Safe reduction plug having fusible metal and related devices and methods

Abstract

A pressure relief device and related apparatus, such as a container, are described. The pressure relief device is adapted to provide pressure relief to a pressurized fluid within the container when a fusible metal component of the relief device reaches its melting temperature.

Description

Technical Field

[0001] The following description pertains to the field of devices, referred to as "plugs", that contain fusible metal and are adapted to provide pressure relief to a storage container when the temperature rises.

Background Art

[0002] Containers used to store or transport gas or liquid materials under conditions of elevated (above atmospheric) pressure sometimes are equipped with a device that opens the interior of the container to the exterior when the container is exposed to dangerously high temperatures, i.e., a "pressure relief device". When the container is exposed to dangerously high temperatures, the pressure relief device creates an open flow path between the interior and exterior of the container that allows the contents within the container to be released, preventing the interior from reaching an internal pressure that would rupture, i.e., explode, the container. The dangerously high internal pressure within the container can be caused by the container being placed in a high temperature environment due to ignition or the like. When the container is in the presence of ignition, the temperature of the container and the pressure relief device will increase, and when the device reaches a certain temperature, the device creates an opening from the interior to the exterior, which allows the pressure within the container to be safely reduced to prevent an explosion. To prevent excessive pressure from accumulating within the container, several types of pressure relief devices are used, but it is necessary to avoid contamination of the container's contents from leaching of the materials of those relief devices.

Summary of the Invention

[0003] The raw material gases and liquids provided to industry include products that are stored and transported, optionally under pressure, in metal tanks constructed to contain the raw material liquid or gas. Many types of raw materials stored in these metal tanks are used in processes that require the raw materials to be in a very pure form. When the raw materials are contained in, stored in, or transported in metal tanks, the tanks should not introduce new contaminants to the raw materials.

[0004] Many metal tanks include pressure relief devices in the form of plugs that contain fusible metals such as tin, bismuth, lead, or cadmium. The fusible metal of the plug is in contact with the raw materials contained in the tank and can become a potential source of contamination by leaching into the liquid or gaseous raw materials contained in the tank.

[0005] The amount of fusible metal that can be added to the raw materials by leaching can be very small, for example, at parts per million levels or lower. However, even this very low level of metal contamination added to the raw materials during storage or transportation from metal storage tanks can have a detrimental effect in some processes that use the raw materials. For example, various types of raw materials used in microelectronics and semiconductor manufacturing processes are used at very high purities. Some of these gaseous and liquid raw materials are stored and transported in metal tanks that include pressure relief devices containing fusible metals. Examples of these types of raw materials are organometallic compounds such as metal amides, metal alkyls (e.g., n-butyllithium), and metal aryls. Other examples are silanes such as chlorosilane.

[0006] Metal (e.g., heavy metal) contaminants such as tin, bismuth, cadmium, and lead, when present in these types of raw material fluids, can have a measurable and detrimental impact on the processes that use these materials to manufacture semiconductor products, ultra-small electronic devices, etc. The presence of heavy metal contaminants such as bismuth or tin can affect the process yield, the performance characteristics of the devices prepared using that process, or both.

[0007] The present disclosure relates to a thin coating of an inert barrier material on the surface of a fusible metal plug for separating the metal material (e.g., heavy metal) of the fusible metal plug from the raw materials contained in a container. The coating should be thin enough so that the fusible metal material does not prevent the fusible metal material from melting, flowing, and relieving the pressure within the container at elevated temperatures, thereby functioning properly as a pressure relief device. Exemplary coatings can be of chemically inert materials such as metals (e.g., nickel), metal oxides (Al or Y-based), or perfluorocarbons (e.g., polytetrafluoroethylene), and can be applied to the plug by deposition techniques such as chemical vapor deposition, physical vapor deposition, atomic layer deposition for metal oxides, electrodeposition for metals, or by coating techniques such as dip coating, brush coating, spraying for fluorocarbon coatings.

