Crucible tongs for gripping platinum crucibles

Abstract

This utility model relates to a crucible clamp for gripping a platinum crucible, comprising first and second clamp arms, each clamp arm including a gripping portion, and each gripping portion including a metal substrate. The metal substrate has at least one ceramic layer on its gripping surface suitable for gripping the platinum crucible, for contact with the platinum crucible. A transition layer, bonding with both the ceramic layer and the metal substrate, with a material thermal expansion coefficient between the two, is also provided between them. This utility model's crucible clamp isolates the platinum crucible and the clamp through a ceramic layer with good high-temperature stability and low thermal conductivity, slowing down the cooling rate at the contact point and effectively preventing the diffusion and contamination of metal atoms from the gripping portion's metal substrate into the platinum crucible, thereby improving the service life of the platinum crucible.

Description

Technical Field

[0001] This utility model relates to the field of high-temperature working tools, and in particular to a crucible tong for gripping platinum crucibles, which is suitable for metallurgy, glass manufacturing, photovoltaic material processing and laboratory applications. Background Technology

[0002] Photovoltaic silver paste is a core auxiliary material in the fabrication of photovoltaic cells, used to make the electrodes and directly affecting the photoelectric conversion efficiency of the cells. The glass powder used to prepare photovoltaic silver paste needs to be melted in a platinum crucible in a high-temperature furnace to form a high-temperature molten glass. After melting, crucible tongs are used to remove the platinum crucible containing the molten glass from the furnace. During this process, the platinum crucible needs to repeatedly undergo rapid cooling from temperatures above 1000°C to room temperature, and the resulting intense thermal shock can affect the lifespan of the platinum crucible. Since the crucible tongs are in direct contact with the platinum crucible, the choice of tongs also greatly affects the degree of damage and lifespan of the platinum crucible.

[0003] Existing crucible tongs are typically made of ceramic or metal. However, ceramic crucible tongs are prone to brittle fracture under high-temperature thermal shock conditions. While metal crucible tongs will not shatter, the metallic element can diffuse at high temperatures, contaminating the platinum crucible at the clamping point and affecting its lifespan. Furthermore, the much higher thermal conductivity of metal compared to air significantly aggravates thermal shock at the clamping point, causing cracks to appear on the platinum crucible and further impacting its lifespan. Utility Model Content

[0004] The purpose of this invention is to solve at least one of the above-mentioned problems and / or other defects in the prior art.

[0005] To achieve the above objectives, this utility model provides a crucible clamp for gripping a platinum crucible, comprising a first clamping arm and a second clamping arm. The first clamping arm includes a first operating part and a first clamping part connected to each other via a first connecting part. The second clamping arm includes a second operating part and a second clamping part connected to each other via a second connecting part. The first clamping arm and the second clamping arm are hinged to each other via pins at the first connecting part and the second connecting part, so that the first and second clamping parts can clamp the platinum crucible facing each other by bringing the first and second operating parts closer together. In the crucible clamp, each of the first and second clamping parts includes a metal substrate. The metal substrate has a ceramic layer for contacting the platinum crucible, at least on its clamping surface suitable for gripping the platinum crucible. A transition layer is also provided between the ceramic layer and the metal substrate, which engages with both and has a material thermal expansion coefficient between the two.

[0006] According to one embodiment of the present invention, the transition layer is a transition coating formed on the metal substrate by thermal spraying of a metal material, and the ceramic layer is a ceramic coating formed on the transition layer by thermal spraying of a ceramic material.

[0007] According to one embodiment of the present invention, the transition layer and the ceramic layer are formed to cover the entire outer surface of the metal substrate, including the clamping surface.

[0008] According to one embodiment of the present invention, the outer surface of the metal substrate to which the transition layer is formed has a micro-uneven structure formed by sandblasting, and the surface roughness Ra value is between 2 and 10.

[0009] According to one embodiment of the present invention, the ceramic material forming the ceramic layer is yttrium-stabilized zirconium oxide or alumina.

[0010] According to one embodiment of the present invention, the thickness of the ceramic layer is between 50 and 200 micrometers.

[0011] According to one embodiment of the present invention, the metal material forming the transition layer is a nickel-chromium alloy or a nickel-chromium-aluminum-yttrium alloy.

[0012] According to one embodiment of the present invention, the thickness of the transition layer is 50 to 100 micrometers.

