The　dielectric　and　ferroelectric　properties　of　Ba1-xSrxTiO3　(BST)　(x　=　0.10,　0.20,　0.30,　0.40　and　0.60)　ceramics　and　Ba1-2xSrxCaxTiO3　(BSCT)　(x　=　0.10,　0.20,　0.30)　ceramics　have　been　investigated.　The　low　temperature　phase　transitions　of　BST　ceramics　vanish　after　Ca2+　substitution　while　the　high　temperature　transition　is　diffused　and　relaxed,　which　becomes　more　obvious　with　increasing　x.　Ca2+　substitution　obviously　decreases　the　dielectric　constant　maximum,　K-m,　of　BST　ceramics　and　changes　the　temperature　of　dielectric　constant　maximum,　T-m,　of　BST　ceramics.　The　shift　of　T-m　in　BST　is　attributed　mainly　to　the　Sr2+　and　Ba2+　concentration.　BST　ceramics　exhibit　almost　normal　ferroelectric　characteristics,　while　a　typical　relaxor　behavior　was　observed　in　BSCT　ceramics.　The　relaxor　behavior　observations　may　be　understood　by　a　random　electric　field　induced　domain　state.　(c)　2007　Elsevier　Ltd.　All　rights　reserved.