[0008] In one aspect, the present disclosure relates to a pressure relief device in the form of a plug. The plug includes a plug body, a flow path extending through the plug body between a first flow path end and a second flow path end, and a fusible metal body contained within the flow path, the metal body including a first metal body end and a second metal body end, and a coating on the surface of the metal body at the first metal body end.

[0009] In another aspect, the present disclosure relates to a container. The container includes a container wall, an interior of the sealed container, and a plug. The plug includes a plug body, a flow path extending through the plug body between a first flow path end and a second flow path end, and a fusible metal body contained within the flow path, the metal body including a first metal body end and a second metal body end, and a coating on a surface of the metal body at the first metal body end.

[0010] In yet another aspect, the present disclosure relates to a method of preparing a plug. The plug includes a plug body, a flow path extending through the plug body between a first flow path end and a second flow path end, and a fusible metal body contained within the flow path, the metal body including a first metal body end and a second metal body end, and a coating on a surface of the metal body at the first metal body end. The method includes applying a coating to a surface at the first metal body end.

Brief Description of the Drawings

[0011]

Fig. 1A

Fig. 1B

Fig. 2A

Fig. 2B

Modes for Carrying Out the Invention

[0012] The figures are not to scale.

[0013] The following description relates to a pressure relief device called a "plug" that includes a plug body, a flow path within the plug body, and a fusible metal body that blocks the flow path. The fusible plug melts at an elevated temperature, opening the flow path and allowing fluid to flow through the flow path.

[0014] When the plug is installed as part of the container, the flow path extends between the interior and exterior of the container. In a normal use state, the container, plug, and fusible metal body are at approximately ambient temperature, which is below the melting temperature of the fusible metal, and the fusible metal remains in solid form. The fusible metal body is located within the flow path, blocking the flow path and preventing fluid from flowing through the flow path of the plug.

[0015] At elevated temperatures, such as those that can occur during ignition, the fusible metal body that normally (at ambient temperature) blocks the flow path melts and flows out of the flow path, causing the flow path to open between the ends of the flow path. At elevated temperatures, the liquid fluid in the container becomes gaseous, and the gaseous fluid at high temperature creates a high internal pressure within the container. At elevated temperatures, the opening of the flow path of the plug due to the melting of the fusible metal body allows the fluid (e.g., gas) to escape, preventing the interior from being pressurized to a dangerous level that could, in some cases, cause the container to explode.

[0016] The fusible metal body is made from a metal alloy that is "fusible," which means that the metal alloy "melts" or fuses at a relatively low temperature compared to many other metals and metal alloys. Examples of fusible metal bodies can be made from metals or metal alloys including bismuth, tin, lead, cadmium, or combinations thereof. An exemplary fusible metal body used herein can have a melting point below about 400 degrees Fahrenheit, for example, within the range of 150 degrees Fahrenheit to 400 degrees Fahrenheit. Some known fusible metal alloys are made of a major portion of bismuth, tin, lead, and optional cadmium in various combinations and relative amounts and have melting points of 165 degrees Fahrenheit, 212 degrees Fahrenheit, 283 degrees Fahrenheit, and 300 degrees Fahrenheit.

[0017] In these types of pressure relief devices, the fusible metal body of the plug is typically exposed directly to the gaseous or liquid contents inside the container and comes into direct contact with the gaseous or liquid contents of the container. Some of the materials stored in these types of containers include materials used in processes that require a very high level of purity for the processes and the raw materials used in the processes. Containers used for storing and transporting raw materials that must be used at high purity levels should not introduce contaminants into the raw materials.

[0018] As identified herein, the metal material used as the fusible metal as part of the pressure relief device can potentially leach into the gaseous or liquid material stored or transported in the container containing the pressure relief device. The fusible metal can include tin, bismuth, lead, or other metals or heavy metal components. The fusible metal is in contact with the raw material inside the container and is a potential source of contamination by any of the metal species, which can leach into the liquid or gaseous material during contact.

