硅酸钡和铝酸钡水泥的制备及性能

铝酸钡和硅酸钡及其为基础的熟料合成条件的研究结果和钡水泥的性能及应用。     

莫来石结合的浇注料

在耐火浇注料中用４种不同的骨料即电熔氧化铝、电熔莫来石、ＳｉＣ和石英对莫来石结合系进行了试验。这４种混合浇注料具有良好的流动性并且经一夜之后就可脱模。测定了高温强度和常温强度。含有电熔氧化铝或电熔莫来石的浇注料在１３００℃以上由于形成了莫来石改进了高温强度。而ＳｉＣ质浇注料在１３００℃以上虽形成莫来石，但没有提高其高温强度。在１２００℃￣１３００℃下，ＳｉＣ质浇注料的高温强度比其它浇注料的高温强度     

铝酸钙水泥结合莫来石-碳化硅浇注料的组成及性能

采用烧结莫来石、Secar71水泥及SiC为原料,制备了不同水泥和SiC含量的莫来石质浇注料,研究了浇注料的常温物理性能、热导率及热震稳定性,并借助XRD和EDS研究了材料的物相组成和显微结构.结果表明:随着水泥的加入,浇注料110℃ 24h显气孔率降低、抗折强度逐渐提高;1100℃ 3h和1400℃ 3h抗折强度呈现出先增大后逐渐减小的趋势,当水泥量为25%(质量分数,下同)时,浇注料的显气孔率最高,同时抗折强度达到最大值.随着水泥加入量的增多,浇注料的热震稳定性稍有降低,当水泥量超过25%后,浇注料的热震稳定性逐渐恢复;通过加入5%～10%的SiC,浇注料的热震稳定性明显改善.浇注料的性能同其物相组成及显微结构相关.     

铝酸钡水泥质耐火浇注料

采用煅烧氧化铝、埃及重晶石和石灰石混合物成球并在大约1600℃烧结的料制备含不同比例铝酸钡的三种高铝水泥成分。烧结体被研磨，以制取合适的水泥细粉末，其中发现主要相是铝酸钡和二铝酸钙，发现三种水泥具有令人满意的粘结性和高耐火度。以制备的水泥为基础，使用烧结氧化镁为骨料，配制成耐火浇注料成分，并评价其物理、机械性能和耐火性能。高强度和低收缩说明了浇注料在固化、干燥和烧结状态时的特性。这种含铝酸钡的浇注料可以有效地用于内衬结构以承受高温。     

自结合莫来石浇注料的相变化及结构特征

用硅溶胶结合超细粉为莫来石浇注料提供一种“自结合相”，以使结合相与颗粒的结合浑然一体，充分发挥浇注料整体性优良的特点。研究表明这种“自结合相”结合的莫来石浇注料与低水泥浇注料等品种相比，具有在整个温度范围内整体性好，莫来石反应温度低、生成量及长大情况良好，并在大颗粒周边形成致密环带，这种显微结构和相变化特征对浇注料的使用性能极为有利。     

硅溶胶结合刚玉-莫来石浇注料的研制及应用

以电熔板状刚玉及莫来石为骨料,以白刚玉粉、α-Al2O3微粉及莫来石粉为细粉,研制了以硅溶胶为结合剂的刚玉-莫来石浇注料.该浇注料已成功应用于武钢铁厂风口处和烧结厂点火炉的炉项及侧墙,有效地简化了干燥和烘烤工艺,缩短了炉衬的烘烤时间.     

莫来石结合碳化硅浇注料的研制

对碳化硅含量在 70 %以上的莫来石结合碳化硅质浇注料进行了试验研究。结果表明 :该浇注料从常温到 150 0℃均有较高的强度 ,并且 150 0℃烧后表面不氧化 ,可在 150 0℃及 150 0℃以下的高温环境中应用     

烧结点火炉用莫来石质浇注料的研制与应用

针对烧结点火炉的使用工况要求,保持特级矾土骨料占70%(质量分数,下同)、结合剂纯铝酸钙水泥占5%、活性α-Al2O3微粉占4%不变,其余21%的细粉为不同组成的莫来石细粉、SiO2微粉、添加剂(分别为蓝晶石粉、碳化硅粉、硅线石粉),同时外加0.15%的三聚磷酸钠研制了莫来石质浇注料,并研究了SiO2微粉加入量(分别为0、1%、2%、3%、4%)和各添加剂加入量(分别为1%、2%、3%、4%、5%)对浇注料烘干或烧后(1 350℃3 h)性能的影响.结果发现,加入3%的SiO2微粉,同时加入3%的蓝晶石和4%的碳化硅时,研制的莫来石质浇注料性能较优良.该浇注料在几家钢厂的烧结点火炉上实际使用寿命目前已超过4年,证明使用效果较好.     

