陶瓷复合材料与金属配副的摩擦学特性研究

发布时间：2018-03-17 05:13

本文选题：陶瓷复合材料　切入点：海水　出处：《陕西科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：本课题来源于国家自然科学青年基金项目(51405278)。论文针对海水环境、干摩擦和纯水环境下,Si_3N_4-hBN陶瓷复合材料与金属配副的摩擦学特性进行了研究,重点对海水环境下摩擦副摩擦磨损机理和润滑进行了深入的探讨,系统地进行了不同外部因素(速度、载荷)以及内部因素(hBN的含量)下Si_3N_4-hBN复合陶瓷与轴承钢(GCr15)配副的摩擦学性能试验。旨在探究海水环境下内外因素对Si_3N_4-hBN/金属摩擦副的摩擦磨损性能的交互影响。利用MMW-1型立式万能摩擦磨损试验机进行摩擦学试验,借助扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)和拉曼光谱(Raman)等测试分析手段,观察和分析摩擦表面的微观形貌和物相组成。本论文完成的研究工作如下所述:(1)本论文研究了在海水环境下,载荷和速度对Si_3N_4-hBN/GCr15摩擦副的摩擦学性能的影响。结果表明,载荷的增大不能有效地降低摩擦副的摩擦因数和磨损率,当载荷持续增大至30N,摩擦因数达1.41,盘的磨损率能达到8.8×10-5mm~3/Nm;另一方面,随着速度的增大,摩擦因数和磨损率显著降低。综合来看,当载荷为10N,速度为1.73m/s时,Si_3N_4-hBN/GCr15摩擦副获得最佳的摩擦学特性,摩擦因数低至0.03,销和盘的磨损率均不超过1.4×10-5mm~3/Nm。当速度一定时(0.52m/s),载荷变化为10N时,摩擦副的磨损机制以粘着磨损和腐蚀磨损为主,其中Si_3N_4-10%hBN(即hBN含量为10wt.%,记为SN10)与GCr15配副的摩擦因数可降低至0.2,这主要归因于摩擦表面发生了摩擦化学反应,生成具有较好润滑特性的摩擦产物,对摩擦副具有边界润滑作用;当载荷增加至20N和30N时,摩擦表面不能形成有效的保护物质,摩擦因数在0.4~1.4之间。当载荷一定时(10N),速度变化为0.86m/s时,摩擦副的因数在0.21~0.48之间;当速度增至1.73m/s,摩擦副的摩擦因数大幅度降低至0.03~0.25之间,这主要是速度的增大促进了表面的摩擦化学反应,使摩擦表面形成了更加完整的自润滑物质,使摩擦副进入了流体润滑状态。(2)干摩擦条件下,在载荷为10N,速度为1.73m/s时,Si_3N_4-hBN/GCr15摩擦副的摩擦因数最低为0.49,销和盘的磨损率整体较大,其磨损机制为磨粒磨损和粘着磨损;纯水环境下,在相同的载荷和速度条件下,摩擦因数有一定幅度的降低至0.06,销的磨损率降低至3.23×10~(-6)mm~3/Nm,均高于海水环境下的摩擦因数和磨损率。(3)在海水环境和纯水环境下,hBN的加入显著地降低了Si_3N_4-hBN/GCr15摩擦副的摩擦因数和磨损率。例如,在海水环境下,当载荷为10N,速度是1.73m/s时,随着hBN的添加,摩擦因数由纯Si_3N_4的0.5降至SN10的0.03。这主要是归因于两方面:一方面,hBN本身自润滑性,能够对摩擦表面起到一定的减摩作用;另一方面,Si_3N_4和hBN会与水分子发生摩擦化学反应,同时Si_3N_4-hBN在摩擦过程中易在表面形成剥落坑,反应产物堆积在剥落坑中并被拖曳成膜,起到保护和润滑的作用。(4)在海水环境下,Si_3N_4-hBN复合陶瓷表现出更优异的摩擦学特性。经研究发现,在海水环境中反应产物SiO_2是以胶体的形式存在,而纯水中由于没有Na~+、Cl~-等离子的凝聚作用,所以SiO_2很容易被水流带走,这就导致在摩擦表面形成的润滑膜较薄,无法实现有效的润滑作用;而海水中含有的Na~+、Cl~-能够加剧SiO_2在摩擦表面凝聚成硅胶,Ca~(2+)、Mg~(2+)能够在GCr15摩擦表面沉积淤泥状的CaCO_3和Mg(OH)_2,使摩擦副处于边界润滑的状态。因此,海水对摩擦副具有复合润滑作用,使其相比于干摩擦、纯水具有更好的摩擦学特性。本论文的研究表明,在海水环境中,Si_3N_4-hBN/GCr15摩擦副在特定条件下具有较好的摩擦学特性。这不仅为海洋工程装备的开发和应用提供了技术指导,还一定程度上丰富和完善了陶瓷摩擦学理论,具有重要的工程应用价值和科学研究意义。
[Abstract]:This subject comes from the project of the National Natural Science Foundation of youth (51405278). The thesis focuses on the marine environment, dry friction and water environment, the tribological properties of Si_3N_4-hBN ceramic composites and metal pairs are studied, with emphasis on the marine environment, the friction wear and lubrication mechanism was deeply investigated systematically different external factors (velocity, load) and internal factors (hBN content) of Si_3N_4-hBN composite ceramics and bearing steel (GCr15) with tribological properties. To explore the factors inside and outside the side friction under seawater environment interaction friction and wear properties of Si_3N_4-hBN/ metal. The effect of vertical universal friction and wear testing machine using MMW-1 tribology experiment type, by means of scanning electron microscopy (SEM), X ray diffraction (XRD), X ray photoelectron spectroscopy (XPS) and Raman spectroscopy (Raman) methods, the concept of Observation and analysis of microstructure and phase composition of the friction surface. Research in this thesis are as follows: (1) this paper researches in the seawater environment, influence of load and speed on the tribological properties of Si_3N_4-hBN/GCr15. The results showed that the increase of the load can not effectively reduce the friction factor and the wear rate, when the load increase to 30N, the friction coefficient reaches 1.41, the disc wear rate can reach 8.8 * 10-5mm~3/Nm; on the other hand, with the increase of the velocity, friction coefficient and wear rate decreased significantly. In general, when the load is 10N, the speed is 1.73m/s, the friction pair of Si_3N_4-hBN/GCr15 obtained the best tribological properties. The low friction coefficient to 0.03, and the rate of wear of a pin disc are not more than 1.4 x 10-5mm~3/Nm. when a certain speed (0.52m/s), the load change is 10N, the wear mechanism of the adhesive side wear and corrosion wear, The Si_3N_4-10%hBN (i.e., hBN content of 10wt.