Ceramic engineering is the science and technology of creating objects from inorganic, non-metallic materials. This is done either by the action of heat, or at lower temperatures using precipitation reactions from high-purity chemical solutions. The term includes the purification of raw materials, the study and production of the chemical compounds concerned, their formation into components and the study of their structure, composition and properties.
Ceramic materials may have a crystalline or partly crystalline structure, with long-range order on atomic scale. Glass ceramics may have an amorphous or glassy structure, with limited or short-range atomic order. They are either formed from a molten mass that solidifies on cooling, formed and matured by the action of heat, or chemically synthesized at low temperatures using, for example, hydrothermal or sol-gel synthesis.
The special character of ceramic materials gives rise to many applications in materials engineering, electrical engineering, chemical engineering and mechanical engineering. As ceramics are heat resistant, they can be used for many tasks for which materials like metal and polymers are unsuitable. Ceramic materials are used in a wide range of industries, including mining, aerospace, medicine, refinery, food and chemical industries, packaging science, electronics, industrial and transmission electricity, and guided lightwave transmission.
CERAMIC ENGINEERING @ IIT (BHU)
The founder of Banaras Hindu University, Pandit Madan Mohan Malviyaji instituted a course in Ceramic Technology as early as 1924 with the noble objective of advancing glass and ceramic technology in India.
In the Year 1956, Department of Glass Technology and Department of Ceramic Technology were merged to form the Department of Silicate Technology, offering a four year degree course by injecting into its curriculum balanced engineering and scientific contents. In the year 1968 the Department was renamed as Department of Ceramic Engineering. Presently this department is unique in the country which offers B.Tech., M.Tech. and Ph.D. Programmes in the areas of Ceramic Engineering and Technology. The Department has so far produced more than 1000 graduates, 100 postgraduates and 30 Ph.Ds.
The Department is pursuing active research in the emerging areas of glass, glass ceramics, refractories, electronic ceramic, cement and pottery & porcelain. Research papers are being published in reputed national and international journals regularly. Considering the important role that the department of Ceramic Engineering has played, the University Grants Commission has granted funds under ‘Special Assistance and COSIST’ Programmes. Many R& D projects have been sponsored by AICTE, DST, CSIR and UGC. The Department celebrated its Platinum Jubilee during 1999 for 75 years of Ceramic education and organized a ‘National Seminar on Challenges of 21st Century’.
The Department of Ceramic Engineering, IIT (BHU) organises its annual departmental festival, Keramos.
Thrust areas of research :
1. Bio-glass and Ceramic Materials
During the last two decades ceramic materials have become widely used in many medical applications, hip prosthesis, cardiac valves and dental implants. Hydroxyapatite (Hap) seems to be the most appropriate ceramic material for artificial teeth or bones due to excellent biocompatibility and bioactivity. Unfortunately, mechanical properties of pure HAp ceramics are poor. Its medical applications are limited to small-unloaded implants, powders, coatings, and low-loaded porous implants. At Present research is in progress for the synthesis of Magnesium and Strontium Substituted Hydroxyapatite by the Chemical route.
These synthesized bioceramic powders are then characterized by various techniques e.g. SEM, XRD, DTA, TGA and FT-IR. Work is also in progress for preparation, crystallization and micro-structural characterization of glasses for biomedical applications.
2. Cement and Advanced Building Materials
Portland cement concrete lands itself to a variety of innovative designs as a result of its many desirable properties. Concrete inherently is brittle and weak in tension. Several methods have been developed to impart ductile behavior. Broadly these can be grouped as mechanical and chemical methods. Reinforcing concrete by steel/fibers are mechanical means to impart ductile behavior and incorporation of polymeric materials form the chemical method of developing the ability of the material of exhibit ductile response.
Portland cement is a complex mixture of inorganic minerals. The organic additives give a significant influence on the hydration and other properties of cement. Besides having physical effects which modify the bond between the particles and therefore the rheology of cementious mixes, some admixture can act on the chemical process of hydration and particularly on the nucleation and growth of new generation products.
The polymer cement composites are useful in construction industry because excellent flexural strength, adhesion properties, water-proofness, carbonation resistance, resistance to chloricle and sulphate attack is observed in the resulting composites. Research work is in progress in the Dept. of Ceramic Engineering for producing corrosives resistant impermeable modified cement mortar and concrete of high durability which can give longer life to the structure and pre cast products. They are also being tested as protective coatings on ancient Indian monuments which are deteriorating fast in the present polluted environment.
