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通过丝网印刷法在SS410合金上涂覆YCo0.6Mn0.4O3抗氧化涂层材料,采用氧化增重法、SEM-EDX、四探针法分别对SS410合金及其涂覆抗氧化涂层后的高温氧化速率、微观形貌和面积比电阻进行了表征. 结果表明,通过丝网印刷法在合金表面涂覆连续致密的陶瓷涂层材料,YCo0.6Mn0.4O3涂层在循环氧化过程中与基底结合牢固,没有出现剥离脱落. 涂覆YCo0.6Mn0.4O3涂层后,在800℃下SS410合金的氧化速率降低1个数量级,在800℃氧化150 h合金的面积比电阻由未涂层的72 mW×cm2降到了16 mW×cm2,大幅度地提高了合金的高温抗氧化性能及电导性能. 相似文献
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采用水热电泳沉积法在SiC–C/C复合材料表面制备了纳米碳化硅和二硅化钼的复相(SiCn–MoSi2)抗氧化涂层。采用X射线衍射和扫描电子显微镜等对制备涂层的晶相组成、表面及断面微观结构进行了表征。研究了水热温度对制备涂层的结构及高温抗氧化性能的影响,分析了涂层在1 600℃静态氧化行为及失效机理。结果表明:外涂层主要由MoSi2和β-SiC晶相组成。复相外涂层的致密程度、厚度及抗氧化性能随着水热温度的升高而提高。SiCn–MoSi2/SiC复合涂层具有较好的抗氧化和抗热震能力,在1 600℃氧化80 h后氧化质量损失为3.6×10–3 g/cm2。复合涂层在1 600℃的氧化失效主要是由于经过长时间氧化后SiO2玻璃膜层不能及时有效填补涂层中的缺陷,涂层中出现贯穿性的裂纹和孔洞导致的。 相似文献
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采用水热电泳沉积法在SiC–C/C复合材料表面制备了纳米碳化硅和二硅化钼的复相(SiCn–MoSi2)抗氧化涂层。采用X射线衍射和扫描电子显微镜等对制备涂层的晶相组成、表面及断面微观结构进行了表征。研究了水热温度对制备涂层的结构及高温抗氧化性能的影响,分析了涂层在1 600℃静态氧化行为及失效机理。结果表明:外涂层主要由MoSi2和β-SiC晶相组成。复相外涂层的致密程度、厚度及抗氧化性能随着水热温度的升高而提高。SiCn–MoSi2/SiC复合涂层具有较好的抗氧化和抗热震能力,在1 600℃氧化80 h后氧化质量损失为3.6×10–3 g/cm2。复合涂层在1 600℃的氧化失效主要是由于经过长时间氧化后SiO2玻璃膜层不能及时有效填补涂层中的缺陷,涂层中出现贯穿性的裂纹和孔洞导致的。 相似文献
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采用阳极氧化法在Ti6Al4V骨螺钉表面制备了二氧化钛纳米管(TNTs)涂层,针对TNTs涂层与基底结合强度较低的问题,通过磷酸阳极氧化在TNTs涂层和基底界面处制备了致密的氧化层,提高了TNTs涂层与基底的结合强度。借助场发射扫描电子显微镜、纳米压痕仪、微动摩擦磨损试验机以及拧入-旋出猪胫骨实验,分析了TNTs涂层的微观结构、力学性能、微动磨损性能及机械稳定性。结果表明,在骨螺钉表面制备的TNTs涂层结构紧凑、排列有序,改善了骨螺钉的力学性能,缓解了植入物植入后的应力屏蔽,并且显著提高了Ti6Al4V合金的微动磨损性能,有效避免了在植入过程中的分层和剥落。 相似文献
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炭纤维表面用化学气相沉积法涂覆碳化硼的研究 总被引:4,自引:0,他引:4
以CH4,BCl3,H2为原料气,采用化学气相沉积法(常压CVD)在炭纤维表面连续涂覆B4C,通过正交实验得到最佳涂覆条件;采用IR、TG—DTA、XRD等技术考察了涂层的组成、结构和形貌,并对最佳涂覆条件下炭纤维的拉伸强度进行测试。实验结果表明:当υH2/υBCl3=3.5、υBCl1/υCH4=1.7、气体总流速=160mL/min,沉积温度1100℃,走丝速度5转/min时,涂层表面有明显的一层致密物质,表面较平整,涂层纤维的氧化温度由未涂层时的350℃提高到630℃,纤维的单丝强度由未涂层时的1.93GPa提高到3.15GPa。在炭纤维表面采用化学气相沉积法涂覆B4C不仅装置简单、操作方便,而且可以明显地提高炭纤维的抗热氧化性和单丝强度。 相似文献
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Xinfa Qiang Hejun Li Yunfan Liu Nan Zhang Xin Li Song Tian Yuan Cong 《Ceramics International》2018,44(14):16227-16236
A multi-layer SiC nanowires reinforced SiC (SiCnws-SiC) coating was prepared in-situ on carbon/carbon (C/C) composites by three chemical vapor deposition (CVD) processes. The microstructure and phase composition of the nanowires fabricated on the first-layer SiCnws-SiC coating and the coatings were examined by SEM, TEM, and XRD. The bamboo-like SiC nanowires with a 50?nm diameter and a length of several tens of micrometers are straight, randomly orientated and distributed like a net on the first-layer SiCnws-SiC coating. The growth direction is [111], and the growth mechanism is VS. The multi-layer SiCnws-SiC coating has three layers: the thickness of the first-layer is roughly 400?µm, and the outer two layers are about 200?µm. Each layer has a sandwich structure. The isothermal oxidation and erosion resistance of the multi-layer SiCnws-SiC coating were investigated in an electrical furnace and a high temperature wind tunnel. The results indicated that the weight loss of the multi-layer SiCnws-SiC coated C/C composites was only 1.8% after oxidation in static air at 1773?K for 361?h. Further, the coated sample failed due to fracture of the coating at the clamping position (i.e. 80?mm) after erosion at 1873?K for 130?h in the wind tunnel. The weight loss of the coated C/C composites occurred due to the formation of penetrating cracks in the coating during the oxidation thermal shock. The maximum bending moment and the larger clamping force caused the coating fracture and resulted in intense oxidation of the substrate and the failure of the specimen. 相似文献
