Composite powder contg. two complex alloys - used to provide coatings resisting abrasion, oxidn. and corrosion at high temps.

摘要

The powder consists of two alloys (I,II), where alloy (I) contains by wt. 0.5-5% C, 2-15% W, 25-55% Cr, 0.5-3.5% B, 1-5% Si, 1-5% Fe, rest Ni. Alloy (II) is a Ni-Cr-B-Si material, in which all or part of the Ni may be replaced by Co, and in which 2-15% W may also be present. In alloy (I), the % C pref. equals C1 + C2 + 0.2; and the % W= 36(C1); whereas the % Cr=17+9(C2)-4(C), esp. using % Cr=25+9(C2)- 4(C). The value (C1) is the % C necessary to form carbides with the refractory metals W, Mo; whereas (C2) is the % C forming chromium carbide; 0.2 is the solubility limit of C in Ni-Cr solid solns.; and (C) is the total % carbon. Used for coatings providing resistance to wear, oxidn., and/or corrosion, and applied by flame- or plasma-spraying; welding; explosion coating; melting; or coating the bore of tubes during centrifugal casting of the latter. The powder may also be used to make sintered parts.