▁An ▁end - face ▁mechanical ▁se al ▁consists ▁of ▁rot ating ▁and ▁station ary ▁components ▁which ▁are ▁tight ly ▁pressed ▁together ▁using ▁both ▁mechanical ▁and ▁hyd ra ul ic ▁forces . ▁ ▁Even ▁though ▁these ▁components ▁are ▁tight ly ▁pressed ▁together , ▁a ▁small ▁amount ▁of ▁leak age ▁occurs ▁through ▁a ▁clear ance ▁that ▁is ▁related ▁to ▁the ▁surface ▁rough ness . ▁ ▁Com ponents ▁ ▁All ▁end - face ▁mechanical ▁se als ▁have ▁both ▁rot ating ▁elements ▁and ▁station ary ▁elements ▁and ▁include ▁five ▁basic ▁components : ▁▁▁ ▁se al ▁ring ▁ ▁m ating ▁ring ▁ ▁secondary ▁se aling ▁elements ▁ ▁spr ings ▁ ▁hardware . ▁ ▁The ▁se al ▁ring ▁and ▁m ating ▁ring ▁are ▁sometimes ▁referred ▁to ▁as ▁the ▁primary ▁se aling ▁surfaces . ▁The ▁primary ▁se aling ▁surfaces ▁are ▁the ▁heart ▁of ▁the ▁end - face ▁mechanical ▁se al . ▁A ▁common ▁material ▁combination ▁for ▁the ▁primary ▁se aling ▁surfaces ▁is ▁a ▁hard ▁material , ▁such ▁as ▁sil icon ▁car b ide , ▁cer am ic ▁or ▁t ung sten ▁car b ide ▁and ▁a ▁so fter ▁material , ▁such ▁as ▁carbon . ▁Many ▁other ▁materials ▁can ▁be ▁used ▁depending ▁on ▁pressure , ▁temperature ▁and ▁the ▁chemical ▁properties ▁of ▁the ▁liquid ▁being ▁se aled . ▁ ▁The ▁se al ▁ring ▁and ▁m ating ▁ring ▁are ▁in ▁int imate ▁contact , ▁one ▁ring ▁rot ates ▁with ▁the ▁sh aft ▁and ▁the ▁other ▁ring ▁is ▁station ary . ▁Either ▁ring ▁may ▁be ▁rot ating ▁or ▁station ary . ▁Also , ▁either