Si - METAL COMPOSITES STRENGTHENING MECHANISM.

Metal matrix composite materials have wide and various applications in modern industry. Some of them require the deposition of a ceramic coating. This paper reports a new approach to formation of surface metal composites based on silicon carbide using an overlaying technology. The latter is based on the application of an arc which is formed between the metal surface acting as an anode and C-welding rod acting as a cathode. When the arc is started the cathode is heated and releases a stream of electrons of a temperature of ca 4000 K bombarding the anode. Partial melting of the surface layer and formation of a coating of silicon carbide is achieved by adjusting the advance distance between the surface and the electrode as well as the current applied. The metal melt covers the reinforcing phase particles and a solid structure is obtained. The realization of the carbothermal reduction requires the deposition of a coating of a silicon dioxide on the metal surface. Its location and size, as well as the border between carbide layer and the metal surface are determined by microscopic analysis. [ABSTRACT FROM AUTHOR]