添加剂对锆质定径水口烧结性能和抗热震性的影响

采用粉末成型工艺,以粒度为0.045mm的斜锆石粉和粒度均为0.154mm和0.074mm的MgO部分稳定电熔氧化锆和CaO部分稳定电熔氧化锆为原料,分别加入不同添加剂Y2O3、CeO2和Y2O3 CeO2,在300MPa的压力下成型,并于1720℃烧后制成锆质定径水口试样。结果表明通过合理控制颗粒级配和优化工艺参数,当添加剂中Y2O3和CeO2的含量(w)分别为0.6%和0.4%时,氧化锆的稳定率约为70%,同时可得到显气孔率低,体积密度高,抗热震次数≥5次的锆质定径水口。     

锆质定径水口热震稳定性的研究

本试验采用粉末成型工艺,以斜锆石和电熔部分稳定氧化锆(PMD、PCD)为原料,采用不同含量的添加剂,在300MPa压力下成型,1720℃烧制成锆质定径水口.结果表明:通过合理控制颗粒级配和优化工艺参数,氧化锆的稳定化率达到70%左右,烧成温度为1720℃保温6h后,可得到热震稳定性不小于5次的锆质定径水口.     

一种塞棒控流中间包上水口的剖析

对一种塞棒控流中间包上水口的外形尺寸、致密度、化学组成、相组成和显微结构进行了分析。结果表明:该中间包上水口由外套和锆质水口芯两部分组成,其中锆质水口芯由碗口部位的低锆系材料和下段部位的高锆系材料组成。低锆系的水口芯为锆英石-氧化锆质材料,体积密度达到4.30 g·cm-3,w(ZrO2+HfO2)为82%左右,主晶相由锆英石与斜锆石组成,显微结构可观察到相对均匀的、不规则锆英石粒状颗粒,斜锆石细粉,高硅玻璃相以及少量气孔,锆英石颗粒尺寸在100~150μm以及30~50μm,斜锆石粉的粒度为10~15μm。高锆系的水口芯为Mg-PSZ型水口材料,体积密度达到5.08 g·cm-3,w(ZrO2+HfO2)为95%左右,颗粒的尺寸均在40μm以下,由m-ZrO2和c-ZrO2组成,显微结构可观察到相对均匀的、不规则ZrO2颗粒和少量气孔,微量杂质SiO2与MgO反应生成镁橄榄石M2S,在颗粒间起填隙作用。     

添加Al_2O_3-ZrO_2复合粉对ZrO_2质定径水口抗热震性的影响

以质量分数45%的Mg,Y-PSZ骨料,55%的Mg,Y-PSZ细粉,外加5%(w)的PVA结合剂为基础配方制备ZrO2定径水口,分别以质量分数为3%、6%、9%、12%的溶胶-凝胶法制备的Al2O3-ZrO2复合粉等量取代Mg,Y-PSZ细粉,研究复合粉对锆质定径水口物理性能、物相组成和显微结构的影响。结果表明:添加3%(w)Al2O3-ZrO2复合粉的改性锆质定径水口的各项性能明显优于目前生产工艺采用的未添加复合粉的锆质定径水口,其抗热震性为未添加复合粉的6倍。     

矾土基电熔锆刚玉和锆莫来石合成料的制备、性能与结构

研究了以高铝钒土为熟料和锆英砂为原料、采用电熔工艺法制备的矾土基电熔锆刚玉和锆莫来石合成料的理化性能、物相组成和显微结构,并用这些合成料制备了Al2O3 -ZrO2 -C试样,检测其常温物理性能、高温抗折强度和抗热震性;同时还与氧化铝基电熔锆刚玉和锆莫来石合成料进行了相应性能的比较。结果表明,矾土基电熔合成料的化学矿物组成、性能和显微结构均与氧化铝基电熔锆刚玉和锆莫来石合成料的相似,而且用其生产的Al2O3 -ZrO2 -C制品的性能也达到了用氧化铝基电熔合成料所能达到的水平,可用于实际生产。     

锆莫来石对Al2O3-ZrO2-C材料性能的影响

以电熔白刚玉、锆莫来石、鳞片石墨、SiC粉和酚醛树酯为原料,通过改变锆莫来石的加入量和粒度制备了7种不同的A l2O3-ZrO2-C试样,主要研究了锆莫来石加入量和试样的粒度组成对A l2O3-ZrO2-C材料的体积密度、显气孔率、常温耐压强度、气孔孔径分布和透气度等性能的影响。结果表明:1)锆莫来石加入量对A l2O3-ZrO2-C材料的体积密度、显气孔率、耐压强度、气孔孔径分布和透气度都有一定的影响,但影响都不大;2)试样的粒度组成对A l2O3-ZrO2-C材料的体积密度和透气度的影响较大,但对显气孔率、常温耐压强度、气孔孔径分布的影响较小。     

Al2O3/Al2O3-ZrO2(3Y)层状纳米陶瓷复合材料的显微结构及弯曲强度

在Al2O3-ZrO2(3Y,即含3%Y2O3,摩尔分数,下同)纳米陶瓷的基础上,以原位合成的Al2O3和Al2O3-ZrO2(3Y)纳米粉体为原料,采用干压成型及热压烧结的方法制备了Al2O3/Al2O3-ZrO2(3Y)层状纳米陶瓷复合材料,研究了ZrO2(3Y)含量对材料显微结构及力学性能的影响.结果表明:复合材...     