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Ceramic films have been applied to improve the resistance against high temperature oxidation of carbon steels. Alumina film was prepared on carbon steel surface by a dip coating technique. Electroless Ni–P plating film has been pre-deposited as an intermediate layer to improve the adherence of the film to carbon steel substrate. The oxidation kinetics of coated sample was investigated by measuring weight gain at 800 °C for 100 h. The surface and cross-section morphology of samples before and after oxidation were characterized by scanning electron microscopy (SEM). The composition and element distribution at the interface of the coated samples were analyzed by energy dispersive spectroscopy (EDS) and EMAX.The results show that the composite coating is uniform. The alumina coating adhesion strength to the substrate is up to 20 ± 2 N in scratch test because the alumina film presents interdiffusion of nickel and aluminum during heat treatment. The oxidation resistance test indicates higher oxidation resistance of as-coated carbon steel comparing to uncoated ones. 相似文献
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采用溶胶-浸渍法在碳纤维表面制备了二氧化钛-二氧化硅复合涂层。考察了钛溶胶与硅溶胶体积比、浸渍方式、浸渍次数对涂层的影响。利用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)分析了涂层的相组成及形貌。通过静态等温氧化实验考察了复合涂层碳纤维的抗氧化性能。结果表明:钛溶胶与硅溶胶体积比为15∶1条件下采用真空超声浸渍3次,制备的复合涂层均匀、完整、致密,与碳纤维表面结合良好,涂层抗氧化性能好,涂层二氧化钛为锐钛矿型、二氧化硅为无定型。将复合涂层碳纤维在400 ℃连续氧化15 h,其质量损失率仅为5.91%。 相似文献
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《Journal of the European Ceramic Society》2022,42(5):1884-1892
In order to improve the oxidation resistance of C/C-SiC composites, a SiC coating was prepared on a C/C-SiC composite by slurry painting combined with a chemical vapor reaction process. The oxidation resistance and microstructural evolution of the coated samples were investigated. The results show that the as-prepared SiC coating contained a large amount of residual silicon, and the presence of these Si promoted the formation of a complete SiO2 glass layer in the initial stage of oxidation. However, the evaporation of the residual Si also accelerated the failure of the SiC coating, which caused the weight loss of the sample to be about 2.2% after oxidation in static air at 1500 °C for 300 h. Attributed to a large number of SiC ceramics in the C/C-SiC composite, the oxidation weight loss rate of the coating sample after coating failure was reduced. 相似文献
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Xin Yang Qizhong Huang Zhean Su Liyuan Chai Xiufei Wang Leping Zhou 《Ceramics International》2013,39(5):5053-5062
