Ferrous metals include iron and any alloy that is iron-based. Examples are iron, steel, cast iron, stainless steel, etc.
Non-ferrous metals are all the rest of the metals and alloys that do NOT contain iron. Examples include copper, brass titanium, aluminum, and many dozens of others.
Alloys are metallic materials that result when a metal is combined with one or more other elements (which may be either metals or non-metals). Common examples are carbon steel (iron plus a small amount of carbon), cast iron (iron with around 4% carbon), brass (copper plus zinc), solder (tin plus lead), bronze (copper plus tin), etc. etc.
Alloys can be simple mixtures, or they can be solid solutions. They may also contain compounds formed from their ingredients. All alloys, however, have metallic properties.’