All types of alloys have the following common features:
(1) The melting point of most alloys is lower than the melting point of any one of its constituent metals;
(2) The hardness is generally greater than the hardness of any metal in its component; (Special case: sodium potassium alloy is liquid and used as a heat transfer agent in atomic reactors)
(3) The electrical and thermal conductivity of the alloy is lower than that of any component metal. Using this characteristic of the alloy, high resistance and high thermal resistance materials can be manufactured. Materials with special properties can also be manufactured.
(4) Some have strong corrosion resistance (such as stainless steel). For example, 15% chromium and 9% nickel are added to iron to obtain a corrosion-resistant stainless steel, which is suitable for the chemical industry.