The　application　of　corrosion　inhibitors　provides　an　efficient　approach　for　mitigating　steel　rebar　corrosion.　However,　the　premature　failure　of　corrosion　inhibitors　in　concrete　remains　a　pending　issue.　The　adoption　of　microencapsulated　inhibitors　shows　significant　promise　in　addressing　this　concern.　This　study　proposes　a　novel　chloride　ion-triggered　microcapsule　designed　for　the　anti-corrosion　protection　of　reinforcement.　The　microcapsules　were　synthesized　using　calcium　carbonate　(CaCO3)　particles　as　a　template　and　sodium　monofluorophosphate　(MFP)　as　the　encapsulated　inhibitory　core.　The　exterior　of　the　CaCO3　particles　was　coated　with　a　silver　alginate　(Alg-Ag)　layer,　which　confers　the　chloride　ion-triggered　release　mechanism.　The　activation　of　microcapsules　occurs　through　a　chemical　reaction　between　silver　ions　in　the　Alg-Ag　layer　and　chloride　ions　from　the　environment,　resulting　in　the　formation　of　silver　chloride　and　the　subsequent　disintegration　of　the　microcapsule.　The　MFP　inhibitor　is　released　as　a　consequence.　The　fabricated　microcapsules　were　characterized　in　terms　of　morphology　and　chemical　composition.　The　inhibitory　performance　of　the　microcapsules　was　analyzed　by　electrochemical　methods.　The　use　of　the　CaCO3　template　was　found　to　be　effective　in　producing　a　porous　matrix　suitable　for　the　loading　of　MFP.　The　microcapsules　exhibit　a　well-defined　spherical　morphology　with　a　distinct　core-shell　structure.　Both　FTIR　and　TG　analysis　confirmed　the　successful　entrapment　of　MFP　within　the　core　of　microcapsules.　Electrochemical　corrosion　tests　demonstrated　that　the　microcapsules　effectively　retarded　the　corrosion　process　of　the　reinforcement,　with　the　corrosion　inhibition　efficiency　increasing　from　59.1　%　at　24　h　to　63.8　%　at　72　h,　indicative　of　a　controlled　and　progressive　release　of　the　inhibitor　from　the　microcapsules.　©　2025　Elsevier　Ltd