It is widely known that angels don't have free will, thus can't disobey Allah's orders. If they could, there would be a test for them too, but I don't read or heard of anything about the test of angels. They are always be mentioned in the context of doing what Allah has commanded them.
Never would the Messiah disdain to be a servant of Allah , nor would the angels near [to Him]. And whoever disdains His worship and is arrogant - He will gather them to Himself all together. (Surat An-Nisā' 4/172)
And to Allah prostrates whatever is in the heavens and whatever is on the earth of creatures, and the angels [as well], and they are not arrogant. (Surat An-Naĥl 16/49)
You can also look at these verses: Surat An-Naĥl 16/50, Surat Maryam 19/64, Surat Al-'Anbyā' 21/19-20, Surat Al-'Anbyā' 21/26-27, Surat Aş-Şāffāt 37/164-166, Surat Az-Zumar 39/75, Surat Ash-Shūraá 42/5 etc.
There are also more verses about angels in the Qur'an, all of them are describing the angels as servants of Allah, as they do whatever Allah commands, as they fear from Allah, as they pray to Allah and never tired for that, etc.
There is no verse about angels's disobedience, or their test, or their punishment in such cases, or any possibility of something like that. In some verses, the word "all" is used for angels, but there is no mention about exceptions.
There is a Satan issue coming from Surat Al-Baqarah 2/34, but we certainly know that he is not an angel, but a djinn from Surat Al-Kahf 18/50. So, he is out of topic.
In conclusion, they are infallible.