Braze for silicon carbide bodies
AssigneeGeneral Atomics
InventorsFrederick C. Montgomery, Holger H. Streckert
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Abstract
Dense monolithic SiC or SiC ceramic composites are strongly bonded using brazing compositions which, in their preferred composition, include a braze alloy consisting essentially of less than 50 weight percent silicon and at least two metals from the group of Fe, Cr, Co and V and produce a joint suitable for use in a high neutron flux environment. Brazing is carried out at a temperature of about 1200.degree. to 1500.degree. C. in an inert atmosphere and is complete in about 15 minutes. Broadly, a genus of brazing compounds are disclosed which include between about 10 and about 45 weight percent silicon and at least two elements selected from the following group: Li, Be, B, Na, Mg, P, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, Ga, Ge, As, Rb, Y, Sb, Te, Cs, Pr, Nd, Ta, W and Tl.
Claims19
A brazing composition for use in the high temperature joinder of silicon carbide materials, which composition has a melting point of 1200.degree. C. or above and consists essentially of an alloy of at least about 10 weight percent of a metal selected from the group consisting of Cr, Fe and V, Si in an amount of at least about 17 weight percent and not more than about 45 weight percent, and Co in an amount of at least about 30 weight percent.
A brazing composition consisting essentially of Si in an amount between about 17 and about 20 weight percent, Fe in an amount between about 17 and 20 weight percent, and the remainder being either Cr or Co in an amount of at least about 60 weight percent.
A method for high temperature reaction brazing of silicon carbide bodies, which method comprises depositing on at least one of said silicon carbide bodies a braze composition consisting essentially of Si and at least two metals selected from the group consisting of Fe, Cr, Co and V,
- one metal of said at least two metals constituting at least about 10 weight % and another metal of said at least two metals constituting at least about 30 weight %,
- Si constituting at least about 10 weight % but less than 50 weight % so that said at least two metals constitute a greater weight percent of said braze composition than Si, and
- pressing said bodies together and heating to a reaction temperature.
A method for high temperature reaction brazing of silicon carbide bodies, which method comprises depositing on at least one of said silicon carbide bodies a braze composition consisting essentially of Si and at least two metals selected from the group Consisting of Fe, Cr, Co and V,
- with said at least two metals constituting a greater weight percent of said braze composition than Si, with Si being present in said braze composition in an amount between about 20 and about 45 weight %, and with Co being present in said braze composition in an amount between about 30 and about 65 weight %, and
- pressing said bodies together and heating to a reaction temperature.
A method for high temperature reaction brazing of silicon carbide bodies, which method comprises depositing on at least one of said silicon carbide bodies a braze composition consisting essentially of Si and at least two elements selected from the group consisting of Li, Be, B, Na, Mg, P, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, Ga, Ge, As, Rb, Y, Sb, Te, Cs, Pr, Nd, Ta, W and Tl said Si constituting between about 10 and about 45 weight % thereof,
- one element of said at least two elements constituting at least about 10 weight % and another element of said at least two elements constituting at least about 30 weight %,
- pressing said bodies together and heating to a reaction temperature of 1200.degree. C. or above.
Dependencies are inferred from the claim text.