Investment cast super-alloys may require surfaces with specially controlled grain sizing. The most common means of obtaining these critical grain domains on the surface is by incorporating nucleating compounds in the prime dip coat. The following lists the most commonly used nucleating compounds.
Cobalt Aluminate 6330 Co 39-41.5%
Cobalt Aluminate K-4704 Co 30.5-33%
Cobalt Aluminate 6370 Co 38.5-41%
Cobalt Meta-Silicate K-4538 Co 40.5-44%
The materials above have helped in the manufacture of engineering components for major aerospace, automotive and medical equipment suppliers throughout the world. Other foundries, including grey-iron (sand molds) occasionally paint the molds at points of stress with a slurry of a nucleating compound such as cobalt-aluminate. It is reported that this tends to reduce cracking. Proprietary compounds will be prepared upon request for both experimental testing and in commercial quantities.