陶瓷现代成型技术的研究进展

分析了成型工艺在陶瓷制备中的重要作用和高质量的陶瓷坯体对成型工艺的基本要求，评述了国内外陶瓷现代成型技术，着重介绍了离心沉积成型、电泳沉积成型、离心注浆成型、注射成型、胶态成型和快速自动成型等新工艺，讨论了上述成型方法的基本原理和特点，指出了陶瓷成型技术的发展思路。     

东盟成为广东潮州陶瓷主要进出口市场

清华大学材料系黄勇教授课题组承担的九五期间863课题“低成本、高性能陶瓷胶态注射原位快速凝固成型新工艺的研究”（简称为“陶瓷胶态注射成型新工艺”）取得重大成果,使陶瓷的制造成本降低一半,可靠性提高一倍以上,使各种复杂形状陶瓷零部件的近净尺寸制造技术获得突破性的进展。制备的陶瓷材料与制品的性能达到;坯体密度均匀（密度分布差小于0．5％）、坯体强度高（抗弯强度在20～30MPa）、易于加工：烧结后产品性能优异;     

高性能陶瓷创新工艺--陶瓷胶态注射成型技术

成型工艺作为制备高性能陶瓷材料及部件的关键技术,介绍黄勇教授创新提出的把胶态成型和注射成型结合的“陶瓷胶态注射成型新工艺”。     

羟基磷灰石陶瓷成型与烧结工艺研究

以磷酸钙为原料用煅烧新工艺制备了羟基灰石粉末，并以此为原料采用凝胶浇注成工艺制备了羟基磷灰石陶瓷坯体，研究了不同成型工艺制备的羟基磷灰石陶瓷坯体的性能。借助ＤＴＡ、ＸＲＤ等分析了陶瓷坯体在烧结过程中的物理化学和晶相转变。     

陶瓷直接凝固注模（DCC）成型

直接凝固注模式型（ＤＣＣ）是一种陶瓷净尺寸胶态成型方法，ＤＣＣ成型的坯体具有成型密度高，密度及组分分布均匀，不含或只含少量有机物等特点，本文了ＤＣＣ成型的原理、成型过程及特点。     

陶瓷材料成型工艺研究新进展

陶瓷制造经历数千年历史,当前阻碍陶瓷材料进一步发文介绍了胶态成型、固体无模成型工艺及气态成型,对上述工艺的原理、工艺过程及特点进行比较,提出了陶瓷成型工艺的关键问题.并介绍了水基非塑性浆料的注射成型新工艺.     

压力对凝胶注模成型95氧化铝陶瓷性能的影响

本文采用低毒的MAM-MBAM凝胶体系代替AM-MBAM有毒体系制备95氧化铝陶瓷,为改善成型后坯体的性能,在凝胶注模成型过程中给予浆料压力.研究发现在压力为0.3 MPa时获得的坯体表面光洁,线收缩率大,体密度高,结构均匀,成品率高,质量好.本文还并研究了压力对95氧化铝陶瓷烧结体线收缩率和体密度以及洛氏硬度的影响.实验结果表明:压力辅助凝胶注模成型所得坯体烧结后性能优于无压直接注模成型坯体,压力为0.3MPa时线收缩率最小,体密度最高可达3.81 g/cm3,洛氏硬度最高.坯体显微结构显示,陶瓷粉料被有机高分子网络很好地粘结在一起,并且压力注模的坯体中陶瓷粉料堆积紧密,结构均匀致密.烧结后,压力注模成型坯体晶粒发育良好,气孔较无压直接注模烧结体少,烧结致密性能优异.     

结构陶瓷的新型凝胶注模成型技术研究与进展

凝胶注模成型是一种先进的陶瓷成型方法,为高性能复杂形状陶瓷的制备提供了有效的技术途径.凝胶注模常用的体系为丙烯酰胺,但由于丙烯酰胺单体具有神经毒性,因此限制了其应用范围.近十余年来无毒体系凝胶注模成型技术受到了国内外学者的广泛重视.本文综述了无毒性凝胶大分子的种类,凝胶成型的基本原理、工艺过程及国内外最新研究成果.这种无毒性凝胶体系具有环境友好、有机物含量少、坯体均匀等优点,将成为今后凝胶注模成型发展的一个重要方向.     

