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求有关复合材料的翻译~单词有点多，金币有点少，谢谢你了啊~160全部给你吧
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Figure 2(a) to (e) shows the morphology of the deposited specimens with Ni , Ni-WC, Ni-CB , Ni-CNT, and Ni-SiC composite coatings. SEM micrographs of the Ni coating shown in Fig. 2(a) exhibit a homogeneous metallic structure of pure Ni with a typical shape of nickel crystallites,which may exceed a size 5 lm. From Fig. 2(b) it can be observed that the WC particles are homogeneously dispersed in the Ni-WC film. The figure also shows the reduction grain size of Ni crystallites due to the presence of WC reinforcement. This reduction is also discernible in SEM micrographs of composite deposits as compared with those of pure Ni deposits even though some of them have formed agglomerated clusters. Both Ni-CB and Ni-CNT coating surface morphology was very rough as observed in Fig. 2(c) and (d) respectively. The possible reasons for the coarse surface under larger current density are many voids or gaps in the deposits of Ni-CB and Ni-CNT apart from clusters of CNTs/ CB are seen in the deposited Ni layers. Also, notice the uneven distribution of the deposition current density due to the existence of CB/CNTs. CB/CNT that are good conductors with a small radius of curvature radius. This fact results in an electric field is stronger around the cluster of CB/CNTs the than in other areas, resulting in increased local deposition current densities during electro-co-deposition and leading to an uneven coating thickness. Figure 2(e) shows Ni-SiC grains that are smaller than 1 lm with some globular grain-agglomerates visible on the surface.Table 2 shows the effect of bath loading on the percentage weight (wt.%) of reinforcement in the composite coating by computing from EDS results (as shown in Fig. 3). The wt.% of reinforcement in the coating in CB and CNT are proportional to loading content in the composite plating bath, but WC and SiC reinforcements showed lower wt.% in the coating. Coating with smaller particles (CB and CNT) exhibited higher activity than coating with larger particles (WC and SiC). This may be attributed to the fact that heavy particles are difficult to be carried by the Ni ions due to lower effect of their throwing power (Ref 12). wt.% of reinforcement in the coating increased with increasing bath loading. The other reason for increasing the CNT/CB concentration in the alloy was to check (a) whether conductivity of reinforcement increased the throwing power, (b) the deposition rate improves the properties of the deposit in terms of reduction of residual stress and porosity (Ref 13).Figure 4 shows the effect of reinforcement loading on the coating thickness of Ni-based composite deposits. The thicknesses of the coatings range from 24 to 65 lm, depending on the reinforcement type and load used. It was observed that varying the reinforcement loading in the bath clearly affects the thickness of the coatings, and also varies with reinforcement. In all cases the coating thickness increased with increasing reinforcement loading. Ni-CNT showed the highest coating thickness due to the dimension and conductivity of CNT. Ni-SiC showed only marginal increment in coating thickness. The thickness of Ni-WC and Ni-CB was in between Ni-CNT and Ni-SiC composite coatings. The WC, CB, CNT, and SiC have a hardening effect on the composite coating and hardness of the coating increases from 510 kgf mm 2 for pure Ni coating to 920 kgf mm 2 (4 g/L WC and 0.4 g/L CNT) as observed in Fig. 5. The effect of reinforcement types and reinforcement content in the bath on the microhardness of the composites layers. The microhardness increased to a maximum and then decreased with reinforcement content. The grain-refining and dispersive