Tin added to copper is known as bronze and is stronger and harder than either of the pure metals. The same is true when zinc is added to copper to form brass. Tin is more effective in strengthening copper than zinc, but is also more expensive and has a greater detrimental effect on the electrical and thermal conductivities than zinc. Another copper strengthening method is precipitation hardening. This process is often used for copper alloys containing beryllium, chromium, nickel, or zirconium.
Precipitation hardening offers distinct advantages.
Fabrication is relatively easy using the soft solution-annealed form of the quenched metal. The aging process can be performed using relatively inexpensive and unsophisticated furnaces. Often the heat treatment can be performed in air, at moderate furnace temperatures, and with little or no controlled cooling. The best way to increase the electrical and thermal conductivity of copper is to increase the purity level. The existence of impurities and all alloying elements, except for silver, will decrease the electrical and thermal conductivity of copper.