成型压力对合成CaZrO3材料性能的影响

以电熔ZrO2粉和活性石灰粉为原料,研究了不同成型压力对合成CaZrO3的影响,并利用XRD和SEM对材料的矿物相和微观结构进行了分析。实验结果表明:随着成型压力的增加,试样的致密程度加大;当成型压力达到200MPa后,成型压力对合成锆酸钙材料的致密度影响减弱。成型压力对合成锆酸钙材料的矿物相无影响,对材料的显微结构影响甚微。综合分析,适宜的成型压力为200MPa。     

铝锆碳质长水口损毁机制的研究

采用SEM、EDS对使用后的铝锆碳质长水口内壁及渣线部位材料的蚀损过程进行了分析研究.结果 表明:1)铝锆碳质长水口内壁蚀损过程为碳首先被氧化和溶解形成脱碳层,之后钢水中的夹杂物FeO与脱碳层中的Al2O3反应形成铁铝尖晶石,随着FeO继续附着,在脱碳层表面形成FeO富集区并生成低熔点相,致使脱碳层在高速钢水的冲刷下逐渐蚀损;2)长水口渣线部位蚀损首先为碳向钢液中溶解,之后为中间包渣侵蚀材料中的氧化物,两个过程交替进行,从而导致了长水口渣线部位材料的蚀损;3)适当降低长水口制品中的碳含量,可以减少铝锆碳质长水口内壁以及渣线部位材料中碳的氧化及溶解所导致的材料结构的破坏,可望延长长水口的使用寿命.     

加入添加剂对MgO-MgAl_2O_4质耐火材料力学性能的改善

研究了ZrSiO4-3mol%Y2O3添加剂对MgO-MgAl2O4耐火材料的力学性能和抗热应力参数的影响。研究表明,加入添加剂后力学性能显著改善,R-Rst参数提高到原材料的2~3倍。改善耐火材料的力学性能和热性能的参数取决于：（1）ZrSiO4分解后生成的Mg2SiO4阻止了裂纹的产生和传播;（2）微裂纹在短距离内相互交叉传播;（3）微裂纹遇到气孔或由ZrSiO4分解产生的ZrO2晶粒（Y2O3与ZrO2晶粒在同一位置分布）会被吸收或扩展;（4）引入ZrSiO4-Y2O3后穿晶裂纹和沿晶裂纹同时存在;（5）致密度增加;（6）MgO晶粒粒径明显变小。     

MgO与ZrSiO_4反应烧结机理研究

应用ＳＥＭ方法观察了ＭｇＯ与ＺｒＳｉＯ_４的反应烧结机理。结果表明,随着ＺｒｓｉＯ_４的分解,ＳｉＯ_２呈不定形态向外扩散,与ＭｇＯ反应生成Ｍｇ_２ＳｉＯ_４,原来的锆英石颗粒中只留下了ＺｒＯ_２,同时ＭｇＯ向ＺｒＯ_２方向移动,与ＺｒＯ_２形成有限固溶体;反应产物之一ＺｒＯ_２大部分聚集成集合体,也有一部分分布比较均匀。     

The effects of molding conditions on the surface composition of sheet molding compound

An improved internal reflection infrared spectroscopy (ATR) technique (1) has been found to be effective for measuring the relative concentrations of polyester and polystyrene (resin) and calcium carbonate filler on sheet molding compound (SMC) surfaces. The technique has been used to determine the effect of molding conditions on the surface compositions of three commercial SMC materials. The surface compositions of two of the materials, of the same formulation but obtained from different sources, were the same and were unaffected by molding conditions. The surface of the third material (or a different formulation) was found to have substantially less resin than the first two materials. The surface composition of the third material varied with molding conditions, the greatest uniformity being obtained with high molding temperatures and pressures. This study has shown that the ATR technique is suitable for determining the relative surface compositions of SMC formulations. This method will be used to correlate the SMC surface composition to SMC properties, such as surface appearance, paintability, and adhesive bond durability.     

Effects of grain size distribution and pressure on the density of magnesite brick

Conclusions With increased pressure the effects of the grain distribution on the porosity of the green compact gradually decreases.The higher the amount of fine fractions in the mixture the lower the porosity of the green compact at similar pressure. As the molding pressure increases the effect of the fineness of the ground batch on the porosity of the green compact decreases.By the introduction of grains with a maximum size of 4, 6 and 8 mm into the mixture and a simultaneous increase in the molding pressure the porosity of brick is reduced. The spalling resistance of the brick is superior to that of brick prepared from 0.0 to 2 mm fractions. Lowest spalling resistance was observed in brick made from a mass with 0.0 to 1.0 mm grains.In order to increase refractoriness-under-load by decreasing the amount of fused substances at elevated temperatures the mixture should be ground finer and the sintering temperature raised during the manufacturing of magnesite powder or brick; increased molding pressures fail to affect refractoriness-under-load.In using high-density magnesite for the production of magnesite brick which contains an insignificant amount of fused inclusions at elevated temperatures regular grinding may be applied (for small fractions) to coarse-grained mixtures and higher pressure as well as regular sintering temperatures. Brick with a low density (6.2%), a rather high spalling resistance (39 air heating — cooling cycles) and a high refractoriness-under-load (1680° C) is produced.Fon T'ienjung, Liu Kung fu, Ch'ang Ai ch'ihn, Hai Ch'eng, Sun shu sheng and Li Yu cheng participated in the study.     

