The admirals seems like they're not affected by haki imbued attacks, this is why so many theories came and some are saying that they bypasses the haki making them godlike characters and invulnerable to haki attacks but come to think of it... in Akainu and Aokiji's fight, Jinbei said that both of them got grave injuries and we saw that Aokiji's left leg was gone and Akainu got scratches on his face and facet on his ear, so I'm concluding that none of them can bypass armament haki attacks....
Admirals didn't bypass haki
Admirals didn't bypass haki