共查询到20条相似文献,搜索用时 78 毫秒
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采用大气等离子喷涂工艺在Ti–6Al–4V基体上制备羟基磷灰石(HA)涂层。通过正交试验考察了喷涂电流、喷涂距离和次气(氢气)流量对HA涂层结合强度和显微硬度的影响。结果表明,当喷涂电流为700 A,次气流量为9 L/min,喷涂距离为120 mm时,涂层品质最好。采用扫描电子显微镜、万能拉伸试验机、接触角测量仪和电化学工作站对此参数组合下所制涂层的微观结构及性能进行表征。结果表明,等离子喷涂制备的HA涂层具有典型的层状结构,与基体结合良好,表面粗糙度(Ra)达到3.56μm,对模拟体液(SBF)的接触角为43.6°。与纯基体相比,有HA涂层的Ti–6Al–4V试样在SBF中的腐蚀电位正移,腐蚀电流密度降低,耐蚀性得到显著提升。 相似文献
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等离子喷涂Cr3C2-NiCr涂层的Vickers硬度研究 总被引:5,自引:1,他引:4
研究了等离子喷涂Cr3C2-NiCr涂层的Vickers硬度服从正态分布,对数正态分布和Weibull分布的拟合优度,在统计分析的基础上,考察了压头载荷和测量位置对涂层Vickers硬度的影响。 相似文献
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本文综述了利用等离子技术喷涂高性能陶瓷涂层的技术特点和应用情况以及几种热点陶瓷涂层的特性,指出了等离子技术喷涂陶瓷涂层中存在的问题,分析了可行的解决方法。 相似文献
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等离子喷涂硅灰石涂层结构和性能的研究 总被引:17,自引:4,他引:17
采用等离子喷涂技术,在Ti-6Al-4V基体上制备了硅灰石涂层,利用SEM和XRD分析技术对涂层的形貌,结构和相组成进行了研究,按ASTMC-633标准对涂层的结合强度也进行了测试,将涂层试样浸泡于模拟体液中以评估其生物活性,利用SEM及配备的能谱仪(EDS),XRD和IR对浸泡后涂层表面产物的形貌,结构和相组成等进行了分析,结果表明,等离子喷涂硅灰石涂层具有粗糙的表面和层状结构,涂层内部存在一些气孔和微裂纹,涂层的主晶相是三斜晶系硅灰口,也存在玻璃相,硅灰石涂层和Ti-6Al-4V基体热膨胀系数相近,因此涂层和T-6Al-4V基体具有较高的结合强度,其值可达约39MPa,模拟体液浸泡试验显示,硅灰石涂层表面能形成含有碳酸根的羟基磷灰石层,这表明硅灰石涂层会有良好的生物活性,可作为生物活性涂层的候选材料。 相似文献
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研究了温度对B_4C微粒复合镀铁层的硬度、沉积速率和耐蚀性的影响。结果表明:随着温度的升高,镀层的硬度下降,沉积速率增大,耐蚀性变化不大。温度为45℃时所得镀层的性能和形貌均较好。 相似文献
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YANGXianfeng WANGJinxiang YANGBin 《中国耐火材料》2004,13(4):21-25
The role of nano-SiO2 and ultra-fine boron carbide on the properties of alumina-graphite materials was investigated.The study showed that the ultra-fine boron carbide added modified the microstructure of residual carbon and promoted the chemical bond between residual carbon from phenolic resin and flake graphite.The carbon white could strengthen the residual carbon from phenolic resin.These two additives improved the mechanical properties of AG refractories at both room temperature and high temperature,and thermal shock resistance was improved noticeably.When the two additives were doped together,carbon white could retard the evaporation of B2O3.Thermal shock resistance was guaranteed with a smaller amount of ultrafine born carbide. 相似文献
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利用自制的不对称交-直流电镀电源进行低温复合镀铁。研究了pH值对B_4C微粒复合镀铁层的显微硬度、沉积速率及耐磨性的影响。结果表明:当pH值为1.0时,复合镀铁层具有最佳的综合性能;随着pH值的降低,复合镀铁层的显微硬度下降,沉积速率减慢,磨损量增大;随着pH值的升高,复合镀铁层的显微硬度升高,沉积速率减慢,磨损量增大。 相似文献
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LILin HONGYanruo SUNJialin OUYANCJunhua HEZhiyong YULi 《中国耐火材料》2004,13(3):20-24
The effects of graphite granularity on the properties of low carbon MgO-C based materials have been investigated in the work. Large crystal fused magnesia, natural flake graphite with different particle sizes and anti-oxidant were adopted as raw material for preparation of specimens. However, the results show that the physical properties oxidation resistance and thermal shock resistance of low carbon MgO-C materials with content of 4.0 wt% graphite are improved obviously through the use of special and suitable size graphite. The excellent performance achieved was considered as a result of microstructure modification of MgO-C materials. Therefore, it is suggested that both fine and micro grade natural flake graphite used for production of low carbon MgO-C bricks. 相似文献
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Jie-Fu Lang Jie-Gang You Xiao-Fang Zhang Xu-Dong Luo Shu-Ya Zheng 《Ceramics International》2018,44(18):22176-22180