熔铸锆刚玉砖生产中的树脂砂造型工艺的探讨

阐述了熔铸锆刚玉砖的材料和生产特点及树脂砂造型工艺在熔铸锆刚玉砖生产中的优点和容易出现的问题,对如何改进树脂砂造型工艺在熔铸锆刚玉砖生产中的应用和提高熔铸锆刚玉砖产品质量和外观色泽进行了探讨。     

锆英石包裹硫硒化镉颜料的制备

研究了锆英石包裹硫硒化镉颜料的制备方法,包括干法合成法,共沉淀烧结法及共沉淀水热合成法。     

玻纤增强酚醛注塑料的制备技术和性能

研究了玻纤增强酚醛注塑料制备过程中基质树脂的选择、固化作用与交联结构的控制及玻纤分散技术,考察了不同基质树脂制备的酚醛注塑料的固化成型结构形态和固化流变特性.进一步采用热固性与热塑性酚醛树脂相复配的基质树脂体系,经配方和制备工艺的优化,制备了高填充量玻纤增强酚醛注塑料.该注塑料具有良好的注塑成型性能,注塑制品具有高强度, 冲击强度达到4.3 kJ•m^-2,弯曲强度137.4 MPa,同时热变形温度为 245 ℃,阻燃性通过美国UL 94 V-0级认证,并具有优良的尺寸稳定性、电绝缘性能和低成本优势.     

ZrSiO_4和TiO_2对铝硅系耐火材料抗热震性的影响

研究了ArSiO4（锆英石）、TiO2（铁白粉）加入物对铝硅系耐火材料抗热震性的影响及其作用机理。认为ZrSiO4、TiO2提高材料抗热震性的机理在于微裂纹增韧以及第二相（钛酸铝）降低了材料的热膨胀系数。     

基于二次回归正交旋转试验熔融沉积超声振动成型研究

为了研究超声振动对熔融沉积成型(FDM)制品力学性能的影响以及各变量之间的相关关系,在原有熔融沉积成型设备的基础上增加了超声振动系统,采用单因素试验与二次回归正交旋转组合试验相结合,分别以打印外壳厚度、填充密度和超声波功率3个因素为研究对象对FDM成型工艺进行研究.结果表明,超声振动功率对材料的拉伸性能具有很大的影响,...     

Rheo-Engineering Properties of Mixed SiO2/Al2O3 Suspensions and Related Materials. III. The Fused Quartz – Fused Corundum System

A corundum suspension at pH = 7 with a 58% volume concentration of the solid phase and a molding porosity of 20% is prepared. The properties of fused quartz + fused corundum mixed suspensions are studied. Based on a mixed binder of composition 50% SiO₂ + 50% Al₂O₃ and a fused quartz filler, a castable is prepared which, heat treated at 1150°C, exhibited the following properties: open porosity — 13%, compressive — 80 MPa, temperature for strain onset under loading — 1250°C, thermal stability — 10 heat-cool cycles (1000°C – water). The new castable exhibits a higher slag resistance against the conventional quartz-based castable.     

Study on the safety and mechanical properties of a new tetrazole-based energetic material

DTDA-THA (tris(hydrazin-1-ium)5,5′-(hydrazin-1-ide-1,2-diylbis((1H-tetrazole-5,1-diyl)))bis(tetrazol-2-ide)) is a novel type of poly-nitrogen energetic material characterized by high nitrogen content, high enthalpy of formation, and low sensitivity. To research the application of DTDA-THA in polymer-bonded explosives (PBXs) and improve the safety performance of DTDA-THA in composite explosives, this study calculated the binding energies between ethylene-vinyl acetate copolymer (EVA), polyvinyl butyral (PVB), polyvinyl acetate (PVAc) and DTDA-THA via density functional theory, respectively. Three types of PBXs molding powders were prepared through the direct method. For further investigation, the moisture absorption of molding powders, the forming density, and the compressive strength of the grains under different binders were characterized. The result of the simulation shows higher binding energy between the crystal surface (2 −1 2) and different binders. The comprehensive order of the binding energies between different binders and the crystal surface of DTDA-THA was DTDA-THA@EVA>DTDA-THA@PVB>DTDA-THA@PVAc. The experimental results show that the addition of binder reduced the hygroscopicity of DTDA-THA and improved the sensitivity and mechanical properties of the molding powders. Under the same binder proportion, the formulation prepared by PVAc had a higher molding density, while the formulation prepared by PVB exhibited the best compressive strength.