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1.
化学镀Ni-P合金层组织结构与性能的研究   总被引:10,自引:0,他引:10  
对非晶态Ni-P合金镀层的组织结构和性能进行研究,结果表明:非晶态Ni-P合金镀层以层片状沉积,表面具有胞状结构.镀层的磷含量及热处理温度对Ni-P合金层的组织结构有影响,同时对非晶态Ni-P合金镀层在不同介质中的耐蚀性进行了研究.  相似文献   

2.
利用复合电镀技术,制备了非晶态Ni-P合金基TiC复合镀层.测定了非晶态Ni-P合金镀层和(Ni-P)-TiC复合镀层的表面形貌、结构、硬度以及耐磨性.研究了TiC微粒对镀层的弥散强化作用.结果表明,与非晶态Ni-P合金镀层相比,(Ni-P)-TiC复合镀层的硬度和耐磨性均超过了非晶态Ni-P合金镀层.  相似文献   

3.
电流密度对Ni-W-B合金电沉积层结构和显微硬度的影响   总被引:2,自引:1,他引:1  
采用电化学技术、XRD、DSC等方法研究电流密度对Ni-W-B合金电沉积、镀层结构和显微硬度的影响,结果表明:沉积电流密度提高,Ni-W-B合金电沉积层W含量增大,B含量降低,电沉积电流效率降低,所获得的合金镀层表现为亚稳态纳米晶结构,在不同电流密度下获得的Ni-W-B合金电沉积层的显微硬度值接近,约为650kg/mm^2,与Ni-W合金相比有明显提高。  相似文献   

4.
本文采用酸性化学镀镍-磷合金镀液,通过改变还原剂浓度,制备一系列不同磷含量Ni—P合金镀层,研究磷含量对镀层性能的影响。表明镀层耐蚀性、硬度等性能与磷含量有直接关系。  相似文献   

5.
非晶态合金镀层的耐蚀性能   总被引:4,自引:0,他引:4  
电沉积Ni-W-P非晶合金中W含量可高达55.2%,硬度为700~1100Hv,经550℃热处理,可达1300~1400Hv,镀层硬度和耐蚀性优于Ni-P非晶镀层,非晶镀层中的类金属元素P可使腐蚀电位正移,高熔点元素W可使合金镀层在酸溶液中发生钝化,有W含量越高维钝化电流密度越低;金属Cr元素除降低维钝电流密度外,还使钝化区范围加宽,孔蚀电位显著变正,浸泡实验结果表明,在30℃,1mol/L的HC  相似文献   

6.
化学镀镍基合金的组织和性能的研究   总被引:1,自引:0,他引:1  
本文对化学镀Ni-P及Ni-P-SiC非晶合金镀层的组织结构、成分、显微硬度、耐磨性、耐蚀性及晶化规律等作了一系列研究.实验结果表明:(1)化学镀Ni-P非晶合金具有优良的耐磨性和耐蚀性;(2)Ni-P非晶在加热过程中具有两个明显的放热峰,235℃为Ni3P相的形核孕育峰和391℃为Ni3P相的析出峰,因而使得Ni-P非晶合金在400℃×1h热处理后具有最大的显微硬度和最佳的耐磨性;(3)化学镀Ni-P-SiC复合镀层具有更高的显微硬度和更佳的耐磨性,尤其是在大载荷长时间下显示出优越性.  相似文献   

7.
利用复合电镀技术,制备了非晶态Ni-P合金基TiC复合镀层,测定了非晶态Ni-P合金镀层和(Ni-P)-TiC复合镀层的表面形貌、结构、硬度以及耐磨性。研究了TiC微粒对镀层的弥散强化作用,与非晶态Ni-P合金镀层相比,(Ni-P)-TiC复合镀层的硬度和耐磨性均超过了非晶态Ni-P合金镀层。  相似文献   

8.
本文报道了制备(Ni-W)一SiC复合镀层的电沉积工艺。研究了SiC固体微粒对于基质合金结构的影响,测试了复合镀层的硬度及耐磨性。结果表明,SiC微粒对于Ni一W合金有较强的晶化作用;SiC微粒的复合,明显增加了Ni一W合金的硬度和耐磨性。  相似文献   

9.
以非晶态合金镀层的高温氧化问题为背景,研究了Ni-W,Ni-W-B合金镀层在高温条件下的抗氧化性能以及镀层经加热处理后的硬度,实验结果表明,随镀层含W和B量的增加,有利于镀层的抗高温氧化性能和硬度的提高。  相似文献   

10.
络合剂对Ni—P化学镀层耐蚀性的影响   总被引:1,自引:0,他引:1  
本研究了各络合剂对化学镀Ni-P镀层磷含量及分布、表面表貌、耐蚀性等方面的影响。浸泡实验、镀层腐蚀后表面扫描电镜观察及能谱成分分析表明:镀层耐蚀性主要受镀层磷含量影响,并且与镀层表面形貌、磷含量变化等因素有关。分析表明:以上因素均可归因于络合剂种类的选择。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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