Microwave heating is a process whereby microwaves couple to materials, which absorb the electromagnetic energy volumetrically and transform it into heat. This differs from conventional methods in which heat is transferred between objects through the mechanisms of conduction, radiation and convection. As the material itself generates the heat, the heating is more volumetric and can be very rapid and selective. When applied to Ceramic materials, microwave processing opens up opportunities to reduce costs and energy consumption while improving productivity and material properties. Thus, microwave sintering techniques allows for the application of high heating rates, markedly shortening the processing time.
The possibility of processing ceramics by microwave heating was discussed over 50 years ago by Von Hippel. Since then, the results of many investigations into microwave sintering and joining of ceramics have been reported. Activity in this field began to accelerate in the late 1970s and 1980s. While most of today’s industrial microwave applications involve the relatively low temperature processing of food, wood, rubber, polymers, etc., interest in high-temperature microwave processing of materials has been growing. In recent years, microwave heating has been widely employed in the sintering and joining of ceramics. In microwave heating, a polar molecule is exposed to electromagnetic radiation at a frequency that is in the microwave range (0.3 GHz to 300 GHz). This exposure to microwave energy causes rotation in the polar molecule, which causes friction resulting in heat being generated. This phenomenon is also referred to as dielectric heating. As the heat is generated within the material and then travels to the outer surface, it saves quite a considerable processing time while keeping the surrounding temperature least affected.
Ceramic products are produced after passing through a tedious process, that being –
- Raw material slurry
- Spray Drying
Microwave radiation comes in use in the last step of the process that is “sintering” which in layman’s language means heating the material so the ceramic particles stick together for better strength & longevity. Sintering is used in the manufacture of pottery and other ceramic objects. These objects are made from substances such as glass, alumina, zirconia, silica, magnesia, lime, beryllium oxide, and ferric oxide.
Advantages of Microwave Radiation in ceramic sintering:
- Uniform heating
- Increases Process speed
- Acceptable chemical and physical effects
- Selective/Volumetric heating
- No fumes and pollutants
- Improves reproducibility
- Reduce wastage of heat
The microwave fast sintering appears as an alternative for the sintering and densification of ceramics with suppressed grain growth. By the reference of various researches, it is confirmed that microwave hybrid fast sintering can be employed successfully to sinter low and high dielectric loss ceramics, producing highly dense ceramics and suppressing grain growth in the final stages of sintering. Successful microwave fast sintering depends on the strict control of sintering conditions, striking an adequate balance between power and time or temperature and time to obtain highly dense and homogeneous microstructures.
In fact, the real benefit of microwave processing has less to do with the direct coupling of microwave energy to the part, and more to do with the flexibility afforded to the equipment designer.
Why choose us?
Since the last 42 years, KERONE has been designing, manufacturing and installing machinery, power sourced by microwave, infrared, radio frequency and convection radiation for all types of industries including Ceramics. Accuracy, efficiency, machine quality and output quality are not just words but KERONE’s lifetime commitment towards our profession since its inception, creating a base of more than 1000 loyal customers. Our microwave heating systems are used to meet the varying demands of numerous industrial applications – all with a level of precision that manufacturers seek. Fulfilling demands as per client’s specification has been our USP and we strive to carry the same forward. We also provide detailed assistance for installation without much hassle of complex functioning of the machinery. We always strive to achieve more than client satisfaction with our timely delivery, quality and efficiency towards every oven manufactured by us.