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。     

金属过滤器用高性能碳化硅泡沫陶瓷的制备

介绍了一种适用于大规模工业化生产高强度金属过滤用碳化硅泡沫陶瓷的方法。采用商用SiC粉体和聚氨酯泡沫通过2次挂浆工艺可以制备出最大平均抗弯强度达到2．87 MPa,平均孔径在3 mm左右,同时具备优良的抗热震性能和高达1700℃耐火度的碳化硅泡沫陶瓷。探讨了浆料的牯度、流变性能对挂浆性能的影响及第2次挂浆对强度的增强机理,说明1次浆料的触变性能和适当固相含量的2次浆料是高强度泡沫陶瓷制备的关键,而2次挂浆工艺对强度提高的主要贡献来源于第2次浆料对1次挂浆烧结后留下空洞的有效弥补。     

Towards a new generation of environmentally-friendly ceramic foam filters: contribution of graphene nanoadditives in calcium aluminate-rich coatings

In this contribution, the widely used non-ecological production process of ceramic foam filters was modified into an environmentally friendly procedure, in which no hazardous materials are involved. Firstly, a large number of carbon-bonded ceramic foam filters were prepared by this approach. In the next step, a thin coating consisting of graphene-doped, carbon-bonded calcium aluminate was applied over these filters. Reference samples as well as coated samples were analyzed in detail with a focus on the phase composition, microstructural analysis, and mechanical as well as thermal properties. The results confirmed that the application of the developed coating improved the cold crushing strength of the ceramic foam filters. In addition, by application of graphene nanoadditives, it is also possible to vary the surface microroughness which will subsequently enable improved efficiency of inclusions elimination from metal melts during the filtration process.     

Sound absorption performance of a lightweight ceramic foam

Porous materials can be effective for sound absorption and noise reduction. A kind of lightweight cellular ceramic foam with bulk density of 0.38–0.56 g cm^-3 was successfully prepared by conventional molding with pore forming agent. The porosity is from 76.4% to 83.7% for the sample with relatively large pores (the average pore size: 5.3–5.6 mm), and from 74.1% to 81.1% for the sample with relatively small pores (the average pore size: 1.5–1.7 mm). The effects were investigated for processing parameters on the structure of samples, and for the pore size, sample thickness and porosity on the sound absorption performance of samples. The results show that the absorption performance of the ceramic foam product with relatively large pores may be superior to that with relatively small pores in the case of the approximately same porosity. The first absorption peak moves from a higher frequency to a lower frequency with the increase of sample thickness. When the porosity increases, the average sound absorption coefficient increases for all of the samples, and the first absorption peak moves from a higher frequency to a lower frequency for the sample with relatively large pores but does not change for that with relatively small pores.     

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.     

Innovation in ceramic foam filters manufacturing process

Ceramic filters have singular properties such as high permeability and specific surface area associated to low density. Some examples of their use can be found in liquid metal deep filtration, water treatment, air purification, and others. These particular properties are dependent on the filters' manufacturing process. One of the most used techniques to produce filters is the replication method, which provides a tridimensional network of struts and interconnected pores. However, a common issue of all ceramic filters produced by this technique is their low mechanical strength due to the hollow struts and microcracking generated during the thermal decomposition of the sponge. Intending to address this limitation and produce filters with higher mechanical strength, this paper analyzed a modified process route for manufacturing filters. Samples of preheated Al₂O₃ filters were vacuum infiltrated with ceramic suspensions (Al₂O₃ and SiO₂) of different solids concentrations (15-40 wt%), particle size distribution (nano to micrometric size) at distinct processing times (1-5 minutes). The data analysis indicated that the best balance among mechanical strength, mass, and strut thickness was achieved by infiltration with SiO₂ colloidal suspension (40 wt%) per 1 minute. SEM analysis confirmed that the struts were filled and microcracks were sealed with colloidal particles.     

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。     

Design of ceramic filters using Clay/Sawdust composites: Effect of pore network on the hydraulic permeability

Clay based ceramic composite materials with hydraulic permeability were elaborated using sawdust as porogent agent. Their mechanical, morphological, microstructural and pore network properties were investigated. Mixtures in various ratios of two kaolinite clay minerals, Ba (highly plastic) and Va (sand-rich) constitute the five ceramic matrixes studied (CM1, CM2, CM3, CM4 and CM5). Due to their high flexural strength, CM3 and CM4 received 0%, 5%, 10% and 15% sawdust before firing, to improve the porosity of the final matrixes. Results revealed that 900–1000 °C is the range of temperature necessary to get good sintering and flexural strength (≥2 MPa). A typical clay-sawdust based materials (parallepipedic bricks) present porosity ≥40 vol% and 1.5 g/cm³ density. Characterizations such as FTIR, SEM, MIP and flow permeability of ceramic candles were performed. A Hydraulic permeability of ~10 mDarcy was obtained and the mean pore diameter varies from 0.05 to 0.1 µm, in agreement with the microstructure exhibited by the ceramic candles. In the presence of sawdust, pores with size up to 10 µm were observed, justifying the increase of flowing permeability. The elaborated matrixes are promising candidates for microfiltration.     

泡沫碳化硅陶瓷材料的研究进展

泡沫碳化硅陶瓷材料除了孔隙率高、比表面积大,还具有相对密度小、优良的热学、力学、电学、声学性能等特性,已经广泛应用于化工、机械、生物、环保等领域。本文总结了泡沫碳化硅陶瓷材料的主要制备技术,包括粉末烧结法、固相反应烧结法、含硅树脂热解法以及气相沉积法等。阐述了泡沫碳化硅陶瓷材料的几种优良特性,包括结构特征、流体阻力、抗氧化性、吸波性等。最后举例介绍了该陶瓷在催化、过滤、生物学等领域的应用现状,重点介绍了其作为塔内件在化工领域中的应用,指出为满足对泡沫碳化硅陶瓷更高性能的需求,不仅要对现有技术进行集成创新,更要挖掘和开发泡沫碳化硅的潜在优势。