高强度耐磨浇注料

实验研究了α－Ａｌ_Ｏ和ＳｉＯ_２混合超细粉与分散剂ＦＤＮ对高强度耐磨浇注料施工和物理性能的影响。试验结果表明：α－Ａｌ_２Ｏ_３和ＳｉＯ_２混合超细粉加入５％～７％时，浇注料的施工和理化性能最佳；加入适量的ＦＤＮ，其降水率可达２０％。     

AZS复合结合剂的制备

以电熔ＡＺＳ细粉为主要原料，加入ＳｉＯ２、Ａｌ２Ｏ３超细粉和外加剂ＣＦ，通过混合共磨的方式制得ＡＺＳ复合结合剂。对复合结合剂进行了化学分析、粒径分析和物相分析，讨论了ＳｉＯ２和Ａｌ２Ｏ３超细粉共同使用的效果和外加剂ＣＦ以及ＡＺＳ细粉的作用。复合结合剂应用在ＡＺＳ不定形耐火材料中，具有较好的使用效果。     

添加Al2O2对ZrO2（Y2O3）粉末性能的影响

采用化学共沉淀法制备了ＺｒＯ２（Ｙ２Ｏ３）和ＺｒＯ２（Ｙ２Ｏ３）／Ａｌ２Ｏ３超细粉末，研究了添加Ａｌ２Ｏ３对粉末性能的影响。添加Ａｌ２Ｏ３提高了ｔ－ＺｒＯ２的结晶化温度，抑制了ＺｒＯ２－ｍ－ＺｒＯ２相变。Ａｌ２Ｏ３相变。Ａｌ２Ｏ３添加量超过２０ｗｔ％时，粉末烧结活性降低，烧结温度提高。     

β-羟乙基乙二胺环合催化剂的研究

本文研究了 Ｃｕ／γ Ａｌ２ Ｏ３ 与 Ｃｕ Ｏ／γ Ａｌ２ Ｏ３ 两种催化剂对β羟乙基乙二胺环合反应的催化作用，证明在一定条件下，上述两种催化剂的作用类似，环合出哌嗪的收率可达８７％ 以上。此外，还对催化剂 Ｃｕ Ｏ／γ Ａｌ２ Ｏ３ 进行了修饰和改性，从而提高了催化剂的稳定性和选择性。用铜抑制剂处理载体而制备的催化剂，哌嗪的最高收率可达９２％ ；以γ Ａｌ２ Ｏ３ 超细粉为载体的催化剂的稳定性可得以提高。     

高炉出铁汉喷补料的研制

采用与出铁沟浇注料相近的Ａｌ２Ｏ３－ＳｉＣ－Ｃ材质研制的出铁沟喷补料适应冷热态喷０补作用,随着率高、耐用性好、使出铁沟的耐火材料消耗进一步下降。     

Al2O3＋TiC陶瓷中Al2O3与TiC化学反应抑制的研究

本文通过Ｙ－盐溶液的形式加入到Ａｌ２Ｏ３粉料中,制备了Ｙ２Ｏ３表面固溶的Ａｌ２Ｏ３粉料,对其阻止Ａｌ２Ｏ３与ＴｉＣ之间的化学反应进行了研究。研究结果表明：采用Ｙ－盐溶液加入Ｙ２Ｏ３,Ｙ原子能均匀的分散在Ａｌ２Ｏ３的表面,高温时Ｙ２Ｏ３在Ａｌ２Ｏ３表面形成固溶体层,少量的Ｙ２Ｏ３加入量（０．３５ｗｔ％）,就能有效的阻止Ａｌ２Ｏ３与ＴｉＣ之间的化学反应。     

