I want to design an inductor working around 2 KHz of 160uH. Going by exprience of you peolple what is the maximum value of Q factor that can be obtained practically?
The Q should be large with a gapped core which reduces core loss. This cannot be gone to extremes as the very large gap requires more wire turns which raises the resistance loss.
Yes, you are right,
because there is a big current, there must be a gap. I think that it is possible to use core with diam. about 26 mm or less, gap about 0.4 mm and Al since 250nH, DC resistance about 1 ohm with wire about 0,7 mm.
There are several other areas to use gapped cores.
One is for large AC signals like in HF transmitters. The currents they produce will saturate not-gapped cores.
Another is precision inductors and high Q inductors.
One assembly trick for all cores is to remove the small flakes of ferrite from the mating surfaces which cause unwanted air gaps. This is done by wiping the mating surfaces on a piece of paper seconds before putting the core halves together.