Building a magnetizer
Hello Marcelo Bonifazio,

I don't think you will need to change some features of the circuit just because of 1N4004 diode. If you observe the schematic asks for 1n4002 or 1N4007 diode without changing the circuit. What do you deduce from it? Any value between these range should be good to go, unless you change anything other than this which is not likely. I noticed that you some how plan to use the 9 volt battery instead of the AC power. If that is the case then it will not work unless you convert the battery into AC or rapidly switch it on and off. The reason for this is because transformer only works on AC power supply. Also the circuit will be a little too powerful for the 9v battery to handle. I might be wrong since I made a few assumptions, you may not be planning to use the 9v battery.

Good Luck!