膜进行了性能和参数的测试,研究表明中温磷化工艺的效果优于原有的高温磷化工艺。  相似文献   

7.
通过水热方法合成了2个夹心型磷钼簇基有机-无机杂化化合物(C4H14N3)(C4H15N3)4{Na[Mo6ot5(H2PO4)4]2)·8H2O(化合物1)和{Ni[Mo6O15(H2PO4)4]2}(4,4'-bipy)3·H2O(化合物2,其中4,4'-bipy为4,4'-联吡啶),并对其进行元素分析、红外光谱和X射线单晶衍射表征.结构解析结果表明2个标题化合物均含有由2个{Mo6P4)簇和1个[MO6](M为Na,Ni)八面体通过共用顶点氧相连形成的中心对称的夹心型结构.化合物1中,具夹心结构的Na(P4Mo6)2与二乙烯三胺及水分子通过氢键连接形成超分子化合物;化合物2中,具夹心结构的Ni(2)[Mo6P4]2与质子化的4,4'-bipy通过氢键相连形成沿bc平面延伸的二维网络结构,Ni(1)[Mo6R4]2填充在其空穴中.  相似文献   

8.
碳化法制备碱式碳酸锌过程的热力学分析及其产物表征   总被引:5,自引:0,他引:5  
分析了碳化法制备碱式碳酸锌过程的热力学,并对产物进行了表征。结果表明,锌以ZnCO3.2Zn(OH)2.H2O形式析出,片状,平均粒径在1μm左右,分解温度在150~300℃范围内,分解时直接放出CO2和H2O,没有中间过程。  相似文献   

9.
以CeCl3·7H2O、Ce(NO3)3·6H2O作为成膜处理槽液的主要成分、H2O2作为氧化剂及少量促进剂和络合剂等(简称双铈盐工艺),在铝表面制备化学转化膜,用于喷涂前处理。重点针对粉末喷涂建筑铝型材最常用的6063铝合金,对双铈盐转化膜的质量要求、成膜工艺参数对转化膜质量的影响进行了研究。  相似文献   

10.
铝合金无铬磷化技术的研究   总被引:2,自引:0,他引:2  
本文研究了铝合金的无铬磷化技术,分析了磷化工艺及磷化液各组分对转化膜的影响,采用正交实验对磷化液配方进行了优选,并对磷化助剂进行了大量的筛选.通过LK98C电化学综合测试系统测定了磷化转化膜的塔菲尔曲线,用金相显微镜观测了磷化膜的形貌.  相似文献   

11.
Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

12.
The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.  相似文献   

13.
鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".  相似文献   

14.
张兴强  叶运福 《冶金设备》2005,(6):71-72,47
针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。  相似文献   

15.
转炉炉壳热应力分析   总被引:5,自引:1,他引:4  
任学平  郭志强  邹家祥 《炼钢》2001,17(6):47-49
根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。  相似文献   

16.
In this paper is treated the fundamental problematic of the fracture of the diaphysis of the tibia and the therapeutic results after the conservative and operative treatment are confronted. Among 518 patients with 433 open fractures and 35 with closed fractures of the diaphysis of the tibia, successful treatment of more 2/3 was obtained in the period from 1968 to 1972. Following our casuistics and literature, whose results are similar, we find out that the average total treatment of the osteosynthesis of the fracture of the diaphysis was shortened for 2,5 months depending upon the type and the localisation of the fracture. Apolied methods of the operative and conservative and conservative treatment in relation to the velocity of the medical cure as well as to the extreme anatomical-functional results are analised. We noticed that osteosynthesis, made by the intermedullary nail and the extension of the canals or by a small AO table, by the achieved stability makes conditions of immediate motions and an early rehabilitation. Because of that it gives the best functional results.  相似文献   

17.
18.
通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。  相似文献   

19.
Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.  相似文献   

20.
为了编制实用性强的基地建设行动方案,首先,确定参与式发展的主体,搭建一个"决策框架";其次,针对行动目标,提出不同参与主体,如管理者、农民、消费者等团队与个人的目标及行动内容;最后,工作应向重塑伙伴式合作关系,挖掘农民自我发展潜力,完成三大角色的转换,打造农业基地文化等方向推进.  相似文献   

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