Development and characterisation of high performance ceramic-metal composites

陶瓷-金属复合材料或金属陶瓷用于需要韧性、高强度和耐腐蚀性和耐磨性的各种工业应用中，特别是在石油、采矿、化学加工、运输以及纸浆和造纸工业中。因此，存在开发用于这些苛刻环境的改进材料的持续动力，无论是散装形式还是涂层形式。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以上严重下降。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（Ni 3Al）合金，消除了与WC/Co和其他金属陶瓷系统相关的许多问题，并提供了显著的益处，即强度实际上随温度增加，高达~ 1，000 °C。 本申请广泛地建立在我们对高性能金属陶瓷的开发和表征的先前研究计划的基础上。我们计划利用各种Ni 3Al基粘结剂制备基于碳化钛和碳氮化物的纳米结构材料。将评估机械性能，如强度和硬度。断裂行为将通过原位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（模拟球形轴承条件）将得到扩展，特别是包括评估强度退化，循环压痕响应和高温损伤（当使用Ni 3Al时，预计会有特定的好处）。此外，这些材料的氧化反应需要更全面的评估，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，这将导致提高部件寿命和增加安全公差。最终，所生产的材料也可以适用于涂料，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.