Can I let my friend borrow my iPad?

Yes, any one device can only change the AppleID associated with it once every 90 days. So your friend would be okay setting up your erased and disassociated device. But you would have to wait 90 days from that before you could set it up again with your AppleID

View and remove your associated devices in iTunes - Apple Support

Not as far as I'm familiar with. What they may be referring to is signing into a single device with multiple IDs in a way that you would share content...as in take Pam's iPad, sign into the app store with Alan's ID to download content then go back to Pam's ID while never wiping the device.

I would think if you remove it from your iCloud, restore it to factory defaults, load it to your friend then have her do the same it would seem like you'd be OK. It's honestly never a situation I've run across. I must say, you seem to trust your friend a lot with a very expensive device. Because once it's wiped and she sets it up as hers, in the eyes of Apple, it's no longer yours, you'd lose all control over the device.

So I was wrong, ignore my post.

No, that 90 day limitation only applies if you download past purchases to a device and then try to switch the Apple ID back to the originating one without wiping the device first.

Once wiped, the previous association is no longer active, and you can associate the original Apple ID to it again.

Basically, the 90 day limit only applies as long as you do not restore the device. Once restored, it is no longer a factor, as all previous associations have been removed from the device by restoring it. And nothing will stop you from using another Apple ID on it.