等离子喷涂Al2O3+TiO2复合陶瓷涂层的组织结构

利用ＳＥＭ,ＴＥＭ,ＥＤＡＸ及Ｘ射线等手段研究了Ａｌ２Ｏ３＋ＴｉＯ２／ＮｉＣｒＡｌＹ复合陶瓷等离子喷涂层的组织结构,涂层呈片层状,Ａｌ２Ｏ３＋ＴｉＯ２陶瓷涂层由γ－Ａｌ２Ｏ３,ＴｉＯ２及少量的α－Ａｌ２Ｏ３组成,由于喷涂层温度比较高,部分熔化的Ａｌ２Ｏ３和大部分熔化的ＴｉＯ２发生了一定程度的互熔,形成了Ａｌ２Ｏ３＋ＴｉＯ２共晶组织。片层内由Ｎｉ基固溶体及弥散分布其上的γ相（Ｎｉ３Ａｌ）组成,片间为     

W18Cr4V钢表面激光熔覆Al2O3陶瓷涂层的组织结构

研究了Ｗ１８Ｃｒ４Ｖ钢表面Ａｌ２Ｏ３／ＮｉＣｒＡｌ复合陶瓷涂层的组织结构、成分分布及界面组织特征。结果表明：Ａｌ２Ｏ３／ＮｉＣｒＡｌ复合陶瓷等离子喷涂层的组织呈层片状,面层由α－Ａｌ２Ｏ３和少量的γ－Ａｌ２Ｏ３组成,层间为机械结合界面,界面处成分变化梯度较大。经激光重熔后的面层组织为单一的α－Ａｌ２Ｏ３柱状晶,Ａｌ２Ｏ３与中间合金ＮｉＣｒＡｌ间存在明显的界面反应,且界面相增多,在ＮｉＣｒＡｌ与基体     

钢包用低SiO_2湿式喷补料的开发

利用泵送施工的湿式喷补料,大多采用添加ＳｉＯ2超细粉的方式提高泵送能力。但原来钢包用Ａｌ2Ｏ3-ＭｇＯ质材料,由于使用ＳｉＯ2超细粉,在施工中容易产生龟裂现象。本研究把原钢包Ａｌ2Ｏ3-ＭｇＯ质浇注料作为湿式喷补料,在调整使其具有良好施工性之后,改变ＳｉＯ2超细粉的使用量,以考查ＳｉＯ2超细粉加入量对材料性能的影响。结果表明,通过调整材料的粒度组成,即使ＳｉＯ2微粉含量较少时,也可以确保具有良好的施工性。而且,ＳｉＯ2超细粉添加量少的试样,熔损量也低。另外,试样经1500℃,3次急冷急热试验后,裂纹较少。还有,ＳｉＯ2超细粉使…     

Al2O3-CoCrAlY 复合陶瓷激光熔覆层的组织与性能

研究了Ａｌ２Ｏ３－ＣｏＣｒＡｌＹ复合陶瓷涂层的组织结构、成分分布及其耐磨性能。结果表明：等离子喷涂层的组织呈层片状,面层由α－Ａｌ２Ｏ３和少量的γ－Ａｌ２Ｏ３组成,层间为机械结合界面,涂层平均硬度为８９７ＨＶ０．２。经激光重熔后的组织为单一的α－Ａｌ２Ｏ３柱状晶,在ＣｏＣｒＡｌＹ与基体间有界面相形成,其界面为冶金结合,层间存在着平缓的成分过渡;Ａｌ２Ｏ３与ＣｏＣｒＡｌＹ间的界面结合状况得到了明显的     

高铝矾土-尖晶石钢包浇注料的开发与应用

采用高铝矾土和矾土基尖晶石为主要原料 ,制备了高铝矾土 -尖晶石浇注料 ,研究了硅微粉和烧结镁砂细粉的加入量对该浇注料高温抗折强度及抗渣性能的影响及新开发的防爆剂对浇注料抗爆裂性能的影响。结果表明 :加入适量的硅微粉和烧结镁砂细粉 ,可改善浇注料的强度和抗渣性 ;新型防爆剂可有效改善浇注料的抗爆裂性 ;研制的浇注料在 4 0t连铸钢包上使用 ,效果很好。     

新型隔热耐磨衬里浇注料的研制

为了提高现有隔热耐磨衬里浇注料的理化性能,改善产品的施工性能,选用页岩陶粒和原皮陶粒搭配作骨料,选用水泥作结合剂,选择六偏磷酸钠和萘系减水剂作外加剂,并加入一定量的混合细粉和硅灰,通过确定颗粒临界粒度和级配,研制了新型隔热耐磨衬里浇注料.结果发现颗粒临界粒度为8 mm,骨料和细粉的基本配比为4951,高铝水泥的加入量为35%,硅灰的加入量为4%,并合理选配外加剂,制备出的新型隔热耐磨衬里浇注料性能优良.     

