Obtenção de uma junta brasada cerâmica-cerâmica usando uma fita de metal solidificado rapidamente entre superfícies metalizadas por plasma.

Abstract

Thin films of Ti using the deposition technique by hollow cathode, were produced under Al2O3 surface aiming at obtaining ceramic-ceramic indirect brazing. Metallizing surfaces of excellent uniformity were obtained, and it is also possible to vary the thickness of the films by controlling the plasma parameters. Indirect brazing was done by using rapidly solidified brazing filler ribbons. Alloys of Cu51-XAg45Cex composition were prepared in arc furnace, and, afterwards processed in meltspinning, by varying the containing from 4-6 at. % Ce. The Brazing was accomplished in vacuum furnace and the following variables analyzed: deposition time of the Ti film, brazing temperature and time; and it were related to the 3-point bending resistance. The linear regression equation was obtained, and it was verified that in this process there was interaction between the deposition time and brazing temperature, and the interaction among these factors: deposition time, brazing temperature and time. Besides, through simulations, it was verified the inverse relationship between deposition time and the brazing temperature on the joint resistance. The joints presented satisfactory values of 3-point bending resistance reaching values up to 176,8 MPa. The influences of the Ti and of Ce on the formation of the union was evaluated, and the results induced the possibility of the Ce has acted as an active metal, by helping the formation of the joint, also figuring in possible intermetallic phases with Ti.