Chromium/nickel contents are mentioned almost always together. 18/10 steel means that chromium content is about 18% and nickel about 10%, which is usually the case for T304 steel that is used for almost all the sinks out there on the market. The chromium content controls the lustre, durability and corrosion protection properties of the steel, while the nickel content affects the hardness and strength of the steel.
Note that T304 steel is surgical grade which should last a life time if you do not intentionally subject the steel to harsh chemicals for a prolonged time. That is why most stainless steelsink manufacturers or suppliers can offer at least 15-year warranty if not lifetime warranty. If you know the skill, you can literally restore the freshness and lustre of any stainless steelsink to its original state. That explains why stainless steel sinks are superior to sinks made of other materials, including the increasing popular Silgranite or Moenstone.
Best of all, stainless steel is chemical free and much safer than any other materials that are made with resin. Remember the fact that all stainless steel sinks are made of T304 steel which is surgical grade? If you want to stay away cancer, stay with stainless steel and away from silgranite or acrylic materials.