平板式汽车ZrO2氧传感器多孔保护层研究

为开发平板式汽车ZrO2氧传感器的保护层,以MgAl2O4为主要原料,研制了适合于ZrO2氧传感器电极保护的多孔复合保护层,并对其气孔率和抗热冲击性能进行了研究。结果表明,保护层中造孔荆含量增多,其气孔率增大,附着强度降低,当造孔剂含量为4％～6％时,满足了多孔性保护层的要求,并且也能保持较好的抗热冲击性。     

固体氧化物燃料电池阳极基底造孔剂含量的研究

采用固相反应法制备阳极支撑型固体氧化物燃料电池的阳极基底,在阳极基底中加入不同含量的造孔剂.采用SEM观察阳极微结构,并用阿基米德排水法测量阳极的孔隙率.随着阳极中造孔剂含量的增多,阳极的孔隙率增加,电池的浓差极化被消除,电池性能明显提高.但是太高的孔隙率会降低阳极结构的强度,减少三相反应区的数量,降低电池的性能.本文通过对阳极中造孔剂的含量的研究,找到了合适的造孔剂的含量.     

宏孔性多孔玻璃载体颗粒的制备

利用填充法直接制备宏孔的多孔玻璃载体颗粒，探讨了造孔剂的种类及含量和烧结过程对颗粒的粒度分布、孔隙率、孔径分布及机械强度的影响，确定了复配造孔剂的适宜比例和工艺条件。结果表明，采用复配造孔剂解决了宏孔颗粒的强度与孔隙率、孔径的矛盾，在烧结温度800℃左右，保温时间2h的条件下，保证孔径在60－180μm，孔隙率稳定在40％以上，而强度达到2.4MPa以上。     

ZrO2基电化学NOx传感器非活化电极浆料的研究

ZrOz基电化学NOx传感器是对柴油机尾气中NOx含量进行检测的重要元件。文中研究了NOx传感器用非活化电极浆料配方,通过调整配方中的造孔剂含量和Au含量,比较传感器的氮氧化物测量泵电流Ip2的零点偏移量,得出造孔剂含量为4％、Au含量为0．4％～O．8％的浆料配方满足NOx传感器使用要求。     

氧化铝透气陶瓷及透气性研究

研究添加造孔剂法和干压成型法制备氧化铝多孔透气陶瓷。以氧化铝为原料,分别用淀粉、蔗糖、蛋清作为造孔剂,用聚乙烯醇做粘结剂,在1700℃下烧结制得以开孔为主的氧化铝多孔透气陶瓷。通过抗弯曲强度测试检测样品的力学性能;利用X射线衍射分析(XRD)、扫描电镜(SEM)表征其物相成分、显微结构,对透气性进行测试。实验结果表明:试样的抗压强度随造孔剂的增多而减小;抗弯曲强度不随造孔剂的增多而增大,但是造孔剂含量过大时作用相反;烧结后试样的主要成分是α-Al2O3。用淀粉(10%)做造孔剂制得的样品具有较好的力学性能且气孔分布均匀.     

粉煤灰多孔陶瓷制备及其吸附Cr(Ⅵ)性能

以粉煤灰为基体材料,用碳酸钠(Na₂CO₃)为造孔剂,氢氧化钠做助熔剂,混合均匀后经压片成型,在马弗炉中经高温煅烧得多孔陶瓷。研究了碳酸钠含量以及煅烧温度,对陶瓷孔隙率和强度的影响,以及制备的粉煤灰多孔陶瓷对 Cr(Ⅵ)的吸附性能的影响。研究结果表明：煅烧温度为800℃,造孔剂含量为15%,所制备的粉煤灰多孔陶瓷的孔隙率为40.28%,抗压强度为8.1MPa,陶瓷片的饱和吸附时间为200min,对0.060 06g·L^-1的重铬酸钾溶液中Cr(Ⅵ)的去除率为71.36%,吸附能力达0.757mg·g^-1。研究发现,粉煤灰陶瓷的吸附位点主要是-SiO₃^2-,陶瓷片经3次吸脱附后 Cr(Ⅵ)去除率仍可达到45%左右。     

造孔剂对多孔Al2O3陶瓷性能的影响

采用干压成型法制备了多孔Al2O3陶瓷,对造孔剂种类、用量以及添加剂对多孔陶瓷性能的影响进行了研究.实验结果表明不同造孔剂对气孔率的影响不同,随着造孔剂加入量的增加,气孔率增大,但试样抗折强度呈下降趋势.在Al2O3基体中加入质量分数为5%～15%的ZrO2时,基体的抗折强度增强,并可以保持30%以上的气孔率.     

