MICROSTRUCTURE AND THERMAL-EXPANSION BEHAVIOR OF SINTERED FE-NI-CO ALLOYS

Low expansion alloys have been joined to Al2O3 producing nearly stress -free joints. This work investigates tbe use of powder metallurgy to t ailor the coefficient of thermal expansion of Fe-Ni-Co alloys to that of Al2O3 by adjusting the composition of the alloy and the particle si re distribution of the starting powders, The microstructure and therma l expansion behavior of the sintered alloys were characterized. It was possible to sinter an alloy with a coefficient of thermal expansion c loser to that of Al2O3 compared to a similar cost alloy. This alloy co n be used safely as tbe metallic component of brazed ceramic-metal joi nts.