[0019] The amount of fusible metal that can leach into raw materials as a contaminant being added is very small and can be, for example, at parts per million levels or lower. However, even this very low level of metal contaminants added to some types of raw materials can have a detrimental effect in some processes using the raw materials. For example, various types of raw materials used in microelectronics and semiconductor manufacturing processes are used at very high purities. Some of these gaseous and liquid raw materials are stored and transported in metal containers sometimes called "tanks" or "pressure tanks", which contain pressure relief devices including fusible metal that allow the contents of the tank to escape to prevent a pressure increase if the tank is exposed to dangerously high temperatures. Examples include organometallic compounds such as metal amides, metal alkyls (such as alkyl lithium compounds like n-butyllithium), and metal aryls (such as aryl lithium compounds), as well as silanes (such as halogenated silanes like silane chloride).

[0020] When these types of raw materials contain heavy metal contaminants such as tin or bismuth when used in semiconductor or microelectronics device processing, the contaminants can have a measurable detrimental effect on the process. The presence of heavy metal contaminants such as bismuth or tin can affect the yield of the process or the performance of the devices prepared using that process.

[0021] As used herein, a pressure relief device (e.g., a "plug") that includes a fusible metal body located within a flow path of a device also includes a coating on the surface of the fusible metal body. The coating is disposed on the surface of the fusible metal body and, when the pressure relief device is installed on a container filled with a gaseous or liquid material, is exposed to the interior of the container and contacts the gaseous or liquid material contained therein. The coating is adapted to prevent the metal material of the fusible metal body from being directly exposed to the interior of the container in which the plug is installed and is adapted to prevent contact between the fusible metal body and the contents of the interior of the container. The coating functions as a physical barrier between the fusible metal body and the contents of the container to prevent potential leaching of an amount of the fusible metal into the gaseous or liquid contents of the container, which would otherwise be considered contaminants of any such metal material.

[0022] The coating is a thin, chemically inert barrier layer placed over the surface of the fusible metal body of the plug to separate the material of the fusible metal body (which can be a heavy metal such as tin, bismuth, or other metal or heavy metal species) from the gaseous or liquid material retained within the interior of the container.

[0023] The coating is effective as a barrier layer between the fusible metal body and the contents of the container, but the coating is also designed to allow the fusible metal body to function as part of the pressure relief device. The fusible metal body with the coating on its surface melts when exposed to a sufficiently high temperature, flows out of the flow path of the plug, clears the flow path, and allows the gas or liquid within the container to exit the container through the open flow path, thereby still being able to avoid dangerous pressure buildup within the container.

[0024] The coating can be made of any material and, in order to clear the flow path, does not unduly affect the function of the fusible metal body, for example, in a form that does not prevent the fusible metal body from effectively flowing out of the flow path when the fusible metal body melts at an elevated temperature, and can be applied by any method of forming the coating material on the barrier layer on the surface of the fusible metal body.

[0025] Exemplary materials for the coating include chemically inert materials such as metal oxides (e.g., based on aluminum or yttrium), metals (e.g., nickel) or metal alloys, fluoropolymers or perfluoropolymers (e.g., Teflon®), and other fluorine compounds.

[0026] Exemplary coatings can be applied to the surface of the fusible body by any technique that can be used to form an effective coating as described. Useful techniques include deposition techniques such as chemical vapor deposition (and its variants such as plasma-assisted chemical vapor deposition), atomic layer deposition, sputtering, and electrodeposition. Other useful techniques include coating techniques such as brush coating, spray coating, and dip coating. The useful technique can be selected based on factors such as the desired thickness of the coating and the desired material of the coating. To deposit a pure metal such as nickel as a coating, the technique selected can be electrodeposition. To deposit an oxide such as alumina or yttria, the technique selected can be atomic layer deposition or chemical vapor deposition. To deposit a fluoropolymer, the fluoropolymer can be formed into a liquid by dissolving the fluoropolymer in a solvent or by heating the fluoropolymer above its melting temperature, and the liquid can be applied to the surface by brush coating, dip coating, spray coating, or another useful coating technique.

[0027] The coating can have a thickness that makes the coating useful as a barrier layer, and when placed on the surface of the fusible metal body, the barrier layer suppresses or prevents a certain amount of the metal of the fusible metal body from transferring from the fusible metal body to a gaseous or liquid material that contacts the coating on the surface of the fusible metal body. The coating is also thin enough so as not to cause an excessive detrimental effect on the function of the pressure relief device for enabling pressure relief from the container at elevated temperatures, and has mechanical properties.

