Development and characterisation of high performance ceramic-metal composites

陶瓷-金属复合材料或金属陶瓷广泛应用于对韧性、高强度、耐腐蚀性和耐磨性有要求的各种工业应用中，特别是在石油、采矿、化学加工、运输以及纸浆和造纸行业。因此，人们继续推动开发用于这些苛刻环境的改进材料，无论是散装的还是涂层的。近100年来，基于碳化钨/钴(WC/Co)的材料一直是金属陶瓷的首选。然而，WC/Co实际上表现出相对较差的耐腐蚀性和抗氧化性，而机械性能在~500°C以上严重退化。由申请人共同开发的一系列新型金属陶瓷利用韧性镍铝化物(Ni3Al)合金，消除了与WC/Co和其他金属陶瓷系统相关的许多问题，并提供了显著的好处，即强度实际上随着温度的提高而增加，最高可达~1,000°C。 目前的应用广泛建立在我们先前对高性能金属陶瓷的开发和特性研究计划的基础上。我们计划利用各种Ni3Al基粘结剂，以碳化钛和碳氮化物为基础，制备纳米结构材料。力学性能，如强度和硬度，将进行评估。断裂行为将通过现场裂纹扩展观察进行评估。我们正在进行的赫兹接触损伤研究(模拟球面轴承条件)将扩大，主要包括强度退化、循环压痕响应和高温损伤的评估(在使用Ni3Al时预计会有特定的好处)。此外，还需要更充分地评估这些材料的氧化响应，这将通过热重分析和静态氧化试验来实现。这项研究的成功成果将是用于各种工业应用的新一代高性能金属陶瓷，这将导致延长部件寿命和提高安全公差。最终，生产的材料也可能被改装用于涂料，进一步扩大其操作范围。

Ceramic-metal composites, or cermets, are used in a wide variety of industrial applications where toughness, high strength, and resistance to corrosion and wear are required, notably in the petroleum, mining, chemical processing, transportation, and pulp and paper industries. There is consequently a continuing drive to develop improved materials for use in these demanding environments, either in bulk or coating form. For approaching 100 years, materials based on tungsten carbide/cobalt (WC/Co), have been the cermet of choice. However, WC/Co actually exhibits relatively poor corrosion and oxidation resistance, while the mechanical properties are severely degraded above ~500°C. A family of novel cermets, co-developed by the applicant, utilising ductile nickel aluminide (Ni3Al) alloys, eliminate many of the problems associated with WC/Co and other cermet systems, and offer the notable benefit that strength actually increases with temperature, up to ~1,000°C. The present application builds extensively on our prior program of research into the development and characterisation of high performance cermets. We plan to prepare nano-structured materials, based on titanium carbide and carbonitride, utilising a variety of Ni3Al-based binders. Mechanical properties, such as strength and hardness, will be assessed. Fracture behaviour will be evaluated through in-situ crack growth observation. Our ongoing Hertzian contact damage studies (simulating spherical bearing conditions) will be expanded, notably to include assessment of strength degradation, cyclic indentation response and elevated temperature damage (where specific benefits are expected when using Ni3Al). In addition, the oxidation response of these materials needs to be more fully assessed, which will be achieved through thermogravimetric analysis and static oxidation trials. The successful outcome of this research will be new generations of high performance cermets for a variety of industrial applications, which will lead to improved component lifetimes and increased safety tolerances. Ultimately, the materials that are produced may also be adapted for use as coatings, further increasing their operational scope.