Si_3N_4-hBN复相陶瓷材料在海水环境中的摩擦学特性研究

Study on tribological properties of Si_3N_4-hBN ceramics composite in seawater

通过热压烧结制备不同含量hBN的Si_3N_4复相陶瓷材料,利用MMW-1立式万能摩擦磨损试验机研究Si_3N_4-hBN复相陶瓷材料与Ti6Al4V钛合金在海水环境下的摩擦学性能,采用扫描电子显微镜(SEM)来观察分析材料的磨损形貌;同时采用EDS能谱仪对摩擦表面的元素分布进行定性分析并且对摩擦表面膜的元素分布进行定性分析.结果表明,hBN的加入降低了Si_3N_4陶瓷材料的物理力学性能;海水环境,20 N、1 000r/min条件下,纯氮化硅(0.467,1.01×10-5 mm^3/Nm)的摩擦因数和磨损率高于hBN含量为5%(0.411,5.58×10-6mm^3/Nm)和10%(0.417,6.55×10-6 mm^3/Nm)的Si_3N_4复相陶瓷材料,低于hBN含量为20%(0.505,2.07×10-5 mm^3/Nm)和30%(0.485,1.34×10-5 mm^3/Nm)的Si_3N_4复相陶瓷材料.当hBN含量为5%时,摩擦配副的摩擦因数和磨损率均最低,表明了Si_3N_4-5 wt.%hBN具有良好的摩擦学性能,这归因于TC4盘试样表面生成了具有润滑作用的SiO_2、TiO_2、Fe_2O_3、Al(OH)3和Mg(OH)2等物质,该物质不仅能改善配副摩擦的摩擦因数,还对摩擦表面起到了一定的保护作用.

Si3N4 ceramics composite with different contents of hBN were prepared by hot pressing,and the tribological properties of Si3N4-hBN ceramics composite and Ti6 Al4 Vtitanium alloy in seawater environment was studied by MMW-1 vertical universal friction and wear tester.The wear morphology of the material was observed by scanning electron microscope(SEM),and the elemental distribution of the friction surface was qualitatively analyzed by EDS spectrometer and the elemental distribution of the friction surface film was qualitatively analyzed.The result shows that the addition of hBN reduces the physical and mechanical properties of Si3N4 ceramics;under the conditions of seawater and 20 Nand 1 000 r/min,the friction coefficient and wear rate of pure silicon nitride(0.467,1.01×10-5 mm3/Nm)are higher than that of hBN content 5%(0.411,5.58×10-6 mm3/Nm)and 10%(0.417,6.55×10-6 mm3/Nm)and lower than hBN Si3N4 composite ceramics with 20%(0.505,2.07×10-5 mm3/Nm)and 30%(0.485,1.34×10-5 mm3/Nm)content.Therefore,under the seawater environment,when the hBN content is 5%,the friction coefficient and the wear rate of the pair are the lowest,indicating that SN5 has good tribological properties,which is attributed to the formation of SiO2、TiO2、Fe2 O3、Al(OH)3 and Mg(OH)2 materials with lubricating action on the surface of the TC4 disc.These materials can not only improve the friction coefficient of the sliding pairs,but also protect the worn surface.