莫来石质自流浇注料的研制与使用

介绍了蓄热式加热炉用莫来石质自流耐火浇注料的研制过程,分析了物料的粒度组成、微粉、外加剂和膨胀剂等对浇注料性能的影响。结果表明,所研制的莫来石质自流浇注料强度高,抗热震性和体积稳定性好,具有优良的自流、摊平、填充和密实等特点,已在蓄热式加热炉上成功使用。     

不同粒度碳化硅对莫来石基浇注料性能的影响

以莫来石、铝矾土为主要原料,铝酸钙水泥为结合系统,分别研究了不同粒度的碳化硅经过不同热处理温度后对莫来石基浇注料性能的影响。试样自然干燥24h脱模后,再经110℃烘干24h,分别于1000℃,1300℃和1500℃热处理3h。检测各温度热处理后试样的线变化率、体积密度、抗折强度、耐压强度以及试样的线胀系数。结果表明,不同粒度的碳化硅对调整浇注料中温的线变化率无明显作用。本实验中,含有粒度75μm SiC的浇注料的体积密度最大,并且含有该粒度SiC的浇注料的力学性能最好。     

Low Temperature Preparation of Carbide Coated Carbon for Refractory Castable Applications

Titanium carbide （ TiC ） coated graphite flakes （GF） and carbon black （CB） powders were prepared at relatively low temperatures （ 750 - 950 ℃ ） using a no- vel molten salt synthesis technique. The in-situ formed TiC coatings were homogeneous and crack-free and their thicknesses could be readily controlled/tailored by simply adjusting the Ti/C ratio. Compared to their uncoated counterparts, as prepared TiC coated GF and CB showed much improved water-wettability/dispersivity and rheological properties, and thus could be potentially used to prepare carbon-containing refractory castables.     

不定型耐火浇注料的发展现状及应用

以高铝质、莫来石质和刚玉质耐火浇注料为例,系统地介绍了不定型耐火浇注料的组成和性能,阐述了典型的耐火浇注料结合剂及外加剂,并总结了耐火浇注料的发展现状及应用领域。     

Physical and Mechanical Properties of Barium Alkali Silicate Glasses for SOFC Sealing Applications

The physical and mechanical properties of two barium alkali silicate glasses were determined as a function of temperature. Their Young's modulus and Poisson's ratio were determined by resonant ultrasound spectroscopy; their viscosity, thermal expansion, and glass transition temperature were determined using a thermomechanical analyzer. The wetting behavior of the two glasses on alumina and 8 mol% yttria stabilized zirconia (8YSZ) substrates was determined by measuring contact angles in air as a function of temperature and time. Values of Young's modulus for both glasses were in good agreement with those predicted by the Makishima and MacKenzie model. The physical and mechanical properties of these glasses are discussed in the context of their potential use for sealing applications in solid-oxide fuel cells.     

耐火浇注料对流与微波干燥的实验研究

进行了耐火浇注料热重分析,热风和微波干燥实验研究,得到了浇注料热风和微波干燥特性曲线。实验结果表明,与热风干燥比较,微波加热极大地降低了耐火浇注料干燥时间、提高了干燥效率和能源效率高,在耐火浇注料干燥过程中有着广阔的应用前景。     

Reaction of Silicate Glasses and Mullite with Hydrogen Gas

The increasing order of corrosion resistance to H₂ gas flowing fast enough to ensure that the reaction is the slow step is fused silica, aluminosilicate glass, and mullite at T =1300° to 1500° C; the activation energies are 347.3, 358.6, and 389.1 kj/mol (83.0, 85.7, and 93.0 kcal/mol), respectively. No detectable reaction with a-Al₂O₃ was observed. Addition of a small amount of CaO to the glass reduced its activation energy (283.7 kj/mol (67.8 kcal/mol)) and made its reactivity with H₂ similar to that of mullite at high temperatures. The reaction product for the glasses consisted of a porous zone composed of an intermediate layer close to mullite in composition and an outer layer of a-AI₂O₃. The reaction product for mullite consisted of a porous a-Al₂O₃ residue layer.     

Preparation and Application of Bauxite-based Sintered Mullite Homogenized Grog in Ladle Castable

Preparation of bauxite-based sintered mullite homogenized grog was introduced and its application in ladle castable was studied.Two kinds of bauxite-based sintered mullite homogenized grogs were used,named as GA and GB,respectively.The results show that bauxitebased sintered homogenized grog with uniform components,stable microstructure and mullite as main crystal phase can be prepared using joint process of three-step homogenization,automatic component batching,wet cogrinding,high-temperature calcinations.It also indicates that carbon steel ladle castables with GA or composite aggregate of GA and GB as main materials have the same excellent general performance indicators,great erosion resistance,anti-strip performance and longer service life in field applications,and compared with castables with single aggregate of GA,the castables with aggregate of GA and GB as main materials had higher cost performance because of lower bulk density of GB.     

Radiation-Induced Defects and Structure of Barium Silicate Glasses

The effect of increasing BaO on the intensity and position of absorption bands induced in barium silicate glasses was studied. Many of these glasses showed a two-step process in the growth and thermal bleaching curves. This process was attributed to two types of defects in the glass, induced and intrinsic. Infrared absorption, molar volume, and X-ray diffraction studies predicted structural changes at compositions containing about 22.5 and 27.5 mole % BaO. The results of gamma-induced absorption were in Une with these predictions, supporting the view that color center studies can be used to detect changes in structure, especially when high radiation doses are applied.