自润滑钨基复合材料的制备与摩擦学性能

In high temperature gas-cooled reactor primary cooler system, it has become a crucial technical matter to explore the material for friction pairs serving under nuclear radiation and dry friction condition in order to keep mechanical facilities free of replacement in their whole lifetime. The traditional materials have significant deficiencies and limited lifespans. Our primary research discovered that heavy tungsten alloy possesses high wear resistance, and can work for a long time under room temperature and low speed. But its friction coefficient is still high, which leads to limited operating temperature, speed and lifespan. This project is going to fabricate self-lubricating tungsten-based composite by introducing solid lubricant to improve its anti-friction and anti-wear performances. By (i) composition design of tungsten-based alloy with low sintering temperature, (ii) surface modification of lubricant and (iii) sintering method to inhibit the melting loss of lubricant, fabrication of self-lubricating tungsten-based composite would be achieved. The effect of lubricant on alloy structure and matrix strength would be revealed. The tribological performance and wear life of self-lubricating tungsten-based composite under different temperatures, speeds and atmospheres would be explored. And its lubricating mechanism and failure mechanism would be discovered. Therefore, this project would provide practical basis and theoretical support for the wider application of self-lubricating tungsten-based composite in nuclear energy and aerospace.

开发在核辐射、干摩擦条件下服役的摩擦副材料，已成为促进高温气冷堆一回路机械设备实现全寿期免更换的关键技术问题，而传统材料存在明显不足，寿命有限。初步研究发现高密度钨合金耐磨性好、能够在常温低速工况下长期工作，但目前仍然存在摩擦系数较大的缺点，导致服役温度和转速不高，使用寿命仍然较短。本项目拟制备自润滑钨基复合材料，引入固体润滑剂，提高减摩耐磨性能，通过低烧结温度的钨基合金成分设计、润滑剂表面改性和抑制润滑剂烧损的烧结方法，实现自润滑钨基复合材料的制备，并探明润滑剂对合金组织结构及基体强度的影响。研究自润滑钨基复合材料在不同温度、转速和气氛条件下的摩擦学性能和磨损寿命，揭示其减摩润滑机理和失效机制，为自润滑钨基复合材料在核能、航天等领域的推广应用提供实践基础与理论支持。

在核电领域和航天领域中，一些重要设备需要在核辐射、无油润滑等极端环境条件下承受摩擦磨损，对所用的材料提出了苛刻要求。以核电领域的高温气冷堆为例，高温气冷堆是具有第四代核能系统安全特征的先进核电堆型，我国自主研发的这项技术在全球长期保持着领先优势。在高温气冷堆一回路中，一些重要机械设备的轴承、丝杠等转动部件的材料需要在高温、核辐射、氦气气氛、无油润滑条件下长期工作。为了尽量提高高温气冷堆中摩擦副的寿命，实现一回路机械设备的全寿期免更换，需要找到新型的耐磨材料进行代替。这对该堆型的改进和完善具有重大的战略意义。.本项目成功开发了含润滑剂的WC-Ni和WC-Co基复合材料。在WC基合金的基体材料中，加入了固体润滑材料，通过研究证实了电流活化烧结法制备该自润滑复合材料的可行性，通过改进烧结模具，提高烧结压力，建立了针对该复合材料的电流活化烧结方法，该方法对固体润滑剂烧蚀破坏小、同时能够保证基体强度。.研究了烧结温度，压力对复合材料的致密化效果。通过性能实验证明，固体润滑剂WS2的自润滑材料具有更低的摩擦系数。.通过摩擦学实验研究及分析，阐明了该材料组织结构与其摩擦学性能的关系，并通过扫描电子显微镜、能谱、拉曼光谱等表征手段，确定了复合材料表面硫元素的含量和存在形式，揭示了固体润滑剂在不同温度、转速和气氛条件下的减摩润滑机理和失效机制。.本项目的工作为含固体润滑剂的WC基自润滑材料在核能、航天等领域的核辐射、干摩擦条件下的应用提供了实践基础与理论支持。