Sintering of Mixtures of Seeded Boehmite and Ultrafine α-Alumina

α-Alumina was fabricated by dry pressing mixtures of seeded boehmite and fine α-alumina (i.e., 0.2 and 0.3 μm diameter) to reduce the large shrinkage of boehmite-derived α-alumina. The maximum green density was obtained with mixtures containing ∼70%α-alumina for both alumina powders. The ∼15% linear shrinkage and microstructures of these samples were comparable to 100% alumina powder samples. Samples with 0.2 μm alumina sintered to densities >95% at 1300°C whereas 1400°C was needed for samples with 0.3 μm alumina. These results indicate that boehmite can be used as a substitute for relatively expensive ultrafine α-alumina powders.     

硅溶胶结合浇注料的流变性能研究

对高纯硅溶胶电熔莫来石细粉泥浆的流变性能研究表明：这种泥浆是存在触变结构的高浓度胶溶悬浮体系，在受较低剪切力作用时产生的是粘滞流动，总的表现符合Ｂｉｎｇｈａｍ流变方程。研究还表明：少量超细粉的加入不改变泥浆的流变模型，但能有效地改善其流变性能，不同的超细粉影响力不同，且这种改善作用有一最佳加入量（活性ＳｉＯ２超细粉影响力大于活性Ａｌ２Ｏ３微粉，其最佳加入量分别为２％和１０％），超过这一加入量将导致流变常数上升，使其流变性恶化。     

不同铝基原料对MgO-Al-C材料性能和显微结构的影响

以烧结镁砂骨料、电熔镁砂细粉、Al粉、N220炭黑为原料,酚醛树脂为结合剂,制备MgO-Al-C材料,研究了三种铝基原料(造粒氧化铝微粉、氧化铝空心微珠、六铝酸钙)对其常温抗折强度、高温抗折强度、抗热震性及抗氧化性的影响,并借助XRD和SEM对其物相组成及显微结构进行分析。结果表明,造粒氧化铝微粉是多孔结构,可吸收热应力,加入量为1%(质量分数,下同)时,可提高材料的常温抗折强度和抗热震性,明显改善材料的抗氧化性。氧化铝空心微珠是中空结构,可缓冲热应力,加入量为3%时,可明显提高材料的常温抗折强度,并具有较高的抗热震性和抗氧化性。六铝酸钙的热膨胀系数较低,可赋予材料较好的韧性,加入量不超过5%时,样品具有较好的抗热震性。     

Laser densification of alumina powder beds generated using aerosol assisted spray deposition

Layered manufacturing involves a range of techniques in which objects can be constructed in a laminated form. Therefore, the deposition technique is a critical part of direct-layered fabrication technologies. In this paper, aerosol assisted spray deposition has been applied to generate spraying of a suspension to prepare powder beds for subsequent selective laser sintering. First, an investigation on preparation of the alumina suspension by adding polyacrylic acid dispersant is presented. An emphasis has been given to identify the most effective dispersant to enhance the dispersibility of alumina suspension for aerosol spraying deposition. Subsequently, a laser has been used to selectively densify the alumina powder beds to produce ceramics. The effects of the laser processing parameters such as scanning speed, power and beam size on the microstructural evolution of the powder beds are investigated and discussed. Also, a laser densification mechanism is also proposed and discussed.     

