Shaykh al-islam Ibn Taymiyyah says: “The niyyah for wudhu, ghusl, tayamum, salah, hajj, zakah, redemption and other ‘ibadaat according to the consensus of the scholars is in the heart and not on the tongue. The niyyah by word is a innovation. Something like that hasn’t been reported from the Messenger of Allah s.a.w.s, neither from his companions. Despite that the ummah today is experienced by this awful innovation”.
Ibn Qayyim said: “The Messenger s.a.w.s started his salah with the words “Allahu akbar”. He never said the niyyah loud, neither some of the companions or the imams of the four madhahib”.
There aren’t any correct or uncorrect ahadith about saying the niyyah loud.