氯化钠作为造孔剂制备含氯多孔羟基磷灰石实验研究

采用化学沉淀法,制备纳米HA粉体．采用造孔剂法,首次利用NaCl作造孔剂,将纳米HA粉体和NaCl颗粒按一定比例混合压制成型,经高温烧结制备出多孔含NaCl的HA材料．利用XRD、SEM、EDX手段研究多孔HA的组成成分、微观形貌、孔径尺寸及孔隙率．研究结果表明：NaCl是比较理想的造孔剂材料,可制备孔隙率、孔径尺寸、形貌可控的多孔材料．造孔剂含量为30％,尺寸在160～200目时,造孔效果最好;在烧结温度1200℃烧结时,NaCl会与HA发生反应,生成Ca5（PO4）3Cl,Ca9．54P5．98O23．58Cl1．6（OH）2．74等新的物相．     

粉末冶金法制备梯度多孔Mg-Ca合金

采用粉末冶金法以碳酸氢铵为造孔剂、镁粉和钙粉为原料,制备了梯度多孔Mg-Ca合金。研究了造孔剂含量、分布和烧结温度对梯度多孔Mg-Ca合金孔隙特性的影响。测量了烧结产物的弯曲性能。研究结果表明随着中间层造孔剂含量的降低,孔隙梯度分布加大,试样的平均孔隙度降低,但梯度孔隙结构导致试样的抗弯强度增加。此外,随着烧结温度的升高,梯度多孔Mg-Ca合金的平均孔隙度降低,抗弯强度增加。XRD和SEM观察结果都表明,烧结产物中没有造孔剂碳酸氢铵的残留,主要有Mg和Mg2Ca两相组成。     

CaCu_3Ti_4O_(12)巨介电常数多孔陶瓷的制备

通过固相合成及常压烧结的方法,以淀粉为造孔剂制备了CaCu3Ti4O12(CCTO)巨介电常数多孔陶瓷材料,采用XRD、SEM等测试手段对其合成与烧结过程中的物相变化进行了表征.结果表明,制备该CCTO多孔陶瓷的适宜烧结温度为1075℃,试样结晶完整,孔隙率大,大孔与小孔之间形成交错分布的开气孔结构,能够达到预期的效果.     

基于浸润参数和表面能理论的沥青与集料黏附性分析

为了解决沥青与集料黏附性缺乏量化评价方法的问题,分别采用光学接触角测量仪、表面张力测试仪和自动压汞仪对沥青与集料的接触角、沥青表面张力和集料的孔隙分别进行了测定,通过试验结果对沥青与集料的浸润参数和表面能参数进行了计算,并据此对沥青与集料的黏附性进行了评价;分析了沥青与集料黏附性的影响因素,并通过测定不同温度下沥青的表面张力,结合理论分析建立了沥青表面张力与温度的关系模型.研究结果表明:可以采用浸润参数和表面能理论对沥青与集料的黏附予以评价;较大的孔隙度和平均孔径有利于集料对沥青的吸附;沥青对集料的浸润深度h越大、浸润时间t越短,有利于产生更好的浸润效果;沥青与集料黏附功和浸润功越大,浸润性越好;沥青与集料间的黏附性与沥青表面张力、沥青与集料接触角以及集料表面特性等因素有关.     

多孔介质孔隙结构重构及水蒸气传递特性

采用随机生长法分别构造了各向同性、各向异性的孔隙率相同,孔径分布和孔隙表面分形维数不同的多孔介质,探索了在多孔介质孔隙率相同的情况下,微观孔隙结构对孔隙内湿传递过程的影响。结果表明：决定多孔介质内部输运特性的孔隙结构参数,除孔隙率以外,孔径分布和孔隙表面分形维数等参数对多孔介质孔隙中水蒸气扩散过程的影响显著;孔隙率相同,孔径分布和孔隙表面分形维数不同的3种各向同性和3种各向异性多孔介质的水蒸气扩散浓度最大差别分别为30.6%和23.3%;各向同性多孔介质的小孔分布率越大,孔隙表面分形维数越大,说明孔隙的连通性和水蒸气在多孔介质孔隙中的扩散性能越好;各向异性多孔介质（水蒸气扩散的方向垂直于其生长率较大的方向）的大孔分布率越大,孔隙表面分形维数越小,水蒸气在多孔介质孔隙中的传递性能越好。     

Structure and mechanical properties of Ni-based porous superalloy

The porous superalloy materials with hollow spherical and oriented linear pores were fabricated by means of powder metallurgy using Ni-based superalloy powders. Structure observation revealed that the pores of the porous material exhibited uniform distribution and the pores were of the same size in principle. The sintering necks created between adjacent particles on metal skeleton after sintering. The porosity of the porous material increased with increasing the addition of pore forming agent, and the hollow spherical porous material with a porosity of 81.62% were obtained when the addition of pore forming agent was 40%. The compression test indicated that this kind of materials possesses excellent, energy absorption capability and the compression resistance decreased with the increasing of porosity and pore size.     