The effect of chemically bonded organic surface layers on the behaviour of fine powders

We have examined the effects of chemically bonded organic surface layers on the behaviour of a ceramic and a metal powder. The thin monomolecular layers were found to improve the corrosion resistance of the sensitive Nd-Fe-B powder and make the fine alumina powder hydrophobic and, as a result, making both coated powders significantly less sensitive to environmental humidity. Our analysis of the flowability of the noncoated and coated powders revealed that the alumina powder can be classified as very cohesive—the addition of the coating even increased its cohesivity. The Nd-Fe-B powder was determined to be easy flowing, and the effect of the coating changed with the applied normal stress. The coating does, however, improve the powder-compaction properties of both powders. In addition, the beneficial effect of the coating in terms of viscosity as well as in resistance to destabilization was also observed for suspensions in organic solvents.     

Effects of different additives on properties of magnesium aluminate Spinel–Periclase castable

Bauxite- and alumina-based spinels were employed as refractory aggregates, and sintered magnesia fine powder, calcium aluminate cement, microsilica, and activated α-Al₂O₃ were utilized as matrices. The effects of alumina powder, analytically pure zinc oxide, and analytically pure zirconia on the properties of magnesium aluminate spinel–periclase castables were studied. The results demonstrated that the addition of the three additives promoted the sintering of magnesium aluminate spinel–periclase castables. Simultaneously, the three additives significantly improved the high-temperature properties of the samples. The thermal shock resistance of the alumina powder sample increased by 200%, that of the pristine zinc oxide sample by 75%, and that of the zirconia sample by 125%. The additives effectively improved the thermal shock resistance of the magnesium aluminate spinel–periclase castable. In addition, the slag resistance depths of the samples with alumina powder and zirconia were 41% lower than that of the sample without additives, which significantly improved the slag resistance of the magnesium aluminate spinel–periclase castable.     

Preparation of low-shrinkage and high-performance alumina ceramics via incorporation of pre-sintered alumina powder based on Isobam gelcasting

Mechanically robust alumina ceramics with low shrinkage were successfully prepared via gelcasting using Isobam as the gelling agent and pre-sintered alumina powder as the raw material for the first time. The influence of amount of pre-sintered alumina powder and powder's pre-sintering temperature on the viscosity of suspension and mechanical properties of low-shrinkage alumina ceramics were systematically investigated. The results showed that low-shrinkage alumina ceramics with flexural strength of 294.5?±?33.0?MPa, linear shrinkage of 7.79% and relative density of 91.5% can be obtained with the addition of 60?wt% alumina powder pre-sintered at 1600?°C. This convenient and facile approach is promising to fabricate low-shrinkage alumina ceramics with large sizes, high dimensional accuracy and complex shapes.     

Effects of particle size distribution and sintering temperature on properties of alumina mold material prepared by stereolithography

Alumina mold materials prepared by stereolithography usually have considerable sintering shrinkage, and their properties related to casting have been rarely studied. In this study, alumina molds materials were prepared by stereolithography, and the effects of particle size distribution and sintering temperature on the properties of the materials were investigated. Results show that the viscosity of the slurries decreases as the fraction of fine powder increases, and the particle size distribution affects the curing behaviors slightly. Sintering shrinkage increases as the fraction of fine powder or the sintering temperature increases. Although lower sintering shrinkage can be achieved by sintering at 1350 °C or 1450 °C, the mold materials sintered at lower temperatures would continue to shrink under the service temperature of 1550 °C, and thus 1550 °C is determined as the optimal sintering temperature. As the fraction of fine powder increases, the creep resistance first increases and then decreases, and specimens prepared with 0.1 fraction of fine powder exhibit the best creep resistance with the droop distance of 4.44 ± 0.45 mm. Specimens prepared with 0.1 fraction of fine powder and sintered at 1550 °C exhibit linear shrinkage of 6.36% along the X/Y direction and 11.39% along the Z direction, and have a flexural strength of 78.15 ± 3.50 MPa and porosity of 30.12 ± 0.08%. The resulting material possesses relatively low sintering shrinkage, proper mechanical strength, porosity and high-temperature properties that meet the requirements for casting purposes.