Not all folding knives have a rust-resistant coating on their blades, but many manufacturers offer models with blades that have some form of rust protection. Common rust-resistant coatings include stainless steel, titanium nitride (TiN), DLC (Diamond-Like Carbon), or ceramic coatings. These coatings help prevent or minimize corrosion and rusting by creating a barrier between the blade and moisture or other corrosive elements. When purchasing a folding knife, its advisable to check the product specifications or inquire with the manufacturer to confirm if the blade has a rust-resistant coating.