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1.
李秋  姜雨杭  耿海宁  陈伟 《硅酸盐通报》2022,41(5):1805-1812
钢结构因具有多种优点而被广泛应用于工程建筑领域,但其在火灾高温环境下会丧失力学性能,造成结构失效,因此对钢结构进行防火保护成为关键。以偏高岭土、矿粉和憎水处理后的膨胀珍珠岩为主要原材料,模数为1.5的钾水玻璃为激发剂,制备非膨胀型钾基地聚物基防火涂料,并采用大板燃烧法研究该涂料在1 200 ℃下的防火性能;同时,对其在室温、1 000 ℃以及1 100 ℃热处理前后的力学性能、表观形貌、物相组成、微观结构演变进行了表征分析,探究地聚物在高温过程中的陶瓷化过程。结果表明:该防火涂料具有优异的防火能力,在1 200 ℃下进行2 h耐火极限试验后,钢板背面温度低于160 ℃;防火涂料在1 100 ℃高温热处理2 h后,抗压强度大幅增加至室温强度的5.8倍,达30.80 MPa;防火涂料基体的无定型地聚物相在800 ℃开始发生陶瓷化转变,1 100 ℃时生成的陶瓷相主要为钙长石、莫来石以及白榴石。  相似文献   
2.
采用铸膜法制备了一种羧甲基壳聚糖/氧化羧甲基纤维素/姜黄素(CMCHS/ OCMC/ CR)三元复合材料。红外光谱和扫描电子显微镜分析显示,复合膜断面结构均匀,无分层,但表面粗糙度有所增大。与不添加姜黄素相比,复合材料具有更好的断裂应力(20.10 MPa),断裂伸长率(18.97%),抗真菌性能(黑曲霉抑菌圈15.33 mm,青霉抑菌圈14.58 mm)和透水性(2.11×10-3 g·m-1·kPa-1·h-1)。草莓保鲜实验结果表明,CMCHS/OCMC/CR复合材料涂膜可减缓贮藏过程中的失重率和可滴定酸、可溶性固形物、还原糖含量的下降。经贮藏8 d,草莓失重率比较空白对照减少了11.38%,较阳性对照减少了1.27%,硬度,可滴定酸、可溶性固形物、还原糖含量的下降分别较空白对照减少了10.00%、42.72%、7.39%、9.32%,较阳性对照分别减少了5.54%、7.42%、2.39%、11.12%。因此CMCHS/OCMC/CR(1%, m/m)复合膜显示出良好护色和抑制霉菌生长的保鲜作用,可作为良好的涂膜抗菌材料应用于食品包装材料中。  相似文献   
3.
层状氧化物正极材料具有良好的结构稳定性和较高的充放电比容量,是一类理想的钠离子电池正极材料。本工作研究了层状氧化物正极材料NaNi1/3Fe1/3Mn1/3O2表面修饰对其电化学性能的影响,采用固相球磨法在正极材料表面包覆一层纳米ZrO2,采用形貌、结构、电化学方法等研究了包覆后性能改进机理。研究结果表明,ZrO2在NaNi1/3Fe1/3Mn1/3O2表面形成一层惰性保护层,有效隔开了电解液与正极材料的接触,缓解了电解液的分解速度,抑制了金属离子的溶出速度,从而显著改善了电池的循环性能以及高温性能。在ZrO2包覆修饰后,55℃下正极材料相比于未包覆的正极材料有明显提升,100次循环后容量保持率达到83.6%,高于未包覆的75.2%。此外,包覆后的NaNi1/3Fe1/3Mn1/3O2正极材料在空气环境存储后,稳定性得到明显提高。  相似文献   
4.
针对垃圾焚烧炉受热面的高温腐蚀,分析了硫/氯协同作用对涂层高温腐蚀性能的影响,以期为未来涂层服役性能的提升提供理论指导,促进垃圾焚烧发电的发展。在实验室模拟气氛(体积分数95%)+O2(体积分数5%)条件下,对涂有Na2SO4盐、NaCl盐及NaCl+Na2SO4混合盐的TC4渗铝样品进行600 ℃的高温腐蚀实验,并利用扫描电镜(SEM)、能量色散光谱仪(EDS)和X射线衍射(XRD)等手段对试样进行了分析。结果表明:当喷涂Na2SO4溶液时,涂层表面发生微弱的腐蚀;当喷涂NaCl+ Na2SO4(质量分数比1:2)混合盐溶液时,在涂层表面生成了多层结构的腐蚀氧化层;当喷涂NaCl溶液时,涂层表面发生了严重的腐蚀,腐蚀产物主要是富含Al、Ti的氧化物和氯化物。在腐蚀过程中,氯化钠在高温下形成Cl-1,其穿透初期形成的氧化膜,随后生成的金属氯化物在高温下汽化,向外扩散到达表面氧分压较高的区域时又被氧化为金属氧化物,此过程连续循环,使表面的多层氧化膜不断被腐蚀,随着Cl-1浓度的增加样品的腐蚀更加严重,但S和Cl的协同作用可以降低涂层的腐蚀速率。  相似文献   
5.
