Development and Characterization of Functionally Graded Materials by Microwave Heating

Abstract

Stainless steel plays a vital role in almost every manufacturing industry worldwide. Austenitic stainless steel represents more than 2/3rd of the total stainless steel world production. Austenitic stainless steels are widely used in many applications due to their excellent corrosion and oxidation resistance. However, this grade of steels has poor wear resistance properties under severe wear working environment and hence causes huge economical loss to the developing countries. The functional properties of these steels can be improved by overlaying the coatings/claddings of wear resistant materials. However, these claddings/coatings generally fail due to the existence of sharp interface. The functionally graded material (FGM) claddings eliminate this problem by replacing the sharp interface with the transition interface. The FGM claddings can be processed through various techniques like powder metallurgy, vapor deposition, centrifugal method, laser cladding etc. However, these techniques are associated with some limitations such as lower deposition efficiency, higher cost (in case of laser cladding), production of toxic gases, higher processing time (in case of vapor deposition technique). The development of alternating material processing technique with lower manufacturing cost, lower processing time and environmental friendliness is the need of the hour. Microwave processing of materials has emerged as a noble processing technique in the past few years. The heating effects of microwave energy were discovered in the mid of year 90 s and with the discovery of microwave oven, the microwaves were successfully utilized in the cooking of food. Due to lower processing time and better efficiency, the utilization of domestic microwave oven spread throughout the world during 1980-1990. At the same time, the commercial applications were discovered such as vulcanization of rubber, wood drying, chemical processing, etc. With the continuous efforts of researchers, the microwave applications were used in the field of sintering