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腐蚀是一种常见的现象，那里有金属，会有生锈。用科学术语来说，腐蚀是一种化学过程，其中精制金属转化为更稳定的形式。
在您的家庭环境中发现的四种基本成分会导致腐蚀：反应性金属，空气，水分和电解质。而且，虽然快速喷雾WD-40战斗腐蚀，从粘性钥匙孔到卡住的铰链，为了避免腐蚀，我们需要从设计开始。
了解腐蚀的原因使其更容易针对它进行设计。本文探讨了增加金属腐蚀性的策略。一张注意：与聚合物上的微生物活动有关的腐蚀类型有几种，我们在这篇文章中不会解决。
被动涂层可避开水和盐
Bicycles are a great example of how you can design a corrosion-resistant product. Typically made of steel, aluminum, and carbon fiber, bicycles are also regularly exposed to the elements. Rain + road dust = water + electrolytes = corrosion. Adding a physical barrier to prevent direct contact with the external environment helps to keep corrosion in check; options include painting, powder coating, vinyl wrapping,阳极氧化，甚至打蜡。这些方法（称为被动涂层）可将水和盐防止，防止腐蚀，并且在设计您知道会在元素外花费时光的产品时为它们进行计划很重要。
Painting
您可以计划通过考虑被动涂层来使设计耐腐蚀性，这是自行车制造商用来提高耐腐蚀性的方法。自行车框架被漆成形成屏障层 - 在干净，干燥的表面上涂上水分，这意味着水分不会被困在外套下面。
粉末涂料
如果您正在设计诸如自行车架之类的产品，其中许多是由aluminium，您需要计划将产品粉末涂成涂层，以避免刮擦铝并与水接触时可能产生的斑点。粉末涂料is done by spraying a layer of dry powder (thermoplastic or thermoset plastic polymer) electrostatically.
在粉末涂料中，粉末涂料枪具有正电荷，而工件则接地。这种电差将微小的颗粒驱动到工件上，就像您在学校可能进行的抬高头发气球实验一样。这样可以确保甚至涂层，然后进行固化课程。
乙烯基包裹
You count on your U-lock for security, and you don’t want it to get corroded, so most U-lock manufacturers wrap the locks in vinyl to protect them from the elements—and as a designer, you’ll want to plan for this. Vinyl wrapping is like shrink wrapping; heat is applied once the U-lock has been sleeved with the vinyl (see the black, U-shaped tubing in the image below).
Anodizing
不锈钢和CNC加工铝具有形成一层保护氧化物的固有能力。但是，在自然形式中，这种氧化层仅约4nm厚。阳极氧化金属是提供额外腐蚀和磨损保护的一种方法，因此请务必将其添加到钢和铝产品计划中。
In some cases, anodizing is used as a decorative element, allowing designers to add different shades of color.苹果用不同的彩色设备来做到这一点: Space Gray, Rose Gold, and Gold.
通过将工件放入稀溶液中来完成阳极化。工件正在连接到阳极的电路。阳性氧气离子将被吸引到工件上，从而在工件上产生更多的氧化物层。
主动涂层提供强大的物理障碍
镀锌
When you’re designing products to be corrosion resistant, you may want to to keep in mind that galvanizing provides a stronger physical barrier than passive coating does, by forming a chemical bond with the physical substrate of the material, instead of just coating the surface. This chemical bond is much stronger than what passive coating can offer, with a bond strength of 3000psi. Best of all, it has dual action—it makes the base metal cathodic by attaching a more reactive metal onto the surface. The thin layer of coating will rust first, instead of the base metal.
在所有次要过程完成后，最好完成镀锌，因为任何新切割都会暴露新鲜金属，从而形成生锈。除了街道轻柱和钢桥外，通常在车辆和紧固件上进行镀锌，以确保耐腐蚀性。
热浸镀锌是一种大型制造技术。该过程如下所示。每个物体都必须经过苛性清洁，然后再进行几个准备阶段，然后才浸入锌浴中并冷却。
确保电流兼容性
When you’re designing fasteners, it’s important to ensure that there is galvanic compatibility with the fasteners and the object. On the Galvanic Scale, metal that is more anodic is more prone to corrosion, and when more anodic metal is in contact with a metal that’s lower on the scale, corrosion activity is enhanced. The greater the disparity, the faster the rate of corrosion.
因此，您不想混合搭配涂层和金属；如果您选择热蘸锌 - 瓦瓦剂化材料，请使用fasteners和带有相同涂料的硬件。Screwsand rivets are the most commonly used fastening methods, and the majority of them are made of steel, which happens to be lower on the Galvanic Scale, so you have to be aware of this.
If you start combining different types, there’s a chance the different metals will start their own corrosive reactions—which is exactly what you are trying to prevent.不锈钢会降解镀锌钢，因此请勿用不锈钢螺钉安装镀锌板。
实际上，您可以利用电力不兼容来实现自己的优势。在海洋工业中，牺牲金属用于保护船体免受腐蚀。锌块直接安装在水线下方的船体上。这是有意允许牺牲锌被腐蚀而不是钢铁船体的。
用塑料代替金属
增强耐腐蚀性的一种方法是计划用合适的惰性材料代替零件，例如塑料。Water pipes used to be made from metal, but have since been replaced with plastic, as have bearings. You may避免用塑料腐蚀，但是塑料存在独特的问题，例如紫外线降解，酸和热的问题，这一点很重要，尽管在这里不会涵盖它们。
避免设计中的缝隙
下图显示了产品体内的水滴如何导致生锈的形成。当反应金属的表面被弄湿时，相对于周围的氧气浓度较低。液滴周围的区域变为阴极，而下面的表面为阳极。
This localization of electrical activity is what causes spots of rust to form on a kitchen basin, which gets worse with a lower grade of stainless steel. You can design against this form of corrosion by removing traps to ensure that there is uniform oxygen concentration around the bodywork.
We can learn from the construction industry, which does crevice corrosion prevention best. Rules like allowing water and dust to flow freely but not get trapped onto the surface are helpful. Designs are simplified to reduce the number of crevices, and if crevices cannot be avoided, weather-sealing can help counter corrosion.
换句话说，减少关节零件，涂料和密封的数量可以帮助避免缝隙腐蚀。
主要要点
It’s important to understand what causes corrosion and to use strategies for increasing metal corrosion resistance in your product design process. Incorporate plans for coatings, vinyl wrapping, and galvanizing into your product design process when working with metals, and avoid crevices in your design. You can check out Fictiv’s Capabilities Guide for more information about materials. As in all hardware development, always be thorough with your测试程序，然后检查使用行为和操作环境。能够理解您的产品在环境中的经历是一半的战斗。
