助熔剂和密着剂对搪玻璃的作用机理及其研究进展

搪玻璃是一种在金属表面喷涂瓷釉(搪玻璃釉),经高温搪烧密着而成的复合材料,既具有玻璃的化学稳定性,又具有金属材料的硬度大、强度高等优良特性,同时表面光滑易清洗,因此在化工、医药等行业广泛应用。搪玻璃性能取决于搪玻璃釉的成分,搪玻璃釉包括基体剂、乳浊剂、助熔剂、密着剂等,其中助熔剂中含有低熔点物质,能够降低熔化温度,破坏搪玻璃釉连续的网络结构,形成新分子键,进而改良搪烧工艺;密着剂能够与金属基体发生化学反应,增强搪玻璃釉和金属基体的结合强度,进而提高力学性能。本文简要介绍了搪玻璃釉中的各类助剂,着重叙述了助熔剂和密着剂的组成及作用机理,为今后设计搪玻璃釉及提高搪玻璃设备性能提供了参考依据。     

工业搪瓷釉在太阳能热水器承压水箱上的应用前景分析

用搪玻璃(工业搪瓷釉)制成的水箱具有耐酸、耐碱强度高、耐高温水的腐蚀性强,抗温差急变性好的特点,且使用寿命高出普通水箱的1倍.搪玻璃釉料被广泛应用于化工、制药领域,能够承受高温、高压、强腐蚀等苛刻条件,这就更突出了它的优势和稳定性.相比之下,搪玻璃水箱必将会受到市场的青睐.     

搪玻璃设备结构对物料反应速度的影响

1 前言 搪玻璃设备是医药、化妆等精细化工生产单位所用的主要设备。我国自有独立的搪玻璃生产行业以来,一直围绕着更好地适应和服务于化学工业发展的主题。在搪玻璃的技术性能方而做了不懈的探索和研究。多年来,主要的研究方向是在提高瓷釉的理化性能方面,就设备的结构而言,只是局部的改进,并没有实质性的进展。笔者通过几年来对数家化工生产单位使用反应罐情况的观察与了解,认为要使搪玻璃行业更好地服务于化工行业,使搪玻璃产品在市场经济中更具有竞争力,今后应该在改进设备结构以便提高罐内物料的反应速度方面进行突破性的研究与改进。这样将大大提高化工行业的生产效率,并且具有一定的社会效益。搪玻璃设备也会更受用户的青睐,同时搪玻璃的技术性能也将会有所发展。     

搪玻璃反应釜在液相法制备一氯甲烷工艺中的应用

介绍了一种液相催化法反应制备一氯甲烷工艺中搪玻璃反应釜的选型、搪玻璃反应釜制作的特殊要求、搪玻璃反应釜在运行过程中损坏的原因和日常维护的针对性防护措施，重点就反应釜气相空间腐蚀原因进行了分析和维护策略阐述。实践证明，搪玻璃反应釜有效的日常维护可大大延长设备使用寿命，降低设备故障率。     

YSZ改性搪玻璃复合材料的性能研究

氧化钇稳定氧化锆(YSZ)可提高搪玻璃的断裂韧性。设置不同的YSZ粒径组分并将其掺入到搪玻璃瓷釉中,采用抗冲击试验、三点弯曲试验和弹性模量试验对YSZ改性搪玻璃性能进行研究。平均粒径为100nm的YSZ掺入显著提高搪玻璃的断裂韧性,但硬度略有降低,搪玻璃断裂力值差可提高到366%以上,搪玻璃断裂位移差可提高到149%以上。当搪玻璃釉中掺杂2%质量分数粒径为100nm的YSZ时,断裂韧性可以提高到较优效果。     

搪玻璃增韧方法的研究进展

搪玻璃兼具玻璃的化学稳定性和金属的高硬度和高强度的特点,在化工等多个领域具有广泛的应用.但韧性差、易爆瓷的缺点限制了搪玻璃化工设备的使用范围和使用寿命,所以增加韧性是搪玻璃研究的一个重点.本文分析讨论了氧化锆相变增韧、颗粒增韧、晶须(纤维)补强增韧和协同增韧等在搪玻璃领域的应用,并展望了搪玻璃增韧技术的发展方向.     

