烧结材料特性对机械密封混合润滑性能的影响

Hybrid lubrication model for mechanical seals is studied based on the hypothesis of homogeneous material in the present although more and more sintering materials, such as carbon, silicon carbon and cemented carbide, which are multiphase materials consisting of matrix phase and binder phase are wildly used in all most all of the industrial fields due to their ideal tribological and mechanical properties. So, the hypothesis of homogeneous material is not available in this condition. In this work, the coupled multi-physics hybrid lubrication model considering the influence of multiphase property of sintering material on the contact pressure and frictional heat will be presented. Furthermore, the mechanism of surface modification by High-intensity Pulsed Ion Beam Irradiation with WC-Ni materials will be investigated in order to find more efficient process to improve their tribological performance of hard material. The results of this research will reveal the mechanism of influence of sintering material multiphase properties on the hybrid lubrication performance of mechanical seals and extend the researching region for mechanical seals which can make us be better understanding the mechanism of hybrid lubrication and failure for mechanical seals.

目前机械密封的混合润滑模型均为材料均质假设的研究。但烧结材料，如石墨、陶瓷及硬质合金由于其优良的摩擦学特性和机械性能，被广泛应用于各个工业领域，其多相特性（基体相与粘结相）对接触压力和摩擦热会产生一定的影响，材料均质假设不再适用。本课题拟基于统计模型，将多学科理论相结合，综合考虑密封环烧结材料多相特性对弹塑性接触和摩擦热的影响，建立机械密封流/固/热耦合混合润滑分析模型；揭示烧结材料多相特性对机械密封混合润滑性能的影响机制与规律。同时，探索强流脉冲粒子束加工工艺对烧结材料密封环表面改性对其微观组织结构的影响机制和对宏观摩擦学性能的影响，为寻求硬质合金等烧结材料更高效的表面改性途径提供理论基础。延长机械密封环的使用寿命的同时，课题研究结果将有助于人们理解烧结材料多相特性对混合润滑的影响，从而更深入揭示机械端面密封混合润滑和失效机理，丰富机械密封理论研究内容。

石墨、陶瓷及硬质合金由于其优良的摩擦学特性和机械性能，被广泛应用于各个工业领域，特别是在核电领域轴封式主泵中的机械密封也采用了这些烧结材料。烧结材料具有多相特性（基体相与粘结相），对接触压力和摩擦热会产生一定的影响，传统的材料均质假设不再适用。. 本课题基于统计模型，将多学科理论相结合，考虑密封环烧结材料多相特性对弹塑性接触和摩擦热的影响，建立了机械密封流/固/热耦合混合润滑分析模型；揭示出烧结材料多相特性对机械密封混合润滑性能的影响机制与规律。研究表明，密封材料的微观不均匀性对密封性能的影响主要反映在材料的弹性模量和热膨胀系数上，随着孔隙和粘结相的增加，密封材料热膨胀系数增大，弹性模量减小，这会导致端面热变形和粗糙峰的弹性接触增大,加剧密封环表面磨损。. 通过强流脉冲粒子束（HIPIB）加工工艺对烧结材料密封环进行表面改性，实验研究获得WC-Ni表面强化优化工艺参数。经辐照改性后的WC-Ni对磨，摩擦系数明显降低，可以达到0.06-0.07，同时有效减少了对石墨的黏着磨损，降低石墨软环的磨损率。该结果为硬质合金等烧结材料更高效的表面改性途径提供理论和实验基础。课题研究结果有助于人们理解烧结材料多相特性对混合润滑的影响，从而更深入揭示机械端面密封混合润滑和失效机理，丰富机械密封设计理论。.