Pulse-managed plasma method for coating on internal surfaces of workpieces
AssigneePratt & Whitney Canada Corp.
InventorsThomas SCHMITT, Oleg ZABEIDA, Joel LAROSE, Etienne BOUSSER, Elvi DALGAARD
Life of this patent
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Abstract
An article has a cavity defined by an inner surface, the cavity having a size such that a largest sphere placeable in the cavity has a diameter of less than 7 cm and a smallest sphere placeable in the cavity has a diameter of 0.5 mm; and a hard coating on the inner surface, the hard coating having a hardness between 18 to 100 GPa, the hard coating distributed on the inner surface such that a ratio of a coating thickness at a first region of the hard coating to that at a second region of the hard coating ranges from 0.75 to 1.33.
Claims19
An article comprising:
- a cavity defined by an inner surface, the cavity having a size such that a largest sphere placeable in the cavity has a diameter of less than 7 cm and a smallest sphere placeable in the cavity has a diameter of 0.5 mm;
- and
- a hard coating on the inner surface, the hard coating having a hardness between 18 to 100 GPa, the hard coating distributed on the inner surface such that a ratio of a coating thickness at a first region of the hard coating to that at a second region of the hard coating ranges from 0.75 to 1.33.
A method of coating an article with a hard coating, the method comprising:
- selecting a frequency and/or a duty cycle of a power supply as a function of a size of a cavity of the article to coat with the hard coating such that a ratio of a coating thickness at a first region of the hard coating to that at a second region of the hard coating ranges from 0.75 to 1.33;
- forming a non-equilibrium plasma inside of the cavity of the article in a plasma enhanced chemical vapor deposition (PECVD) chamber;
- introducing one or more gases into the PECVD chamber, the one or more gases including one or more inert gases and one or more precursor gases to start a reaction between the one or more precursor gases;
- and
- pulsing the power supply with the selected frequency and/or the selected duty cycle of the power supply to coat an inner surface delimiting the cavity of the article with the hard coating having a hardness between 18 to 100 GPa.
A method of coating an article, the article defining an internal passage delimited by an inner surface, the method comprising:
- vacuuming the inside of the PECVD chamber containing the article;
- heating the article inside the PECVD chamber;
- injecting one or more gases into the PECVD chamber, the one or more gases including one or more inert gases and one or more precursor gases including a titanium precursor gas;
- circulating an electric current through the article while the article is inside the PECVD chamber;
- and
- coating the article by forming a non-equilibrium plasma inside of the internal passage of the article and pulsing the electric current at a given frequency and/or at a given duty cycle such that a ratio of a coating thickness at a first region of the hard coating to that at a second region of the hard coating ranges from 0.75 to 1.33 and that a hardness of the hard coating is at least 18 GPa.
Dependencies are inferred from the claim text.