Influence of Binder Composition and Concrete Pore Structure on Chloride Diffusion Coefficient in Concrete

The influence of binder composition and pore structure of concrete on chloride diffusion coefficient in concrete were investigated by the natural immersion test, MIP test, SEM and EDS test, respectively. The experimental results showed that the effect of binder composition on chloride diffusion coefficient was the comprehensive result of concrete pore structure and binder hydration products, and the porosity and pore size distribution were the main factors that influence the changes of diffusion coefficient...     

Effect of Sand Content on Strength and Pore Structure of Cement Mortar

The effects of four sand contents on the compressive, flexural and splitting-tensile strength of cement mortars were evaluated. Moreover, we experimentally investigated the pore structure of cement mortar brought about by changing the sand content and water/cement ratio. The changes in the pore structure were quantified by measuring the porosity and pore size distribution obtained by using mercury intrusion porosimetry(MIP) technique. The test results show that the strengths of cement mortar increase with increasing sand content. It is also suggested that the traditional water/cement ratio law can be applied to cement mortar with different sand contents, provided that a slight modification is introduced. Sand content is an important parameter influencing the pore structure of cement mortar. Moreover, there is a good relationship between the pore structure and strength of cement mortar.     

氮化硅结合碳化硅多孔陶瓷支撑体的制备与表征

以碳化硅、硅粉为主要原料,以氧化铝和氧化钇为烧结助剂,通过添加不同质量分数的淀粉为造孔剂,采用反应烧结方式制备了系列氮化硅结合碳化硅多孔陶瓷支撑体,并对烧成样品的物相、显微结构、孔隙率、抗折强度、孔径分布、纯水通量和耐酸碱性能进行了分析和表征. 结果表明,样品的主晶相为碳化硅和氮化硅,还有少量的焦硅酸钇和塞隆;随着淀粉质量分数的增加,样品的孔隙率随之增大,样品的抗折强度随之减小,同时样品的平均孔径和纯水通量随淀粉质量分数的增加均呈现先增大后减小的趋势;样品有良好的耐酸碱性能,在标准酸性和碱性条件下的质量损失率分别为1.96%~2.04%、3.96%~4.13%;当淀粉的质量分数为3%时,烧成样品的孔隙率为41.8%,抗折强度为18.1 MPa,孔径主要分布在0.7 μm~2.5 μm之间,纯水通量最高,可达9.2 m³/（m2*h）,综合性能较佳.     

化学镀Ni－B合金的研究

研究以硼氢化钾为还原剂，乙二胺为络合剂，硫酸亚铊为稳定剂的化学镀Ｎｉ－Ｂ合金镀液的最佳组成和操作工艺。确定了稳定剂的最佳含量。并在此基础上研究了化学镀Ｎｉ－Ｂ合金镀层的结合力、孔隙率、耐烧碱腐蚀性及镀层的硬度与热处理温度的关系等特性。     

Effectiveness of Surface Coatings Against Intensified Sewage Corrosion of Concrete

Three different kinds of coatings were coated on the concrete surface, and the changes in appearance, surface roughness, microstructure and components of coatings in artificial sewage were investigated. In addition, the strength, micrograph, mineral compositions and pore structure of concrete specimens after removing coatings were also studied. The results show that epoxy coal tar pitch coating(ECTPC) has the best effect of protecting concrete from the sewage corrosion. After being immersed in sewage for 90 days, the compressive strength of concrete coated with ECTPC is still as high as that of specimen immersed in water, and the cement paste has a high CH content and dense structure with low porosity, which mainly accounts for its excellent barrier property and certain antibacterial function. Cement-based bactericidal coating(CBC) also has good effectiveness to sewage corrosion of concrete. The strength and microstructure of concrete coated with CBC in sewage are still significantly superior to those of uncoated concrete. Although cement-based capillary crystalline waterproofing coating(CCCWC) is a good waterproof material, it is not suitable for the corrosion resistance of concrete in sewage. After 2 months corrosion, almost all of the CH crystals in coating reacted with the metabolic acid substance by microbes. Therefore, the strength and pore structure of concrete coated with CCCWC are only slightly superior to those of uncoated concrete. Overall, the protective effect of cement-based inorganic coatings is relatively poor.