陶瓷注射成型的研究

注射成型是可批量制备形状复杂陶瓷部件的一种先进技术,本工作研究了陶瓷注射成型悬浮体的流变特性,考察了不同注射工艺参数对成型过程和坯体质量的影响,对脱脂过程中有机物的热分解和热失重特性进行了分析,研究了脱脂机理及陶瓷部件的实际脱脂过程,制备了完好的大尺寸陶瓷涡轮转子和叶片。     

炭黑对丙烯酰胺单体自由基聚合的影响

凝胶注模成型是一种先进的胶态成型工艺，是制备大尺寸、复杂形状陶瓷制品最有效的一种方法。该方法在制备氧化铝等陶瓷制品时获得了巨大成功，但对含碳陶瓷料浆成型时却遇到了难题，由于碳对聚合体系具有较强的阻聚作用，往往造成含碳料浆不聚合或聚合程度较弱，影响成型坯体的质量，因此研究炭黑对丙烯酰胺单体自由基聚合的影响是解决以上难题的关键。为此通过测量聚合反应的热效应，研究了炭黑含量、反应温度、引发剂用量等因素对丙烯酰胺单体聚合的影响，计算了聚合反应的活化能。实验发现在聚合体系中添加极少量的乙酰丙酮可以显著提高丙烯酰胺的聚合转化率，通过对聚合体系聚合过程的分析，发现炭黑对聚合体系除了具有阻聚作用外，还会影响聚合体系的聚合诱导期。     

精密陶瓷原位凝固制备技术的研究

七十年代末，世界范围内伴随着陶瓷热机部件的热潮，精密陶瓷受到了各国政府、研究部门及产业界的充分重视。进入九十年代后，精密陶瓷的发展遇到了许多问题，其中形状复杂结构部件的成型工艺是制造高性能陶瓷材料最为关键的环节之一。本文综合分析了近年来精密陶瓷成型工艺的研究进展，着重强调指出砂位凝固成型技术是保证坯体均匀性和解决高性能陶瓷可靠性的重要环节，同时，指出成型工艺今后需要加强和解决的几个关键技术。     

Recent developments in gelcasting of ceramics

Gelcasting is a well-established colloidal processing method with a short forming time, high yields, high green capacity and low-cost machining, and has been used to prepare high-quality and complex-shaped dense/porous ceramic parts. In this article, we reviewed recent developments in gelcasting technology for ceramic preparation. For environmental pollution reduction during ceramic preparation by gelcasting, the development of low-toxic and nontoxic gelcasting systems is discussed. The occurrence and control of inner stress and surface-exfoliation in ceramic green bodies prepared by gelcasting are analyzed, and then some methods to control and eliminate the inner stress and surface-exfoliation in ceramic gelcast green bodies, especially for colloidal injection molding of ceramics (CIMC) are proposed. Finally, the applications of gelcasting for the fabrication of porous ceramics and complex-shaped ceramics (e.g., microbeads, rutile capacitor, thin-wall rutile tube, refractory nozzle) are summarized.     

Colloidal processing: enabling complex shaped ceramics with unique multiscale structures

Colloidal processing of fine ceramic powders enables the production of complex shaped ceramics with unique micro and macro structures which are not possible to produce via conventional dry processing routes. Because of this enhanced structural control and shaping capabilities, colloidal processing has been exploited to produce ceramic components with ever increasing complexity and functionalities. In this review, we revisit some of the research efforts on this topic to highlight its relevance and growing importance for the advanced manufacturing of functional ceramics. Selected examples of colloidal systems with increasing level of complexity are discussed to showcase the wide range of structures that can be generated through wet processing approaches. The historical development and background knowledge pertaining to colloids and surface interactions is first briefly reviewed. The major colloidal shape forming and additive manufacturing processes that utilize colloidal pastes and inks are then reviewed, highlighting the control of suspension rheology needed in these techniques. Next, methodologies that combine suspended particles with a pore‐forming phase are discussed as a means to produce porous ceramic materials. Further control over the interactions between anisotropic particles and their alignment in suspensions can be gained via externally applied fields (such as magnetic) to produce texturally aligned green bodies. This leads to bioinspired ceramics that can programmably morph into complex shaped objects upon sintering. Hierarchical porous structures with high mechanical efficiency are also shown as an example of the multiscale designs that can be generated through advanced colloidal processing. As drying of ceramic bodies is an inevitable consequence of wet colloidal processing, the current understanding of this critical processing step is reviewed. Finally, the gaps in knowledge in these fields are discussed to provide our perspective on where the field may support advances in ceramics in the future.     

