Each item can only get a specific enchantment. Like armor for expample, can only get HP, and Defense Rate or Defense or somewhere along those lines.
Gloves get hit rate, and Added to attack, or soemthing.
Boots get HP and Defense Rate.
Helm gets critical damage, and something else.
Weapons can get critical damage, and something else as well.
It all depends on your catalyst. Each catalyst has a certain attribute.
You have a slotted helmet. You use a Slotted Great sword as a catalyst. Now you will have a Critical damage enchant added. Depending on how many Cores you use it could be a higher llevel.
My friends played the Korean version, and they will release what catalyst does what, and what Item can have what attribute. Its sorta confusing, I don't know it all myself but some of it.