[0013] According to one embodiment of the present invention, pores are formed inside the transition layer and the ceramic layer, and the pores are filled with solid particles formed by applying a sealing agent to the outer surface of the ceramic layer away from the transition layer and allowing the sealing agent to penetrate into the pores and then drying.

[0014] According to one embodiment of the present invention, the material of the solid particles is sodium silicate or silicon oxide.

[0015] According to this invention, a crucible clamp has a ceramic layer for contacting the platinum crucible on the clamping surfaces of the metal substrates of its first and second clamping portions, suitable for clamping the platinum crucible. The ceramic layer has good high-temperature stability and a lower thermal conductivity than the metal substrate. Therefore, isolating the platinum crucible and the clamp through the ceramic layer, allowing the clamp to contact the platinum crucible via the ceramic layer, slows the cooling rate at the contact points between the platinum crucible and the first and second clamping portions of the clamp, reducing thermal shock at the clamping point. Simultaneously, the ceramic layer effectively prevents the diffusion of metal atoms from the metal substrates of the first and second clamping portions into the platinum crucible. All of these factors contribute to reducing damage to the platinum crucible and extending its service life. Compared to a case where at least the entire clamping portion of the clamp is made of ceramic, the ceramic layer, provided only on the surface of the metal substrate of the clamping portion, has a significantly reduced thickness, better heat dissipation, and a smaller internal temperature gradient and thermal stress under high-temperature thermal shock, thereby greatly reducing the risk of brittle fracture. In addition, a transition layer is provided between the ceramic layer and the metal substrate. The thermal expansion coefficient of the transition layer is between that of the ceramic layer and the metal substrate. This can not only effectively buffer the damage caused by the expansion difference between the ceramic layer and the metal substrate during thermal shock, but also increase the adhesion of the ceramic layer to the metal substrate, which helps to avoid the peeling and cracking of the ceramic layer, thereby improving the service life of the crucible tongs and reducing the risk of damaging the platinum crucible. Attached Figure Description

[0016] The features and advantages of this utility model will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on this utility model, wherein:

[0017] Figure 1 A schematic diagram of a crucible tong according to an embodiment of the present invention is shown.

[0018] Figure 2 Show Figure 1 The diagram shows the crucible clamps holding a platinum crucible.

[0019] Figure 3 Show Figure 1 The cross-sectional view shown is taken at line AA.

[0020] Figure 4 The crucible tongs according to another embodiment of the present invention are shown in Figure 1 A sectional view showing the location of line AA. Detailed Implementation

[0021] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that implementations of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be conceived to be implemented with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0022] The terms "first" and "second" are used below to describe the elements of this application. These terms are used only to distinguish the individual elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusion and mean that there may be additional elements / components besides those listed.

[0023] Figure 1 A crucible clamp for gripping a platinum crucible according to one embodiment of the present invention is shown. Figure 2 A schematic diagram of the crucible clamps in this embodiment holding a platinum crucible is shown. Figure 1 and Figure 2 As shown, the crucible clamp according to this embodiment may include a first clamp arm 1 and a second clamp arm 2.

[0024] The first clamp arm 1 may include a first operating part 11 and a first clamping part 12 connected to each other via a first connecting part 13. The first operating part 11 may be a straight rod extending from one end of the first connecting part 13, or it may include a handle formed by bending the straight rod in a circle for easy gripping. The first clamping part 12 extends from the other end of the first connecting part 13 and is bent into, for example, an arc shape. A first through hole is provided at the first connecting part 13.

[0025] The second clamp arm 2 may include a second operating part 21 and a second clamping part 22 connected to each other via a second connecting part 23. By way of example and not limitation, the second operating part 21 may have the same shape as the first operating part 11 but be a mirror image of it, and the second clamping part 22 may also have the same shape as the first clamping part 12 but be a mirror image of it. A second through hole is provided at the second connecting part 23.

[0026] The first clamp arm 1 and the second clamp arm 2 are mirror images of each other, crossing each other and hinged together by pins 4 passing through the aligned first and second through holes. Thus, as... Figure 2As shown, by grasping the first operating part 11 and the second operating part 21, the two can be brought closer together, causing the arc-shaped first clamping part 12 and the second clamping part 22 to also move closer together, thereby forming a shape that fits the outer contour of the platinum crucible 3 with a circular cross-section and clamping the platinum crucible 3. It is understood that, although in Figure 2 The platinum crucible 3 shown has a circular cross-section, but in practical applications, the cross-section of the platinum crucible 3 can also be square, elliptical, or other shapes. In this case, the first clamping part 12 and the second clamping part 22 are also designed accordingly to form other shapes, such as square or elliptical, that fit the cross-section of the platinum crucible 3 when they are closed together.

