B4C/hBN复相陶瓷与球墨铸铁配副在乳化液润滑下的摩擦学性能研究

本文中以热压烧结法分别制备纯碳化硼陶瓷(B_4C)及含30%质量分数的六方氮化硼的碳化硼/六方氮化硼复相陶瓷(B_4C/h BN)作为销试样,与球墨铸铁(QT)盘试样分别在浸入及滴入乳化液润滑条件下进行摩擦磨损试验.借助对摩擦表面的观察,对试验前后乳化液成分的分析等手段,结合摩擦系数及磨损率规律,澄清了在不同乳化液加入方式下,纯B_4C陶瓷及B_4C/h BN复相陶瓷与铸铁配副各自的磨损机制及润滑机理.研究表明:在浸入乳化液润滑条件下,纯B_4C陶瓷与QT配副时,摩擦系数随着摩擦过程的进行可降低至0.03,达到流体润滑,而B_4C/h BN复相陶瓷与QT配副时,配副的摩擦系数始终高于0.1;相反,在滴入乳化液润滑条件下,纯B_4C陶瓷与QT配副的摩擦系数高于0.1,而B_4C/h BN复相陶瓷与QT配副的摩擦系数降低至0.003.

Tribological Behavior of B4C/hBN Ceramic Composites Sliding against Ductile Iron in Emulsion

In this paper, pure boron carbide (B₄C) and boron carbide/boron nitride (mass fraction of 30%) ceramic composites (B₄C/hBN), both fabricated via hot press sintering, were coupled with ductile iron (QT) under the lubrication condition of full immersed emulsion and drop feeding emulsion. By virtue of the observation of worn surfaces and the component analysis of the emulsion before and after the test, combined the law of friction coefficient and wear rate of each couple in the meantime, the wear and lubrication mechanisms of both couple in full immersed and drop feeding emulsion were clarified. The results show that, under the lubricating condition of full immersed emulsion, with the increase of sliding distance, the friction coefficient of B₄C coupled with QT was as low as 0.03 and the fluid lubrication regime was established. While that of B₄C/hBN ceramic composites coupled with QT was higher than 0.1. On the contrary, under the lubrication of drop feeding emulsion, the friction coefficient of B₄C/hBN ceramic composites coupled with QT was 0.003 while that of B₄C coupled with QT was higher than 0.1.