The transformation mechanism from suspension to green body and the development of colloidal forming

Colloidal forming is a novel wet-processing way to prepare complex shaped ceramic parts with high reliability at low cost. In this article, the transformation mechanisms from suspension to green body and the development of colloidal forming are reviewed. The transformation from suspension to green body in colloidal forming is mainly dependent on the characteristics of suspension, and solidification is the key link in colloidal forming. Various colloidal forming methods are developed to produce ceramic parts, and these methods include slip casting, tape casting, direct coagulation casting, injection molding, gel-casting and so on. The study of defects during colloidal forming should be focused on the defects formation, inheritance and evolution during drying, de-binding and sintering processes. External free controllable technology of colloidal forming is an effective way to achieve ceramic fabrication industrialization, and stress-free colloidal forming is important for the future development of ceramic fabrication.     

关于陶瓷成型工艺的讨论

陶瓷制造经历数千年历史,直到20世纪中叶因为烧结理论的创立获得了飞速发展,上世纪七八十年代关于超细粉体制备和表征的发展,促使陶瓷工艺第二次大发展,当前阻碍陶瓷材料进一步发展的关键之一是成型工艺技术没有突破,压力成型不能满足形状复杂性和密度均匀性的要求,传统的湿法成型工艺可以获得复杂形状,但不能保证坯体的均匀性,90年代以来发展起来的多种胶体原位成型工艺和气相成型工艺有望促使成型工艺获得突破。     

α-Al2O3悬浮体的流变性及凝胶注模成型工艺的研究

陶瓷凝胶注模型工艺是一种新颖的成型工艺,具有很好的应用前景。它将高分子化学单体聚合的思路引入到陶瓷的成型工艺中,可制备高强度、高均匀性的陶瓷坯体。     

凝胶注模制备多孔陶瓷的研究进展

凝胶注模是将传统的陶瓷粉体成型与有机物原位聚合相结合的一种新型成型工艺,为制备高性能、复杂结构的多孔陶瓷提供了一条新途径.在阐述凝胶注模工艺原理的基础上,综述了凝胶注模结合不同成孔方法制备多孔陶瓷的成孔机制以及最新研究进展,并展望了凝胶注模制备多孔陶瓷的发展趋势.     

Gelcasting of through-pore hydroxyapatite ceramics

Although the near-net-shape forming ability of gelcasting has been well demonstrated, current attention mainly was focused on manufacturing compact ceramics. In this work we demonstrated that the combination of the gelcasting technique and the ceramic sintering process could prepare the near-net-shape through-pore hydroxyapatite (HAP) ceramics, in which the pore diameter at the range of < 2 μm could be adjusted by changing the content of HAP in green bodies and with the aid of alcohol immersion. Experiments demonstrated that the gels in green bodies and alcohol immersion played important roles in improving the strength of green bodies and decreasing the shrinkage and deformation of green bodies, and thus improving the through-pore and near-net-shape forming of HAP ceramics. Such method reported here possibly extends the gelcasting technique to manufacture other through-pore ceramics for precise filtration, protein separation, or high performance liquid chromatography.     

酯化淀粉原位凝固成型Al2O3陶瓷的研究

研究了以淀粉作凝胶剂原位凝固成型Al2O3陶瓷的新方法.当淀粉大分子在水溶液中加热到一定温度时,淀粉颗粒吸水溶胀,陶瓷浆料脱水并固化成坚硬的坯体;而且溶胀后的淀粉可作为粘结剂,有助于坯体固化并增加其强度.详细探讨了酯化淀粉添加量不同时,对陶瓷浆料流变特性的影响,以及对成型出素坯的线收缩、相对密度、干坯强度以及显微结构的影响.     

高性能陶瓷成型工艺进展

本文论述了高性能陶瓷成型工艺的和重要性，重点介绍了陶瓷胶态成型工艺的研究进展及陶瓷成型工艺的最新动向，提出了瓷成型工艺研究中必须重视和加强的若干研究领域。