The continuous roll-to-roll slot die coating technique has shown great potential for fuel cell electrode fabrication. It is essential to determine the particulate coating window to obtain a defect-free film of uniform thickness and uniform particle dispersion. For this dual-purpose, an additional upper operating limit has been proposed via a “flow field analysis scheme” that combines analysis and simulation. In this analysis, the fundamentals of flow pattern transition (Poiseuille–Couette–bubbly flow) behind coating limits are clarified. The Couette flow is advantageous for uniform shear rate and dispersion. Furthermore, phase-field simulations systematically investigate the effect of fluid and geometrical parameters and quantitatively present the flow limit with explicit expression. Results reveal that the slope of the upper limit is inversely correlated with shear-thinning index n while proportional to the coating gap H. Combining the bubble entrainment boundary, lower n and H are favorable for a larger particulate coating window.  相似文献   
6.
SnO2-coated TiNb2O7 powders were synthesized via the solution coating method in the present research. The SnO2 layers with a thickness of 3–5 nm were homogeneously coated on the surface of TiNb2O7 particles. TiNb2O7 coated with SnO2 of 5 mol% with high Li+ diffusion coefficient delivered the discharge capacity of 319.5 mAh/g, which was 6.6% higher than that of the non-coated samples. The enhancement of capacity for the coated TiNb2O7 was owing to the low charge-transfer resistance of 17.5 Ω in contrary to the non-coated TiNb2O7 (27.8 Ω). SnO2-coated TiNb2O7 possessed an improved capacity retention of 85.2% at 5 C after 100 cycles, superior to the non-coated TiNb2O7 (79.8%). On the other hand, the excessive amounts of SnO2 coating led to the reduction in the capacity of the prepared samples. The excessive amounts of SnO2 layers suppressed the Li+ diffusion and increased the charge-transfer resistance. The obtained results in this study indicated that coating of TiNb2O7 with appropriate amounts of SnO2 significantly improved the electrochemical performance of TiNb2O7.  相似文献   
7.
In this study, Ca/Tb co-doped HfO2 coatings were prepared by atmosphere plasma spraying. The chemical composition, morphology and infrared property of the coatings were characterized. The coatings possessed a layer-stacked morphology. When the Ca/Tb doping atomic ratio was 1:1, the phase of the coatings gradually changed from monoclinic to cubic with increasing the doping mass. The CTH2 coating had the highest emissivity which was 0.820 in 0.75–6.5 µm and 0.902 in 6.5–15 µm respectively. The enhancement in short band was mainly due to the introduction of Ca2+ and Tb3+ ions that generated oxygen vacancies in the lattice forming impurity levels within the forbidden band, moreover, the transfer of Tb3+ to Tb4+ increased the concentration of free electrons, which promoted the absorption of free carriers. The increase in long band attributed to the lattice distortion that reduced the lattice symmetry and strengthened the absorption of lattice polar vibration.  相似文献   
8.
The influences of the SiC infiltration and coating on the compressive mechanical behaviours of 2D C/SiC composites were determined up to 1600 °C at 0.001 and 1000/s strain rates in argon and air. In addition, the failure mechanisms responsible for the compressive mechanical behaviours were elucidated through in-situ observation and micro-analysis-based methods. The 2D C/SiC composite compressive strength was highly sensitive to temperature, loading rate, and oxidation, and was enhanced by the change in the thermal residual stress and decreased by oxidation. In argon, because of the extra infiltrated SiC matrix, SiC treated 2D C/SiC specimens exhibited higher compressive strengths and lower strain rate sensitivity factors than SiC untreated 2D C/SiC specimens. The SiC coating effectively improved the oxidation resistance of the 2D C/SiC composites in air, regardless of the temperature, strain rate, and oxidative damage-which depends on SiC coating, strain rate, and temperature.  相似文献   
9.
通过系统分析延长组伊利石包膜的成因及其地质意义,开展了薄片分析、扫描电镜观测及能谱分析,对伊利石包膜的产状、成分、分布及其与绿泥石包膜的关系进行了研究。研究结果表明:①鄂尔多斯盆地三叠系延长组伊利石包膜与自生蒙脱石包膜具有相似的特征,是自生蒙脱石包膜伊利石化的产物;②研究区自生蒙脱石和绿泥石包膜均是火山物质溶蚀的产物,其相对含量受火山物质的组份控制,且二者均以颗粒表面为基底同时垂直生长;蒙脱石包膜发生伊利石化时,常伴随着钾长石的溶蚀;③弯曲片状伊利石晶体直径和晶间孔均远大于竹叶状绿泥石,但厚度薄,导致显微镜下黏土包膜内层为绿泥石、外层为伊利石,而扫描电镜下仅易见伊利石;伊利石包膜虽然降低了储层渗透率,但有利于砂岩孔隙的保存和亲水性的保留,对油气的开采具有重要意义。该研究成果对鄂尔多斯盆地三叠系延长组优质储层预测及开发均具有借鉴意义。  相似文献   
10.
This study deals with the manufacturing of catalyst-coated membranes (CCMs) for newcomers in the field of coating. Although there are many studies on electrode ink composition for improving the performance of proton-exchange membrane fuel cells (PEMFCs), there are few papers dealing with electrode coating itself. Usually, it is a know-how that often remains secret and constitutes the added value of scientific teams or the business of industrialists. In this paper, we identify and clarify the role of key parameters to improve coating quality and also to correlate coating quality with fuel cell performance via polarization curves and electrochemical active surface area measurements. We found that the coating configurations can affect the performance of lab-made CCMs in PEMFCs. After the repeatability of the performance obtained by our coating method has been proved, we show that: (i) edge effects, due to mask shadowing - cannot be neglected when the active surface area is low, (ii) a heterogeneous thickness electrode produces performance lower than a homogeneous thickness electrode, and (iii) the origin and storage of platinum on carbon powders are a very important source of variability in the obtained results.  相似文献   
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