广域温度陶瓷基复合材料的制备及摩擦性能研究

发布时间：2018-06-21 09:31

  本文选题：陶瓷基复合材料 + SrSO_4　； 参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：本文用化学沉淀法制备了不同颗粒尺度、微观形貌的SrSO_4纳米粉体。选用具有耐磨损、耐高温和良好力学性能的Zr O2(3mol.%Y2O3)-20wt.%Al2O3(TZ3Y20A)作为基体材料,试验制备的SrSO_4纳米粉体作为固体润滑剂添加到TZ3Y20A粉体中,放电等离子烧结出TZ3Y20A-SrSO_4陶瓷基自润滑复合材料。试验利用SEM、XRD、Raman、维氏硬度仪、密度天平、高温摩擦磨损试验机等测试手段观察了SrSO_4粉体形貌,探究其生长机制,研究了TZ3Y20A-SrSO_4复合材料的组织结构、力学性能以及摩擦学性能。改变试验中的Sr~(2+)与SO_42-浓度比能得到不同形貌、粒度的SrSO_4。Sr~(2+)与SO_42-浓度比较低时制备出棒状的SrSO_4粉体,其颗粒的平均粒度为长约250 nm,宽约100 nm,随着Sr~(2+)与SO_42-浓度比增加,能够制备片状的SrSO_4粉体,其颗粒的平均粒度为长约350 nm,宽约300 nm。TZ3Y20A-SrSO_4复合材料烧结后物相主要由t-Zr O2、α-Al2O3及SrSO_4构成。SrSO_4在复合材料中的含量不断增大,材料整体的致密度、硬度都不断增大。TZ3Y20A测试温度由室温至600℃升高,平均摩擦系数、磨损率随之增大。数值曲线的波动越来越剧烈,波动的幅度也越来越大。TZ3Y20A室温下,平均摩擦系数、磨损率分别为0.42、9.2 10-6 mm3/N m,在600℃时,平均摩擦系数0.91,磨损率为3.6 10-5 mm3/Nm。而对添加棒状SrSO_4的TZ3Y20A-50wt.%SrSO_4复合材料,随着测试环境温度的升高,平均摩擦系数、磨损率均是先增大后减小,都是在200℃时最高,600℃时最低,在600℃下的平均摩擦系数为0.22,磨损率为0.03 10-5 mm3/N m,对添加片状SrSO_4的TZ3Y20A-50wt.%SrSO_4复合材料摩擦系数、磨损率随着测试环境温度的升高,同样是在200℃时最高,600℃时最低,600℃下摩擦系数、磨损率则为0.26、0.2 10-5 mm3/N m。TZ3Y20A-SrSO_4复合材料具有明显优于基体陶瓷材料的摩擦学性能,随着SrSO_4含量不断增加,复合材料摩擦系数和磨损率都有所降低,摩擦性能得到改善。棒状的SrSO_4与片状的SrSO_4相比,因其颗粒尺度较小,有利于烧结的致密化,所以添加棒状SrSO_4粉体制备的复合材料有更高的致密度以及维氏硬度。在磨损过程中,添加棒状SrSO_4复合材料形成更为均匀、平整、致密的表面润滑膜,从而得到更低的摩擦系数和磨损率,表现出了更加优异的摩擦磨损性能。SrSO_4具有塑性变形能力,测试温度升高,SrSO_4的塑性变形能力变强,SrSO_4在磨损表面富集。受到摩擦剪切力和压应力的作用,富集的SrSO_4平铺在磨损表面,逐渐形成一层致密、均匀、光滑的自润滑膜在摩擦磨损过程中表现出了减磨润滑的作用,整体提高了材料的摩擦磨损性能。
[Abstract]:In this paper, SrSOs _ 4 nanocrystalline powders with different particle size and micromorphology were prepared by chemical precipitation method. ZR O _ 2 O _ 2 O _ (2) O _ (3) mol.and Y _ 2O _ (3) -20wt.Al _ 2O _ (3) Al _ (3) O _ (3) Y _ (20) A) were used as matrix materials. The SrSO4 nano-powders were added as solid lubricant to TZ3Y20A powder, and TZ3Y20A-SrSO4 ceramic self-lubricating composites were sintered by spark plasma. The morphology of SrSO4 powder was observed by means of SEMXRDX Raman, Vickers hardness tester, density balance and high temperature friction and wear tester. The growth mechanism of SrSO4 powder was investigated. The microstructure, mechanical properties and tribological properties of TZ3Y20A-SrSO4 composite were studied. Different morphologies can be obtained by changing the concentration ratio of SrLi _ 2 to so _ 42-. SrSO4. SrSO42-) and so _ 42- are used to prepare the rod-like SrSO4 powder. The average particle size is about 250nm in length and 100nm in width, with the increase of SrSO2) and SO42- concentration ratio, the average particle size of SrSO4 powder is about 250 nm and 100 nm, with the increase of SrSO2) and SO42- concentration ratio, the average particle size of SrSSO4 powder is about 250 nm in length and 100 nm in width. The average particle size of SrSO4 powder is about 350nm in length and 300nm.TZ3Y20A-SrSO4 composite is about 300nm.TZ3Y20A-SrSO4 composite. The phase after sintering is mainly composed of t-Zr O _ 2, 伪 -Al _ 2O _ 3 and SrSO _ 4. The content of SrSO4 in the composite is increasing, and the density of the whole material is obtained. The hardness of TZ3Y20A increases from room temperature to 600 鈩，

本文编号：2048092