strengthening effect become stronger with increasing reinforcement content, resulting in the microhardness of the Ni-based composite coatings increasing with larger reinforcement content. Ni-WC and Ni-CNT composite coatings showed higher hardness compared to other types. These results show improved both toughness and strength of the composites with co-deposition of WC/CNT s with nickel. Ni-CB composite coating showed lower hardness than the other three types of coatings. Ni-CB has more irregular surface finish as also more porosity that can be seen in the microstructure illustrated in Fig. 2(c). Ni-SiC composite coating hardness lies between Ni-CNT and Ni-CB due to its lower strength and lower SiC content in the coatings. The hardness increase noted in these composite coatings could be linked to a dispersion strengthening effect (Ref 14). With increasing the WC (4 g/L), CB (1.0 g/L), CNT (0.4 g/L), and SiC (15 g/L) content Ni composites coatings, the hardness was improved from 510 to 920, 760, 920, and 810 vH. However, the hardness dropped drastically to 750, 720, 850, and 730 vH for the specimen with the 6 g/L WC, 1.5 g/L CB, 0.6 g/L CNT, and 20 g/L SiC, respectively. This might be due to the porous microstructure of the higher loading composites. The stress strain curves of the Ni-WC coatings (Fig. 6a), Ni-CB coatings (Fig. 6b), Ni-CNT (Fig. 6c), and Ni-SiC (Fig. 6d) are compared with pure Ni coating. For all tests the strain was determined by a sudden drop in the flow curve (catastrophic failure of coatings). Figure 6 shows the addition of reinforcement significant contribution on the composite coating behavior. In pure Ni coating curves show sooth behavior, which due to dynamic recovery and re-crystallization process occurring within the coating. For composite coatings the apparent softening after a strain of 0.2 is due to micro-crack formation at the specimen surface and in the interior as shown in Fig. 6. All graphs clearly show an increase in tensile strength, compared to pure Ni coating with the addition of reinforcement. The composite coating containing WC and CNT show the tensile strength was significantly higher than pure Ni coating, but SiC and CB coating show only a nominal increase in tensile strength. This can be attributed to the higher propensity of particle fracture in Ni-SiC composite coating.Variation in bath loading and reinforcements were found to have a significant effect on the tensile properties of the composites. Figure 7 shows the variation of the tensile strength with different reinforcements and bath loading. It is also important to note that the reinforced particulate clusters also have a significant effect on the tensile properties of the composites coating. With increase in the WC (4 g/L), CB (1.0 g/L), CNT (0.4 g/L), and SiC (15 g/L) content in Ni composites coatings, the tensile strength improved from 620 to 810, 740, 910, and 808 MPa respectively. However, the tensile strength dropped to 740, 710, 860, and 710 MPa for the specimen with the 6 g/L WC, 1.5 g/L CB, 0.6 g/L CNT, and 20 g/L SiC, respectively. Increase in reinforcement (WC, CB, SiC, and CNT) loading into the bath caused more particles clustering as seen in coated materials.XRD diagrams of the Ni and Ni-based coatings are shown in Fig. 8. The average crystal size of the coating was 43, 10.3, 9.1, 8.2, and 13, 5 nm for Ni, Ni-WC, Ni-CB, Ni-CNT, and Ni-SiC composite coatings, respectively. Fine-grained deposits are generally obtained at higher rate of formation of nuclei (Ref 15). The addition of reinforcement may provide a larger number of cathodic sites and consequently more number of fresh nuclei are formed on the metal surface. This results in a fine-grained composite deposit.It is apparent that the diffraction pattern of pure Ni deposit