Yes, she can be appointed as judge, but it is makrooh tahrimi, i.e. doing so is near haram. It is mentioned in hadith:
لن يفلح قوم ولوا امرأة (بخاري شريف)
It means that a nation that makes a woman their ruler will never succeed, hence woman should not be appointed as judge.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband