Colloidal ceramic injection molding process is a new low viscosity, high solid volume fraction of concentrated water-based ceramic suspension is injected into the non-porous mold and allowed to solidify in situ quickly, and then sintered to obtain a uniform microstructure, no defects and near net shape-performance, high-reliability ceramic components, and greatly reduce the manufacturing costs of ceramic. After nearly 10 years of research breakthroughs, colloidal ceramic injection molding new technology to achieve significant results, performance materials and preparation of ceramic products reached: body of uniform density (density difference is less than 0.5%), high green strength (bending strength at 20 ~ 30MPa), ease of processing; excellent performance sintered products: silicon nitride based ceramics product performance, bending strength is more than 900MPa, Weibull modulus m stable at 20 or more, up to 33; Alumina based ceramic bending strength 700MPa, Weibull modulus greater than 15 m (sampled from the member test piece). While the lower half of the ceramic manufacturing costs, increased reliability more than doubled.
Special ceramic industrial core technology
Currently two major problems facing the application of high-performance ceramics are ceramic high manufacturing costs and poor performance of reliability. Due to the high production cost of ceramic, resulting in higher product prices, it can not compete with metal and composite materials, there is currently only used in some special areas. Which cost ceramic machined ceramic manufacturing costs accounted for almost 1 / 3-2 / 3, primarily because molded ceramic components is difficult to achieve near net shape forming. In addition, the performance of ceramic material dispersion, which means the poor reliability of the ceramic material, so did not dare to get involved in many areas of ceramic products. If these two issues are not resolved, high-performance ceramics market is difficult to open up the situation.
Recalling the late 1970s, the emergence of worldwide oil energy crisis, high-performance ceramic its excellent high temperature, high strength, wear resistance, corrosion resistance and other properties, and as candidate for engine parts, Meanwhile ceramic molding has become an important research topic. In the United States, Japan and other developed countries led, have developed a hot dryer. In particular, the application of high-temperature structural ceramic materials in automobile engines of national development plans. "Plan" and "August 5" key components of the ceramic insulation around the engine, in-depth study of the ceramic injection molding, extrusion molding type, grouting and filter press molding process, and the preparation of a high performance engine component samples. According to some authoritative research institutes abroad and related lab report evaluated one of the main reason why Japans leading research in structural ceramics in the United States and quickly is a world leader in ceramic forming technology. Twenty years later, the molding process as a key technology for preparing high-performance ceramic materials and components, it is not only the premise of material design and material formulations to achieve, and reduce the ceramic manufacturing costs and improve the reliability of the material is particularly important aspects.
Since the 1990s, the international community forming around the basic theory and techniques carried out extensive research, new molding technologies are emerging. In the "Nine Five" period, in order to promote the popularization and application of structural ceramics research, and in 863 the molding technology as the key technology of structural ceramics. Professor Huang Yong group undertook the study of the subject, and "colloidal injection molding new technology," this major achievement. Colloidal injection molding technology, not only can significantly reduce the manufacturing cost of the ceramic material, and can improve the reliability of ceramic materials. By this molding technology, to achieve high-density, high uniformity and high strength ceramic body, this molding technology can eliminate aggregates ceramic powder particles during sintering reduce parts of complex shape deformation, cracking, thus reducing the final part of the processing capacity of the machine, high reliability ceramic materials and components. It is a new near net shape forming technology, suitable for large-scale production of specialty ceramics industry of core technology.
Due to the high hardness special ceramics crisp, like metal can be processed into a variety of shapes, so near net shape forming technology has become an important research topic and industrialization of key technologies.
Traditional ceramic injection molding technology from polymer materials for injection molding, a large number of polymer binder and ceramic powder kneaded together, and then the preparation of various ceramic parts by injection molding of complex shapes. In the 1980s, the technology worldwide launched a special ceramic industrial boom, but because it contains a large amount of polymer binder, the ceramic body skim insurmountable problem, until now injection molding degreasing problem remains unresolved, severely limits its application and development. However, due to the high dimensional accuracy of the molded body, easy to scale and degree of automation of production, still the ceramic industry and research institutions have enormous appeal.
In order to avoid the use of a large number of ceramic injection molding technology shortcomings polymer binder nineties Ceramic molding technology gradually turned to the study of organic matter containing a small amount of water-based colloidal forming technology, the new molding technologies are emerging, such as the United States gelcasting process oaks National Laboratories, the Swiss Federal Institute of Technology invention is directly solidified injection molding technologies. In short, the nineties has made great progress in terms of colloidal forming non-plastic water-based slurry.
