dermatology - DermaAmin

6 Michels
iron, and, in some versions, nickel. Aluminum imparts both strength and
oxidization resistance by virtue of the formation of alumina (Al2O3)-rich
protective films. These alloy are very wear resistant, and exhibit good casting
and welding characteristics. Their corrosion resistance is superior in
seawater, chloride, and in dilute acids. Applications are varied and include
propellers and valves, pickling hooks, pickling baskets, and wear rings. Aluminum
bronzes and especially nickel–aluminum bronzes are desirable alloys
for fluid moving applications such as pump impellers, because of superior
erosion-corrosion and cavitation resistance.
Copper Nickels
The copper–nickel alloys (wrought: C70000–C73499, and cast: C96000–
C96999) are simple solid solutions of nickel in copper. Nickel content varies
from 9% to 33%. A small amount of manganese (0.05–1.5%) and iron
(0.4–1.8%) is present. Their excellent corrosion resistance in seawater, combined
with their high strengths and good fabricability, accounts for their
wide use in piping, heat exchangers, valves, ship tail-shaft sleeves, and other
marine applications. They are also used in coins.
Nickel Silvers
Nickel silver alloys (wrought: C73500–C79999, and cast: C97000–C97999)
contain nickel (11–27%) and zinc (1–25%). The presence of nickel primarily
accounts for their pleasant silver luster but, in contrast to their name, the
nickel silvers do not contain silver. In spite of their high degree of alloying,
the nickel silvers are simple solid solution alloys. They offer good corrosion
resistance, ease of castability, and good machinability. Major uses include
hardware for food processing, seals, architectural trim, musical instrument
valves, and door keys.
Other Copper Alloys
In the interest of completeness, two other types of copper alloys, which are
both cast alloys, should be mentioned. They are the leaded coppers
(C89000–C98000), which are typically employed where their high lead provides
lubricity, and the special alloys (C99000–C99999), which have unique
specific properties needed for specialized applications.
CONCLUSIONS
The copper alloys offer a wide range of properties to meet the needs of many
applications that humans touch. The list is almost endless. End-use applications
are limited only by the knowledge, creativity, and imagination of those
who specify, design, produce, and process these copper alloy products.