Silicon solid-state sintering

The measures of solid state reactivity to be described include experiments on solid-gas, solid-liquid, and solid-solid chemical reaction, solid-solid structural transitions, and hot pressing-sintering in the solid state. These conditions are achieved in catalytic activity measurements of rutile and zinc oxide, in studies of the dissolution of silicon nitride and rutile, the reaction of lead oxide and zirconia to form lead zirconate, the monoclinic to tetragonal transformation in zirconia, the theta-to-alpha transformation in alumina, and the hot pressing of aluminum nitride and aluminum oxide. 

Silicon carbide can be pressureless sintered by a solid stated process with the aid of B and C to near full density at temperatures in excess of 2100 C. However, the lower fracture toughness (3 to 4 Mpa-m ) limit their use in many potential structural applications [1]. 

Nonoxides can be formed from polymeric precursors that are already mixed in the right proportion on an atomic scale. The atoms in silicon carbide are bonded with covalent bonds and are not mobile. Similar to most other carbides and nitrides SiC is difficult to sinter and so has slow solid state reactions even at high temperatures. A good precursor for solid state formation of SiC is the polymer polycarbosilane, which is made at 450°C from polysilanes formed from dimethyl-dichlorosilane and sodium ... 

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