Silicide-Strengthened Steel - A New Method of Wear Protection within Nuclear Environments

钴基(Co)钢合金广泛应用于核反应堆，特别是水冷反应堆中的阀门和泵。这是因为它们提供了出色的耐磨性，从而提高了部件寿命并减少了维护要求。然而，这些合金价格昂贵，而且由于钴-60的形成，也增加了核设施工人的辐射暴露。钴-60是一种发射伽马的放射性同位素。因此，从健康、安全和成本以及长期退役的角度来看，在未来的核反应堆中更换钴基堆焊合金是非常可取的。然而，到目前为止，铁(Fe)和镍(Ni)基合金等替代材料还无法与Stellite 6的出色性能相提并论，Stellite 6是一种著名的钴基合金，用于堆焊应用(即磨损特别重要的应用)。为响应EPSRC关于进行与能源研究相关的可行性研究的号召，我们建议探索新型硅化物强化不锈钢的可制造性，以提供一种新型的无钴堆焊材料，用于核部件，具有高耐磨性和耐腐蚀性。直到最近，我们才发现了一种用于堆焊应用的新型铁基合金，这为最终拥有一种在磨损和腐蚀性能上与钴基合金相匹配的材料体系提供了一个真正而宝贵的机会，同时还为核电工人提供了巨大的成本优势和降低暴露风险。这里提出的成功证明这种材料的可行性，可能会在许多其他需要高强度不锈钢解决方案的领域产生重大影响(例如在石化行业的高腐蚀性环境中)。

Cobalt-based (Co) steel alloys are extensively used in nuclear reactors, particularly in the valves and pumps employed in water-cooled reactors. This is because they provide outstanding wear resistance, and so improve component life and reduce maintenance requirements. However, these alloys are expensive, and also raise the radiation exposure of workers at nuclear utilities, due to the formation of Cobalt-60, a gamma-emitting radioactive isotope. For this reason, replacing Co-based hardfacing alloys in future nuclear reactors is highly desirable in terms of health and safety and cost, as well as long-term decommissioning. To date, however, alternative materials such as iron (Fe)- and nickel (Ni)-based alloys have not been able to match the outstanding properties of Stellite 6, a well-known Co-based alloy for hardfacing applications (i.e. applications where wear is of particular importance). In response to the EPSRC call for feasibility studies related to energy research, we propose to explore the manufacturability of novel silicide-strengthened stainless steels in order to deliver a new class of Co-free hardfacing materials for nuclear components, with high galling- and corrosion-resistance. We have discovered a new class of Fe-based alloys for hardfacing applications only very recently, providing a real and valuable opportunity to finally have a material system that can match Co-based alloys in their wear and corrosion performance, while also offering great cost advantages and reduced exposure risk for nuclear utility workers. Success in demonstrating the viability of this class of material, as proposed here, could further have great impact in many other areas where high-strength stainless steel solutions are required (such as in highly corrosive environments in the petrochemical industry).