The aluminum-bearing (5-12% of aluminum) alloys retain high strength, good corrosion resistance and good oxidation resistance at temperatures up to 400°C. The aluminum manganese bronzes are noted for high strength and good corrosion resistance at temperatures on the order of 400°C. These bronzes are available only as castings. They have good machining qualities combined with easy welding. With regard to corrosion resistance they appear to behave at least as well as the true bronzes.
Silicon Bronzes
Containing up to 3% silicon, silicon bronzes are characterized by high mechanical and antifriction properties. They are made in all wrought forms,such as plates, sheets and castings. The silicon bronzes are well molded, cold- and hot-pressure shaped (rollings, forging, stamping, etc.) and welded.
These alloys have corrosion resistance similar to that of copper, with mechanical properties equivalent to mild steel. Because silicon bronzes do not generate sparks under shocks, they can be used in the fabrication of explosion-proof equipment. Compared to tin bronzes, the tinless bronzes have a higher shrinkage (1.7-2.5% against 1.3-1.5% of tin bronzes) and less fluid-flow, which is an important consideration in designing.
Cupro-nickels
The cupro-nickel alloys (5-30% of nickel) are perhaps the best of all for strength and resistance to corrosion. Table 3.20 gives typical properties.