Can I use my iPad to unlock my iPhone

No.

If it is disabled due to passcode lock, you will need to use a computer. See: If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

I recommend that you ask a friend or a family member to use their computer. If you do not have those options available then perhaps check with the Apple Store or an Authorized Service Center and see whether they can help you out.

Axel F.

I doubt it. For one thing, I don't think they would have iTunes installed on their computers (assuming they don't have Macs) and don't think they would allow you to install it.