Investigation of Techniques for the Preparation of High-Temperature Alloys Capable of Forming Protective Silica Scales. Final Report

摘要

A series of melting and casting techniques and powder metallurgical techniques was attempted to produce iron- and nickel-based alloys containing SiC particles. The results indicated that it is technically feasible to introduce nickel-coated SiC particles into the melt, but that the melt must be quickly cast to preserve the dispersoids. Advances in the state of the art of melting and rapid-casting methods are required to achieve good control of the SiC particle distribution. Powder metallurgical techniques provide a viable approach if a simple blending process is used to mix the powders instead of mechanical alloying. The SiC particle distribution can be controlled by choosing alloy powders of required sizes. It appears that if the SiC particles are present along the alloy grain boundaries (achieved by choosing coarse alloy powders), the oxidation resistance is excellent. Alloys containing 5% Cr and 6 to 9 wt% SiC particles have oxidation resistance comparable to that of 304 stainless steel. (ERA citation 07:004663)