The slow process of decay or oxidation or metal due to the effect of air, moisture and acids on it is known as corrosion.
(1) Gold is a noble metal. There is no effect or moist air or action of acid on it at any temperature.
(2) Pure gold is a very soft metal. it breaks and gets bent easily. Hence, in gold ornaments, gold is alloyed with other metals 1ike copper or silver in appropriate proportion to make it hard and resistant to corrosion. Hence gold ornaments do not get corroded.