A double layer nanostructure SiC coating was prepared by chemical vapor reaction and chemical vapor deposition to protect carbon/carbon composites from oxidation. The obtained dense coating reveals a typical crystalline structure and combines well with the substrate. The outer layer of the coating consists of SiC nanocrystals and nanowires, whereas the inner layer is mainly composed of SiC microcrystals, nanocrystals and nanowires. The oxidation and cyclic thermal shock test performed at 1400 °C in air demonstrates that the prepared dense nanostructure coating has excellent anti-oxidation behavior and thermal shock resistance at high temperature. After 400 h oxidation and 34 cycles of thermal shock from 1400 °C to room temperature, the weight loss of the coated sample is only 1.67%. In the oxidation process, the amorphous silica formed at the beginning of the oxidation crystallizes to cristobalite as oxidation time increased. The formation of cristobalite resulted in micro-cracks formed along grain boundaries in the cyclic thermal shock test. As only cracks are formed on the coating surface, it can be concluded that the formation of the penetration cracks may be the reason for the weight loss of the SiC coated composite. 相似文献
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Oxidation resistance of SiC nanowires reinforced SiC coating prepared by a CVD process on SiC‐coated C/C composites
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Xinfa Qiang Hejun Li Nan Zhang Yunfan Liu Song Tian 《International Journal of Applied Ceramic Technology》2018,15(5):1100-1109
Oxidation protective SiC nanowires‐reinforced SiC (SiCNWs‐SiC) coating was prepared on pack cementation (PC) SiC‐coated carbon/carbon (C/C) composites by a simple chemical vapor deposition (CVD) process. This double‐layer SiCNWs‐SiC/PC SiC‐coating system on C/C composites not only has the advantages of SiC buffer layer but also has the toughening effects of SiCNWs. The microstructure and phase composition of the nanowires and the coatings were examined by SEM, TEM, and XRD. The single‐crystalline β‐SiC nanowires with twins and stacking faults were deposited uniformly and oriented randomly with diameter of 50‐200 nm and length ranging from several to tens micrometers. The dense SiCNWs‐SiC coating with some closed pores was obtained by SiC nanocrystals stacked tightly with each other on the surface of SiCNWs. After introducing SiCNWs in the coating system, the oxidation resistance is effectively improved. The oxidation test results showed that the weight loss of the SiCNWs‐SiC/PC SiC‐coated samples was 4.91% and 1.61% after oxidation at 1073 K for 8 hours and at 1473 K for 276 hours, respectively. No matter oxidation at which temperature, the SiCNWs‐SiC/PC SiC‐coating system has better anti‐oxidation property than the single‐layer PC SiC coating or the double‐layer CVD SiC/PC SiC coating without SiCNWs. 相似文献
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《Ceramics International》2017,43(2):1722-1730
To protect carbon/carbon composites (C/Cs) against oxidation, SiC coating toughened by SiC nanowires (SiCNWs) and carbon nanotubes (CNTs) hybrid nano-reinforcements was prepared on C/Cs by a two-step technique involving electrophoretic co-deposition and reactive melt infiltration. Co-deposited SiCNWs and CNTs with different shapes including straight-line, fusiform, curved and bamboo dispersed uniformly on the surface of C/Cs forming three-dimensional networks, which efficiently refined the