Present Status of Structural Ceramics in Thailand Thailand has enjoyed 'comparative advantage' from rich natural resources, cheap labour, strategic location and so on. The export value of ceramic products, mostly traditional ceramics is more than five times their import value every year (Table 1). Although Thai ceramic technology was historically established over 3,000 years ago, the main products to date still based on household applications e.g., tableware, sanitary ware, tiles, souvenirs etc. These are mainly clay-based and fired at temperature no higher than 1300oC. Most of the producers are small- to medium- sized industries (SMIs). Nonetheless, they have accumulated ceramic production expertise for generations, and Thai workers are notable in their manual skill, possessing high potential for product and technology development. Table 1. Import-export data on ceramics for Thailand in 2001 and 2002 [1]. | | | 69 | Ceramic products | 4,709 | 20,052 | 5,231 | 20,363 | | 82 | Machine tools | 18,065 | 2,763 | 17,828 | 3,139 | | 84 | Machinery | 446,025 | 497,295 | 444,400 | 472,048 | However, more and more strategic global production base has moved to Thailand, especially the automotive and electronic sectors. These industries require local support for raw materials, supporting parts, spare parts, and services. For instance, industrial machinery needs interchangeable machine tools and Thailand has to improve these parts at significant cost. Structural ceramic products are among the key parts used in these supporting industries. Their excellent wear-resistant, high temperature capability, high strength and chemical inertness are critical properties required by many industries, ranging from basic industries- i.e. glass, cement and construction industries, to those in the leading edge- i.e. automotive, electronics, and telecommunications etc. This situation provides excellent opportunities to promote the development of basic industries and linkages with related supporting industries. Figure 1 exhibits statistical data2 for the last decade, showing that Thailand imports industrial ceramics costing more than 5,500 million Baht a year (Figure 1), which is more than five times the export figure. However, this import figure does not include ceramic parts already fitted in machines and equipment which is imported at a cost of more than 400,000 million Baht a year. | 
| | Figure 1. Trend of (a) export and (b) import value of industrial ceramics for 1989-1999 [2]. | Main Hindrances Technology Gap Previously, technology sources for the ceramic industry in Thailand can be divided into three types; i.e. local experience, imported turnkey machines and multinational companies. Technology transfer from experience is widespread in small- to medium-sized factories. However, because of limitations in funding and personnel, technology from experience has yielded only modest improvement. Secondly, very popular among medium- to large-sized industry is technology transfer by turnkey imported machines. Although very convenient to start production, in the long run turnkey machines inevitably lead to high-level technology dependence and costly import of machine know-how. Generally, Thai technical staff could proceed, maintain and adjust production plans without assistance from technology owners. Some industry could replace original parts with local ones. However, most of the industries struggles maintain product quality to specifications, not to mention quality improvement. Finally, some 'advanced' technology could be transferred to Thailand via geographical movement of multinational companies. This know-how is hardly ingrained locally because it moves with the factories from one country to another. Therefore, the overall technological capability of Thai ceramic industry has been improved at an unsatisfactorily slow rate. Broadly speaking, the size of the conventional ceramic household sector has stayed rather constant but its competitiveness has seriously decreased. Awareness-Demand Gap Although markets for industrial ceramics have grown at an accelerated rate, many Thai industrialists (not restricted to the ceramic sector) who are very interested in production of the 'more' advanced industrial ceramics, could not adjust their production process readily, especially for the SMIs. The main hindrances are not only that the downstream users are ignorant of ceramic parts and the producers have limited technology and funding, but also unfamiliarity with industrial markets. These hindrances arise from a few causes as followed: • Ceramic industrialists focus on household products and are not familiar with the manufacturing market. The investment and marketing of industrial products are perceived as too high a risk. • Rather high investment for machine and equipment replacement is needed. Especially, kilns and furnaces require high temperature capability and other machines also require significantly higher specifications than those used for clay-based ceramics. • SMIs who are familiar with industrial markets have limited access to target technology and can not afford to do research and development by themselves. Structural Ceramics R&D in MTEC In order to respond to needs from industry, the NSTDA (National Science and Technology Development Agency) mission was designated to raise the technological capabilities of Thai productive sectors. MTEC, as an organisation under NSTDA, has as its main goals to collaborate with target industry by identifying target R&D that is apparent and