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本文分别采用硫酸、草酸以及酒石酸阳极氧化工艺对铝合金支架进行阳极氧化处理,比较了采用不同工艺阳极氧化处理后支架的外观,表征了不同氧化膜的相结构,并测试了不同氧化膜的耐腐蚀性能、硬度和耐磨性能.结果表明,采用不同工艺阳极氧化处理后支架的外观与裸支架基本相同,都具有银白色光泽.不同氧化膜的物相都以Al相为主,还有α-Al2O3相和γ-Al2O3相,且都能提高铝合金基体的耐腐蚀性能、硬度和耐磨性能.与硫酸氧化膜相比,草酸氧化膜和酒石酸氧化膜的性能相对较好,主要归因于草酸和酒石酸对氧化膜的溶解性较弱,制备的氧化膜致密程度较高.酒石酸氧化膜具有良好的致密度,其硬度最高,达到357 HV,耐腐蚀性能和耐磨性能都最好,因此酒石酸阳极氧化工艺更适用于铝合金支架阳极氧化处理,能较大幅度提高铝合金支架的性能. 相似文献
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选取在建筑领域常用的6463铝合金作为研究对象,为使其耐蚀性能得到显著提高,进行酒石酸阳极氧化然后采用镍盐封闭,同时进行硫酸阳极氧化及镍盐封闭作为对比.表征和测试了酒石酸氧化膜、硫酸氧化膜的显微形貌、成分和耐蚀性能,并研究了封闭对酒石酸氧化膜和硫酸氧化膜的影响.结果表明,Ni元素通过封闭被引入氧化膜中,封闭后硫酸氧化膜... 相似文献
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为改善5052铝合金的耐腐蚀性能,对其进行阳极氧化处理.分别采用草酸阳极氧化和铬酸阳极氧化工艺,在5052铝合金试样表面制备了两种阳极氧化膜.比较了草酸阳极氧化膜和铬酸阳极氧化膜的厚度、形貌和耐腐蚀性能.结果表明:两种阳极氧化膜的厚度比较接近,都是20μm左右;草酸阳极氧化膜呈浅灰色,表面粗糙度约为0.170μm,铬酸... 相似文献
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对汽车用2024铝合金板材进行酒石酸阳极氧化处理,并研究了阳极氧化对铝合金的成分、结构、表面形貌及耐蚀性的影响。研究发现,铝合金阳极氧化膜是由表面多孔层和内部无孔层构成的。铝合金阳极氧化过程是一个氧化铝生成和溶解的动态过程。阳极氧化膜由刚玉结构的α-Al_2O_3和八面结构的γ-Al_2O_3构成,α相和γ相大大提高了阳极氧化膜的硬度和耐蚀性。阳极氧化膜为典型的多孔结构,孔洞分布均匀,孔径为50nm左右。 相似文献
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使用铝合金挂钩对装入网兜的排球进行悬挂和管理,具有取用方便、节约空间、美观等优点。使用硫酸阳极氧化技术对排球挂钩用5005铝合金基材进行了处理,并对阳极氧化膜的性能进行了研究。结果表明:阳极氧化膜主要由铝、氧、硫、碳元素构成,其中铝和氧的总质量分数超过80%,少量的硫来自硫酸。经过硫酸阳极氧化处理后,铝合金表面形成高硬度和高熔点的a-Al2O3和y-Al2O3,大大提高了铝合金的硬度。阳极氧化膜由高电阻的阻拦层和多孔层构成,可以有效地分散和降低自腐蚀电流密度,大大提高铝合金基材的耐蚀性。 相似文献
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The effects of using ultraviolet irradiation (UV), ozone (O3) and the combined O3-UV advanced oxidation process (AOP) on humic acid (HA), which is regarded as the main disinfection by-products (DBPs) precursor, have been evaluated and compared. In particular, aromatic acids, short-chain aldehydes and carboxylic acids were measured. The purpose of this study was to determine the different classes and yields of oxidation intermediates, compare O3, UV and O3-UV for HA removal, as well as investigate the effects of O3, irradiation time, UV intensity on the mineralization of HA. Based on that, the knowledge gap of DBPs generation was made up. The results showed that by UV irradiation and O3 oxidation, HA broke down into smaller molecules that were more hydrophilic, namely formaldehyde, acetaldehyde, propaldehyde, butyraldehyde, glyoxal, methyl-glyoxal, formic, acetic, fumaric, benzoic, phthalic, protocatechuic and 3-hydroxybenzoic acids. Meanwhile, unsaturated conjugated double bonds in the structure of HA were destroyed, which lead to UV254 a slight decrease. Due to the synergistic effect of O3-UV, DOC and UV254 significantly decreased and remained stable after the reaction of 10 min, indicating that O3-UV system had stronger potential of mineralization and lower nonselectivity. Besides, the kinds and concentration levels of the intermediates were obviously reduced with light intensity increasing. Hydroxyl radical (.OH) could mineralize some organics that could not be mineralized by O3. 相似文献
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石蜡与微晶蜡质量比6∶4的混合原料,经纯氧氧化、酯化一步法合成高酯值蜡.与传统的空气氧化法进行了对比研究,并以皂化值为参数建立了两种氧化法的动力学模型.由不同反应温度下的实验数据回归得到氧气氧化反应的活化能为6.49 kJ/mol,指前因子为3.09h-1;空气氧化反应的活化能为11.56 kJ/mol,指前因子为11... 相似文献
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ROBERT A. SCHOENLAUB 《Journal of the American Ceramic Society》1969,52(1):40-43
