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C-Si 梯度涂层对碳纤维性能的影响 总被引:1,自引:0,他引:1
本文提出并探索了在碳纤维表面化学气相沉积 C-Si 梯度涂层的新方法,研究了 C-Si 梯度涂层对碳纤维性能的影响。实验结果表明,碳纤维表面化学气相沉积 C-Si 梯度涂层结构中的 C,Si 元素均呈非晶态结构;梯度涂层能大幅度提高碳纤维的抗氧化性。梯度涂层减少了涂层与纤维基体的各种不匹配因素,缓和了涂层中热应力,限制了氧化反应的进行,使梯度涂层纤维氧化前后强度均明显高于 Si,SiC,SiO_2等单一涂层纤维。 相似文献
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铜基体上制备ZrO2-NiCrAlY梯度喷涂层的组织及其性能 总被引:1,自引:0,他引:1
功能梯度涂层能提高涂层与基体问的结合力、耐磨性,以往对铜基体上喷涂功能梯度涂层的研究较少.用等离子喷涂法,在铜基体上制备了zrO2-NiCrAlY梯度涂层.利用扫描电镜对涂层的组织形貌、成分进行了分析,对涂层的结合强度和抗热震性能进行了试验研究,并对试样进行了高温扩散处理.结果表明,梯度涂层设计合理,实现了成分和组织的连续梯度变化;与双层涂层相比,梯度涂层的结合强度和抗热震性有显著提高,涂层的结合以机械结合为主,梯度涂层内部是基体-涂层体系中最薄弱的环节;600℃热处理后,基体与涂层之间出现了扩散层. 相似文献
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功能导水涂层纤维的可控缓释水机制研究 总被引:1,自引:0,他引:1
将吸水性有机高分子PVA与超细蒙脱石颗粒混合成胶体,涂敷于天然植物纤维表面,制备出一种具有可控缓释水功能的导水涂层纤维.利用环境扫描电镜观察涂层纤维表面形貌,采用热重法分析涂层材料吸-脱附水特性,采用快速水分测定仪测量了膜材包装水后失水率和土壤湿度的关系,分析涂层纤维的动态水分运移机制.实验结果表明,蒙脱石颗粒充分分散在PVA胶体网络间隙,纤维水势高的一端PVA溶胀,蒙脱石颗粒发生断桥,水分运移依靠PVA吸-脱附作用;纤维水势低的一端PVA脱水,蒙脱石颗粒桥接形成传水通道.由此实现了由分子传水和层间传水能垒不一致导致的沿纤维纵向水势梯度变化而形成的水分运移的过程机制. 相似文献
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提出了一种新型涂层导水纤维的制备方法.用粉煤灰和有机溶剂溶解的EVA混合做涂层材料,选用与膜材成分相同的聚乙烯纤维作为预涂层纤维基体.用比表面积分析仪表征粉煤灰的孔径分布,在环境扫描电子显微镜下观察纤维表面微观真实形貌,用快速水分测定仪测试纤维在不同温度下的连续失水情况.改变土壤的相对含水量,测定了优选配比涂层纤维的失水.结果表明:EVA含量最少的纤维涂层渗水效果最好,涂层纤维的保水功能是由于粉煤灰的多孔产生了毛细孔凝聚现象,该涂层导水纤维对温度以及土壤湿度都具有自调节功能. 相似文献
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在钢基体(EUROFER、F82H、CLAM、316L)上喷涂钨涂层已成为制备面向等离子体材料的一个重要方法.为了防止钨涂层与钢基体间由于材料热膨胀不匹配而开裂失效,采用热应力缓和型功能梯度涂层是一种行之有效的解决方案.利用有限元分析软件(ANSYS 10.0)分析了梯度涂层厚度对W/316L功能梯度涂层残余应力的影响.模拟结果表明,纯钨层厚度确定时,制备厚的梯度涂层可降低残余应力.当顶层厚度为1mm、梯度涂层厚度为100~200μm时,将产生较大的轴向应力,制备涂层时应当避免此厚度范围.此模拟结果可为该涂层设计和制备提供理论依据和指导. 相似文献
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康伟峰邢欣张禹闫德轩苟燕子 《材料工程》2023,(8)
SiC纤维作为陶瓷基复合材料(CMC)的常见增强体之一,具有较低的密度、较高的拉伸强度以及优良的耐高温和耐氧化性能。在SiC纤维表面制备涂层,不仅可提升纤维本身的力学性能、耐高温性能、抗氧化性能以及电磁功能特性,而且还可有效改善纤维与基体界面的结合性能,提高复合材料的断裂韧性与力学性能。本文首先对SiC纤维表面涂层的制备方法进行了综述,阐述了刻蚀法、沉积法、化学气相渗透法以及先驱体转化法等方法的基本过程及相关研究进展,并对比了不同制备方法的优缺点,然后综述了涂层对SiC纤维及其增强的复合材料的影响,最后对SiC纤维上制备涂层的发展趋势进行了总结归纳,可以采用实验研究与计算仿真相结合的手段来模拟SiC纤维涂层的真实服役环境,并可以通过制备热障复合涂层来提高纤维在极端服役条件下的使用性能。 相似文献
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SiC纤维作为陶瓷基复合材料(CMC)的常见增强体之一,具有较低的密度、较高的拉伸强度以及优良的耐高温和耐氧化性能。在SiC纤维表面制备涂层,不仅可提升纤维本身的力学性能、耐高温性能、抗氧化性能以及电磁功能特性,而且还可有效改善纤维与基体界面的结合性能,提高复合材料的断裂韧性与力学性能。本文首先对SiC纤维表面涂层的制备方法进行了综述,阐述了刻蚀法、沉积法、化学气相渗透法以及先驱体转化法等方法的基本过程及相关研究进展,并对比了不同制备方法的优缺点,然后综述了涂层对SiC纤维及其增强的复合材料的影响,最后对SiC纤维上制备涂层的发展趋势进行了总结归纳,可以采用实验研究与计算仿真相结合的手段来模拟SiC纤维涂层的真实服役环境,并可以通过制备热障复合涂层来提高纤维在极端服役条件下的使用性能。 相似文献
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A functionally gradient coating on carbon fibre for casting C/Al composites with an ultimate tensile strength up to 1250 MPa (V
f=0.35) has been produced. The coating consisted of three layers: an inner pyrocarbon layer, an outer silicon layer and an intermediate gradient layer C/SiC/Si, and their optimum thicknesses were 0.1–0.15, 0.1 and 0.2 m, respectively. This coating was fabricated by chemical vapour deposition and the C/Al composite was performed by pressure-regulated infiltration. Auger electron spectroscopy and X-ray diffraction analyses confirmed that the structure of the coating was in keeping with its design. The excellent ultimate tensile strength of the C/Al composite also proves that the functionally gradient coating has many functions, including wetting agent, diffusion and reaction barrier, releaser of residual thermal stresses, and tailor of interfacial shear strength. According to the mechanical, physical and chemical coordination between fibre and matrix, the functionally gradient coating can solve nearly all the problems of the interface during fabrication and service. 相似文献