concrete. Current research in the Structural Ceramics program (Table 2) has been performed to realise these goals and can be divided into four groups as follows: raw materials synthesis, processing technology, development for target applications, and evaluation testing techniques. Firstly, raw materials synthesis covers a wide range of basic research from carbothermic reduction of silicon carbide from rice husk, glass ceramics from zinc waste, SiO2-TiO2-ZrO2 sol-gel, and Al2O3-TiC microwave-induced combustion synthesis. Secondly, processing technology seems to be more relevant to industrial needs. However, since there are limitations in the equipment available, current projects are focused on relatively ‘advanced’ technology in Thai industry; i.e. pressure casting, die pressing, extrusion, pressureless sintering, and reaction bonding. Thirdly, the development of target applications is aimed at medium term (2-3 years) utilisation to support strategic alliances in up-grading the activity or business. The projects include alumina industrial parts, seal faces for industrial pumps, and hard enamel for agricultural parts. Finally, the evaluation and testing projects focus on the main function of structural ceramics as wear-resistant parts. A patent-pending slurry-jet erosion tester was invented [3] and an improved version ‘high temperature erosion tester’ is being developed. Table 2. Structural Ceramics Program | | | 1. Material Technology | | | | | | 1.1 Raw material synthesis technology | Microwave synthesis | Dr. Duangduen Atong | | Microwave-induced combustion synthesis of Al2O3-TiC for cutting tools application | | | Glass-ceramics | Dr. Parjaree Thavorniti | Mat.Sci./CU | Conversion of zinc hydro-metallurgical waste to glass-ceramics | | | Sol-gel | Dr. Anucha Wannagon | | Sol-gel synthesis of amorphous SiO2-TiO2-ZrO2 | | | Carbothermic reduction | Dr. Pakamard Saewong | | Development of SiC products from rice husk: Phase I | | 1.2 Processing technology | Reaction-sintering | Dr. Kuljira Sujirote | Metallurgy/CU | Reaction-bonding silicon nitride for nozzle application | | | Pressureless sintering | Dr. Kuljira Sujirote | Mat.Sci./CU | Development of low cost Si3N4 ceramics | | | Die pressing | Dr. Pakamard Saewong | Ceraparts group | Dimensional shrinkage of geometrical morphology | | | Pressure casting | Dr. Anucha Wannagon | SAL | Ceramic pressure casting prototype construction | | | Extrusion | Dr. Pavadee Aungkavattana | Petrochemical college/CU, Private sector, USA | Development of ceramic membrane for micro- and ultra-filtration, and zeolite membrane for ethanol separation | | 3. Application | Agriculture | Dr. Paisan Setasuwon | | Hard enamel for agricultural wear parts | | | Supporting industry | Dr. Kuljira Sujirote | Ceraparts group | Pilot scale production of complex-shaped alumina products | | | Industrial pumps | Dr. Kuljira Sujirote | Ceraparts group | Development of Si-SiC seal face | | | Fuel cell | Dr. Anucha Wannagon | Fuel cell group | Development of glass seal for fuel cell | | 4. Evaluation & testing | Wear | Dr. Pakamard Saewong | | High temperature erosion testing | Ceraparts Group Ceraparts Group was founded in 2003 with its main objectives to link the awareness and technology gaps in the Thai industrial ceramic scenario. Thus immediate tasks are to develop linkages with target industries in order to develop awareness and availability of target products. Based on a technical survey of structural ceramics in Thailand [2], alumina of various grades is in present demand in Thai industry. For instance, parts for tribological application are needed as seal rings, valves, liners, thread guides, extrusion nozzles, etc. Parts for electrical and electronic applications are used as surge divertors, insulators for telecommunication systems, and so on. Currently, a wide range of relevant services including technical workshop, product design, prototype making and pilot scale production are being established. Long term development of target technology with high potential to respond to existing and near-future needs is in its development stage. Two directions considered to be meaningful to the Thai predicament are development of wear-resistant silicon carbide materials from local or abundant raw materials; i.e. rice husk, and development of high-precision fabrication technology. These two aspects should ultimately complement each other and give rise to sustainable competitiveness of new industry. These technologies require not only much more in-depth analysis of the actual requirements of relevant stakeholders but also interdisciplinary comprehension, collaborative effort and apt decision among strategic alliances. Organisations with complementary expertise could develop strategic alliances and discuss how to synergise their tasks. Silicon Carbide Roadmap Silicon carbide activities have been focused on two aspects: silicon carbide formation from rice husks (RH SiC) and the infiltration process for silicon-silicon carbide. RH SiC was successfully produced on a laboratory scale [4, 5]. However, the bulky nature of the husk makes it difficult to handle and yields low productivity. Therefore, one way to overcome these problems will be focused on fabrication from rice husk ash [6]. Various products could be economically produced by taking advantages of highly reactive nature of this ash. In addition, since the resultant product is nanometer in size it exhibits complex reaction kinetics of silicon carbide formation. In-depth analysis of nano-SiC