金属搪瓷复合材料高温自润滑与抗氧化耦合机制的研究

Under the co-effect of oxidation and wear, oxides developed upon metal matrix composites are able to transform to a glaze layer by consecutive extrusion and crushing. An intact and stable glaze layer on surface can play a role of self-lubrication and oxidation protection. Previous study has proved that adding SiO2 in composites favors the nucleation and stabilization of such a glaze layer. Enamel has the similar network microstructure with SiO2, enabling it with high oxidation resistance. We have studied and demonstrated that the thermo physical properties of enamel can be adjusted to a large extent by controlling the composition and percentage of network modifiers, making the enamel more compatible with the metal matrix. Therewith, self-lubricating and oxidation protective metal-enamel composites can be designed and prepared. However, there is still no detail study and discussion of the mechanisms of the enamel and SiO2 phase affecting the formation of glaze layer on the metal matrix composites. In this project, metal-enamel composites will be prepared by spark plasma sintering (SPS). Thereafter, compatibility between enamel and the alloy phase and its oxides is studied, and the formation thermodynamic and kinetic characteristics of glaze layer on wear surface are researched. Though that, the underlying regulation of enamel affecting self-lubrication and oxidation resistance of the metal matrix composites are explored, and the broking mechanisms of the composites by the synergistic actions of high-temperature oxidation and wear are revealed. This systematic study helps to establish the theoretic foundation to design novel high-temperature self-lubricating and oxidation protective metal matrix composites. It shows significant scientific importance and broaden application prospect.

在氧化与摩擦的共同作用下，金属基复合材料表面的氧化产物经不断挤压、碾碎后可形成釉质层。完整稳定的釉质层能起到自润滑与抗氧化的作用。研究发现，SiO2的添加有利于复合材料表面釉质层的形核与稳定。搪瓷具有与SiO2类似的网络结构，抗高温氧化性能优异。我们前期已证实，通过网络中助溶剂组元与含量的调整，可大幅度调控搪瓷的热物理性能，使其与合金匹配，进而设计制备抗氧化、自润滑的金属搪瓷复合材料。然而，搪瓷相以及SiO2在复合材料中的作用机制，目前尚欠详细的研究与探讨。本项目拟通过放电等离子烧结制备镍基合金与搪瓷的复合材料，开展搪瓷相与合金及其氧化物的相容性、釉质层的形成热力学与动力学等方面内容的研究，探讨搪瓷影响复合材料自润滑与抗氧化性能的内在规律，揭示金属搪瓷复合材料的高温氧化与摩擦磨损耦合破坏机理，为新型耐高温抗氧化金属基自润滑复合材料的设计奠定理论基础，具有重要的科学意义及广阔的应用前景。

在高温摩擦时，一些金属基复合材料表面可形成釉质层，发挥自润滑与抗氧化的作用。研究发现，SiO2的添加有利于复合材料表面釉质层的形核与稳定。搪瓷具有与SiO2类似的网络结构，抗高温氧化性能优异。我们前期已证实，通过网络中助溶剂组元与含量的调整，可大幅度调控搪瓷的热物理性能，使其与合金匹配，进而设计制备抗氧化、自润滑的金属搪瓷复合材料。然而，搪瓷相以及SiO2在复合材料中的作用机制，目前尚欠详细的研究与探讨。本项目通过放电等离子烧结制备镍基合金与搪瓷的复合材料，开展搪瓷相与合金及其氧化物的相容性、釉质层的形成热力学与动力学等方面内容的研究，探讨搪瓷影响复合材料自润滑与抗氧化性能的内在规律，揭示金属搪瓷复合材料的高温氧化与摩擦磨损耦合破坏机理，为新型耐高温抗氧化金属基自润滑复合材料的设计奠定了理论基础，具有重要的科学意义及广阔的应用前景。.通过该项目的资助，在搪瓷高温自润滑机理研究的基础之上，掌握了金属搪瓷高温自润滑复合材料的设计原理，并与中航发沈阳发动机研究所合作，研制了可用于发动机工况的高温自润滑复合材料及其零部件产品。项目执行四年时间内，发表了SCI收录论文共19篇，培养博士毕业研究生4名，硕士研究生3名。