SiO_2/ZrO_2无机膜的正交实验研究

以氧氯化锆(Zr OCl2·8H2O)和正硅酸乙酯(TEOS)为先驱体,乙醇(Et OH)为溶剂,四乙基溴化铵(TEAB)和N,N-二甲基甲酰胺(DMF)为模板剂,采用溶胶-凝胶法在Al2O3基体上制备Si O2/Zr O2复合无机膜。正交实验和单因素实验综合分析了锆含量、提拉速度、浸没时间和模板剂对膜性能的影响。结果表明,正交实验中各因素影响的大小顺序为:锆含量模板剂提拉速度浸没时间。并就模板剂和提拉速度对膜性能的影响进行了单因素考察。     

SiO_2-ZrO_2复合无机膜的制备研究

用溶胶-凝胶法在Al2O3基体上制备了SiO2-ZrO2复合无机膜,其中以正硅酸四乙酯(TEOS)、氧氯化锆(ZrOCl2.8H2O)和水为原料,乙醇(EtOH)为溶剂,盐酸(HCl)为催化剂,N,N-二甲基甲酰胺(DMF)为添加剂。考察了提拉速度、溶胶浓度、涂膜方式以及DMF对膜性能的影响。结果表明,采用6 cm/min的提拉速度可以得到较好的涂层;采用稀溶胶虽然涂膜周期较长,但膜的综合性能较好;此外采用浓稀交替的涂膜方式也可以提高膜性能,添加DMF能够均化膜孔径,同样有助于膜性能的提高。     

TEAB和DMF对SiO_2/ZrO_2无机膜制备的影响

以正硅酸乙酯(TEOS)、氧氯化锆(Zr OCl2·8H2O)、无水乙醇(Et OH)和水为原料,四乙基溴化铵(TEAB)和N,N-二甲基甲酰胺(DMF)为模板剂,盐酸为催化剂,采用溶胶-凝胶法制备无机复合膜。在锆含量不同的情况下,分别考察两种模板剂对无机膜涂膜液稳定性的影响;并探讨了模板剂对膜性能(即渗透比和渗透通量)的影响。研究表明,两种模板剂均对溶胶的稳定性存在一定程度的作用,且在高锆含量下两者对稳定性的影响更显平稳些;模板剂能够显著提高膜的综合性能。     

TEAB和DMF对SiO_2/ZrO_2无机膜制备的影响

以正硅酸乙酯(TEOS)、氧氯化锆(Zr OCl2·8H2O)、无水乙醇(Et OH)和水为原料,四乙基溴化铵(TEAB)和N,N-二甲基甲酰胺(DMF)为模板剂,盐酸为催化剂,采用溶胶-凝胶法制备无机复合膜。在锆含量不同的情况下,分别考察两种模板剂对无机膜涂膜液稳定性的影响;并探讨了模板剂对膜性能(即渗透比和渗透通量)的影响。研究表明,两种模板剂均对溶胶的稳定性存在一定程度的作用,且在高锆含量下两者对稳定性的影响更显平稳些;模板剂能够显著提高膜的综合性能。     

溶胶-凝胶法制备二氧化硅无机膜工艺研究

通过实验考察了在用溶胶-凝胶法制备二氧化硅无机膜的过程中涂膜温度、干燥条件及浸没时间对膜性能的影响。结果表明,控制适宜的涂膜温度、干燥环境和涂膜时间可以提高膜的性能。     

SiO2无机膜的实验研究

以正硅酸四乙酯(TEOS)、水为原料,乙醇(EtOH)为溶剂,盐酸(HCl)为催化剂,N,N-二甲基甲酰胺(DMF)为添加剂,用溶胶-凝胶法在Al2O3基体上制备了SiO2无机膜.考察了提拉速度、溶胶浓度以及涂膜方式对膜性能的影响.结果表明采用6 cm/min的提拉速度可以得到较好的涂层;较大的醇硅比虽然涂膜周期较长,...     

ZrO2中孔膜的制备及其耐酸碱腐蚀性能

以正丙醇锆为前驱体,通过颗粒溶胶路线制备ZrO2溶胶,并以此溶胶制备出稳定的制膜液. 采用浸浆法,经过一次涂膜,在平均孔径约为70 nm的片状a-Al2O3支撑体上制备出完整无缺陷的孔径小于10 nm的中孔ZrO2陶瓷膜,详细考察了烧成温度对ZrO2粉末和ZrO2中孔膜性能的影响. 在450℃的烧成温度下制备出孔径约为7 nm的ZrO2中孔膜,该膜对PEG的截留分子量为19500,在原料液侧压力为0.76 MPa、温度(23±1)℃条件下,纯水渗透通量为30~35 L/(m2×h). 经HNO3(pH=2)和NaOH(pH=13)溶液动态腐蚀后的ZrO2中孔膜对PEG截留分子量的变化表明,所制ZrO2膜具有较高的耐酸碱腐蚀性能.     

