مرکز منطقه ای اطلاع رساني علوم و فناوري - Synthesis of Co-based Metallic Glass Coatings by Pneumatic Squeezing Method

Abstract :

Metallic glasses have superior properties such as high strength, hardness and corrosion resistance. However, the production cost of the metallic glasses is very high due to the difficulties in manufacturing and constituents used in high purity. As an alternative to this limitation, if the metallic glass alloys will be considered in the composite material as a surface coating element, it may be provide solutions to the cost problems. When the production of a coating having amorphous structure was considered, a coating system which satisfies rapid cooling capability and also transmits the coating material to the surface of the substrate, is needed. In this study, pneumatic-assisted squeezing apparatus which could be used for coating the small parts was designed. By this way, it was simultaneously provided that the liquid form of an alloy could be cooled rapidly and squeeze to the substrate surface with an impact effect. In this context, amorphous coatings having a composition of Co43Cu1Fe20Ta5,5B26,5Si5 with thicknesses of 20-80 μm, was produced on the surface of different metal substrates. Structural and thermal characteristics of the coating layers were evaluated by XRD, SEM and DSC analysis. Microstructural analysis showed that relatively thicker substrates used were beneficial to obtain fully amorphous coating layer, while thinner substrates have led to crystallize in a certain amount of coating near the interface. Consequently, metal substrates having relatively low hardness and wear resistance were coated with a Co-based metallic glass by using an alternative method. The hardness of the amorphous coating were measured about 1000 Hv.