Method of passivating a gas vessel or component of a gas transfer system using a silicon overlay coating

A corrosion resistant gas storage vessel having a passive interior surface, comprising:

• a) a metallic interior surface having an average surface roughness RA;
• b) a silicon passivation layer formed over the entire interior surface;
• said interior surface having an average roughness RA less than about 20 microinches, and said silicon layer having a thickness in the range of 120 to 500 angstroms,
• said silicon passivation layer being substantially free of silicon dust and having been formed according to the following steps:
• a) dehydrating the interior surface of the vessel;
• b) evacuating the interior of the vessel;
• c) introducing a silicon hydride gas into the vessel;
• d) heating and pressurizing the silicon hydride gas in the vessel;
• e) depositing a layer of silicon on the interior surface of the vessel;
• f) controlling the duration of the silicon depositing step to prevent the formation of silicon dust in the vessel;
• g) purging the vessel with an inert gas to remove the silicon hydride gas;
• h) cycling the vessel through steps b-g until the entire interior surface of the vessel is covered with a layer of silicon;
• i) evacuating the vessel;
• and
• j) cooling the vessel to room temperature.

A method of passivating the interior surface of a gas storage vessel to protect the surface against corrosion, comprising the steps of:

• a) dehydrating the interior surface of the vessel;
• b) evacuating the interior of the vessel;
• c) introducing a silicon hydride gas into the vessel;
• d) heating and pressurizing the silicon hydride gas in the vessel;
• e) depositing a passivation layer of silicon on the interior surface of the vessel;
• f) controlling the duration of the silicon depositing step to prevent the formation silicon dust in the vessel;
• g) purging the vessel with an inert gas to remove the silicon hydride gas;
• h) cycling the vessel through steps b-g until the entire interior surface of the vessel is covered with a layer of silicon;
• i) evacuating the vessel;
• and,
• j) cooling the vessel to room temperature;
• said dehydration step comprising heating the storage vessel to a temperature in the range of 360° to 600° C. for 30 to 240 minutes;
• including the step of heating the storage vessel in an inert gas or in a vacuum;
• said silicon hydride gas being selected from the group comprising SiH4 and SinHn−2;
• said silicon hydride gas being heated to a temperature approximately equal to the gas's decomposition temperature;
• said silicon hydride gas being heated to a temperature in the range of 360° to 600° C.
• said silicon hydride gas being pressurized to a pressure in the range of 2 to 45 p.s.i.a.;
• said layer of silicon being deposited on the interior surface for a period in the range of 30 to 240 minutes;
• including the step of measuring the average roughness RA of the interior surface of the vessel before dehydrating the vessel;
• including cycling the vessel 1 to 2 times if the surface RA is less than about 20 microinches;
• including cycling the vessel until the silicon layer is 120 to 500 angstroms in thickness if the surface RA is less than about 20 microinches;
• including cycling the vessel 2 to 5 times if the surface RA is greater than about 20 microinches;
• including cycling the vessel until the silicon layer is 501 to 50,000 angstroms if the surface RA is greater than about 20 microinches.

A method of passivating the interior surface of a gas storage vessel to protect the surface against corrosion, comprising the steps of:

• a) measuring the average surface roughness (RA) of the interior surface of the vessel and then dehydrating the interior surface of the vessel;
• b) evacuating the interior of the vessel;
• c) introducing a silicon hydride gas into the vessel;
• d) heating and pressurizing the silicon hydride gas in the vessel;
• e) depositing a layer of silicon on the interior surface of the vessel;
• f) controlling the duration of the silicon depositing step to prevent the formation of silicon dust in the vessel;
• g) purging the vessel with an inert gas to remove the silicon hydride gas;
• h) cycling the vessel through steps b-g until the entire interior surface of the vessel is covered with a layer of silicon;
• i) evacuating the vessel;
• and,
• j) cooling the vessel to room temperature,
• including cycling the vessel 1 to 2 times if the surface RA is less than about 20 microinches and cycling the vessel 2 to 5 times if the surface RA is greater than about 20 microinches.

A corrosion resistant gas storage vessel having a passive interior surface, comprising:

• a) a metallic interior surface having an average surface roughness RA;
• b) a silicon passivation layer formed over the entire interior surface;
• said interior surface having an average roughness RA greater than about 20 microinches, and said silicon layer having a thickness in the range of 501 to 50,000 angstroms,
• said silicon passivation layer being substantially free of silicon dust and having been formed according to the following steps:
• a) dehydrating the interior surface of the vessel;
• b) evacuating the interior of the vessel;
• c) introducing a silicon hydride gas into the vessel;
• d) heating and pressurizing the silicon hydride gas in the vessel;
• e) depositing a layer of silicon on the interior surface of the vessel;
• f) controlling the duration of the silicon depositing step to prevent the formation of silicon dust in the vessel;
• g) purging the vessel with an inert gas to remove the silicon hydride gas;
• h) cycling the vessel through steps b-g until the entire interior surface of the vessel is covered with a layer of silicon;
• i) evacuating the vessel;
• and
• j) cooling the vessel to room temperature.