红柱石添加量对矾土质浇注料高温性能的影响

本文以特级铝矾土、红柱石颗粒、红柱石细粉、活性α-Al2O3微粉、硅微粉为原料,纯铝酸钙水泥为结合剂,三聚磷酸钠为减水剂,研究加入不同量红柱石颗粒及细粉对矾土质浇注料高温性能的影响.结果表明:红柱石反应生成莫来石和二氧化硅玻璃相可以显著提高矾土质浇注料的高温抗折强度和热震稳定性.综合考虑,红柱石的添加量以30％为宜,用于化铜炉内衬材料提高炉子的使用寿命.     

搪玻璃瓷层异色点产生的原因及对策

搪玻璃瓷层性能与搪玻璃釉的化学组成、熔制工艺、搪烧工艺、搪玻璃层瓷层厚度及均匀性和搪玻璃层缺陷控制都有密切的关系,瓷层性能的好坏决定搪玻璃设备的使用寿命。异色点是搪玻璃瓷层常见的缺陷之一,本工作分析了产生异色点的原因并根据不同情况确定了合理的解决方案。     

防腐衬玻璃管道试验方法研究制定

1 前言防腐衬玻璃管道是一种新型化工防腐管道,其原料易得、生产工艺简单、价格低廉经化工行业厂家使用可代替其它防腐输送管道。为了能够更好控制防腐衬玻璃质量,降低企业能耗,1991年10月,我们受有关企业委托,根据产品特点,结合现场使用情况,制定了有关产品检验方法。 2 防腐衬玻璃性能、用途将配好的特殊玻璃原料,经高温熔炼后得防腐衬玻璃,采用吹制法将玻璃衬于铁制管道内壁。防腐衬玻璃管道主要用于化工溶液、粉料等的输送,具有较强的耐冲刷性和耐腐蚀性,使用寿命高于搪瓷玻璃和不锈钢,有较高的耐机械冲击性能及耐冷急变性能。     

t-ZrO2相变提高搪玻璃抗拉强度的研究

采用添加四方相氧化锆(t-ZrO₂)的方式增强搪玻璃涂层的力学性能,通过三点弯曲试验研究搪玻璃表面应变变化情况,对断裂截面进行XRD、SEM、拉曼分析。结果表明,添加适量t-ZrO₂改善了搪玻璃的表面形貌,减少了气孔数量。在三点弯曲试验中,2%t-ZrO₂质量含量的搪玻璃承受的最大力值提高了7 kN,在11 kN三点弯曲压力作用下出现裂纹,应变值提高约37%。含有t-ZrO₂搪玻璃试样的截面断裂前后发生t相到m相的相变,t-ZrO₂相与搪玻璃原始釉相的边界处出现裂纹的偏转,从而抑制裂纹扩展。     

Effect of bentonite content on the suspension stability of a glaze slurry and final enamel performance

The influence of bentonite as a suspending agent on the processing and performance of the final enamel product was studied with the aim of prolonging the service life of enamel. The suspension stability of the glaze slurry was also evaluated, and the influence of the layered structure of bentonite on the suspension was explored. In addition, the effect of bentonite on the flexural strength and fracture toughness of enamel coatings on metal substrates was investigated. Finally, acid corrosion resistance experiments were performed to evaluate the effect of bentonite on the corrosion performance of the enamel coating. The results showed that the stability of the glaze slurry and mechanical properties of the enamel products were significantly improved by adding 1 wt% bentonite to the glaze slurry. The addition of 0.5 wt% bentonite was optimal for enhancing the acid corrosion resistance of the enamel. This study provides a useful reference for improving the quality of enamel products and prolonging their service life.     

