电沉积稀土改性陶瓷涂层磨损性能研究

Study on the Tribological Properties of Electron Beam-deposited Ceramics Composites Coatings with Rare Earth Oxides

探讨了在电火花加工机床上沉积碳化钛金属陶瓷涂层方法,利用TiC,WC,Mo,N i粉未添加不同比例稀土元素在高压下压制并烧结了试验电极,在45#钢表面沉积了不同稀土含量的TiC陶瓷涂层,并用扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度计、环块式磨损试验机对涂层组成、组织形态进行、硬度及摩擦学性能分别进行了研究,并结合试验结果进行了理论分析。试验结果表明:用电火花放电法可沉积TiC陶瓷涂层,涂层中加入质量分数为0.5%的氧化镧后,涂层的耐磨性能较未加稀土涂层提高了3倍,摩擦因数减少10%,而加入过多的稀土镧氧化物则不利于涂层组织性能及耐磨性能的改善。稀土氧化镧对涂层的组织有改善作用,加入适量的稀土元素使得涂层致密性提高,减少涂层中的缺陷,涂层表面呈多孔结构特性。

The method of electrical discharge coating with TiC ceramic layer in ordinary electrical discharge machining （EDM） tool was studied. The composition of TiC, WC, Mo, Ni powders with different contents of oxide lanthanum were shaped to electrode with high pressure,TiC ceramic layer was deposited on 45^# carbon steel substrate by EDM technique. The effects of rare earth lanthanum oxide on the microstructure and anti - wear properties of ceramic coating were investigated. The clad coatings were examined and tested for microstructural features, chemical compositions, phase structure, hardness, friction and wear properties by scanning electron microscopy （ SEM）, X-ray diffraction （ XRD）, hardness tester, block-on-ring friction and wear tester separately. Experimental results show that the friction coefficient of the clad coating doped with rare earth lanthanum oxide is reduced, while the wear resistance of clad coating doped with rare earth lanthanum oxide is enhanced, when the content of lanthanum oxide is increased to 0. 5 %, the clad coating shows the best antiwear ability, and as the content of lanthanum exceeds 0. 5 %, the wear weight loss increases quickly. The rare earth lanthanum oxide to be doped in the ceramic clad coatings helps to reduce surface defects, and refine the grain of ceramic phase, surface has a porous structure.