The research team has on ceramic injection molding, filter press molding, electrophoretic deposition modeling, gelcasting, direct solidification techniques such as injection molding a lot of fruitful research, and established extensive links with research institutions internationally. In the early 1995 and put forward the bold innovation colloidal molding and injection molding combines "colloidal ceramic injection molding new technology" that is water-based slurry of non-plastic injection molding. Traditionally, ceramic non-plastic water-based slurry injection molding can not be achieved. The researchers in the study of several key technologies are well-experienced capture hard to break. However, he did not flinch in the face of difficulties, after repeated demonstration that as long to find a rapid cure for the control fluid condition solids, water-based slurry of non-plastic injection molding is entirely possible. Through five years of hard work, the researchers often live and eat in the laboratory, how much experience sleepless nights, and in the field of new materials 863 Group of Experts on the active support and encouragement, and finally broke through a number of key technologies colloidal ceramic injection molding, creativity and invention of colloidal ceramic injection molding equipment and the development of new technology and international success the first water-based slurry of colloidal injection molding machine to achieve a non-plastic ceramic water-based slurry injection molding. This is a major breakthrough in ceramic preparation technology is a revolution in the ceramic molding process. This achievement is an international initiative to reach international advanced level. Information Retrieval proven technology of the same content no reports on the current international. The scientific and technological achievements have originality. Colloidal ceramic injection molding new technology is an ideal near-net size forming technology, to avoid the traditional ceramic injection molding using latex difficulties caused a lot of organic matter, colloidal achieve the injection molding process.
Colloidal ceramic injection molding must address the following two important key technologies: fast-situ concentrated suspension of ceramic curing and controllability of the injection process. Popular terms namely slurry prior to injection can not cure, good liquidity and stability, Injection molding after curing to achieve rapid in situ, the key point is that to be able to find an outside controllable factors, such as pressure, temperature, electromagnetic waves, etc., is commonly used to induce a slurry temperature curing. Major scientific discoveries in science are often accidentally discovered the practice. Group debugging colloidal injection molding, in order to find how the injection pressure and filling the relationship between the exhaust system test. It found that the injection pressure is very sensitive to the slurry curing drew attention during the test. Further tests also found that at room temperature, the slurry can be quickly cured. Thus the invention of pressure-induced colloidal ceramic injection molding technology, which not only overcomes the curing temperature of the slurry to bring the temperature field caused by uneven curing body microstructure inhomogeneity and complex injection molding machine control system, but also has general adaptability. The original major discovery has laid a solid foundation for the technology to large-scale production and commercialization.
At the same time, we further expanded research, successfully developed a water-based rapid solidification colloidal cast molding new technology and equipment, low-cost water-based rapid casting molding; coarse system for the first time in the international advanced silicon nitride bonded silicon carbide refractory Rapid solidification of molding material, recognized and appreciated by the US CARBORUNDUM; invention of enzymatic and non-toxic system gelatin in situ solidification of sodium alginate gel injection molding process. In the study, strengthen basic research and academic exchange and international cooperation, made in situ solidification temperature theory, normal pressure-induced solidification theory. The international community for the first time revealed the formation mechanism of crack concentrated suspension of ceramic destabilization process, causes and ways to avoid the establishment of latency, ion concentration and gel strength body affect the microstructure of the theoretical model. These theoretical results colloidal injection molding technology to lay a solid theoretical foundation.
Application and Prospect
To test the colloidal ceramic injection molding technology and new technology innovations and advanced, and whether it can promote special ceramic industrialization, we must choose a typical product in the test. The researchers conducted a nationwide market survey, select the market prospects and difficult to manufacture a number of products. In order to accelerate the speed of the pilot test and solve the problem of funding, self-financing to build 300 square meters in the pilot production line. Test, test proved that the whole focus of a paper-making machine ceramic dewatering elements, high power rutile ceramic capacitors, the double helix Desanding mouth, ozone generator with ceramic thin-walled tubes and twin-screw kneading machine full ceramic lining and other products use colloidal ceramic injection forming a new process to produce a stable product quality, high pass rate, already have industrial conditions.
New material special ceramic material known as the 21st century, it is widely in many fields of information, energy, automotive, textile, chemical, aerospace, petroleum, paper, machinery, marine and other metal materials and polymer materials of incompetence application, to promote the development of national economy, play a positive role in promoting.
The history of mankind has proven advances in materials is the material basis of human social development, is a milestone in human progress, but progress is based on material technology for the pilot. Colloidal ceramic injection molding can improve the reliability of the ceramic material and a significant reduction in the manufacturing cost is high, wide application of special ceramic material is within reach. Of course, it must be recognized that colloidal ceramic injection molding equipment and technology to promote and scale applications has just started, long way to go yet to the State, the business community, the investment community insight to work together to create our special Ceramic brilliant career, to make our ceramics industry to catch up with developed countries, the world famous again.