In order to improve the thermal shock resistance of CaZrO3, CaZrO3 was synthesized by a solid-state reaction method with analytical ZrO2 and CaCO3 as raw materials, and MgO as additive. The effects of MgO on Flexural strength at room temperature, thermal shock resistance, XRD and microstructure of CaZrO3 were characterized. The results show that the grain growth of CaZrO3 is inhibited and the thermal shock resistance of CaZrO3 is improved by adding MgO. With the increasing of MgO, the flexural strength at room temperature of samples are improved due to the grain refinement. When the addition of MgO is 8%, the flexural strength at room temperature increases to 270.15?MPa. The thermal shock resistance of samples are improved by MgO deflecting and bridging cracks. When the addition of MgO is 4%, the residual flexural strength of samples is the maximum (26.94?MPa). 相似文献
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《Ceramics International》2023,49(18):30196-30203
Y2O3 materials have become a popular candidate for preparing refractory crucibles for ultra-pure high-temperature alloy melting in recent years. However, its difficulty in sintering and poor thermal shock resistance limited its industrial application. The effect of CaF2 on the densification microstructure, mechanical properties, and thermal shock resistance of Y2O3 materials was investigated in this paper. The main purpose of this study was to optimize the amount of CaF2 added in the preparation of Y2O3 materials to improve its thermal shock resistance and get better mechanical properties. The mechanism of the densification process of CaF2-doped Y2O3 materials was analyzed by phase analysis and microstructure. The results showed that successive doping of large Ca2+ ions caused more lattice distortion in the Y2O3 materials, and the diffusion rate of Y3+ was increased, thus enhanced grain boundary diffusion and promoted sintering densification in the Y2O3 materials. Meanwhile, the addition of CaF2 also significantly reduced the apparent porosity and enhanced the mechanical properties of the materials. The improvement of these properties was attributed to the increased relative density of CaF2-doped Y2O3 materials and the high sintering activity of CaF2. In addition, crack deflections effectively improved the thermal shock resistance of the materials. The residual flexural strength ratio of Y2O3 materials doped with 1 wt % CaF2 was increased by 21.2% after thermal shock test compared with undoped specimens. 相似文献
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《Ceramics International》2023,49(19):31846-31854
In this study, the effect of the alumina particle size on the formation of mullite using a silica gel powder and micro- and nano-scale Al2O3 powders as raw materials was investigated. The optimized Al2O3 source was then reacted with the silica gel to prepare porous mullite-based ceramics. The results revealed that the highly reactive nano-Al2O3 powder could form mullite at a relatively low firing temperature. Therefore, the nano-Al2O3 powder was used to prepare porous mullite-based ceramics by firing at 1600 °C, 1650 °C and 1700 °C. The pore size of the prepared porous mullite-based ceramics ranges from tens to hundreds of micrometres, with the apparent porosity being 42.8–58.0%. Further, the mullite content in the samples increased with increasing firing temperature, and a higher firing temperature promoted sintering, resulting in improved strength of the sample. After calcination at 1700 °C, the mullite content in the sample reached 81.8%, and the sample showed excellent thermal shock resistance. The strengths of the samples before and after thermal shock were found to be 23.6 and 15.58 MPa, with the residual strength ratio being 66%. 相似文献
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以铝矾土为主要原料,铝酸钙水泥、硅微粉为结合系统,分别研究了不同添加量的Cr2O3对矾土基喷涂料性能的影响。试样自然干燥24h脱模后,再经110℃烘干24h,分别于1000℃、1300℃和1500℃热处理3h。检测各温度热处理后试样的线变化率、体积密度、抗折强度、耐压强度以及试样的热膨胀系数、耐磨性能和抗热震性能。结果表明,在矾土基喷涂料中添加Cr2O3不利于提高材料的低温和中温强度,但利于提高材料的高温强度;在矾土基喷涂料中添加Cr2O3不能提高材料的耐磨性能;试样中添加Cr2O3后增大了试样的热膨胀系数。添加适量的Cr2O3可提高试样的抗热震性能;过量的添加Cr2O3会对试样的抗热震性产生负面的影响。 相似文献