The　poor　thermodynamic　and　thermal　stability　of　self-healing　glass　sealants　restrict　their　applications　in　planar　solid　oxide　fuel　cells　(SOFCs).　In　this　paper,　a　calcium　borate　crystalline　is　prepared　by　melting-quench　and　a　subsequent　crystallization.　The　crystalline　phases　include　CaB4O　7　and　CaB2O4.　The　in　situ　observation　reveals　that　the　micro-indentation　on　the　surface　of　such　crystalline　can　be　healed　when　heating　from　room　temperature　to　840　°C　at　a　heating　rate　of　40　°C　min-1.　Combining　with　the　improved　thermal　stability,　the　crystalline　sealant　with　desired　self-healing　property,　at　the　operational　temperature　of　SOFCs　(e.g.,　700-900　°C),　provides　additional　solution　for　the　sealing　challenge　of　SOFCs.　©　2010　Elsevier　B.V.