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毛孔釉疤是陶瓷生产中常见的主要缺陷之一,对产品质量影响很大,本文针对其产生原因做了深入分析,提出“釉坯的坯釉分离是产生毛孔轴疤的根本原因”这一新观点,对其形成过程做了细致的描述,认为毛孔、釉疤、水泡边,薄坯泡是同一类缺陷,并提供了克服方法和应用实例。 相似文献
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釉疤、色疤在陶瓷缺陷中术语的解释是这样的.“指由于施釉不合要求而致烧后产品釉出现的局部严重不平”。但在实际生产中,釉疤、色疤样式有多种。这一缺陷在整体缺陷中的比例虽然不大,但就某个品种或某个色调是相当突出的,而且影响实物质量。这两种缺陷大多集中发生在大件产品、杯把根处、有孔雀绿、黑色等颜色的的绘产品。釉疤、色疤缺陷是一种现象,其实质是由于瓷体的气相、坯体、釉层三者吸附、湿润、粘附物理化学变化的结果。 相似文献
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在实际生产中,釉疤、色疤缺陷在整体缺陷中的比例虽然不大,但就某个品种或某个色调是相当突出的,而且影响产品质量。这两种缺陷大多集中出现在大件产品、杯把根处及采用孔雀绿、黑色等颜色的手绘产品。釉疤、色疤缺陷是由瓷体的气相、坯体、釉层三者吸附、湿润、粘附物理化学变化引起的。 相似文献
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毛孔虽小、产生因素却很多。无釉毛孔若控制釉浆粘度,加强黑坯除尘、水洗、即可防止;釉面毛孔比较复杂,涉及釉方、料方、工艺控制、燃煤质量等,本经简略分析后提出了解决办法。 相似文献
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通过选用合适的原料,合理的坯釉配方设计,适当的工艺路线,研制出在欧美市场畅销的高级乳白中温日用瓷。对釉面毛孔和釉泡缺陷进行了一些探讨。 相似文献
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答:釉疤一般出现在上釉白坯的表面或沟角处,以沟角凹面处居多。表现为发丝状小裂纹,或者凸起鸡爪丝状小裂纹。有该缺陷的白坯一经入窑烧成,会造成产品滚釉,形成废品。因此,有该缺陷的白坯严禁入窑。 相似文献
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Cynthia Bruckner-Lea Ryan J. Kimmel Jiri Janata John F. T. Conroy Karin Caldwell 《Electrochimica acta》1995,40(18):2897-2904
Octadecanethiol (ODT) and octanethiol (OT) films at the mercury-electrolyte interface are examined using cyclic voltammetry and differential capacitance measurements at a single frequency. A mercury flow-system is used to alter the volume, and therefore, the surface area and surface pressure of the mercury electrode. Manipulation of the mercury electrode's volume enables the introduction and removal of defects in the insulating thiol films. OT and ODT film behavior are contrasted under conditions of expansion and contraction. ODT forms extremely impermeable layers that allow 1000 time less redox probe current than seen on uncoated drops. Expansion of the mercury electrode to increase the electrode surface area produces defects and pinholes in the thiol film. These defects are almost completely removed when the drop is compressed back to its initial surface area. OT also forms insulating films on mercury sessile drops, however these films contain more defects than ODT films. While expansion of an OT-coated mercury drop increases redox probe current, recompression of the drop does not return the film to its initial condition. Pinholes and defects in the OT and ODT films can also be produced by cycling to negative potentials, which produce abrupt stripping peaks. 相似文献
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Formation and Control of Agglomerates in Alumina Powder 总被引:2,自引:0,他引:2
High-purity alumina powder with submicrometer particle size was colloidally dispersed and classified in either water or ethanol to remove agglomerates from as-received powder. After the slurries were dried, fine alumina particles cohered to form agglomerates, which were "hard" when formed in a water slurry, and "soft" in an ethanol slurry. Firing of the powder compacts with "hard" agglomerates resulted in inhomogeneous microstructures, and homogeneous microstructures were formed with "soft" agglomerates. The reasons for their formation are discussed and experimentally confirmed. In the case of water slurry, a small amount of transition alumina reacted with water at low pH. After drying, alumina gels were formed and acted as a strong binder between α-alumina particles to form "hard" agglomerates. 相似文献