is characterized by the intense (200) diffraction line corresponding to a (100) texture shown in Fig. 8(a), where the diffraction pattern of Ni-WC (Fig. 8b), Ni-CB(Fig. 8c), Ni-CNT (Fig. 8d), and Ni-SiC(Fig. 8e) reinforcements is characterized by (311) and (111) lines accompanied with an attenuation of the (200) line (Ref 7). It is of interest to note that the reinforcement of lines (311) and (111) are attributed to a dispersed (211) orientation (Ref 7). Hence, the composite coatings show maximum strength and hardness. The other reason for improvement in the strength is the reduction of grain size of Ni crystallites due to the presence of reinforcement in the composite coatings as compared with those of pure Ni coatings. |
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jacy_cheyn
铁杆木虫 (知名作家)
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【答案】应助回帖
★ ★ ★
kunlunlx(金币+160, 翻译EPI+1): 辛苦了~感激万分啊！！ 2011-06-03 09:47:24
Mally89(金币+3): 感谢应助！~ 2011-06-03 11:32:42
kunlunlx(金币+160, 翻译EPI+1): 辛苦了~感激万分啊！！ 2011-06-03 09:47:24
Mally89(金币+3): 感谢应助！~ 2011-06-03 11:32:42
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如图2所示，（a）到（e）五个图分别是在Ni , Ni-WC, Ni-CB , Ni-CNT, 和 Ni-SiC复合材料的样本的形貌。图二（a）为Ni涂层的扫面电镜形貌，具有与典型的Ni晶体颗粒一样得到均匀的金属Ni的金属结构，尺寸可能超过5 lm. 如图二(b)所示，可以观察到，WC颗粒均匀的分散在Ni-WC膜的表面，也表明了由于WC的存在使得Ni晶体的颗粒尺寸变小。可以在复合镀层的扫面电镜上看到，和纯Ni镀层相比，尽管有些团聚形成了簇，但是尺寸变小了。 可以观察到，如图二（c）（d）所示，Ni-CB 和 Ni-CNT图层的表面形貌很粗糙。在大电流下，形成粗糙的表面形貌的可能原因是，除了镀在Ni层的可见的CNTs/ CB簇以外，在Ni-CB 和 Ni-CNT沉积过程中的孔洞或者缝隙。并且，注意由于存在CB/CNTs，因而电流密度分布不均匀。CB/CNTs是具有一种小半径曲率半径的良导体，这使得在CB/CNTs簇周围的电场强度比其他地方要高，进而使得在电工沉积过程中的电流密度的增加，导致了涂层厚度的不均匀。 如图二（e）所示，可以看到Ni-SiC 颗粒在表面是团聚成为球形，并且尺寸小于1 lm。 m表二所示由EDS计算结果得知的在复合物涂层里面的水浴重量百分比的影响（如图三所示）。在复合物电镀液中，CB 和CNT的比例与加入的物质事成比例的，但是WC和SiC 的比例表偏低。相对于大颗粒的（ＷＣ和SiC），用小颗粒（CB和CNT）的涂层表现出了更高的活性，这可能是因为重力比较大，使得其由Ni粒子携带的分散性比较差的缘故。随着水浴负载量的增加，涂层的质量比也增加。在合金中的CNT/CB 浓度的增加的其他原因（a）主要是增加物的导电能力增加了布散能力,(b)沉积速率提高了沉积的性能，因为其减少了残余应力和孔道。 图四表明了附加物的负载量对镍基复合镀层的涂层厚度的影响。厚度为24-65lm,取决于加固的类型和负载的种类。观察到改变在水浴中的加固类型会影响涂层的厚度，并且与加固类型相同。在所有类型中，涂层厚度随着负载的增加而增加.Ni-CNT由于其维数和电导率而有最高的厚度，Ni-SiC在旨在边缘上的涂层厚度有所增加。Ni-WC 和Ni-CB的厚度在Ni-CNT 和 Ni-SiC复合涂层之间。 如图5所示，WC, CB, CNT, 和 SiC对复合涂层的硬度有影响，使得其硬度从纯Ni的510 kgf mm 2增加到920 kgf mm （24 g/L WC and 0.4 g/L CNT)。水浴锅中的加固类型和内容对复合涂层的微硬度有影响。随着加固的增加，微硬度增加到最高点之后开始下降。随着加固的增加，粒子细化和色散强度的增加，使得随着加固的增加，镍基复合涂层的微硬度也增加。Ni-WC和Ni-CNT复合涂层相对于其他类型来说，表现出了更高的硬度，这一结果表明经过WC/CNT共沉积的镍的任性和强度都增加了。而由Ni-CB复合的涂层的强度比其他三种都要小，并且由图二（c）所示，可以看到有更多的表面缝隙，因而表面更不规则。由于其比较低的强度和ＳｉＣ的浓度比较低，Ni-SiC复合涂层的硬度介于Ni-CNT 和Ni-CB之间。那些硬度增加的复合涂层，可能是由于其弥散强化效果。当用WC (4 g/L), CB (1.0 g/L), CNT (0.4 g/L), 和SiC (15 g/L)来做镍基复合涂层的时候，随着浓度的增加，强度也有所增加。分别从510增加到920, 760, 920, and 810 vH.但是，当起始浓度为6 g/L WC, 1.5 g/L CB, 0.6 g/L CNT, 20 g/L SiC时，硬度急剧的下降到720, 850, and 730 vH，这可能是由于高负载的复合物产生了多微孔结构所致。 如图六所示，四条曲线分别为相对于纯镍的Ni-WC 涂层 Ni-CB涂层, Ni-CNT涂层和Ni-SiC 涂层的应力应变曲线。在所有实验中，所有的应力都是通过测量曲线上的突然骤减得到的。图六显示了加固的增加对于复合涂层材料的作用。在纯镍曲线中，平滑的曲线，主要是由于在涂层过程中出现了动态的恢复以及重结晶过程。对于复合涂层在应力大于0.2之后出现的明显的软化是由于如图六所示在试样表面和内部形成微裂。所有的曲线相对于纯镍来说，在拉伸强度上都有所提高。被含有WC 和CNT的涂层包覆的复合材料的拉伸强度明显强于纯镍的，但是被SiC和CB包裹的就几乎在拉伸强度上所有增加。这可能是由于在Ni-SiC复合材料中的的粒子更容易发生粒子的断裂所致。水浴载荷的不同和强度的不同都会对复合材料的拉伸强度有明显的影响。 图七为不同种类的加固以及水浴载荷对于拉伸强度的影响，我们注意到增强的颗粒簇对于复合材料涂层的拉伸强度也有很大的影响。当镍基上的浓度为WC (4 g/L), CB (1.0 g/L), CNT (0.4 g/L), 和 SiC (15 g/L)时，随着浓度的增加，拉伸强度明显的分别从620到810, 740, 910, 808MPa，但是当镍基上的浓度为6 g/L WC, 1.5 g/L CB, 0.6 g/L CNT, 和20 g/L SiC时，拉伸强度又分别降低到740, 710, 860, 710 MPa。可以看到在涂层材料中，水浴里面负载的增加引起颗粒的簇的形成。 如图八所示为纯镍和镍基涂层的XRD图。对于纯镍和Ni-WC, Ni-CB, Ni-CNT, 和 Ni-SiC 复合涂层来说，其平均的晶体尺寸分别为43, 10.3, 9.1, 8.2,和 13, 5 nm。通过快速成核可以得到比较精细粒子的沉积。加固的增加可以提供很多数量的阳极，从而在金属表面形成更多的新的核，因而生成了具有精细粒子的复合物沉积。在图8（a）中，很明显可以观察到，纯镍沉积的很高强度的(200)面的衍射峰，相应于(100)结构，而相对于Ni-WC (Fig. 8b), Ni-CB(Fig. 8c), Ni-CNT (Fig. 8d), Ni-SiC(Fig. 8e)中，（311）和（111）面衍射峰很明显，伴随着（200）面的减小。很有趣的是，（311）和（111）面使得（211）面消失。所以，复合物涂层具有很大的硬度和拉伸强度。提高强度的其他的可能原因就是相对于那些纯镍涂层来说，由于在复合物涂层中的加固的存在使得镍晶体的颗粒尺寸减小了。 |
2楼2011-06-03 09:27:48