[0028] The exemplary thickness of the coating may also depend on the type of coating and the process for applying the coating. As a general range, a useful coating can have a thickness within a range from 100 angstroms to 2 microns, such as from 500 angstroms to 1 micron.

[0029] The pressure relief device can be in the form of a plug including a plug body, and can be installed, for example, as a plug for closing and sealing an opening in the sidewall structure of a container, as part of a fluid distribution valve, or as part of any other fluid control or fluid handling device or apparatus. The plug can include the plug body, a flow path extending through the plug body, a fusible metal body within the flow path, and a coating on the surface of the fusible metal body.

[0030] The plug body can include a mechanical engagement that enables the plug body to be firmly connected to components such as a container, a flow control valve, a conduit, etc. Useful mechanical engagements can be, for example, a threaded engagement between the container and the plug body, a flange, a compression fitting, a variable compression fitting, or an equivalent mechanical structure that enables a firm engagement between the plug body and a container, a valve, a conduit (e.g., a pipe), or another component of the container or flow control structure.

[0031] An exemplary pressure relief device in the form of a plug includes a cylindrical plug body that includes mechanical engagement on its outer surface, and a flow path that extends through the plug body along the length of the cylindrical plug body from a first flow path end at one end of the cylindrical plug body to a second flow path end at a second end of the cylindrical plug body. In the normal "plug-connected" use state of the pressure relief device, a solid (room temperature) fusible metal body is disposed within the flow path to block the space of the flow path between the ends of the flow path and prevent any fluid flow through the flow path. The fusible metal body includes two ends, one fusible metal body end configured toward the first end of the flow path and a second fusible metal body end configured toward the second end of the flow path. A coating is disposed on the surface of the fusible metal body at one of the two ends of the fusible metal body, particularly at the end that will be exposed to the interior of the container or flow control device.

[0032] FIG. 1A shows an example of a pressure relief device, i.e., a "plug", as part of a container containing a highly purified liquid or gas raw material. The plug 100 includes a cylindrical plug body 110 that includes a flow path 112 having a first flow path end 114 and a second flow path end 116. A fusible metal body 120 is included within the flow path 112 and, in the plug 100 under ambient temperature conditions, the fusible metal body 120 is in a solid form, which blocks the flow of any fluid 130 contained within the container 132 through the flow path 112. Also shown, the fusible metal body 120 includes a first fusible body end 124 oriented toward the first flow path end 114 and a second fusible body end 126 oriented toward the second flow path end 116. The described inert coating 128 is disposed on the surface of the first fusible body end 124. Mechanical engagement 140 on the outer surface of the plug body 110 engages a corresponding mechanical engagement surface on the side wall of the container 132 and, as shown, the mechanical engagement is a mating thread.

[0033] As shown in FIG. 1A, the fusible metal body 120 is in a solid (unmelted) condition and fills the flow path 112, preventing any flow of fluid 130 through the plug body 110. The coating 128 is the coating described herein that functions as a physical barrier between the surface of the first fusible body end 124 and the gas 130 inside the container 132.

[0034] As shown in FIG. 1B, the container 132 and the plug 100 are at an elevated temperature, such as the temperature in an ignition atmosphere that would cause the liquid contents of the container to evaporate, which causes an increase in the internal container pressure. The fusible metal body 120 is melted and flowing out of the flow path 112, leaving the flow path 112 open and allowing the gaseous fluid 130 to flow through the flow path 112 and out of the interior of the container 132. Allowing the fluid 130 to exit the interior of the container 132 prevents pressure buildup, which may otherwise occur due to the increased temperature of the fluid 130 caused by ignition, and prevents catastrophic pressure rupture and explosion of the container 132 due to excessive pressure inside.

