Abstract: Novel poly(imide-siloxane) block copolymers and a process for their preparation are disclosed. The process of this invention involves reacting a hydroxy-terminated polyimide oligomer with a siloxane oligomer, which has reactive end groups capable of displacement by reaction with the hydroxyl groups of the hydroxy-terminated polyimide oligomer.

Abstract: Cobalt-base superalloys having special utility in the production of industrial gas turbine hot gas path components because of their unique combination of properties in specially heat-treated condition including excellent hot corrosion resistance, stress-rupture strength at high temperature, metallurgical stability, tensile ductility and weldability, consist essentially of 0.3 to 0.6% carbon, 27-35% chromium, 9-16% nickel, 6-9% tungsten, 0.45 to 2.0% tantalum, up to 3.0% hafnium, up to 0.7% zirconium, not more than 2.0% iron, 1.5% manganese and silicon and 0.