牺牲阳极

sageman · 发表于 2011-5-10 20:24

牺牲阳极有锌块和铝块两种，前者便宜但较重，后者轻但较贵，牺牲阳极布置时，除了考虑成本，重量外，是不是还要根据船的各类不同来确定用锌块还是铝块，比如，散货船压载舱用铝块，油船压载舱用锌块？请高手指点，不胜感激！

昙花一现 · 发表于 2011-5-17 14:39

好像没这么分吧？我也不懂，刚进入行业还不了解

owen5242 · 发表于 2011-5-17 14:57

回复 1# sageman

不是啊，我们这散货船用的也是锌块，我问了我们同事，我们这边造的船所使用的牺牲阳极全部都是用锌块，好像没用到铝块

gejie521 · 发表于 2011-5-17 17:47

都是用锌块的，很少用铝的

sageman · 发表于 2011-5-17 19:58

回复 3# owen5242

3Q

andy.sir · 发表于 2011-5-17 20:15

铝块牺牲太快！高处脱落易爆，性价比不高啊！

andy.sir · 发表于 2011-5-17 20:16

铝块牺牲太快！高处脱落易爆，性价比不高啊！

石头 · 发表于 2011-5-17 20:21

我知道铝制品容易形式铝迹，而铝迹很容易产生局部的爆炸（规范里面说的），而且铝阳极安放位置与势能也有关系，而锌块几乎不受什么限制。我是学船体的，对这个不是很懂……求指教

swl1314ai · 发表于 2011-5-17 20:42

阿尔法阴极保护装置一套
全船就不用锌块了。用锌块的一般都是小船吧

wc149999426 · 发表于 2011-5-18 08:46

这个属于舾装了！不是船体的撒！

topbobby · 发表于 2011-5-18 10:57

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Zinc Anodes

The equilibrium potential of zinc is -763 mV vs. SHE (-1000 mv vs SCE) and therefore it is anodic to iron (equilibrium potential -440 mV vs. SHE). However, the polarity of the zinc-iron couple could reverse, with the iron becoming anodic to the zinc when the temperature is raised above 60ºC in an aerated electrolyte. This limits the use of zinc anodes to ambient temperature applications. Zinc anodes are generally specified to strict chemical compositions because of harmful impurities which impair the performance of the anode. The most detrimental impurity is iron. If present in excess of 0.0014%, iron will precipitate out as discrete intermetallic particles which will set up local galvanic cells on the zinc anode.

This has the effect of reducing anode efficiency. Moreover, the corrosion products of this self corrosion, namely the electrically non-conductive zinc hydroxide, tend to induce passivity making the anode redundant. This problem is effectively overcome by the addition of aluminum and silicon which combine with the iron to form less harmful intermetallics. Cadmium is also added to promote uniform corrosion and the formation of non-adherent corrosion products. As a result anode efficiencies greater than 90% can be achieved. Zinc anodes, because of their driving voltage, are suitable for the protection of coated pipelines in high conductivity electrolytes, such as in seawater, and at ambient temperatures. Zinc anodes are also used in applications where spark hazards need to be avoided as in storage tanks containing flammable hazards

topbobby · 发表于 2011-5-18 10:57

Aluminum Anodes

Aluminum has an equilibrium potential of -1.90 V vs. SCE and therefore thermodynamically it is a very reactive metal. However, in most natural environments aluminum has been found to be stable due to the formation of a thin protective oxide.
This film has a high electrical resistance and thus renders pure aluminum useless as a sacrificial anode. Even when galvanically coupled to a more active metal in a chloride containing environment aluminum corrodes by pitting rather than uniform dissolution. But in the light of aluminum other favorable properties, including a large electrochemical equivalent, relatively low cost and low density, attempts have been made to modify this oxide film. To disrupt the physical integrity of the protective film several aluminum alloys have been developed. Alloying elements which were found to induce activation included Hg, In, Sn, Ga, Bi, Zn, Cd, Mg and Ba. Commercially successful aluminum anodes mainly contain zinc (0.5-4%) with either indium (0.01-0.05%) or mercury (0.030-0.050%). The current capacity of such alloys is in the region of 2500 A hr/kg and anode efficiencies can be greater than 90%.

The role played by the zinc in the enhancement of aluminum activation is thought to be due to a modification of the passive film on aluminum. For mercury, it is believed that Hg2+ ions dissolved near the anode interface are plated scale (as Hg) at the weak points. The amalgamated areas formed may either allow direct corrosion through the amalgam or enhance the adsorption of Cl- ions and cause film breakdown. Similarly, indium ions are also thought to plate at film defects and thus prevent repassivation by enhancing chloride adsorption. Further since mercury and indium are poor cathodes for hydrogen evolution, this results in higher anode efficiencies

wyg355000 · 发表于 2011-5-20 14:12

一般压载舱里用的是锌块，外板用的是铝块

sageman · 发表于 2011-5-20 21:04

回复 8# 石头

谢谢了哈，嘿嘿

xxx099 · 发表于 2011-5-24 20:07

大部分压载舱用的牺牲阳极都是锌的，分为A型和B型；外板用的是阴极防护。

hutopone · 发表于 2012-5-10 15:52

锌块和铝块各有优缺点现在广泛用的是锌--铝--镉主要考虑的是材料来源丰富冶炼方便

天地情缘阿肖 · 发表于 2012-5-11 12:35

我们用的是辛

天地情缘阿肖 · 发表于 2012-5-11 12:36

我们用的是新快

天地情缘阿肖 · 发表于 2012-5-11 12:36

我们用的是新快

jiangfuxx · 发表于 2013-1-22 12:26

从什么方面来看了，锌块和铝块都可以用，多数小船用的是锌块，锌块腐蚀均匀，电流效率高。铝块发生电流大，腐蚀物较大些，容易出现坑蚀。目前来说，很多精明的船东选择用铝块的多，铝块密度小，轻，单船用的量比锌块少很多，费用省很多。

外加电流I***，当然目前大船用I***的很多，也有小船也用I***，论我的经验来说，小船用用锌块得了，也方便。有多少船上的机务懂I***的，维护起来麻烦的。锌块2年~5年，没了就换就好了，方便。

压舱用I***目前来说好像有安全方面的隐患的，不适合。

尽量选择能出船级社证书的厂家吧，新厂或者没有一点资质的工厂，容易出现原料不纯，惨假等，不腐蚀的话，一切都是白搭。

[船体] 牺牲阳极