[0035] As a different example of a pressure relief device (e.g., a "plug") described, the plug may include a plug body that is part of a larger valve body that includes a fluid distribution valve useful for dispensing fluid from the container while also housing the pressure relief device. The fluid distribution valve can be of any design, and in particular, can be of a design useful for delivering a very pure gaseous fluid from the container to a processing device, such as to a deposition apparatus. The deposition apparatus can be a device useful for performing atomic layer deposition, chemical vapor deposition, sputtering, etc. The valve can include a valve body connected to the container, a distribution port that can be connected to one processing device, and a pressure relief device (e.g., a plug) that can be engaged with and disengaged from the valve body.

[0036] Figure 2A shows an example of the pressure reducing device described, i.e., a "plug", contained within a larger valve device 201 installed at the outlet of a container containing a liquid or gas raw material in a highly purified form. The valve device 201 includes a valve body 202 that includes a valve handle 204, a valve stem 206, and a valve actuator 208. The valve handle 204 can be rotated to rotate the stem 206, and accordingly, move the valve actuator 208 between an open position (shown) and a closed position. In the open position, gas 230 will flow through the valve body 202, exit the valve body 202 through the distribution port 222, and be distributed to a processing device (not shown).

[0037] The valve device 201 includes a plug 200, which is an example of the plug of the present specification. As shown, the plug 200 includes a cylindrical plug body 210 that includes a flow path 212 having two ends. A fusible metal body 220 is contained within the flow path 212, and in the plug 200 under ambient temperature conditions, the fusible metal body 220 is in a solid form, which impedes the flow of any fluid 230 contained within the container 232 through the flow path 212. The fusible metal body 220 includes a first fusible body end oriented towards the first flow path end and a second fusible body end oriented towards the second flow path end. An inert coating 228 (not to scale) as described is disposed on the surface of the first fusible body end. A mechanical engagement 240 on the outer surface of the plug body 210 engages a corresponding mechanical engagement surface of the valve body 202, and as shown, the mechanical engagement is a mating screw.

[0038] As shown in Figure 2A, the fusible metal body 220 is in a solid (unmelted) condition, filling the flow path 212 and impeding any flow of fluid 230 through the plug body 210. The coating 228 is the coating described herein that functions as a physical barrier between the surface of the end of the fusible body 220 and the gas 230 within the interior of the container 232.

[0039] As shown in FIG. 2B, the container 232 and the plug 200 are at an elevated temperature, such as the temperature in an ignition atmosphere that will cause the liquid contents of the container to evaporate, which causes an increase in the internal container pressure. The fusible metal body 220 is melted and flowing out of the flow path 212, keeping the flow path 212 open and allowing the gaseous fluid 230 to flow through the flow path 212 and out of the interior of the container 232. Allowing the fluid 230 to exit the interior of the container 232 prevents pressure build-up, which may otherwise occur due to the increased temperature of the fluid 230 caused by ignition, and prevents catastrophic pressure rupture and explosion of the container 232 due to excessive pressure inside.

[0040] The pressure relief device described can alternatively be included as part of a different type of container, valve, conduit (e.g., pipe), connector, or any other flow control device or structure used to store, contain, or control the flow of a gaseous or liquid raw material. Examples include, among others, unions, half unions, and other pipes, conduits, or connectors, pressure regulators, pressure relief valves.

[0041] A container including a pressure relief device can be any type of container that can be used to store, transport, dispense, or handle a liquid or gaseous fluid and can incorporate a pressure relief device for safety purposes. Generally, the container can be any type of sealed vessel or conduit, including the interior, that contains or is used to control a liquid or gas, either under pressurized or non-pressurized conditions. Examples include vessels that may be referred to as cylinders, canisters, tanks, etc.

[0042] The interior of the container may contain a liquid or a gas, or both, at any pressure, designed to be compatible therewith, at ambient temperature (e.g., at 23 degrees Celsius). The internal pressure of the container may be below atmospheric pressure, above atmospheric pressure (e.g., at pressures up to or exceeding 20 pounds per square inch, 50 pounds per square inch, 100 pounds per square inch, 500 pounds per square inch, or 1000 pounds per square inch), or approximately equal to atmospheric pressure, e.g., within a range of (absolute) pressures from 0.7 atmospheres to 1.3 atmospheres.

