Charlton boss Powell delighted with capture of Man City's Razak
The Ivory Coast international is on a three-month loan at The Valley and is available to play on Tuesday against Watford.
"For a player that's so young obviously you are looking for someone to fit into the pace of things straight away," said Powell.
"We had him watched against Villa and he did very well, and we've had our eye on him for quite a while.
"He went out to Brighton last year and we are hopeful he will bring his qualities and do extremely well for us, because we have lost a few players recently through injury.
"I've wanted to bolster the midfield area and get the numbers in there, as I just felt it was an area that needed looking at. So he's come in and will have to earn the right to play, but hopefully he will do very well for us."