| MoAlB陶瓷的制备及摩擦学性能研究 | |
| 于增光 | |
| Thesis Advisor | 杨军 ; 咸春雷 |
| 2020-06-01 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Name | 工程硕士 |
| Degree Discipline | 材料工程 |
| Keyword | MoAlB 力学性能 高温摩擦 海水润滑 摩擦学性能 |
| Abstract | 三元层状MoAlB陶瓷具有高强度、高硬度、耐高温、抗氧化和易加工等优点，有望在摩擦学领域得到广泛应用。然而，现有的烧结工艺难以制备高纯度MoAlB陶瓷块体，MoAlB陶瓷的摩擦学性能还需要进一步研究。本论文研究了高纯度MoAlB陶瓷块体的制备以及力学性能，并系统考察了MoAlB陶瓷在高温和在模拟海水环境下的摩擦学性能，讨论了不同工况条件下的磨损机制，得出的主要结论如下： （1）以元素粉末Mo粉、Al粉和B粉为原料，结合无压烧结和放电等离子烧结成功制备了高纯MoAlB陶瓷块体。相对于传统陶瓷如Al2O3和Si3N4等，MoAlB陶瓷具有优异的力学性能，压缩强度、弯曲强度和断裂韧性分别为1.67 GPa、476.6 MPa和6.5 MPa•m1/2。通过MoAlB陶瓷的腐蚀以及断裂形貌，可清楚的观察到其层状结构。 （2）研究了MoAlB陶瓷从25 ºC至800 ºC的摩擦学性能。实验表明温度和对偶材料是影响MoAlB陶瓷摩擦学性能的主要因素。在整个温度范围内，MoAlB/Inconel 718摩擦副比MoAlB/Al2O3摩擦副表现出更好的摩擦学性能，MoAlB的磨损率最低可达9.37 × 10-7 mm3•N-1•m-1，比与Al2O3配副时低了两个数量级。温度的升高促进了压实磨屑层和摩擦膜的形成。对于MoAlB/Al2O3摩擦副而言，连续的压实磨屑层降低了MoAlB的磨损率，主要磨损机制为磨粒磨损。而当MoAlB与Inconel 718配副时，含有Ni，Cr和Fe氧化物的摩擦膜能够提供良好的润滑作用。 （3）研究了MoAlB陶瓷在模拟海水和去离子水环境下的摩擦学行为。与去离子水相比，在模拟海水环境下MoAlB陶瓷表现出更好的摩擦学性能，这主要归因于海水的润滑作用。对偶材料也是影响MoAlB陶瓷摩擦学行为的重要因素。当MoAlB陶瓷与Si3N4和316L不锈钢配副时，表现出较差的摩擦学性能，主要磨损机制为机械磨损。而当MoAlB与Al2O3配副时，在海水中的摩擦系数可低至0.19，磨损机制为机械磨损和粘着磨损。另外，无论在模拟海水还是去离子水环境下，MoAlB/SiC摩擦副均表现出较好的摩擦学性能，摩擦系数和MoAlB陶瓷的磨损率可分别低至0.13和2.76 × 10-7 mm3•N-1•m-1。对于MoAlB/SiC摩擦副而言，载荷对其摩擦学性能有重要的影响。增大载荷可以诱导摩擦膜重复破坏-再生的循环，新生的摩擦膜易剪切从而提供良好的润滑作用。 |
| Other Abstract | The ternary layered MoAlB ceramic holds great potential for use in tribological fields, due to high strength, high hardness, high temperature resistance, oxidation resistance and easy processing. However, the existing sintering process is difficult to prepare high-purity MoAlB ceramic bulk, and the tribological properties need to be further studied. In this work, the preparation process and mechanical properties of high-purity MoAlB ceramic were studied. In addition, the tribological behaviors of MoAlB ceramic under high-temperatures and that in artificial seawater were systematically investigated. Wear mechanisms under different conditions were discussed. The main conclusions were shown as follows: (1) Combined with pressureless sintering and spark plasma sintering, high-purity MoAlB ceramic bulks were successfully prepared from element powder of Mo powder, Al powder and B powder. In comparison with traditional ceramic like Al2O3 and Si3N4, MoAlB ceramic exhibits excellent mechanical properties. The compressive strength, flexural strength and fracture toughness of MoAlB are measured as 1.67 GPa, 476.6 MPa and 6.5 MPam1/2, repectively. Lamellar structure can be clearly observed by corrosion and fracture morphology. (2) The tribological properties of layered MoAlB ceramics sliding against Al2O3 and Inconel 718 alloy from 25 ºC to 800 ºC were studied. The tribological behaviors of MoAlB ceramics are found to be greatly influenced by the test temperature and the counterpart. From room temperature to 800 ºC, the MoAlB/Inconel 718 tribo-pairs exhibit better tribological properties compared with the MoAlB/Al2O3 tribo-pairs, and the wear rate of MoAlB is as low as 9.37 × 10-7 mm3•N-1•m-1, which is two orders of magnitude lower than that slides against Al2O3. The increase of temperature promotes the formation of the compacted wear debris layer and the tribo-film. For the MoAlB/Al2O3 tribo-pairs, the continuous compacted wear debris layer reduces the wear rate of MoAlB. The main wear mechanism is abrasive wear. However, the tribo-film, which consists of oxides of Ni, Cr and Fe, can provide a good lubrication effect when MoAlB slides against Inconel 718. (3) The tribological behaviors of MoAlB ceramics in artificial seawater and deionized water were studied. By comparison with deionized water, MoAlB ceramics exhibit better tribological properties in artificial seawater, which is mainly due to the lubricating effect of seawater. The counterpart is also an important factor affecting the tribological behaviors of MoAlB ceramics. When coupled with Si3N4 and 316L, MoAlB ceramics exhibit poor tribological properties, and the main wear mechanism is mechanical wear. While when MoAlB ceramics slide against Al2O3, the friction coefficient is as low as 0.19, and the wear mechanisms are mechanical wear and adhesive wear. Besides, the MoAlB/SiC tribo-pairs show good tribological properties both in artificial seawater and deionized water. Friction coefficient and wear rate of MoAlB can be as low as 0.13 and 2.76 × 10-7 mm3•N-1•m-1, respectively. For the MoAlB/SiC tribo-pairs, it can be found that the load has a great influence on the tribological properties. Increasing the load can induce the repeated destruction-regeneration cycle of the tribo-film and the new tribo-film is easy to shear to provide good lubrication. |
| Pages | 74 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.licp.cn/handle/362003/27335 |
| Collection | 固体润滑国家重点实验室（LSL） |
| Affiliation | 1.中国科学院兰州化学物理研究所; 2.中国科学院大学 |
| Recommended Citation GB/T 7714 | 于增光. MoAlB陶瓷的制备及摩擦学性能研究[D]. 北京. 中国科学院大学,2020. |
| Files in This Item: | ||||||
| File Name/Size | DocType | Version | Access | License | ||
| 202041于增光.pdf（6378KB） | 学位论文 | 开放获取 | CC BY-NC-SA | View Application Full Text | ||
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.
Edit Comment