Preceramic monomers for silicon carbonitride and nitride production by means of chemical vapor deposition

Abstract

Tris(N-methyl)trimethylcyclotrisilazane (cyclosilazane-1) and tetra(N-methyl)tetramethylcyclotetrasilazane (cyclosilazane -2), that are promising preceramic monomers for the production of oxygen-proof materials based on silicon carbonitride and nitride by СVD and CVI, were obtained through methyldichlorosilane aminolysis, isolated and characterized by 1Н, 29Si NMR and gas-liquid chromatography. The conducted research resulted in the identification of factors effecting the reaction direction. According to solvent nature the reaction may be directed either towards cyclosilazane-1 formation or cyclosilazane-2 formation. In terms of efficiency, that is defined as cyclosilazane-1 to cyclosilazane-2 ratio, the solvents may be arranged in the following sequence: rubber solvent > rubber solvent + DE (diethyl ether) > nefras + DE > dichloromethane + DE > benzene.

Keywords

• methyldichlorosilane
• aminolysis
• tris(n-methyl)trimethylcyclosilazane
• tetra(n-methyl)tetra-methylcyclotetrasilazane
• silicon nitride
• silicon carbonitride
• cvd/cvi