[0043] An exemplary container can be of the type that includes side walls of steel (e.g., carbon steel, stainless steel, etc.) for containing gas under pressure and a valve or outlet to which a dispensing valve can be attached to enable the gaseous contents to be delivered from the container. The container can be of the type that includes welded seams or does not include seams (i.e., is "seamless").

[0044] The container can be of standard or approved design, such as the type that contains and is useful for transporting propane for consumer sales. These can be rated at an "operating pressure" of 260 pounds per square inch.

[0045] An exemplary container can meet certain specifications of the United States Department of Transportation, such as DOT - 4BW260, or in Canada, those specified in TC - 4BWM18.

[0046] An exemplary container can have any useful internal volume, e.g., an internal volume ranging from 10 liters to 500 liters, such as from 20 liters or 50 liters up to 200 liters, 300 liters, or 400 liters.

[0047] Containers can be designed to hold highly pure fluids (liquids or gases) while minimizing the potential introduction of impurities into the fluid. These can be lined with inert materials such as polymers or fluoropolymers, such as perfluoropolymers like polytetrafluoroethylene (e.g., Teflon®).

[0048] In a first aspect, a plug is disclosed herein that includes a plug body, a flow path extending through the plug body between a first flow path end and a second flow path end, and a fusible metal body contained within the flow path, the metal body including a first metal body end and a second metal body end, and a coating on the surface of the metal body at the first metal body end.

[0049] In a second aspect according to the first aspect, the coating includes a metal, a metal oxide, or a fluoropolymer.

[0050] In a third aspect according to the first or second aspect, the fusible metal body has a melting point in the range of 150°F to 400°F.

[0051] In a fourth aspect according to any one of the first to third aspects, at a temperature between 150°F and 400°F, the fusible metal body melts and flows out of the flow path in a molten state, opening the flow path between the first flow path end and the second flow path end.

[0052] In a fifth aspect according to any one of the first to fourth aspects, the coating enables the fusible metal body to flow out of the flow path in a molten liquid state path and open the flow path.

[0053] In a sixth aspect according to any one of the first to fifth aspects, the fusible metal body includes bismuth, tin, lead, cadmium, or a combination thereof.

[0054] In a seventh aspect according to any one of the first to sixth aspects, the coating has a thickness in the range of 100 angstroms to 2 microns.

[0055] In an eighth aspect according to any one of the first to seventh aspects, the plug body has an outer surface including an engagement selected from screwing, flanging, and compression fitting.

[0056] In a ninth aspect, a pressure reducing device including a plug according to any one of the first to eighth aspects is disclosed herein.

[0057] In a tenth aspect according to the ninth aspect, the pressure reducing device is selected from the group consisting of a pressure reducing valve, a conduit, a connector, a pressure regulator, a pipe, a union, and a half union.

[0058] In an eleventh aspect, a container including a container wall, the interior of a sealed container, and a plug according to any one of the first to eighth aspects is disclosed herein.

[0059] In a twelfth aspect according to the eleventh aspect, the plug body engages the container at the side wall.

[0060] In a thirteenth aspect according to the eleventh or twelfth aspect, the plug body engages the container in a pressure reducing device selected from the group consisting of a pressure reducing valve, a conduit, a connector, a pressure regulator, a pipe, a conduit, a union, and a half union.

[0061] In a fourteenth aspect according to any one of the eleventh to thirteenth aspects, the coating is exposed to the interior of the container.

[0062] In a fifteenth aspect according to any one of the eleventh to fourteenth aspects, the interior of the container further includes an organometallic compound or a silane disposed therein.

[0063] In a sixteenth aspect according to any one of the eleventh to fifteenth aspects, the interior of the container further includes a metal amide, a metal alkyl, or a metal aryl disposed therein.

[0064] In a seventeenth aspect according to any one of the eleventh to eighteenth aspects, it further includes organometallic alkyl lithium disposed inside the container.

[0065] In an eighteenth aspect, a method of preparing a plug, comprising disposing a fusible metal body in a flow path extending through the plug body between a first flow path end and a second flow path end, the metal body including a first metal body end and a second metal body end; and applying a coating on the surface of the metal body at the first metal body end, is disclosed herein.