[0027] Figure 3 The first clamping portion 12 of the crucible clamp according to this embodiment is shown along... Figure 1 The cross-sectional view shown is taken along line AA. The first clamping portion 12 may include a metal substrate 121 and a ceramic layer 122. The metal substrate 121 may be made of, for example, stainless steel or a high-temperature alloy, and is generally arc-shaped and has an outer surface suitable for clamping the platinum crucible 3 (referred to as the "clamping surface" in this invention). Figure 3 The left side of the metal substrate 121 is shown in the center. This clamping surface has a shape adapted to the clamped portion in the outline of the platinum crucible 3. A ceramic layer 122 is disposed on the clamping surface of the metal substrate 121 and is used to contact the platinum crucible 3 when the crucible clamp holds it, thereby isolating the metal substrate 121 and the platinum crucible 3. The ceramic layer 122 has excellent high-temperature stability and a low thermal conductivity. Therefore, the first clamping portion 12 of the crucible clamp contacts the platinum crucible 3 via the ceramic layer 122 (instead of the metal substrate 121 directly contacting the platinum crucible 3), which slows down the cooling rate of the contact area between the platinum crucible 3 and the first clamping portion 12, reducing the degree of thermal shock at the clamping point. At the same time, the ceramic layer 122 can also effectively prevent the diffusion and contamination of metal atoms from the metal substrate 121 into the platinum crucible 3. Therefore, the ceramic layer 122 helps to reduce damage to the platinum crucible 3 by the crucible clamp and extend its service life. In addition, compared with the prior art where at least the entire clamping part of the crucible clamp is made of ceramic material, the ceramic layer 122 provided only on the surface of the metal substrate 121 is only a thin layer with a significantly reduced thickness. This makes it have better heat dissipation and a smaller internal temperature gradient and thermal stress under high temperature thermal shock, thereby greatly reducing the risk of brittle fracture of the ceramic layer.

[0028] In the above embodiments, the ceramic layer 122 and the metal substrate 121 have significantly different coefficients of thermal expansion. Therefore, during high-temperature thermal vibration, the difference in expansion and deformation between the two materials may lead to structural damage. Therefore, [further details are needed]. Figure 3As shown, the first clamping part 12 also has a transition layer 123 between the metal substrate 121 and the ceramic layer 122, which is bonded to both. The thermal expansion coefficient of the transition layer 123 is between that of the metal substrate 121 and the ceramic layer 122. This can effectively buffer the damage caused by the expansion difference between the ceramic layer 122 and the metal substrate 121 during thermal shock, and also increase the adhesion of the ceramic layer 122 to the metal substrate 121, which helps to avoid peeling and cracking of the ceramic layer, thereby improving the service life of the crucible clamp and reducing the risk of damaging the platinum crucible 3.

[0029] In one embodiment of this invention, the transition layer 123 can be a transition coating formed on at least the clamping surface of the metal substrate 121 by thermal spraying of a metal material using methods such as plasma spraying or flame spraying, while the ceramic layer 122 can be a ceramic coating formed on the transition layer 123 by thermal spraying of a ceramic material using methods such as plasma spraying or flame spraying. Thermal spraying can achieve high material bonding strength and is simple, fast, efficient, and cost-effective. Of course, depending on factors such as the thickness and material of the transition layer and ceramic layer, other processes can also be used to apply the transition layer and ceramic layer, such as laser cladding or vapor deposition.

[0030] The metal material of the transition layer 123 can be, for example, a nickel-chromium alloy or a nickel-chromium-aluminum-yttrium alloy, which not only meets the requirements for the coefficient of thermal expansion of the material, but also has good resistance to high-temperature oxidation. The thickness of the transition layer 123 is preferably 50 to 100 micrometers to facilitate the subsequent adhesion of the ceramic layer 122 and to provide sufficient bonding between the ceramic layer and the metal substrate.

[0031] In an optional configuration of this invention, the outer surface of the metal substrate 121 to which the transition layer 123 is to be disposed can be treated, for example, by sandblasting to create a rough surface with a micro-uneven structure, thereby improving the adhesion of the transition layer 123 to the metal substrate 121. Advantageously, the surface roughness Ra value of the rough surface with the micro-uneven structure can be controlled between 2 and 10.

