It is indeed more powerful against the Shayṭān than iron.
The Fear Prayer has a number of descriptions; each description is in accordance to the level of the fighting:
The First Description: That the Muslims perform the prayer by gesturing, neither bowing nor prostrating; only gestures.
The Second Description: That he prays with the Takbeer and indications (of his movements) only. This is in the case of engaging in battle with the enemy.
The Third Description: That they (the Muslims together) pray with bowings and prostrations. This is the case in which the rank lines up in front of the enemy without engaging them in the battle and without retreating. For verily Allāh’s Messenger (ṣallallāhu ʿalayhi wa-sallam) performed the Fear Prayer with one of the two groups while the other group was facing the enemy. Then they finished and stood in the place of their companions facing the enemy while (the second group) came and the prophet (ṣallallāhu ʿalayhi wa-sallam) led them in prayer for a Rak’ah, then the Prophet (ṣallallāhu ʿalayhi wa-sallam) gave the Tasleem; therefore this group completed a Rak’ah and the other group completed a Rak’ah. The description (of the fear prayer) has come in the Noble Qurʾān. The Most High has said:
When you (O Messenger Muḥammad (ṣallallāhu ʿalayhi wa-sallam)) are among them, and lead them in al-Ṣalāt (the prayer), let one party of them stand up [in Salat (prayer)] with you taking their arms with them; when they finish their prostrations, let them take their positions in the rear and let the other party come up which has not yet prayed, and let them pray with you taking all the precautions and bearing arms. Those who disbelieve wish, if you were negligent of your arms and your baggage, to attack you in a single rush, but there is no sin on you if you put away your arms because of the inconvenience of rain or because you are ill, but take every precaution for yourselves. Verily, Allāh has prepared a humiliating torment for the disbelievers. (Sūrah-Nisāʾ’, 4:102)
Many descriptions have come for the fear prayer. The People of Ḥadīth say that for the fear prayer which has come with an authentic chain, the Muslim may perform it in accordance with the situation of the Jihād.
 Taken from Explanation of the Prophet’s Prayer Described pg. 140