铸造用泡沫陶瓷过滤器的生产工艺

本文详细介绍了泡沫陶瓷过滤器的生产工艺,并简单介绍了其过滤机理。对海绵加工、浆料调节及产品烧结等生产工序分别作了阐述,并提出了生产过滤器的技术要求和铸造使用过程中的注意事项。     

镁铝质泡沫陶瓷过滤器的研制

研究了镁铝质泡陶瓷过滤器的成分，成型工艺，烧结工艺，性能及应用效果。实验结果表明，镁铝质泡沫陶瓷过滤器具有良好的应用前景。     

过滤熔融金属的陶瓷泡沫过滤器

引言随着科学技术的不断发展,对金属材料的综合性能提出越来越高的要求。大到制造巨型超音速飞行器的航天航空材料,小到制造薄壁易拉罐的材料,如超细铜芯线材料、高速运转的曲轴、气缸头材料、高压高流速的阀体材料等等。在熔炼及加工过程中,为了提高金属材料的延展性能、拉伸性能、光亮度等性能,先进工业国家都使用陶瓷泡沫过滤器对熔融状态的金属     

锆刚玉—莫来石泡沫陶瓷过滤器的研究及应用

以氧化铝粉和锆英石粉为原料，通过反应烧结制成了锆刚玉－莫来石泡沫陶瓷过滤器，研究了锆英石对抗弯强放抗热震性的影响，对球墨铸铁和铸钢的过滤试验结果表明，过滤后的夹杂物减少，冲击韧性明显提高。     

AS型泡沫陶瓷过滤器的研制

详细说明了用网状弹性聚氨基甲酸乙酯切片浸渍陶瓷料浆压制AS型泡沫陶瓷过滤器的工艺。采用非磷酸盐添加剂粘合,由碳化硅、氧化铝、硅胶及少量硅酸铝纤维制成的AS型泡沫陶瓷过滤器抗压强度可达1．65MPa而厚度仅为15mm,并且不会造成环境污染,完全可以满足过滤铁溶液的要求。     

铝用泡沫陶瓷过滤器现状与应用趋势

简述了过滤净化对于铝及铝合金熔铸的重要意义,通过国内外现有铝用泡沫陶瓷过滤器(CFF)的对比分析,提出了国内铝用CFF在性能与应用方面存在的问题以及面临的竞争,并从材料、制备工艺、效用评价等方面提出了改善铝用CFF性能的若干措施。     

汽车柴油机排气颗粒泡沫陶瓷过滤器的研制

着重论述了汽车柴油机排气颗粒泡沫陶瓷过滤器滤芯的性能要求，确定了泡沫陶瓷过滤器的配方、工艺和结构。所制得泡沫陶瓷的性能：抗弯强度为1．5MPa；膨胀系数为2．89×10－6／K－1；耐温性为1300℃．用此泡沫陶瓷做成的滤芯碳颗粒过滤效率为50％左右。根据台架试验与性能检测结果数据，集中讨论了工艺、添加剂和滤芯结构的影响。     

泡沫陶瓷的研究进展

介绍了泡沫陶瓷的特性、制造工艺、用途及在冶金工业中的应用。指出除现有的堇青石质、氧化铝质、堇青石－氧化铝质过滤器外，还开发了氮化硅质、碳化硅质、氧化铝质产品。     

泡沫陶瓷过滤器几种常见错误使用方式及纠正办法

探讨泡沫陶瓷过滤器的设计应用过程中不合理导致铸件缺陷上升,原使用泡沫陶瓷过滤网的作用:①过滤金属液中夹杂物;②整流,紊流金属液;最终目的,提升铸件品质,改善铸件表面缺陷.但是,使用过程中设计不合理,导致铸件缺陷更加恶化.     

Preparation and properties of enstatite ceramic foam from talc

The effective method of preparation, stabilization and high temperature treatment of enstatite ceramic foam is described in this work. The technique is based on foaming of suspension of talc, on the stabilization of foam structure and on final high temperature treatment after drying. The spontaneous delamination of aggregates and the redistribution of talc particles in foam are driven by decreasing surface energy. The changes of phase composition as well as the mechanism and the kinetics of processes which take place during the thermal treatment were described. The treatment within the temperature range from 1150 to 1250 °C provides the ceramic foam via sintering without melted phase, whereas a liquid phase sintering occurs at higher temperatures. The final temperature of sintering is 1300 °C. Increasing amount of melted phase supports the formation of enclosed porosity and formed glass stabilizes the high temperature protoenstatite polymorph in the foam.     

Preparation and characterization of ceramic foam supported nanocrystalline zeolite catalysts

The influence of the viscosity of the ceramic slip on the manufacture of ceramic foams by the polymer sponge method was studied. The foams were coated with silicalite (100 nm) and HZSM-5 (650 nm) crystals by dipping them in a zeolite suspension without binder additives. The amount of zeolite loaded can be controlled through the zeolite content of the dipping suspension. Uniform coatings are achieved starting with about 1 g zeolite/m² foam.     

