Environmentally friendly anti-biofouling and anti-corrosion coatings for steels based on multilayer plasma-deposited doped amorphous carbon

腐蚀是一个严重的世界性问题；据估计，工业化经济体中金属腐蚀的直接经济成本约为国内生产总值的3%。[资料来源：NACE腐蚀成本研究(2002年)，IOM3腐蚀委员会(2013年)]加上间接成本，这个数字略高于这个数字，可能在5%-6%左右。除了经济成本外，与腐蚀问题相关的环境和其他成本也很大。例如，处理饮用水的系统可能会受到腐蚀产物的污染；含有潜在危险材料的油罐车、废物设施和管道也可能容易受到腐蚀--此类系统的故障对公共和环境安全具有明显的风险。生物污垢是指微生物、植物、藻类或动物在潮湿的结构物上聚集，特别是在海洋工程中，这是一种不受欢迎的现象。例如，生物污垢在船体和螺旋桨上的积累会显著增加阻力，从而增加燃料消耗，从而增加二氧化碳排放。不幸的是，它几乎在所有情况下都会发生，包括水基液体与其他材料的接触。例如，在海洋环境中，微生物首先形成生物膜，然后使更大的微生物连续附着在表面，最终导致大型生物，如贻贝、海鞘和藤壶附着。防污染是清除这些沉积物的过程，或首先防止积聚的预防措施。通常，这种行动可以包括使用可能含有生物剂的防污涂层，或其他防止生物附着在表面上的方法，例如仿生涂层。过去使用的许多防污剂，如三丁基锡(TBT)，已经变得不适合，在某些情况下，出于环境和毒性考虑，禁止使用化学品。考虑到作为海洋工程问题的污垢的规模和性质，以及由污垢引起的经济和性能问题，大量的研究活动继续集中在这一领域。本研究提案的主要重点是对掺杂、多层、耐用的无定形DLC，同时防止腐蚀和生物污染。这种涂层继续被开发用于其他应用；该项目源于UWS对用于干涉型引力波探测器的DLC涂层和用于红外光学系统的耐用保护性抗反射涂层的研究。我们小组目前正在评估DLC和改性DLC与其他表面处理相结合，以提高硅、二氧化硅和蓝宝石悬浮元件的强度和耐用性，这些悬浮元件用于法国-意大利的Virgo探测器、美国的LIGO探测器和正在建设中的日本KAGRA探测器。此外，我们最近提供了一系列用于探测器挡板管的改性类金刚石涂层供Virgo小组评估。此外，PI申请者之前的工作重点是通过沉积多层类金刚石涂层来防止海军合金的腐蚀；在环境测试中，注意到某些膜组分表现出防污效果。尤其是一种设计，在夹层中混合了掺杂材料，表现出与未涂覆的海军镍铝青铜相似的抗污性，可防止铜离子在腐蚀时释放出污垢；寡头动力效应。因此，我们的研究目标将是开发和测试用于管状、平面和复杂形状基材的此类涂层，并评估它们在防护应用中的适用性，以及未来商业化的可扩展性和潜力。

Corrosion is a significant problem worldwide; it is estimated that the direct economic cost of corrosion of metals in the industrialised economies is in the region of 3% of GDP. [Sources: NACE Cost of Corrosion study (2002), IOM3 Corrosion Committee (2013)] Adding the indirect costs, the figure is somewhat higher than this, likely in the region of 5-6%. In addition to the economic costs, there are significant environmental and other costs associated with the corrosion problem. For example, systems processing drinking water can become contaminated by corrosion products; tankers, waste facilities and pipelines containing potentially hazardous materials can be susceptible to corrosion, too - and failure of such systems has clear risks for public and environmental safety. Biofouling, or biological fouling, is an accumulation of microorganisms, plants, algae, or animals on wetted structures, and is, particularly in marine engineering, an undesirable phenomenon.For example, the accumulation of biofouling on ships' hulls and propellers can significantly increase drag, and thereby increase fuel consumption and, consequently, CO2 emissions. Unfortunately, it occurs in almost all circumstances involving the contact of water based liquids with other materials. In marine environments, for example, formation of a biofilm by microorganisms, in the first instance, then enables successively larger macroorganisms to attach to the surface, eventually resulting in large organisms, such as mussels, sea squirts and barnacles, attaching.Anti-fouling is the process of removing such deposits, or preventative measures to avoid the accumulation in the first instance. Typically, such action can include the use of antifouling coatings, which may contain biocides, or other methods of preventing organisms from attaching to surfaces, e.g. biomimetic coatings.Many anti-fouling agents used in the past, such as tributyltin (TBT), have become unsuitable and, in some cases, banned chemicals due to environmental and toxicity concerns.Given the scale and nature of fouling as an issue in marine engineering, and the economic and performance problems caused by fouling, a good deal of research activity continues to focus on this area.The main focus of this research proposal is to carry out a proof-of-concept study into the use of doped, multi-layered, durable amorphous DLC, in the simultaneous prevention of corrosion and biofouling.Such coatings continue to be developed for other applications; this project is derived from research undertaken at UWS into DLC coatings for interferometric gravitational wave detectors and durable protective anti-reflection coatings for infrared optical systems. Our group is currently evaluating DLC and modified DLC in combination with other surface treatments for improvements in the strength and durability of silicon, silica and sapphire suspension elements as used in the French-Italian Virgo detector, the American LIGO detectors, and the Japanese KAGRA detector currently under construction. Furthermore, we have recently provided a range of modified DLC coatings for evaluation by the Virgo group for use in detector baffle tubes.Additionally and separately, previous work by the PI applicant focused on prevention of corrosion of naval alloys by deposition of multilayer DLC-based coatings; during environmental testing it was noted that certain film compositions exhibited an antifouling effect. One design in particular, containing a mix of dopant materials in the interlayers, exhibited a similar resistance to fouling as uncoated naval nickel aluminium bronze, which prevents fouling by release of copper ions as it corrodes; the oligodynamic effect. Our research will therefore be targeted towards development and testing of such coatings for tubular, planar and complex-shaped substrates, and assessing their suitability for use in protective applications, as well as scalability and potential of future commercialisation.