氧化锆陶瓷注凝成型研究

本文对ZrO2注凝成型工艺中分散剂、固相体积含量对浆料流变性的影响进行了研究.研究表明分散剂的加入可以使浆料的Zeta电位值提高近40mv,浆料粘度降低;随固相体积含量增加,浆料粘度增加,但使浆料粘度降至最低所需分散剂的量减少.     

ZTA陶瓷注凝成型工艺中浆料性能的研究

对ZTA陶瓷注凝成型工艺中分散剂、pH值、氧化锆含量、固相体积分数、有机单体含量对浆料流变性的影响进行了研究.研究表明:合适的分散剂加入量可使浆料粘度降低;pH值的改变对浆料粘度有较大影响;随氧化锆含量、固相体积分数、有机单体含量增大,浆料粘度也会增大.     

浆料的固相含量对注凝成型氧化锆增韧氧化铝陶瓷的影响

研究了浆料的固相体积分数对注凝成型氧化锆增韧氧化铝(zirconia toughenedalumina,ZTA)生坯和烧结样品物理力学性能的影响。实验所用Al2O3和ZrO2的质量比为80∶20。用压汞法分析了生坯的孔结构,结果表明:高固相体积分数浆料制备的生坯孔结构呈双峰分布。SEM和XRD研究显示了高固相体积分数浆料制备的烧结体具有结构致密、ZrO2分布均匀和tZrO2含量高等特点。采用55%固相体积分数的桨料制备的坯体,经1600℃烧结2h后,ZTA样品的抗弯强度和断裂韧性分别达631.5MPa和7.64MPa·m1/2。     

注凝成形制备氧化锆陶瓷刀

本文采用注凝成形工艺制备氧化锆陶瓷刀。以超细氧化锆粉为原料。加入丙烯酰胺（单体）、N,N-亚甲基双丙烯酰胺（交联剂）、过硫酸铵（引发剂）、四甲基乙二胺（催化剂）、JA-281分散剂及氨水制备出了固相含量52％的氧化锆基陶瓷悬浮体,经注凝成形,1500℃烧结。文中比较了不同规格的锆粉．并确认了较适用于注凝成形的锆粉。同时,检测了注凝干燥坯体及烧结样品的相关理化性能,并将其与干压冷等静压成形坯体进行对比。结果表明．悬浮体固化后颗粒仍保持原有的位置,坯体光滑致密无气孔。生坯抗弯曲强度为24．19MPa,高于干压冷等静压的15．24MPa,注凝坯体经1500℃烧结．样品吸水率为0％、体积密度为6．13g／cm^3、抗弯强度为929．70MPa。     

注凝成型工艺的研究进展

介绍了陶瓷的注凝成型工艺原理、工艺流程、浆料分散机理、凝胶固化过程和素坯干燥理论,分析了pH值、分散剂、固相含量及粉体特性对注凝成型浆料流变性能的影响,指出了陶瓷注凝成型工艺的发展趋势及存在的问题。     

钛酸铝陶瓷注凝成形过程中浆料性能的研究

笔者研究了注凝成形钛酸铝陶瓷过程中分散剂、pH值、有机单体含量对浆料流变性的影响,并制备出体积分数为62%,粘度为500mpa·s的钛酸铝陶瓷注凝成形浆料.研究表明,当分散剂含量为2.5%,pH值为10.7,有机单体与交联剂比例为24:1,有机单体含量为2.1%时,浆料粘度最低.     

陶瓷注凝成型工艺的新进展

本文综述了注凝成型工艺特点及其进展状况,对其应用前景进行了展望。     

石英陶瓷注凝成型影响因素的研究

介绍了熔融石英陶瓷的注凝成型机理及其工艺过程,分析讨论了影响熔融石英陶瓷注凝成型的主要因素,通过研究确定了合理的制备工艺参数.     

ZrO_2基陶瓷注凝成型料浆流变性的研究

陶瓷料浆流变性能是注凝成型工艺的关键,料浆流变性要求高固含量,低粘度。实验通过在ZrO2表面包覆A l2O3,形成ZrO2-A l2O3复相陶瓷料浆。根据静电位阻稳定理论,通过调节pH值和分散剂的加入量,可得到满足成型要求的高固含量,低粘度的料浆。结果表明,在pH值为10左右,分散剂加入量为粉料质量的3%时,料浆固相体积分数可以达到40%。同时表明了A l2O3对ZrO2颗粒表面有改性作用,提高了悬浮体的稳定性。     

水基凝胶注模法制备稳定氧化锆坯体的研究

采用水基凝胶注模法制备稳定氧化锆坯体，测试其气孔分布，并与干压成型法制备的坯体在密度、强度和形貌上进行比较。结果表明，水基凝胶注模法制备的坯体微观结构较为均匀，气孔分布范围较窄，颗粒分布好，团聚少，坯体强度和密度较干压法高。随固相体积分数的增加，水基凝胶注模法坯体密度逐渐增加，但强度逐渐降低。     

