The Ruling on Writing on Graves
Question:
Is it permissible to place a metal strip or an inscription on the grave of a dead person containing Qur'anic Verses, plus the name of the dead person, the date of death etc.?
Answer:
It is not permissible to write on the grave, neither Qur'anic Verses, nor anything else, whether in metal or on a sign or on anything else. This is because of what has been authentically reported from the Prophet in the Hadith of Jabir, may Allah be pleased with him, that he forbade plastering over the graves, sitting on them and building over them. This was narrated by Muslim and At-Tirmithi, and An-Nasa'i added with an authentic chain of narrators: "and writing on them."
Source:
Fatawa Islamiyah, Vol. 1 Pages 182-183