离子液体接枝型纳米二氧化硅对聚偏氟乙烯膜的亲水化改性研究

采用溶液接枝法合成了离子液体接枝型纳米二氧化硅(IL-Si O2),并利用浸没沉淀相转化法制备了聚偏氟乙烯/离子液体接枝型纳米二氧化硅(PVDF/IL-Si O2)杂化膜,考察了IL-Si O2含量对杂化膜性能的影响。采用流动电位、接触角和水通量等手段分析研究了杂化膜的性能。研究结果表明,PVDF/IL-Si O2杂化膜表面带有正电荷;IL-Si O2的加入显著提高了杂化膜的亲水性、拉伸强度和断裂伸长率;杂化膜纯水通量显著增加的同时,对蛋白质的吸附量和截留率均有一定程度上的提高。     

ZrO2/SiO2无机复合膜的灰色关联分析

以硅酸乙酯和氧氯化锆为先驱体，用乙醇为溶剂，采用溶胶凝胶法在Al2O，基体上制备ZrO2／SiO2无机复合膜用灰色关联分析方法考察了各主要因素（涂膜温度、ZrOCl2摩尔百分含量、乙醇含量、添加剂DCCA量）对ZrO2／SiO2无机复合膜的影响，研究结果表明：乙醇含量（即溶胶浓度）对无机复合膜的影响最为显著。控制干燥化学添加剂（DCCA）对成膜性的影响仅次于乙醇含量。研究给出了各主要因素对ZrO2／SiO2无机复合膜影响的大小先后顺序为：乙醇含量添加剂DCCA量ZrOCl2摩尔百分含量涂膜温度。     

溶胶-凝胶法制备二氧化硅无机膜的实验研究

以正硅酸乙酯为先驱体,用溶胶-凝胶法在A l2O3基体上制备了SiO2无机膜。重点考察了涂膜温度、溶胶浓度及添加剂对膜性能的影响。结果表明:在较高的温度下涂膜可以提高膜的性能;采用浓溶胶和稀溶胶结合的方式涂膜不但可以提高制膜效率,还可以提高膜的性能。添加剂DMF能够均化膜孔径,提高膜的性能。     

溶胶-凝胶法制备不锈钢表面SiO2-TiO2-Al2O3-ZrO2涂层

在乙醇中,分别以盐酸、醋酸为催化剂,以正硅酸乙酯、钛酸正丁酯、硝酸铝、氧氯化锆为金属醇盐前躯体,通过分步水解法制备了SiO2-TiO2-Al2O3-ZrO2复合溶胶,利用浸渍法将陈化后的复合溶胶涂覆到不锈钢表面制得透明的复合涂层。对SiO2-TiO2-Al2O3-ZrO2复合涂层进行了差热分析(DTA)、失重分析(TG)、红外光谱(IR)、X射线衍射分析(XRD)以及耐HCl、CuSO4和FeCl3溶液浸泡腐蚀实验。结果表明,涂层中存在TiO、SiO、AlO键的氧化物网状结构,其XRD图中出现了锐钛矿和板钛矿的相结构。该涂层致密,具有良好的耐蚀性能。     

Electrochemical and morphological properties of zirconium conversion coating in the presence of nickel ions on galvanized steel

A hexafluorozirconic acid-based conversion coating was applied on a galvanized steel substrate and the influence of nickel ion from nickel sulfate solution (in zirconium solution and in a separate solution) on the corrosion resistance behavior and morphology of zirconium conversion coating was investigated. Electrochemical impedance spectroscopy and DC polarization were conducted in 3.5 wt% NaCl solution in order to optimize practical conditions of zirconium conversion coating and NiSO₄ solution on the galvanized steel substrate. Field emission scanning electron microscopy and X-ray photoelectron spectroscopy were employed to study the morphology and composition of the coated surfaces. Results revealed that the conversion coating obtained from solution containing zirconium and nickel ions (Zr + Ni) did not improve corrosion resistance and uniformity of the coating in comparison with Zr conversion coating in optimized condition. However, a positive effect was obtained from samples coated with separate solutions of zirconium and nickel (Zr–Ni). Improved corrosion resistance and morphology of Zr-based conversion coating were observed in Ni²⁺ concentration, pH, and immersion time of 10 g/L, 6 and 300 s, respectively. Morphology and surface composition analysis proved that two separate layers of conversion coating containing zirconium, zinc, and nickel oxide/hydroxide compounds were formed in the case samples that were treated by separate solutions. This led to better uniformity and higher thickness of the coating. Finally, adhesion strength of epoxy organic coating on galvanized steel with and without conversion coating was investigated by pull-off measurement. Zr–Ni conversion coating in optimum conditions had a positive effect on adhesion of organic coating in comparison with blank sample and samples pretreated with Zr and Zr + Ni conversion coatings through increased surface roughness and physical interlocking.     