%, denoted as SN10) with friction coefficients and GCr15 can be reduced to 0.2, which is mainly due to the friction surface of tribochemical reaction, friction product has good lubricating properties, with boundary lubrication friction; when the load increased to 20N and 30N, friction the surface can not form effective protective material, the friction coefficient between 0.4~1.4. When the load is fixed (10N), rate of change is 0.86m/s, the side friction factor between 0.21~0.48; when the speed is increased to 1.73m/s, the friction factor is greatly reduced to 0.03~0.25, which is mainly to promote the chemical friction speed increases the reaction surface, the formation of self lubricating material more complete surface friction, the friction in the fluid lubrication condition. (2) under dry friction condition, the load is 10N, the speed is 1.73m/s, Si_3N_4-hBN/GCr15 The friction factor for a minimum of 0.49, and the wear rate of pin disc large, the wear mechanism is abrasive wear and adhesive wear; water environment, in the same load and speed conditions, the friction coefficient decreases to a certain extent to 0.06, pin wear rate decreased to 3.23 * 10~ (-6) mm~3/Nm, were higher than the friction coefficient and wear rate of the seawater environment. (3) in the water environment and water environment, the addition of hBN significantly reduced the Si_3N_4-hBN/GCr15 friction factor and wear rate. For example, in the marine environment, when the load is 10N, the speed is 1.73m/s, with the addition of hBN the friction coefficient of pure Si_3N_4, from 0.5 to SN10 0.03., which is mainly attributed to two aspects: on the one hand, hBN itself to self lubrication, friction reduction effect on the friction surface; on the other hand, Si_3N_4 and hBN will have friction chemical reaction with water molecules, and Si _3N_4-hBN in the friction process to form pits on the surface, the reaction products accumulate in the pits and towed into film, the protection and lubricating effect. (4) in the seawater environment, Si_3N_4-hBN composite ceramics exhibit excellent tribological properties. The study found that in the sea water environment in the reaction products of SiO_2 in colloidal form, and pure water because there is no Na~+, Cl~- plasma coagulation, so SiO_2 is easy to flow away, which leads to the lubricating film formed on the friction surface is thin, can not achieve effective lubrication; and sea water containing Na~+, Cl~- can increase in the friction surface condensed into SiO_2 silica gel, Ca~ (2+), Mg~ (2+) to the friction surface of silt like in GCr15 CaCO_3 and Mg _2 (OH), which is the boundary lubrication state of friction. Therefore, the seawater with composite lubrication friction, which compared to the dry friction, Pure water has better tribological properties. The research shows that in seawater, Si_3N_4-hBN/GCr15 friction under certain conditions has better tribological properties. This is not only for the development and application of marine engineering equipment to provide technical guidance, but also to a certain extent, enrich and improve the ceramic tribology theory, has important engineering application the value and scientific significance.

【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH117.1

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