formation and its sinterablility would be crucial for the feasibility of actual exploitation in industry. Collaboration with the Laboratory V.41 Structural ceramic and ceramic components (BAM, Germany) is being developed. Table 3. Tentative Collaboration | | | 1. Near-net-shape technology | Ceraparts Group | KMITT | Birmingham University UK | | 1.1 Die design | Powder Metallurgy | | | | 1.2 Rheology | Polymer Engineering | | | | 2. Nano silicon carbide | Ceraparts Group | | BAM, Germany | Based on collaboration studies on the infiltration process of Si-SiC, seal face prototypes have been fabricated. The material possesses excellent mechanical properties. Other industrial wear-resistant parts or defence application could be developed from similar technology. Additionally, the fabrication process could be improved by developing knowledge on slurry preparation and spray drying of silicon carbide. And if the near-net-shape program is to be established, detailed studies on the extrusion rheology of silicon carbide will have to be carried out. Silicon Nitride Roadmap The Group has been running parallel projects on reaction-bonded silicon nitride (RBSN) in collaboration with the Department of Metallurgy (Chulalongkorn University) for more than 5 years. The objectives are to study the nitridation kinetics [8], to develop expertise on ceramic machining [9], and to produce near-net-shape RBSN products. Because of its remaining porosity, high temperature applications in highly corrosive environments of RBSN tend to be questionable. An investigation on this subject is planned to outline the actual limit of the material. Furthermore, as next step in exploiting the RBSN near-net-shape technology, it is possible to produce composites of superior quality such as Si3N4-SiC. Furthermore, collaboration with the Department of Materials Science at Chulalongkorn University was established a few years ago on the development of low cost silicon nitride ceramics in air. The project leader, Prof. Wada, has long experience in developing silicon nitride technology [10]. His initiatives to overcome the weak points of conventional technologies include low cost Si3N4 raw powder, low cost sintering additives and sintering in air [11]. Further work in this area could be investigation of sintering aids for SiAlON formation or integrating this knowledge with near-net-shape processing. Near-Net-Shape Processing Roadmap Recently, Ceraparts Group has initiated collaboration with internal research programs; namely plastic engineering and powder metallurgy. The concept is still at its pre-commencement stage. However, it is expected that a near-net-shape program will be established in MTEC with three technology groups; viz. extrusion, injection moulding, and investment casting. Currently, tentative collaboration with King Mongkut’s Institute of Technology Thonburi (KMITT) and with the Interdisciplinary Research Centre (IRC) in materials processing (UK) has been approached. More collaboration with external organisations is being sought. Summary / Future outlook MTEC’s Structural ceramics program performs a wide range of research and development, which could be divided into four groups: raw materials synthesis, processing technology, application, and evaluation & testing. Within the program, Ceraparts Group has been established to respond to the Thai awareness- and technology-gap in the structural ceramics industry. The short-term mission of the Group is to develop awareness of the products among both Thai ceramic producers and industrial users. The long term mission, being developed simultaneously, is to develop linkage in two directions. One is to improve materials exhibiting imminent future need, and accordingly roadmaps for R&D on silicon carbide and silicon nitride are proposed. Another aims at establishing a near-net-shape program in collaboration with internal programs (plastic engineering and powder metallurgy) and with other organisations with complementary expertise. Acknowledgements Assistance from staff of Ceraparts Group; Dr. Pakamard Saewong, Dr. Duangduen Atong, MS. Kannikar Dateraksa, MS. Rapeepan Rahong, Mr. Kritdipak Goyadoolya, Mr. Praman Tripopklang, and Mr. Thanawat Piyadamrong, is kindly acknowledged. References 1. Statistics from www.customs.go.th 2. P. Seawong, J. Leudtaharn and K. Sujirote “Technical Survey of Structural Ceramics Collaboration”, Internal report, National Metal & Materials Technology Center, Thailand (2000) 3. P. Saewong, “Slurry Jet Erosion Tester,” Silver medal award, 31st International Exhibition of Inventions of Geneva, New Technique Products, April 2003. 4. K. Sujirote, P. Leangsuwan and P. Saewong, "SiC Synthesis from Rice Husk," in K. Hilpert, F.W. Froben and L. Singheiser (eds.) Proceedings of the10th IUPAC conference on High Temperature Materials Chemistry, Forschungszentrums Juelich, Germany, p.168-172 (2000) 5. K. Sujirote and P. Leangsuwan, "SiC Formation from Pretreated Rice Husks", to-be-published in J. Mater. Sci. 6. P. Saewong private communication, 2003. 7. K. Tantikom, K. Sujirote and S. Danchaivijit, “Machinability of Heat Treated Silicon Powder Compacts”, J. of the Metals, Materials and Minerals, 11 [2] (2002) 1-7. 8. S. Wada, “Control of instability of Si3N4 during Pressureless Sintering”, J. Cer. Soc. Japan, 109 [10] (2001) 803-808. 9. S. Wada, T. Hattori and K. Yokohama,”Sintering of Si3N4 Ceramics in Air Atmosphere Furnace,” J. Cer. Soc. Japan, 109 [11] (2001) 281-83. 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