3. Electrical and Electronic Ceramics
Valence compensated solid solution systems of the type A1-xAx’B1-xB’xO3 show interesting electrical and dielectric properties. Valence compensated perovskites are formed by substituting the cations at A and B site with heterovalent cations in equivalent amounts to maintain electrical charge neutrality and to reduce the electrical strains in the crystal structure. Over the last many years investigation have been carried for synthesis and characterization of Valence compensated alkaline earth titanates and stannates. These materials were prepared by solid state as well as various chemical methods. Extensive solid solutions form over wide range of compositions. Some of the compositions exhibit very high value of dielectric constant. Impedance and modulus analysis of electrical data for these materials show that the high value of dielectric constant is due to the formation of barrier layers at grain-grain boundary interfaces. Efforts are also being made to prepare and characterize giant dielectric constant materials of the type Ca Cu3Ti4O12. Gas sensing (CH4 and CO) characteristics of alkaline earth titanates are being studied. ZnO varistors are electronic ceramic devices having non linear V-I characteristics and are used to clamp transient voltage surges. Investigations have been carried out to synthesize cobalt and manganese doped varistors in the systems ZnO-BaO and ZnO-TiO2. Since the varistors characteristics depend on electrical characteristics of grains, grain boundaries, complex plane impedance and modulus techniques are utilized to separate their contributions on the overall characteristics of the varistors.
4. Glass and Glass Ceramics
Work is in progress for the development of special coloured glasses, infrared filter glasses suitable for night vision and high density radiation shield glasses. Stains for sheet glasses with copper and silver and heat resistant coating on glasses are being developed. Studies on different micronutrient glasses have been carried out for their suitable application in agriculture for different soil conditions. These micronutrient glasses may be helpful in increasing the yield and quality of major crops like wheat, paddy etc. Valency of redox ions plays an important role in coloration, decolorization, refining and quality of glasses. Spectrometric methods are being developed for determination of different ions in glasses.
Glass ceramics also have a number of diverse applications for electronic devices and circuits, which include microelectronic substrate, packaging, multilayer and barrier layer capacitors etc. Perovskite titanates show many useful properties for various electronic applications. Investigations are being carried out for preparation of glass ceramics with perovskite phases e.g. strontium titanate, lead strontium titanate in pure as well as solid solution form. The dielectric characteristics of the glass ceramics doped with various rare earth and transition metal oxides are also being investigated. Some of the glass ceramic samples show relaxor like behavior with high value of dielectric constant while other show temperature stable dielectric behavior.
5. Pottery, Porcelain and Ceramic Whiteware
Work in progress on the methods of improvement of the quality of earthenware. Development of semi-vitreous china wares, Dental and Art ceramics and chemical porcelain is being done. Studies have been carried out and are still in progress on the development of different types of pottery bodies by using local-red-clay which is available in Varanasi (Water works clay).
Sintering and micro-structural studies of refractory oxides like Al2O3, ZrO2, Mgo, Cr2O3 etc. are carried out to attain the maximum sintered densities and desirable microstructure so that optimum refractory properties are obtained in the end product. The work is also in progress to develop sintered grains of single oxide or binary refractory oxides for the development of refractory castables of desirable preparation.
Facilities of major equipments :
1. Scifert X-Ray Diffraction System
2. Netzsch Simultaneous Thermal Analyser (Microprocessor controlled)
3. Microprocessor Controlled Particle size analyzer.
4. UV-Visible Spectrophotometer
5. Fluorescence Spectrometer (Perkin Elmer)
6. HP LCR Meter
7. HIOKI, LCR Meter
8. Micro hard tester
9. Zeiss Polarising Microscope (Transmission cum Reflection)
10. Optical Microscope
12. 100 Ton capacity Hot Press
13. 100 Ton Compression Testing Machine
14. High Temperature Furnaces
15. High Temperature Furnace with Programmable Controller
16. PCE Furnace
17. Environmental Chamber
18. Vibro Energy Mill
19. Pilot Plant for Pottery and Glassware
20. Annealing-cum-decorating lehr
The department organizes its annual departmental festival Keramos.
Many renowned companies organize campus selection for students of Ceramic Engineering which include Tata Steel, Misys, Kohler, Murguppa, Wipro, Vodafone, Zostel etc. in core and non-core jobs.
– Akasmat Pradhan, Senior Undergraduate, Dept. of Ceramic Engineering