Procedimento per realizzare rivestimenti di carburo di silicio

Viene descritto un processo per realizzare un rivestimento di carburo di silicio su superleghe mediante: trattamento nitrurante della superlega oppure nitrurazione per sputtering reattivo sulla superlega di un film di nitruro di titanio; deposizione chimica in fase vapore di un film sottile di nitruro di titanio; ricottura in atmosfera di azoto-idrogeno; deposizione chimica in fase vapore di uno strato di carburo di silicio

Silicon carbide coatings

A process is describe for forming a silicon carbide coating on nickel-based superalloys by: nitriding the alloy or depositing a coating of titanium nitride by reactive sputtering; vapour phase chemical deposition of a coating of titanium nitride; annealing in a nitrogen and hydrogen atmosphere; vapour-phase chemical deposition of a silicon carbide coating

Silicon Carbide Coatings

A process is described for forming silicon carbide coatings on nickel based superalloys by: i) nitriding the alloy or depositing a titanium nitride film on the alloy by reactive sputtering; ii) vapour phase chemica deposition of a thin film of titanium nitride; iii) annealing in a nitrogen and hydrogen atmosphere; iv) vapour phase chemical deposition of a silicon carbide layer

MORPHOLOGICAL ASPECTS OF SILICON CARBIDE CHEMICALLY VAPOR-DEPOSITED ON GRAPHITE

The morphological features of silicon carbide coatings, deposited on graphite from SiCl4, C3H8 and H2 mixtures, were investigated. Based on preliminary thermodynamic calculations, the experiments were performed at atmospheric pressure in a cold wall reactor by varying the deposition temperature TD in the 1473-1673 K range and the deposition time between 10 and 120 min. SEM examinators showed considerable differences in surface morphology depending on the process parameters. A transition from a modular to a faceted structure was observed by moving towards higher TD values. A double layer structure was detected on the thickest coatings due to a sharp columnar-microcrystalline transition. The coatings prepared at TD - 1673 K showed surface microhardness values as high as 4000 HK and an optimum capability to protect graphite substrates against oxidation at 1273 K