Platinum-enhanced graphitisation in sandwich structures of silicon carbide and borosilicate glass

Abstract

Heat-treated sandwich structures of borosilicate glass and 6H-SiC single crystals (with and without platinum pre-coating) were used as model composites to study the reaction kinetics of the interlayer formation in the system Si-C-O. High resolution and analytical electron microscopical methods revealed a complex interlayer system, mainly consisting of different phases of carbon and silica. A distinct increase in the degree of graphitisation and texturisation of the reaction layer was observed after Pt deposition on the silicon carbide surface, which is attributed to the graphitising effect of both platinum and platinum silicide.

Structuring of carbon layers in Si–C–O systems studied on atomic scale

“…As we have shown in Ref. [18], the lattice spacings of these particles can be attributed to any of the platinum silicides PtSi, Pt 2 Si, or Pt 12 Si 5 , with a preference of Pt 2 Si. In Fig.…”

“…Parallel to the reaction processes with Pt or Ni oxidation effects occur due to the oxygen diffusion from the borosilicate glass into the SiC [17,18]. This is exemplarily shown in Fig.…”

“…Before merging with the glass at 977 8C, the 6H-SiC crystal slides were coated with a thin layer of platinum or nickel of about 5 nm in thickness [18]. By positioning tantalum foils inside the tube, the partial pressure of oxygen could be reduced to about 10 À13 Pa at 977 8C while heating-up the furnace with a ramp of 200 8C/h to the maximum temperature, which was kept for 30 min before cooling-down again with 200 8C/h.…”

Joining of Sintered Silicon Carbide Ceramics Using Sodium Borosilicate Glass as the Solder

“…First, during cooling from high temperature, carbon might condense from carbon monoxide and form a thin layer between the ordered atomic planes of SiC substrate and the amorphous NBS glass according to the boundary equilibrium (Eq. ), which is evidenced by the formation of a narrow layer of C.…”