Process for the deposition of high temperature stress and oxidation resistant coatings on silicon-based substrates
- Lexington, MA
A process for depositing a high temperature stress and oxidation resistant coating on a silicon nitride- or silicon carbide-based substrate body. A gas mixture is passed over the substrate at about 900.degree.-1500.degree. C. and about 1 torr to about ambient pressure. The gas mixture includes one or more halide vapors with other suitable reactant gases. The partial pressure ratios, flow rates, and process times are sufficient to deposit a continuous, fully dense, adherent coating. The halide and other reactant gases are gradually varied during deposition so that the coating is a graded coating of at least two layers. Each layer is a graded layer changing in composition from the material over which it is deposited to the material of the layer and further to the material, if any, deposited thereon, so that no clearly defined compositional interfaces exist. The gases and their partial pressures are varied according to a predetermined time schedule and the halide and other reactant gases are selected so that the layers include (a) an adherent, continuous intermediate layer about 0.5-20 microns thick of an aluminum nitride or an aluminum oxynitride material, over and chemically bonded to the substrate body, and (b) an adherent, continuous first outer layer about 0.5-900 microns thick including an oxide of aluminum or zirconium over and chemically bonded to the intermediate layer.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-84OR21400
- Assignee:
- GTE Laboratories Incorporated (Waltham, MA)
- Patent Number(s):
- US 5035923
- OSTI ID:
- 867926
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
deposition
temperature
stress
oxidation
resistant
coatings
silicon-based
substrates
depositing
coating
silicon
nitride-
carbide-based
substrate
gas
mixture
passed
900
degree
-1500
torr
ambient
pressure
halide
vapors
suitable
reactant
gases
partial
ratios
flow
rates
times
sufficient
deposit
continuous
dense
adherent
gradually
varied
graded
layers
layer
changing
composition
material
deposited
thereon
defined
compositional
interfaces
exist
pressures
according
predetermined
time
schedule
selected
intermediate
5-20
microns
thick
aluminum
nitride
oxynitride
chemically
bonded
outer
5-900
including
oxide
zirconium
resistant coating
chemically bonded
halide vapor
halide vapors
reactant gases
aluminum nitride
predetermined time
outer layer
flow rates
silicon nitride
flow rate
silicon carbide
gas mixture
partial pressure
reactant gas
intermediate layer
deposited thereon
partial pressures
microns thick
oxidation resistant
resistant coatings
ambient pressure
silicon carbide-based
temperature stress
chemically bond
defined composition
pressure ratio
silicon nitride-
silicon-based substrates
graded coating
nitride material
process time
determined time
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