| 碳纤维涂层对碳纤维增强镁基复合材料界面影响的研究 | |
| Alternative Title | Study on Influence of Carbon Fiber Coatings on Carbon Fiber Reinforced Magnesium Based Composites Interface |
| 黄元飞 | |
| Subtype | 硕士 |
| Thesis Advisor | 刘越 |
| 2009-05-27 | |
| Degree Grantor | 中国科学院金属研究所 |
| Place of Conferral | 金属研究所 |
| Degree Discipline | 材料加工工程 |
| Keyword | 碳纤维 镁 涂层 复合材料 界面 |
| Abstract | Cf/Mg复合材料具有高比强度、高比模量、低热膨胀系数（CTE）和良好的抗阻尼性能等特点，在航空、航天、国防和运动器材等领域有着良好的应用前景。 本文分别在碳纤维表面采用化学法制备Ni涂层和采用Sol-Gel制备SO2涂层。采用真空压力法制备了无涂层、镀Ni和镀SiO2涂层三种碳纤维增强镁基复合材料。 碳纤维表面真空高温除胶工艺为：400°C保温30min。用化学法碳纤维表面涂覆了均匀、厚度为0.5-0.8μm的Ni涂层，其最佳工艺为：碳纤维经除胶、粗化、敏化、活化之后，在PH值为4.5-4.9，加热85°C的镀液中涂覆10min。 用Sol-Gel法在碳纤维表面制备SiO2。涂胶时溶胶用超声波震荡，其粘度为1.8mPa•s，提拉速度为1.6mm/s，烧结温度在30-210°C升温速率为1°C/min，在210°C保温30min，在210-500°C升温速率为2°C/min，500°C保温30min后随炉冷却，得到厚度约为30-100nm的SiO2涂层。 采用自行设计的真空压力浸渗设备分别制备无涂层、镀Ni和镀SiO2三种碳纤维增强镁基复合材料。Cf/Mg复合材料为：热压炉先抽真空，加热，温度达到670°C保温（镁的熔点为650°C）20分钟把镁液压下少许之后充入0.1MPa氩气保护，温度达到710°C保温20分钟，并施加约0.1-2MPa压强浸渗。Ni和SiO2涂层改善镁与碳纤维的界面润湿性，使Mg液充分浸渗碳纤维，界面结合致密，碳纤维分布均匀。碳纤维的错排和分布不均降低材料的性能。由于Mg与碳纤维CTE的差别，过快的冷却速度使Cf/Mg复合材料内部出现裂纹。 Cf/Mg复合材料中无涂层碳纤维与Mg界面干净，无反应发生；碳纤维表面Ni涂层与Mg反应生成Mg2Ni，并与Mg形成共晶组织；SiO2涂层与Mg发生少量反应生成MgO。镀SiO2碳纤维增强镁基复合材料强度最高为325MPa，无涂层碳纤维增强镁基复合材料其次为240MPa，碳纤维镀Ni增强镁基复合材料最低为190MPa；无涂层碳纤维增强镁基复合材料的延伸率2.2%，镀SiO2碳纤维增强镁基复合材料1.9%，镀Ni增强镁基复合材料碳纤维1.3%。Cf/Mg复合材料断裂机制为：无涂层碳纤维与镁基体界面脱粘明显，拔出长度较长；镀SiO2碳纤维与镁基体界面脱粘，拔出长度较短；镀Ni碳纤维无明显的脱粘、拔出，材料呈现脆性断裂。 关键字：碳纤维；镁；涂层；复合材料；界面 |
| Other Abstract | Study on the Influence of Carbon Fiber Coatings on Carbon Fiber Reinforce Magnesium-Based Composites Interface Huang Yuanfei (Material Processing and Engineering) Supervised by Pro. Liu Yue Carbon fiber reinforced magnesium (Cf/Mg) composites have good application in the area of aviation, aerospace, and automobile industries, as well as sport equipments, due to their extraordinary low density and coefficient of thermal expansion (CTE), high tensile strength, mould and damping capacity. In this paper Cf/Mg composites were fabricated by vacuum pressing method with three kinds of carbon fibers without coating and coated with Ni and SiO2, respectively. Ni and SiO2 coatings were fabricated on the surface of carbon fibers by electroless and Sol-Gel plating, respectively. Organic adhesives on the surface of carbon fiber were cleaned up in vacuum furnace at 400°C for 30 min. The uniform and compact Ni coating 0.5-0.8μm in thickness was fabricated on carbon fiber surface in a plating solution with a PH value of 4.5-4.9, a temperature of 85 °C, and a coating time of 10min. Uniform SiO2 coating was fabricated by Sol-Gel method with a sol solution viscosity of 1.8mPa•s, a pulling rate of 1.6mm/s. The heating rate was 1°C/min and 2°C/min, respectively, for the sintering temperature of 30-210°C and 210-500°C, and the sintering time was 30min at both 210°C and 500°C. Cf/Mg composites were fabricated by vacuum pressing method with three kinds of carbon fibers without coating and coated with Ni and SiO2, respectively. The preparative procedure of Cf/Mg composites was: vacuum pumping and heating the furnace, filling argon of 0.1 MPa press into the furnace when the temperature was heated to 670°C and maintained for 20min. Mg was infiltrated into carbon fibers after the temperature was maintained at 710°C for 20min. Cf/Mg composites were cooled down in the furnace after infiltration was completely finished. Both Ni and SiO2 coatings on carbon fiber surface enhanced the wettability between carbon fiber and Mg matrix, which made Mg completely infiltrate into the fibers gaps, and the interface be compact, carbon fiber distributed uniformly in Cf/Mg composites. The staggered arrangement and asymmetrical distribution of carbon fibers lowered the mechanical properties of Cf/Mg composites. There were some cracks in the Cf/Mg composite if it cooled very fast due to different CTEs between carbon fiber and Mg. The interface was very clean without any chemical reaction in non-coated carbon fiber reinforced Mg matrix composite. Ni coating on the surface of carbon fiber reacted with Mg to form Mg2Ni, which formed an eutectic structure with Mg. SiO2 coating on the surface of carbon fiber reacted with Mg to form a small amount of MgO. The tensile strength of the Mg matrix composites was 325MPa, 240MPa, and 190MPa, respectively, for SiO2-coating, non-coating, and Ni-coating, and the elongation 2.2%, 1.9%, and 1.3% for three composites. In the fracture process of Cf/Mg composites, non-coated fibers pulled out from the matrix with a large length, and the pull-out length of the SiO2-coated carbon fibers was smaller. By comparison, Ni-coated carbon fibers did not pull out and the composite exhibited a brittle fracture. Kew words: Carbon Fiber; Magnesium; Coatings; Composites; Interface |
| Pages | 66 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/17251 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | 黄元飞. 碳纤维涂层对碳纤维增强镁基复合材料界面影响的研究[D]. 金属研究所. 中国科学院金属研究所,2009. |
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