Nanostructured high performance metal matrix composites for high temperature, load, wear and corrosion applications

在过去的几年里，纳米结构的陶瓷-金属复合材料与传统复合材料相比，具有更高的耐温度、耐载荷、耐磨损和耐腐蚀的潜力。然而，由于纳米颗粒在加热过程中的粗化和溶解以及成本的提高，这些材料在技术上无法成功。因此，拟议的研究计划旨在开发基于纳米技术和分散强化的高性能低成本复合材料和涂层。在相对低熔点金属基体上具有热稳定陶瓷纳米颗粒的粉末将得到开发。这种组合，加上相对较低的加工温度，将确保最小化甚至消除纳米颗粒的粗化和溶解。将采用高能机械合金化（MA）。MA将传统的微尺寸陶瓷粉末粉碎成纳米尺寸，并在低温下将它们同时放入金属基体中。生产的粉末的一部分将用于HVOF热喷涂开发涂层。在HVOF喷涂过程中，氧气和燃料的燃烧可以加热并将半熔融粉末颗粒投射到基材表面，从而形成涂层。其他粉末部分将用于粉末冶金，包括压实和烧结，以开发复合材料和组件。陶瓷含量低于2% b.w（重量比）的复合材料的重点将是加强铝、银、铜、铬及其合金的导电性和耐高温性。潜在的应用包括固体氧化物燃料电池（SOFC）的互连以及中高压触点和开关。陶瓷含量在50% b.w.以上的复合材料将针对经受强磨损的部件。潜在的应用是油泵的密封和阀门，以及燃气轮机和反应堆的部件。加拿大将受益于组件的更高性能，减少机器和设备的磨损和故障损坏，停机时间和维护成本，特别是对关键能源行业。

The potential of nanostructured ceramic-metal composites to possess higher resistance to temperature, load, wear and corrosion compared to conventional composites has been proven in the past years. However, these materials could not succeed technologically because of the coarsening and dissolution of nano-particles during thermal processes and elevated cost. The proposed research program therefore aims at developing high performance and low cost composite materials and coatings based on nanotechnology and dispersion strengthening. Powders with thermally stable ceramic nano-particles in a relatively low melting metal matrix will be developed. This combination, together with relatively low processing temperatures, will insure minimisation or even elimination of nano-particle coarsening and dissolution. High energy Mechanical Alloying (MA) will be used. MA crushes conventional micro-size ceramic powders down to nano-size and forces them simultaneously into the metal matrix at a low temperature. One fraction of the produced powders will be used to develop coatings by HVOF thermal spraying. During HVOF spraying, combustion of oxygen and fuel enables heating and projecting semi-molten powder particles onto the substrate surface to create a coating. The other powder fraction will be used to develop composite materials and components by powder metallurgy, which consists of compacting and sintering. The emphasis for composites with ceramic fractions below 2% b.w. (by weight) will be the strengthening of aluminium, silver, copper, chromium and their alloys for applications requiring electrical conductivity and resistance to high temperature. Potential applications include interconnects for Solid Oxide Fuel Cells (SOFC) as well as medium and high voltage contacts and switches. Composites with ceramic fractions above 50% b.w. will target components subjected to strong wear. Potential applications are seals and valves for oil pumps, as well as components for gas turbines and reactors. Canada will benefit from the higher performance of components and from the reduction of wear and failure damage, downtime and maintenance costs of machines and equipment, especially for key energy industries.