A process comprising: coating a substrate with a first polysulfide sealant composition to form a sealant layer, the first polysulfide sealant composition having a first viscosity and comprising: (a) a curable polysulfide polymer; and (b) a plurality of core-shell particles comprising: (i) a core comprising a ferromagnetic material; and (ii) a shell comprising silica treated with an organic sulfur-containing compound capable of bonding with the polysulfide polymer and the substrate; exposing the sealant layer to a magnetic field to consolidate the core-shell particles at an interface between the sealant layer and the substrate; and coating the sealant layer with a second polysulfide sealant composition, comprising: a curable polysulfide polymer; a crosslinking agent; and a powder comprising MnO 2 particles having a particle size of 100 nm or less, wherein the second polysulfide sealant composition has a viscosity that is greater than the first viscosity and which ranges from about 1,000 g/cm.s (1,000 Poise) to about 100,000 g/cm.s (100,000 Poise) and wherein viscosity is as determined at 25°C using a Brookfield Model RVF viscometer according to AS5127/1C. coating a substrate with a first polysulfide sealant composition to form a sealant layer, the first polysulfide sealant composition having a first viscosity and comprising: (a) a curable polysulfide polymer; and (b) a plurality of core-shell particles comprising: (i) a core comprising a ferromagnetic material; and (ii) a shell comprising silica treated with an organic sulfur-containing compound capable of bonding with the polysulfide polymer and the substrate; (a) a curable polysulfide polymer; and (b) a plurality of core-shell particles comprising: (i) a core comprising a ferromagnetic material; and (ii) a shell comprising silica treated with an organic sulfur-containing compound capable of bonding with the polysulfide polymer and the substrate; (i) a core comprising a ferromagnetic material; and (ii) a shell comprising silica treated with an organic sulfur-containing compound capable of bonding with the polysulfide polymer and the substrate; exposing the sealant layer to a magnetic field to consolidate the core-shell particles at an interface between the sealant layer and the substrate; and coating the sealant layer with a second polysulfide sealant composition, comprising: a curable polysulfide polymer; a crosslinking agent; and a powder comprising MnO 2 particles having a particle size of 100 nm or less, wherein the second polysulfide sealant composition has a viscosity that is greater than the first viscosity and which ranges from about 1,000 g/cm.s (1,000 Poise) to about 100,000 g/cm.s (100,000 Poise) and wherein viscosity is as determined at 25°C using a Brookfield Model RVF viscometer according to AS5127/1C. a curable polysulfide polymer; a crosslinking agent; and a powder comprising MnO 2 particles having a particle size of 100 nm or less, wherein the second polysulfide sealant composition has a viscosity that is greater than the first viscosity and which ranges from about 1,000 g/cm.s (1,000 Poise) to about 100,000 g/cm.s (100,000 Poise) and wherein viscosity is as determined at 25°C using a Brookfield Model RVF viscometer according to AS5127/1C. <EOS>