I am being garnished for student loans, can they garnish my tax refund and how do I find
Out if they have a garnishment against my tax refund

Yes, your tax refund will be garnished.
Read Your U.S. Tax Return: When will I get my tax refund? (http://taxipay.blogspot.com/2009/01/when-will-i-get-my-tax-refund.html)

You can get the details of the garnishment by contacting the IRS.

Also, expect them to also garnish any STATE tax refund as well.

They almost always get the tax refunds so yes they can,

You can call the Treasury offset line and it will tell you if your SS# is on record for offset, You can only check for yourself (It is illegal to check someone else's SS#). The number is 800-304-3107