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采用聚醚砜超滤膜对ZSN-330低不饱和度聚醚多元醇进行精制,粗聚醚多元醇由正己烷1∶1体积比稀释,精制效果很好,大部分检测时间下锌、钴离子截留率高达90%以上,含量低于1 mg /g。采用红外分析并验证了截留物中含有双金属氰化络合物催化剂(DMC)成分。考察了膜截留分子量、料液黏度、操作压力、料液流速等对膜通量的影响,确定了较佳的超滤条件为膜截留分子量为150 kDa、由正己烷1∶1稀释、操作压力0.5 MPa、料液流速40 L /h。分别采用去离子水、2‰氢氧化钠溶液、正己烷溶剂超声清洗污染的膜,2‰氢氧化钠溶液的清洗效果较好,膜通量恢复率达66.4%。 相似文献
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分别采用"两步法"和"三步法"两种不同工艺方法制备植物纤维纸蜂窝芯材,通过测试压缩性能、剪切性能研究两种工艺方法所制得芯材的力学性能;测试水迁移和垂直燃烧研究芯材的物理阻燃性能;比较芯材的力学性能和物理性能,选出两种方法中效果较好的工艺方法。结果表明,三步法工艺中芯材的压缩强度比两步法增加了52%;L向剪切强度增加了47.6%,W向剪切强度增加了72%。水迁移测试中两步法水迁移孔格数平均值为5,三步法平均值为0,垂直燃烧测试中两步法平均烧焦长度为41.8 mm,比"三步法"烧焦长度长12.8 mm。通过扫描电子显微镜测试分析了三步法力学性能较好的原因。综合比较芯材的力学性能和物理性能,三步法工艺好。 相似文献
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C. McDougall B. J. R. Philogène J. T. Arnason N. Donskov 《Journal of chemical ecology》1988,14(4):1239-1252
Two plant-derived allelochemicals, berberine and -terthienyl (- T), were tested for their effects on the European corn borer,Ostrinia nubilalis, and its endoparasitoidDiadegma terebrans. The compounds were administered to the host insect in meridic diets, and the responses of the host larvae and parasitoids reared from treated hosts were measured in terms of growth parameters and survival. InO. nubilalis, survival to pupation and adult emergence were reduced significantly by the inclusion of berberine and -T in larval diets at a concentration of 100 g/g. However, in the parasitoid, adverse effects were much more apparent with the -T treatment than with the berberine treatment. -T and one of its metabolites were found in host larvae and in emerged adult parasitoids and their cocoons. Berberine residues were not detected. The implications of these responses to compounds of widely differing physiological properties are discussed with reference to host-plant resistance and biological control. 相似文献
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Influence of alkylaluminium on TiClx/ MgCl2/ THF catalyst——Effect of Al-alkyl on chemical structure and catalyst performance
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研究了一系列不同烷基铝处理的TiClx/MgCl2/THF体系Ziegler-Natta催化剂,并采用XPS、EPR对其化学结构进行表征,初步探讨了烷基铝变化对催化剂化学结构的影响,特别是对Ti价态的影响。研究结果表明,由于烷基铝的作用,催化剂中活性组分Ti的结构发生了明显的改变,而其中烷基铝预还原过程对催化剂的结构影响较大。借助催化剂的这些结构上的变化引起其催化性能的显著提高,对比评价结果表明,小试催化剂的乙烯均聚活性从预还原前的4890 gPE/gcat提高到9300 g PE/gcat,工业生产催化剂从8400 g PE/gcat提高到11000 g PE/gcat。 相似文献
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以优化制备工艺为目的,研究不同制备方法对Ni-Mo/Al2O3加氢催化剂性能的影响。分别采用常规负载法、“一步成型法”和“沉淀打浆法”制备了Ni-Mo/Al2O3加氢催化剂,以氮气吸附(BET)、X射线衍射(XRD)、程序升温脱附(NH3-TPD)、程序升温还原(H2-TPR)和高分辨透射电镜(HR-TEM)等表征手段对3种方法制备的催化剂进行分析,并以50mL高压加氢装置考察了催化剂的反应性能。研究结果表明,与负载法相比,采用“一步成型法”和“沉淀打浆法”制备催化剂,孔容和比表面积大幅提高,但物相形态并没有发生转变;“一步成型法”制备的催化剂酸分布呈现出强酸比例升高的趋势,金属还原性及分散度也比负载法有所下降,“沉淀打浆法”制备的催化剂则显示出较高的中强酸量比例,金属还原性与分散度亦优于负载法催化剂。对催化剂的评价结果显示,针对不同的原料,3种催化剂均具有较好的加氢脱硫、脱氮和芳烃饱和活性,但总体上“一步成型法”制备的催化剂活性较负载法有所不足,而“沉淀打浆法”制备的催化剂活性则优于负载法,评价结果与催化剂的表征分析相吻合。 相似文献