Improving the mechanical impact and bending resistances of enamel via B2O3 addition

Enameled metal equipment possesses the advantages of the material strength of metal and the corrosion resistance of glass; therefore, such equipment is used extensively in industries involving chemical processes. However, the mechanical properties of enamel affect its service life. Therefore, the enhancement of the mechanical properties of enamel to extend its service life is important. To improve the mechanical impact and bending resistances of enamel, we used enameled samples with Q345R steel as a metal matrix for controlled-temperature sintering. The enameled samples were prepared using varying amounts of B₂O₃ in the formulation of the enamel glaze, and the mechanical impact and bending resistances of the enamel were studied via the ball impact and three-point bending methods. The results show that B₂O₃ addition improves the mechanical impact and bending resistances of enamel significantly, although these resistances decrease when the B₂O₃ content is too high. The enamel exhibits an optimal mechanical impact resistance with a B₂O₃ content of 2%, and an optimal bending resistance with a B₂O₃ content of 3%. These results provide important reference values that can be used to optimize the formulation of enamel and extend the service life of enamel equipment.     

Improving the bending and corrosion resistance of an enamel by the addition of β-Si3N4 whiskers

Enamel–metal composite materials with high strength and corrosion resistance are often used for fabricating enameled pressure vessels for pharmaceutical and chemical production. However, the low bending resistance of the enamel can result in the cracking and delamination of the enamel layer, leading to the loss of corrosion resistance of the enameled pressure vessel, which can result in accidents. Here, based on the goal of increasing the bending resistance of the enamel to prolong its service life, the effect of β-Si₃N₄ whiskers on the mechanical properties of enamel was studied by three-point bending tests. The effect of β-Si₃N₄ whiskers on the acid and alkali corrosion resistance of enamel was studied using aqueous H₂SO₄ and NaOH solutions, respectively. A sudden change in the force of an enameled sample under the three-point bending test was used to evaluate the bending resistance of the enamel–metal samples, and can also be used to evaluate the mechanical properties of other comparable materials. With the addition of 0.5 wt% β-Si₃N₄ whiskers, the bending resistance was significantly improved, along with the acid and alkali corrosion resistance. These findings are expected to provide guidance for the design and production of enamel-metal vessels with improved performance that can significantly lengthen the service life of enameled pressure vessels and reduce the occurrence of accidents.     

Improvement in mechanical properties of enamel via carbon nanotube addition

Enameled metal equipment exploits the strength of metal materials and the corrosion resistance of enamel; therefore, it is widely used in the chemical industry. However, the mechanical properties of the enamel restrict its service life. Multi-walled carbon nanotubes (MWCNTs) are one-dimensional nanomaterials with high-specific surface area, C–C bond structure, and SP₂ hybrid orbital. Herein, the effect of the dosage of MWCNTs on the mechanical properties of enamel is studied by adding MWCNTs to improve the mechanical properties of the enamel. Microscopic observation showed that the toughening mechanism of MWCNTs was mainly manifested in fracture and pull out behaviors. According to three-point bending test, when 0.4 wt% carbon nanotubes were added, the reinforcing effect of enamel layer reached the best state. These results provide reference for optimizing the formulation of enamel and extending the service life of enamel.     

Evaluation of 316L stainless mill additives on microstructure and alkali corrosive behavior of enamel coatings

Excellent chemical stability, good corrosion resistance, and compositional controllability make vitrified enamel promising coating materials. The corrosion resistance of the [–Si–O–]/[–Si–O–Al–]-based enamel coatings decreases in alkaline environments, whereas can be improved by incorporating metal oxides, such as ZrO₂ and SnO₂. The introduction of these oxides results in an increase in the sintering temperature and a decrease in the toughness of the coatings. It was observed that the corrosion resistance of the coatings in an alkaline medium could be improved using metal powder-based additives without increasing the sintering temperature and affecting the mechanical properties of the coatings. We used powdered 316L stainless steel as the mill additive, and the effects of this additive on the structure and alkali corrosion resistance of the vitrified enamel coatings were studied. Results indicate that the addition of an appropriate quantity of the additive (4 wt.%) improves the extent of gas consumption during the enamel sintering, decreases the degree of porosity and the size of the pores. Furthermore, the mechanical properties of the skeleton formed between the pores could be improved, because blocklike corrosion products are not peeled off, which increases the corrosion resistance of the coatings. The corrosion products, such as Ca-based compounds, block the corrosion holes, resulting in a decrease in the corrosion rate also.     