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Ni-P功能梯度层及均质Ni-P化学镀层的磨损性能 总被引:1,自引:0,他引:1
目前,Ni-P化学镀层内应力大,结合强度低,耐磨性差,功能单一,不能满足工业应用要求.为此,采用化学镀技术在45钢表面制备了Ni-P功能梯度镀层,并与3种不同磷含量的均质Ni-P镀层对比,研究了镀层硬度、结合力、耐磨性等特征,分析了成分与结构的梯度变化对Ni-P镀层耐磨性能的影响.结果表明:Ni-P梯度镀层的硬度高于中磷和高磷镀层,略低于低磷镀层,400℃热处理1 h后其硬度达到最大值;镀层与基体结合紧密;在相同条件下试验,Ni-P梯度镀层的耐磨性均优于均质Ni-P镀层,热处理后其耐磨性比均质Ni-P镀层提高1~2倍;与单层Ni-P镀层相比,梯度镀层在整个磨损过程中摩擦系数变化平稳,波动范围较小,镀层内部成分和结构的梯度化进一步提高了镀层与基体的结合力和耐磨性能. 相似文献
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Charvet JL Cordes JA Alexander H 《Journal of materials science. Materials in medicine》2000,11(2):101-109
Tensile and fracture tests were conducted on thin panels of a fiber-reinforced bioabsorbable material. The composites were made of polycarbonate matrix and calcium phosphate fibers. Both matrix and fibers were bioabsorbable orthopaedic biomaterials. The fibers were short and randomly distributed. The properties were compared for composites with and without a coating of methane on the fibers. Composites with the methane coating had a higher elastic modulus, a higher proportional limit, but a lower load at failure on pre-cracked panels. Electron microscopy showed that the coating resulted in a better bond between the matrix and the fiber. 相似文献
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利用净能量控制的PRAXAIR4500型等离子喷涂系统,在钛合金基体上制备出HA/ZrO2功能梯度涂层,采用HTEM、XRD、SEM等对涂层过渡层ZrO2相的结构特征进行分析.结果表明:(1)富锆的过渡层存在ZrO2 3种晶型,主要以四方氧化锆为主,含有少量的立方氧化锆及微量的单斜氧化锆和CaZrO3,单斜氧化锆的出现说明材料内发生了四方氧化锆向单斜氧化锆马氏体相变,这种马氏体相变有利于提高HA材料的韧性;(2)生物活性功能涂层的富锆过渡层致密,与钛合金基体结合紧密,纯羟基磷灰石的表面层具有典型的多孔结构特征,整个涂层沿垂直基体方向从过渡层致密结构向表面层多孔结构过渡;涂层的这种结构特征有利于改善功能梯度涂层的综合性能,提高涂层与基体的结合强度,其结合强度达到48.6MPa. 相似文献
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Latex film matrix systems with a nonuniform drug distribution were prepared by a coating process. In this process a drug concentration gradient in the coating dispersion was generated by the programmable pumping of the latex into a drug reservoir which contained the drug and latex. The film matrix formed by the dispersion would have a built-in drug concentration gradient as the coating process proceeded. A mathematical model was developed to describe the concentration change of the active ingredient in the coating dispersion as a function of the spraying rate of the coating dispersion, the pumping rate of the latex into the drug reservoir, and the initial drug concentration in the dispersion. The applicability of this process was demonstrated by the controlled in vitro dissolution of acetaminophen from ethylcellulose latex film matrices formed on glass beads. The release profile of the active ingredient from the systems changed as the drug concentration gradient profile in the matrix was altered, and a higher drug concentration gradient in the matrix resulted in a slower release rate and a more linear release profile. A faster drug release rate can also be achieved by incorporating a highly water soluble ingredient in the concentration gradient matrix. 相似文献