[0066] In a nineteenth aspect according to the eighteenth aspect, the coating is applied to the surface by a deposition method selected from chemical vapor deposition, atomic layer deposition, physical vapor deposition, and electrodeposition.

[0067] In a twentieth aspect according to the eighteenth or nineteenth aspect, the coating is a metal oxide coating applied to the surface by chemical vapor deposition, physical vapor deposition, or atomic layer deposition.

[0068] In a twenty - first aspect according to the eighteenth or nineteenth aspect, the coating is a metal coating applied to the surface by electrodeposition.

[0069] In a twenty - second aspect according to the eighteenth or nineteenth aspect, the coating includes a fluoropolymer and is applied to the surface by a coating method selected from brush coating, spraying, and dip coating.

Claims

1. A plug body, A flow path extending through the plug body between a first flow path end and a second flow path end, A fusible metal body contained within the flow path, the metal body including a first metal body end and a second metal body end, And a coating on the surface of the metal body at the first metal body end A plug comprising.

2. The plug according to claim 1, wherein the coating comprises a metal, a metal oxide, or a fluoropolymer.

3. The plug according to claim 1, wherein the fusible metal body has a melting point in the range of 150°F to 400°F.

4. At a temperature between 150°F and 400°F, the fusible metal body melts and flows out of the flow path in a molten state to open the flow path between the first flow path end and the second flow path end, the plug according to claim 1.

5. The coating enables the fusible metal body to flow out of the flow path in a molten liquid state path to open the flow path, the plug according to claim 1.

6. The plug according to claim 1, wherein the fusible metal body comprises bismuth, tin, lead, cadmium, or a combination thereof.

7. The plug according to claim 1, wherein the coating has a thickness in the range of 100 angstroms to 2 microns.

8. The plug according to claim 1, wherein the plug body has an outer surface including an engagement selected from screwing, flanging, and compression fitting.

9. A pressure relief device comprising the plug according to claim 1.

10. The pressure reducing device according to claim 9, wherein the pressure reducing device is selected from the group consisting of a pressure reducing valve, a conduit, a connector, a pressure regulator, a pipe, a union, and a half union.

11. A container comprising a container wall, the interior of the sealed container, and a plug wherein the plug comprises: a plug body, a flow path extending through the plug body between a first flow path end and a second flow path end, a fusible metal body contained within the flow path, the metal body including a first metal body end and a second metal body end, and a coating on the surface of the metal body at the first metal body end. The container further comprises:

12. The container according to claim 11, wherein the plug body engages the container at a side wall.

13. The container according to claim 11, wherein the plug body engages the container in a pressure reducing device selected from the group consisting of a pressure reducing valve, a conduit, a connector, a pressure regulator, a pipe, a union, and a half union.

14. The container according to claim 11, wherein the coating is exposed to the interior of the container.

15. The container according to claim 11, further comprising an organometallic compound or silane disposed within the interior of the container.

16. The container according to claim 11, further comprising a metal amide, a metal alkyl, or a metal aryl disposed within the interior of the container.

17. The container according to claim 11, further comprising an organometallic alkyl lithium disposed within the interior of the container.

18. A method of preparing a plug, comprising: Disposing a fusible metal body in a flow path extending through the plug body between a first flow path end and a second flow path end, the metal body including a first metal body end and a second metal body end, and disposing the fusible metal body; Applying a coating to the surface of the metal body at the first metal body end; A method comprising.

19. The method according to claim 18, wherein the coating is applied to the surface by a deposition method selected from chemical vapor deposition, atomic layer deposition, physical vapor deposition, and electrodeposition.

20. The method according to claim 18, wherein the coating is a metal oxide coating applied to the surface by chemical vapor deposition, physical vapor deposition, or atomic layer deposition.

21. The method according to claim 18, wherein the coating is a metal coating applied to the surface by electrodeposition.

22. The method according to claim 18, wherein the coating includes a fluoropolymer, and the coating is applied to the surface by a coating method selected from brush coating, spraying, and dip coating.

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