环氧粉末涂层对金属基材附着力的影响因素

环氧粉末涂料具有附着力好、耐腐蚀性强、耐温性能好等优点,在金属防腐特别是重防腐领域应用非常广泛。在环氧粉末涂层的诸多性能中,涂层对基材的附着力是非常重要的一项技术指标,也是满足其他性能的基础,附着力的好坏直接影响着涂层对基材的保护寿命。本文主要从喷涂温度、基材表面处理的表面粗糙度以及粉末涂料原材料等方面讨论了环氧涂层对金属基材表面附着力的影响因素。研究表明：喷涂温度提高有利于涂层附着力的提高,表面粗糙度提高且锚纹深度相对均匀有利于涂层附着力的提高,填料以及助剂的种类对附着力具有一定的影响。     

钢筋混凝土中防腐添加剂的研究进展

在钢筋混凝土结构服役过程中,由环境侵蚀因素导致的耐久性问题是制约结构长效服役的重要原因,其中,氯离子侵蚀导致的钢筋锈蚀是引起钢筋混凝土耐久性劣化的主要因素之一。在混凝土内掺加防腐添加剂,可从促进钢筋表面成膜和改善混凝土自身性能(孔隙结构、水化过程、Friedel’s盐生成)等方面提升阻锈能力,近年来逐渐成为研究热点。本文将防腐添加剂分为传统阻锈剂、绿色植物提取物阻锈剂、纳米材料以及矿物掺合料等四类,从材料开发、作用机制、阻锈影响因素等方面对防腐添加剂的研究进行了综述。最后,探讨了防腐添加剂研究中存在的问题,并对未来的研究提出了建议,以期为防腐添加剂能够更好地防治混凝土中的钢筋锈蚀问题提供参考。     

聚丙烯焊缝耐蚀性能研究

采用高温静态浸渍法，测定了聚丙焊缝在各类介质中的耐蚀性能，为改进焊接条件和进一步提高设备使用寿命提供参考数据。     

Improving the mechanical properties of enamel by nickel nanoparticle addition

In order to improve the mechanical properties of enamel and prolong its service life, the effects of nickel particles on the microscopic morphology and mechanical properties of enamel were studied by XRD, FTIR, DSC, SEM, porosity analyses, nanoindentation, and bending experiments, and the following conclusions were drawn. When the addition amount of Ni nanoparticles added to enamel ranges from 1 to 5 wt.%, the mechanical impact resistance of enamel is improved compared with no addition. With the addition of 1 wt.% Ni nanoparticles, it enhanced the toughness of the enamel and the maximum bending strength of the enamel was achieved, which was 10% higher than that of the samples without Ni nanoparticles. Therefore, the addition of the optimal Ni nanoparticle content of 1 wt.% significantly improved the performance of enameled pressure vessels.The findings in this work are valuable for extending the life of enamel-coated pressure vessels and thus reducing accidents caused by them.     

Application of electrochemically produced and oxidized poly(3,4‐ethylenedioxythiophene) as anticorrosive additive for paints: Influence of the doping level

This work investigates the resistance against marine corrosion of an epoxy‐based coating modified by the addition of electrochemically produced and oxidized poly(3,4‐ethylenedioxythiophene) (PEDOT). For this purpose, electrodeposition of PEDOT was performed on steel electrodes by electrochemical polymerization of 3,4‐ethylenedioxythiophene. The doping level of the resulting material was increased by chronoamperometry and chronopotentiometry (CP), three different oxidation degrees being achieved. The electrochemical and electrical properties of such three samples, which were used as anticorrosive additives, were examined. Furthermore, the physical properties of the coating before and after addition of the conducting polymers were characterized using FTIR, thermal analyses, and mechanical properties evaluations. Accelerated corrosion tests indicated that the polymer with the highest amount of positive charge per monomeric unit, which was achieved by CP, enhances considerably the anticorrosive protection imparted by the coating. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1592–1599, 2006