Development and testing of carbon-bonded alumina foam filters for continuous casting of steel

Carbon-bonded alumina filters with special design for continuous casting were produced by the replication technique using different coating procedures. The filters were investigated regarding filter strut diameter, porosity and cold crushing strength. The potential filter capacity and the mechanical load expected during the immersion in a continuous casting tundish were calculated. The best compromise between mechanical strength and structural features was achieved by combining the advantages of centrifugation, dip coating and spray coating. This filter type was analyzed by computed tomography and withstood the contact with molten steel in a casting test. After melt contact, the filter material exhibited near-surface decarburization and alumina-based in-situ layer formation. The observed layers were more pronounced in zones with potentially lower melt flow velocity. The results of the study indicated that the produced filters are able to withstand the severe conditions in continuous casting.     

TZP(Al_2O_3)质泡沫陶瓷过滤器

研究了TZP（A12O3）材质泡沫陶瓷过滤器的制备工艺。结果表明，泡沫陶瓷过滤器的烧结滞后于普遍压制成型的试块，于1550℃左右烧成的过滤器强度可达1．5MPa；过滤器加热至1100℃保温数分钟空冷后，强度有回升现象。产生上述现象的机理有待于进一步分析。     

Hydrodynamic and mass transfer efficiency of ceramic foam packing applied to distillation

In addition to a high void volume and specific area, solid foams possess other properties (low density, good thermal, mechanical, electrical, and acoustical behaviour) that make them attractive for applications such as heat exchangers and reformers. Applications using foams as catalysts or structured catalyst supports have demonstrated higher performance than classical catalysts. Several studies have explored the hydrodynamic behaviour of foams in monophasic and countercurrent systems and have reported very low pressure drops. This paper describes the application of ceramic foam to distillation. The β-SiC foam contains 5 pores per inch (PPI) with a 91% void volume and a surface area of 640 m²/m³. Performance parameters including pressure drop for the dry and wet packing, flooding behaviour, and dynamic liquid hold-up were measured in a column of 150 mm internal diameter. The mass transfer efficiency in terms of the height equivalent to theoretical plate (HETP) was determined by total reflux experiments using a mixture of n-heptane and cyclohexane at atmospheric pressure. The experimental results were used to develop a set of correlations describing pressure drop and liquid hold-up in terms of a dimensionless number. The hydrodynamic performance and mass transfer efficiency were compared with classical packing materials used in distillation.     

Fracture mechanics analysis of delamination buckling of a porous ceramic foam coating from elastic substrates

Ceramic foams are ideal materials for thermal protection systems such as those used as a thermal shield on the space shuttle. The working temperature difference between the outer and inner surfaces of the ceramic foam is extremely high. Under this adverse condition, the ceramic foam coating could buckle from its underneath structures. Therefore, the general problem of damage due to buckling delamination of a ceramic coating on an elastic substrate is investigated in this paper. The delamination buckling amplitude and the stress intensity factor at the tip of buckling region are derived in closed form in terms of the porosity of the ceramic foam. Based on the maximum amplitude and the critical stress intensity factor criteria, critical temperatures of coating buckling from the substrate are established. A fitting formula of maximum buckling amplitude as a function of outer surface temperature is given. It is found that higher porosity and length-to-thickness ratio of the coating will result in a smaller stress intensity factor. However, it seems that the buckling amplitude is independent of the porosity of ceramic foams.     

Factors affecting the microstructure of a fine ceramic foam

Sintered cellular ceramics with varying degrees of reticulation were prepared using coarse and fine alumina powders and a 70/30 mixture thereof. The ceramic foams had fine cell size (about 150 μm diameter ) in each case. The method of preparation involved the free expansion of suspensions of these powders at 20 vol.% in a polyurethane foaming system. In order to modify the microstructure, the expansion was opposed using a die, and this reduced the void fraction and window size. In addition, directional rising was achieved by expanding the foam in a long cylindrical vessel and this modified the cell shape of the final foam. These foams have potential use in a range of applications including catalysis, but the main aim of the present work was to prepare preforms for metal matrix composites.     

Properties of ceramic foam catalyst supports: mass and heat transfer

Mass and heat transport properties have been determined for 30 PPI -Al₂O₃ ceramic foam containing 6 wt.% γ-Al₂O₃ washcoat. The foam was loaded with 5 wt.% platinum and the rate of carbon monoxide oxidation measured for a 0.3 cm cylindrical segment of the foam operating with mass transfer controlling at 550 °C. This gave a mass transfer factor versus Reynolds number correlation that was equivalent to a packed bed of particles.

A correlation for the radial heat transfer coefficient in a bed of ceramic foam was determined by measuring outlet temperatures achieved when air at varying flow rates and inlet temperatures was passed through a bed of foam pellets. Correlation parameters of a 1D model were fitted from 700 to 1000 °C using a Simplex optimization routine. Radial heat transfer coefficients were two to five times higher than those predicted from packed bed correlations.     

纳米科技在耐火材料中的研究现状及发展趋势

简单介绍了纳米科技的特点,重点阐述了国内外纳米科技在耐火材料中的研究、应用现状和纳米粉体的分散技术种类及其发展趋势。