不同环境条件下铝合金微弧氧化陶瓷膜的摩擦磨损性能

Tribological properties of ceramic coating prepared by micro-arc oxidation for aluminum alloys in various environments

在2A12铝合金表面通过微弧氧化制备氧化铝陶瓷膜。用X射线衍射仪分析薄膜的相构成,用涡流测厚仪测量膜层的厚度,用自动转塔显微硬度计测量薄膜的显微硬度,利用微摩擦磨损试验机研究Al2O3薄膜/Si3N4球在干摩擦及水润滑下的摩擦磨损特性,用非接触表面三维形貌仪测量薄膜的磨损体积,并采用扫描电镜观察磨痕的表面形貌。结果表明:2A12铝合金微弧氧化陶瓷膜主要由α-Al2O3相和γ-Al2O3相组成;干摩擦时,薄膜主要发生磨粒磨损和疲劳磨损,摩擦因数随法向载荷和滑行速度的增大分别从0.79和0.82增加到0.87,磨损率则分别从4.07×10?5mm3/(N.m)和4.36×10?5mm3/(N.m)增加到9.69×10?5mm3/(N.m);水润滑时,薄膜主要发生摩擦化学磨损和疲劳磨损,摩擦因数随法向载荷和滑行速度的增大分别从0.69和0.67下降到0.65,磨损率则分别从3.84×10?5mm3/(N.m)和2.89×10?5mm3/(N.m)增加到4.47×10?5mm3/(N.m);薄膜在干摩擦时的摩擦因数和磨损率都大于相同实验参数下水润滑时的摩擦因数和磨损率,表明水介质有效地改善了体系的摩擦条件,降低了薄膜的磨损。

The alumina ceramic coating was prepared by micro-arc oxidation （MAO） technique on 2Al2 Al alloy. The phase structure of Al2O3 coating was analyzed by X-ray diffractometry, its thickness was measured using MINITEST1100 equipment, and its micro-hardness was determined using micro-hardness equipment. The friction and wear properties of Al2O3 coatings sliding against silicon nitride ceramic ball were carried out under dry and water-lubricated conditions using tribo-meters. The wear volume of Al2O3 coatings was measured using non-contact surface profilometer, and the worn surface of Al2O3 coatings was observed by scanning electron microscopy （SEM）. The results show that the alumina ceramic coating on 2Al2 AI alloy is mainly composed of α-Al2O3 and γ-Al2O3 phase. Under dry condition, the wear mechanism of Al2O3 coatings is mainly abrasive wear and fatigue wear. With an increase in normal load and sliding speed, the friction coefficient of Al2O3 coatings increases from 0.79 and 0.82 to 0.87, and the specific wear rate of Al2O3 coatings increases from 4.07×10^-5mm^3/（N·m） and 4.36×10^-5mm^3/（N·m） to 9.69×10^-5 mm^3/（N·m）,respectively. Under water-lubricated condition, the wear mechanism of Al2O3 coatings is mainly tribo-chemical wear and fatigue wear. With an increase in normal load and sliding speed, the friction coefficient of Al2O3 coatings decreases from 0.69 and 0.67 to 0.65, respectively, and the specific wear rate of Al2O3 coatings increases from 3.84×10^-5mm^3/（N·m） and 2.89×10^-5mm^3/（N·m） to 4.47×10^-5mm^3/（N·m）, respectively. Moreover, the friction coefficient and specific wear rate of Al2O3 coatings under dry condition are lower than those under water-lubricated, condition, which indicates that water-lubrication availably improves the friction condition and decreases the wear loss of Al2O3 coatings.