The decomposition of pyrite was investigated in a thermo-balance. In neutral or reducing gases it decomposes between 550° and 700°C to volatile sulfur and ferrous sulfide. In oxygen it oxidizes in two stages: between 445° and 520°C, it forms sulfur dioxide and ferrous sulfide: between 610° and 660°C. it forms more sulfur dioxide and hematite'In air Or with fast cycles, the reactions are overrun and do not show the two stages. Carbon dioxide reacts very slowly and gives magnetite. Water vapor had an insignificant effect on the reactions. DTA did not show the second stage with normal technique. Fine grinding and testing in oxygen disclosed the reaction. 相似文献
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A series of NM/MO
x
/Al2O3 (NM = Pd, Ag, Pt, and Au) catalysts were prepared and tested in the oxidation of CO and CH4. The catalysts were characterized with X-ray diffraction and transmission electron microscopy. Where addition of MO
x
generally does not seem to affect the catalyst activity in CH4 oxidation, a large enhancement in CO oxidation was observed. Fourier transform infrared spectroscopy has been used to identify the role of MO
x
as a promoter for low-temperature CO oxidation. The results were found to support a Mars and van Krevelen type model. 相似文献
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T. E. EASLER R. C. BRADT R. E. TRESSLER 《Journal of the American Ceramic Society》1981,64(12):731-734
The room-temperature strength distributions of a sintered and a hot-pressed SiC were examined as-machined, after oxidation at 1370°C, and after oxidation under load at 1370°C. The strengths were observed to be dependent on both the duration of oxidation and the magnitude of the applied load. Processes resulting in both strengthening and weakening behavior were observed to occur, at times simultaneously within the same strength distribution. This dynamic situation indicates that the strength-controlling flaw populations are highly transient in nature. 相似文献
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The effects of oxygen pressure, substrate concentration and solvent on the rate and products of oxidation of methyl linoleate
were studied at 50 C with azobisisobutyronitrile as a radical initiator. The absolute and quantitative numbers for oxygen
uptake, substrate disappearance, and formation of conjugated diene and hydroperoxides were measured. Under the present conditions,
4 conjugated diene hydroperoxides, 13-hydroperoxy-9-cis, 11-trans-(2a), 13-hydroperoxy-9-trans, 11-trans-(3a), 9-hydroperoxy-10-trans, 12-cis-(4a), and 9-hydroperoxy-10-trans, 12-trans-(5a) octadecadienoic acid methyl esters, were formed almost quantitatively. The rate of oxidation decreased with decreasing oxygen
pressure. However, the ratio ofcis,trans totrans,trans hydroperoxides, (2a+4a)/(3a+5a), was independent of oxygen pressure, and this ratio increased with increasing methyl linoleate concentration, as found recently
by Porter. Further, the rate of oxidation and the ratio ofcis,trans/trans,trans hydroperoxides were dependent on solvent and increased with an increase in dielectric constant of solvent. A mechanism of
methyl linoleate oxidation consistent with these results is discussed.
Presented at the 15th Symposium on Oxidation Reactions, Nagoya, October 1981. 相似文献