SiC grains and meanwhile suppressed the cracking deflection of the coating during the fabrication process. The presence of SiCNWs and CNTs contributed to the formation of continuous glass layer during oxidation, while toughed the coating by introducing toughing methods such as bridging effect, crack deflection and nanowire pull out. Results showed that after oxidation for 45 h at 1773 K, the weight loss percentage of SiC coated specimen was 1.35%, while the weight gain percentage of the SiCNWs/CNTs reinforced SiC coating was 0.03052% due to the formation of continuous glass layer. After being exposed for 100 h, the weight loss percentage of the SiCNWs/CNTs reinforced SiC coating was 1.08%, which is relatively low. 相似文献
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Yan Jiang Chaochao Ye Hongqiang Ru Wei Wang Cuiping Zhang Xinyan Yue 《Ceramics International》2018,44(5):5171-5178
A novel kind of dense MoSi2-SiC-Si coating was prepared on the surface of graphite substrate by slurry dipping and vapor silicon infiltration process. Mo-SiC-C precoating was fabricated via slurry dipping method, and then MoSi2-SiC-Si coating with dense structure consisting of Si, MoSi2 and SiC was obtained by vapor silicon infiltration process. The isothermal oxidation tests at temperatures from 800 to 1600 °C and TGA test from room temperature to 1500 °C were used to evaluate the oxidation resistance ability of the MoSi2-SiC-Si coating. The experimental results indicate that the prepared coating has good oxidation protection ability at a wide temperature range from room temperature to 1600 °C. Meanwhile, the oxidation of the coated samples is a weight gain process at temperatures from 800 to 1500 °C due to the formed SiO2 layer on the surface of coating. After oxidation for 220 h at 1600 °C, the weight loss of the coated sample was only 0.96%, which is considered to be the excessive consumption of the outer coating and the appearance of defects in the coating. Two layers can be observed in the coating after oxidation, namely, SiO2 layer and MoSi2-SiC-Si layer. 相似文献
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Chemiluminescence (CL) analysis was used for determining the oxidation layer formed by the irradiation of polypropylene for medical supplies. The depth of the oxidation layer from the surface depended on dose rate and increased with decreasing dose rate. The oxidation occurred remarkably at a region near the surface area of the film where the diffusion of oxygen is more sufficient. On the contrary, there was very little oxidation in the interior portion. The oxidation layers of polypropylene samples irradiated with electron beam showed U-shaped profiles in the cross-section of film as did as a sample irradiated with γ-rays. However, the degree of oxidation by irradiation with electron beam was very small; CL intensity at the surface area was only one-third that for the γ-irradiated samples. 相似文献
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采用溶胶-浸渍法,在三维碳纤维编织体(简称:RB)的纤维表面涂覆ZrO2-SiO2复合涂层,通过XRD、SEM、等温氧化失重和非等温TG-DSC等手段研究了制备方法对涂层完整性的影响,并对涂层/编织体材料(简称:CB)氧化反应的动力学进行了系统研究。结果表明:采用该方法所得到的涂层均匀完整,与纤维表面结合良好,能显著提高编织体材料的抗氧化性能;等温条件下,材料失重低于70%时,其失重率与氧化时间呈线性关系,反应速率常数随温度的升高而增大,材料失重高于70%时,其失重率与氧化时间呈抛物线关系;非等温条件下,材料的氧化过程呈现自催化特征。 相似文献