Black components and manufacturing process thereof

An internal part or movement component for a timepiece of piece of jewellery comprising:

• a substrate including at least one portion coated with a black coat comprising at least one aluminium oxide, the coated portion having in the CIELAB colour system a value of L* less than 12, preferably less than 7, a value of a* between −2 and +2, preferably between −1 and +1, a value of b* between −3.5 and +5, preferably between −3.5 and +1.

A process for manufacturing a component for internal parts of a movement of a timepiece or piece of jewellery, said component including a substrate coated at least partially with a black coat comprising an aluminium oxide, the process comprising:

• a) providing the substrate and machining said substrate, and
• b) adding the black coat to at least a portion of the substrate.