Monoclinic Zirconia Bodies by Thermoplastic Ceramic Extrusion

Two ultrafine, undoped ZrO₂ powders with median primary particle sizes of 9 and 25 nm were used to prepare ceramic suspensions for thermoplastic extrusion. The organic vehicle consisted of an industrial-grade poly(ethylene- co -vinyl acetate) (EVA) or polyethylene (PE-HD) and decanoic acid as a dispersing agent. The powder volume loadings achieved were 44% and 52% by volume for the two powders, respectively. The amount of dispersant needed was calculated from a new model based on available chemisorption sites on the powder surface. Mixing and extrusion were conducted using a conventional modular plastic processing unit. Green bodies were dewaxed up to 450°C in an inert atmosphere and sintered to full density in air at 1060° and 1100°C, respectively. Analysis of the ceramic phase content and the microstructure of the bodies is presented.     

High-Temperature Extrusion Behavior of a Superplastic Zirconia-Based Ceramic

Workability of 3-mol%-yttria-stabilized tetragonal ZrO₂ has been gauged through a series of extrusion experiments performed under vacuum with graphite dies at 1500°C and 35 MPa piston stress. It is shown that dense and smooth extrusions can be obtained from solid billets when graphite paper is used as a lubricant. Sigmoidal dies and conical dies with cone angles of 18.4°, 26.6°, and 45° and diameter ratios of 1.5, 2, and 3 were used to explore extrusion behavior. Observed piston velocities correspond to what may be predicted from the experimental uniaxial constitutive creep equation and a simple slab analysis. A precise analysis, however, is not attempted because of lack of steady-state behavior of the material itself.     

Effect of the Interparticle Pair Potential on the Rheological Behavior of Zirconia Powders: I, Electrostatic Double Layer Approach

Aqueous slurries containing 20 vol% ZrO₂ powder doped with 3 mol% Y₂O₃ were prepared by first dispersing the powder at pH 11, then adding 0.1 M to 1.0 M tetramethylammonium chloride (TMACl), or 1.0 M of TPACl, CsCl, and LiCl to produce different, weakly attractive particle networks. The particle pair potentials in the slurries were investigated by viscosity versus shear rate measurements. Slurries exhibited increasing viscosities (at a given shear rate) with increasing salt concentration and decreasing (unhydrated) counterion size. The viscosities for these weakly attractive networks were intermediate to dispersed (pH 11 without added salt) and flocced (isoelectric point, pH 7.5) slurries. Cylindrical bodies were consolidated from these slurries by pressure filtration at different applied pressures. The bodies consolidated from slurries formulated with TMACl had the highest packing densities relative to those consolidated from a flocculated slurry, but the relative densities were much lower than those achieved from bodies consolidated from a dispersed slurry. The plastic or brittle nature of these bodies was determined in uniaxial compression. Powder compacts consolidated from flocced slurries and slurries coagulated with 1 M TMACl, CsCl, and LiCl showed plastic behavior for filtration pressures ≤7.5 MPa. Results for ZrO₂ will be compared with those previously obtained for Al₂O₃, which produces plastic, consolidated bodies over a much broader range of slurry conditions.     

水溶性高分子对氧化锆悬浮体分散性和流变性的影响

在氧化锆陶瓷的凝胶注模成型制备中,为了消除空气中坯体表面脱粉现象,试图在常用的丙烯酰胺体系的基础上增加了一种新的水溶性聚合物组分,形成一种新型的聚合物-单体共存的凝胶注模成型体系。这种体系在某种条件下要优于原有单一丙烯酰胺体系。着重研究了添加聚乙二醇对氧化锆悬浮体的分散特性、固化特性及其流变行为的影响。结果表明,通过添加1.5wt%水溶性聚合物聚乙二醇发现可以消除坯体的表面脱粉,同时大大地改善了氧化锆浓悬浮体的分散性和流动性。     

粉·福（粉锈宁＋福美双）悬浮剂物理稳定性的研究

详细地研究了粉·福（粉锈宁＋福美双）悬浮剂的流变学行为,提出了用相对趋近值来判断悬浮体系的物理稳定性,并取得了良好的效果。     

注凝成型纳米防火玻璃

采用分散剂对纳米硅溶胶进行分散,和丙烯酰胺衍生聚合物结合,应用注凝成型（gelcasting）工艺制成具有高防火性能的纳米防火玻璃。其组成为硅溶胶、分散剂、丙烯酰胺、N-羟甲基丙烯酰胺。     

陶瓷釉中锆的快速测定的研究

本文研究了对乙酰基偶氮胂与锆反应的最佳条件。实验表明：锆在稀硫酸介质中与对乙酰基偶氮胂显色反应灵敏，表观摩尔吸光系数ε（６４０）＝４．６４×１０４Ｌ·ｍｏｌ（－１）·ｃｍ（－１），锆在０～３５μｇ／２５ｍｌ范围内服从比耳定律。应用于陶瓷釉中锆的测定，结果准确，令人满意。