Title

SEÇÃO ISOTÉRMICA DO SISTEMA CO-SI-B A 1000

ISOTHERMAL SECTION OF CO-SI-B SYSTEM AT 1000

Authorship

Faria, Maria Ismênia Sodero Toledo; Coelho, Gilberto Carvalho; Nunes, Carlos Ângelo; Avillez, Roberto Ribeiro de

Faria, Maria Ismênia Sodero Toledo

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Coelho, Gilberto Carvalho

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Nunes, Carlos Ângelo

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Avillez, Roberto Ribeiro de

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DOI

10.5151/2594-5327-0158

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Abstract

Este trabalho apresenta a seção isotérmica do sistema Co-Si-B a 1000

In this work the isothermal section of the Co-Si-B system in the Co-rich region has been established based on microstructural characterization of ar-melted and heat treated alloys through X-rays diffraction (XRD) and scanning electron microscopy (SEM). The alloys of different compositions were prepared by arc melting Co (min. 99.97%), Si (min.99.99%) and B (min. 99.5%) under argon atmosphere in water- cooled copper crucible with nonconsumable tungsten electrode and titanium getter. All alloys were heat-treated at 1000°C for 240h. The principal results are: (i) six three-phase equilibria were observed; (ii) the ternary compound (61%at. Co, 15%at. B e 23%at. Si) was observed.; (iii) the EDX results have indicated low solubility of B in silicates and the low solubility of Si in borides; (iv) the EDX results have indicated high solubility of Si in Coss (

Keywords

Sistema Co-Si-B; Diagrama de fases; Seção isotérmica.

Co-Si-B system; Phase diagram.