Surface Control of High Strength Steel for Galvanization

为了能够以环境和经济的方式开发和生产更智能的材料，需要更灵活的技术。其中一项潜在的突破性技术是灵活的高速物理气相沉积(PVD)。在这一过程中，在真空中产生蒸汽，然后将其喷洒到带材上，从而形成一层薄的固体薄膜。这项技术允许在高质量的带材产品上沉积独特的涂层选择，从而实现基材和涂层的优化。追求PVD技术的动机不仅在于其未来的应用，也在于当前的问题。汽车行业被推动减少二氧化碳排放，提高燃油经济性，而实现这一目标的一条途径是减轻车辆重量。汽车可以通过使用涂覆的新型先进高强度和超高强度(UHSS)钢等级来使其更轻，因为它们在较薄的部分提供相同的强度。这些钢种是用相对较高的锰、硅和铝合金水平生产的。然而，这种合金化添加剂会影响耐腐蚀涂层(通常是镀锌)，这会导致每个钢种的涂层配方不同。有些牌号是不可能用热浸镀锌的。因此，为了能够帮助汽车行业实现未来的重量减轻，钢种和涂料的开发都是至关重要的。灵活的PVD技术将使这一系列的超高硬度涂层成为可能，并将使未来的基材/涂层系统的制造具有目前无法生产的增强性能。这个与塔塔钢铁欧洲公司合作的博士项目将解决以下研究问题：如何在带钢生产过程中控制氧化物的形成和类型？不同的氧化物如何影响涂层的性能-附着力、表面外观和腐蚀？如何在涂层前去除带材中的氧化物？例如，等离子清洗？衬底上的锌/锌镁涂层的厚度/应力如何影响整体性能？

To be able to develop and produce smarter materials in an environmental and economical way, more flexible technologies are required. One such a potential breakthrough technology is flexible high-speed Physical Vapour Deposition (PVD). In this process, a vapour is generated in a vacuum and then sprayed onto a strip, thus forming a thin solid film. This technology allows the deposition of a unique selection of coatings onto high quality strip products enabling the optimization of both the substrate and the coating. Motivation to pursue PVD technology not only lies in its future applications, but also in current issues. The automotive industry is pushed to reduce CO2 emissions and improve fuel economy, and one route to achieve this is reducing vehicle weight. Cars can be made lighter by using coated novel Advanced High Strength and Ultra High Strength (UHSS) Steel grades as they deliver the same strength in thinner sections. These steel grades are produced with relatively high alloy levels of Mn, Si and Al. However, such alloying additions influence the coatability for corrosion (typically Zn galvanising), which results in different coating recipes for each steel grade. Some grades are impossible to coat with Hot Dip Galvanizing. Hence, to be able to assist the automotive industry in achieving the future weight saving both steel grade and coating development are essential. The flexible PVD technology will make it possible to coat this range of UHSS and will enable the manufacturing of future substrate/coating systems with an enhanced performance that can presently not be produced. This PhD project in collaboration with Tata Steel Europe will address the following research questions: How can the oxide formation and type be controlled during the strip production?How do different oxides affect the coating performance - adhesion, surface appearance, corrosion? How can the oxides be removed from the strip before coating - e.g, plasma cleaning?How does the thickness/stress in the Zn/ZnMg coating layer on top of the substrate influence the overall performance?