Huang Yong, professor at Tsinghua University, doctoral tutor. He graduated from Tsinghua University in 1962 and stayed, 1986-1987 visiting scholar at the University of Michigan, from November 1992 to March 1993 a senior visiting scholar at MIT, a research scientist, in June 1996 to 8 month Swiss Federal Institute of Technology professor, June 2000 to July at lectures and Cooperation Department of Materials Science at Monash University, Melbourne, Australia. The current Department of Materials Science and Engineering Institute executive vice president, deputy director of the new ceramic and fine craft, State Key Laboratory Academic Committee, Chinese Ceramic Society executive director of the Chinese Ceramic Society special ceramic branch chairman, sixth, discipline review team members seventh National Natural Science Foundation of China, deputy chief editor of Chinese Ceramic Society. Inorganic non-metallic materials have long been engaged in teaching and research work in advanced ceramic composition, structure and properties as well as the preparation of the scientific high-tech ceramics, ceramic strengthening and toughening mechanism and other aspects of research intensive.
Our ceramics has a long history, it ingenious, elegant crystal, famous. The development of Chinas ceramic history, recording the history of Chinese civilization. With the development and in-depth scientific research of social progress and science and technology, so that the ancient ceramics meaning given to high performance, the development of modern special ceramic, which has excellent physical and mechanical properties, as well as electrical, magnetic, thermal, light, sound, chemical, biological and other aspects of magic superior functionality, high technology and major projects become key materials. But using traditional ceramic preparation process and equipment is difficult to obtain a uniform microstructure, free of defects and near net shape ceramic parts. Coupled with structural ceramics special ceramics in particular is hard and brittle and difficult to process both prone sudden rupture, resulting in high production cost of special ceramics, performance discrete large, poor product reliability, reproducibility and performance. In order to achieve special ceramic industry, Professor Huang Yong led group proposed a new specialty colloidal ceramic injection molding new technology.
Structural ceramics special ceramics in particular is hard and brittle and difficult to process both prone sudden rupture, resulting in high production cost specialty ceramics, performance discrete large, production performance and poor reproducibility and reliability, so many results difficult to translate into large-scale production.
In order to achieve special ceramic industry, Professor Huang Yong led group proposed a new specialty colloidal ceramic injection molding new technology, low viscosity, high solid volume fraction of concentrated water-based ceramic suspension is injected into the non-porous mold and make it fast curing in situ, and then sintered to obtain a microscopic uniform structure, free of defects and near net shape-performance, high-reliability ceramic components, and greatly reduce the manufacturing costs of ceramic.
The study was funded project National High Technology Program, the National Natural Science Foundation of China and the Ministry of Educations special fund disciplines. After nearly 10 years of research breakthroughs, colloidal ceramic injection molding new technology has made significant achievements, the results of national invention patent applications 13 (authorized 2), utility model patents 2 (already authorized), as of 2000 Until July, the domestic and foreign journals published more than 60 papers. October 2000 adopted eight series of results of identification organized by the Ministry of Education, "colloidal ceramic injection molding new technology," reached the international advanced level, "colloidal ceramic injection molding" for the international initiative, the results of the remaining six have reached the international advanced level.
Special Ceramics: is refining high-purity synthetic inorganic compounds as raw materials, the use of sophisticated control technology obtained by sintering. Generalized special ceramics and inorganic non-metallic materials meaning equivalents include artificial crystals, amorphous, ceramics, and composites, semiconductors, refractories, cement and the like.
Traditional ceramics: generally include daily ceramics, sanitary ceramics, building ceramics, art pottery, etc. It is natural inorganic materials such as clay firing from.
Colloidal forming: the ceramic powder can be uniformly dispersed in an organic solvent or aqueous medium, adding curing agents and additives with high solid content, low viscosity concentrated suspension of ceramic, non-porous artificial injection mold, depends on the temperature-induced hardener chemical reaction or polymerization curing the slurry.
Ceramic Injection Molding: mixing the powder with an organic binder, is made by heating the mixture kneaded. The mixed material into the injection molding machine at a certain temperature the mixture has a certain fluidity, by injection pressure injection mold. After cooling and molding curing adhesive.
Colloidal ceramic injection molding (? Col loidalInjectionMouldingofCeramics, referred to as CIMC): with colloidal advantages of integrated molding and injection molding, popular terms refers to water-based slurry of non-plastic injection molding.
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