Preparation of PFSA‐PVA/PSf hollow fiber membrane for IPA/H2O pervaporation process

Using Na⁺ form of perfluorosulfonic acid (PFSA) and poly(vinyl alcohol) (PVA) as coating materials, polysulfone (PSf) hollow fiber ultrafiltration membrane as a substrate membrane, PFSA‐PVA/PSf hollow fiber composite membrane was fabricated by dip‐coating method. The membranes were post‐treated by two methods of heat treatment and by both heat treatment and chemical crosslinking. Maleic anhydride (MAC) aqueous solution was used as chemical crosslinking agent using 0.5 wt % H₂SO₄ as a catalyst. PFSA‐PVA/PSf hollow fiber composite membranes were used for the pervaporation (PV) separation of isopropanol (IPA)/H₂O mixture. Based on the experimental results, PFSA‐PVA/PSf hollow fiber composite membrane is suitable for the PV dehydration of IPA/H₂O solution. With the increment of heat treatment temperature, the separation factor increased and the total permeation flux decreased. The addition of PVA in PFSA‐PVA coating solution was favorable for the improvement of the separation factor of the composite membranes post‐treated by heat treatment. Compared with the membranes by heat treatment, the separation factors of the composite membranes post‐treated by both heat treatment and chemical crosslinking were evidently improved and reached to be about 520 for 95/5 IPA/water. The membranes post‐treated by heat had some cracks which disappeared after chemical crosslinking for a proper time. Effects of feed temperature on PV performance had some differences for the membranes with different composition of coating layer. The composite membranes with the higher mass fraction of PVA in PFSA‐PVA coating solution were more sensitive to temperature. It was concluded that the proper preparation conditions for the composite membranes were as follows: firstly, heated at 160°C for 1 h, then chemical crosslinking at 40°C for 3 h in 4% MAC aqueous solution. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrochemical study of tailored sol–gel thin films as pre-treatment prior to organic coating for AZ91 magnesium alloy

The behaviour/resistance of four optimised sol–gel coating systems (inorganic, hybrid organic–inorganic, containing zirconium ions and containing cerium ions) against corrosion of AZ91 magnesium alloy were studied. The coatings obtained by the sol–gel process were evaluated as autonomous protective coatings as well as a pre-treatment prior to acrylic top coat. The coating obtained from tetramethoxysilane (TMOS) and diethoxydimethylsilane (DEDMS) as precursors and doped with Ce³⁺ was especially effective as pre-treatment for a final acrylic coating. For non-defected coating the impedance modulus has not changed during the time of immersion (7 days) in 0.5 M Na₂SO₄. An inhibition of coating delamination at the defect of the acrylic coating was recorded by means of LEIS.     

SiO_2无机膜涂膜液稳定性的研究

制备SiO2溶胶作为SiO2无机膜的涂膜液,以正硅酸乙酯(TEOS)、水为原料,乙醇(EtOH)为溶剂,N,N-二甲基甲酰胺(DMF)为添加剂,盐酸(HCl)为催化剂。先后用正交实验法和单因素实验研究了乙醇、水、DMF、pH值和配制温度对SiO2溶胶稳定性的影响,结果表明:pH值影响因素中占权重最大;其次为水,随着水量的增大溶胶的稳定时间明显变长,比值在12~14;随着乙醇含量的增加,溶胶稳定性的增长速率由快变慢,n(EtOH)/n(TEOS)保持在16~20;DMF对其影响不大;而配制温度的影响在单因素实验中得到体现。     

硅溶胶辅助制备Beta分子筛膜

采用二次生长法，通过在晶种涂覆液中添加硅溶胶，在不锈钢丝网载体上制备牢固的Beta分子筛膜，系统考察晶种层中硅溶胶含量、晶种涂覆量、结晶温度和结晶时间对分子筛膜生长的影响。实验中发现，硅溶胶的存在可以增加涂覆层的牢固度，促进Beta分子筛膜的生长；硅溶胶既具有黏合剂的作用又可以补充硅源。当涂覆量较低时，无法得到一个完整的分子筛膜，分子筛膜负载量随着涂覆量的增加而增加；当结晶温度升至一定程度，分子筛膜组成不再单一。晶化过程中伴随着晶种的脱落和溶解。制备的Beta分子筛膜对N₂O催化分解具有良好的催化活性。