Carbonization is the name of a change: something is heated with little or no air, so it does not burn away to ordinary ash. The other parts leave, and what remains is mostly carbon. Wood treated this way becomes charcoal. Food that has gone far past brown into black has started down a similar road, though a cook will usually say burnt or charred, not carbonization. This word is a noun — the process, the event, the change itself. The ‘do it’ word is carbonize; the ‘already like that’ word is carbonized. You will meet carbonization in chemistry, materials, and sometimes archaeology (old wood or bone that has slowly turned toward carbon). Though actually, it is easy to hear it as carbonation, which is a completely different thing: putting fizz into a drink. One is heat and black carbon; the other is bubbles. British spelling sometimes uses carbonisation with an s; same word.

碳化（指這個過程；不是飲料加氣）