[0032] The ceramic material of the ceramic layer 122 can be, for example, one of various forms (e.g., rod-shaped, powdered, or wire-shaped) such as alumina, chromium oxide, tungsten carbide, yttrium-stabilized zirconium oxide, titanium oxide, or magnesium aluminum spinel, preferably alumina or yttrium-stabilized zirconium oxide. The ceramic layer 122 made using either of these two ceramic materials exhibits particularly excellent high-temperature stability, a very low thermal conductivity, and a very high melting point. It can safely slow down the cooling rate at the contact area between the platinum crucible 3 and the crucible clamps and effectively prevent the diffusion of metal atoms from the metal substrate 121 into the platinum crucible 3 at temperatures up to 1500 degrees Celsius. The thickness of the ceramic layer 122 is preferably 50 to 200 micrometers, a thickness range that maintains the thermal shock resistance of the ceramic layer under optimal conditions.

[0033] Figure 4 The first clamping portion 12 of the crucible clamp, as shown in another embodiment of the present invention, also extends along... Figure 1 A cross-sectional view taken at the location of line AA in the diagram. (Compared to...) Figure 3 The embodiment shown differs from the one described above in that... Figure 4 In this embodiment, the transition layer 123 and the ceramic layer 122 are not only disposed on the clamping surface of the metal substrate 121 of the first clamping portion 12, but are formed to completely cover the entire outer surface of the metal substrate 121 (including the clamping surface). Figure 3 The transition layer shown is formed only on the clamping surface of the metal substrate, compared to the ceramic layer. Figure 4 The transition layer and ceramic layer that completely cover the entire metal substrate are less likely to peel off from the metal substrate, making them easier to handle when formed, for example, by thermal spraying (without having to precisely define the spraying position on the metal substrate), and reducing the risk of damage to the platinum crucible when other parts of the crucible tongs accidentally touch the platinum crucible, except for the clamping surface.

[0034] like Figure 3 and 4As shown, pores 125 may be generated inside the ceramic layer 122 formed, for example, by thermal spraying, and pores 126 may also exist inside the transition layer 123. These pores 125 and 126 can affect the isolation effect between the ceramic layer 122 and the transition layer 123. Therefore, one embodiment of the present invention is designed to fill these pores. For example, a sealing agent can be applied to the outer surface of the ceramic layer 122 facing away from the transition layer 123 (for example, two or three times). The sealing agent will penetrate from the outer surface of the ceramic layer 122 into its interior and into the pores 125, and further penetrate through the ceramic layer 122 into the pores 126 of the transition layer 123. After drying, the sealing agent in the pores 125 and 126 will solidify and form solid particles, thereby filling the pores 125 and 126. By filling the internal pores 125 and 126, the isolation effect between the ceramic layer 122 and the transition layer 123 can be improved, protecting the surface of the metal substrate 121 from oxidation at high temperatures. This also helps reduce stress concentration at the edges of the pores within each layer, resulting in a more uniform distribution of mechanical or thermal loads within each layer. This reduces the risk of layer peeling or breakage, thereby improving the long-term stability and service life of the entire crucible clamp structure. The solid particles formed by the drying of the sealing agent filling the pores 125 and 126 can be, for example, sodium silicate or silicon dioxide. Correspondingly, the sealing agent applied can be sodium silicate sol or silicon dioxide sol.

[0035] The structure of the crucible clamp 12 has been described above with reference to its first clamping part 12. Those skilled in the art will understand that the description also applies to the second clamping part 22 of the crucible clamp. The second clamping part 22 may have the same structure as the first clamping part 12, such as including a metal substrate, a transition layer, and a ceramic layer, etc., and the specific materials, shapes, or dimensions of each of them may be the same as or different from those of the first clamping part 12.

[0036] As described above, the crucible clamp according to the present invention has a ceramic layer and a transition layer on the clamping surfaces of the metal substrate of the first clamping part 12 and the second clamping part 22. The ceramic layer, which is tightly attached to the metal substrate through the transition layer and has good high-temperature stability and low thermal conductivity, can isolate the platinum crucible 3 and the crucible clamp, thereby slowing down the cooling rate of the contact area between the platinum crucible 3 and the first and second clamping parts, and effectively blocking the diffusion and contamination of metal atoms from the metal substrate to the platinum crucible 3, thereby improving the service life of the platinum crucible.

[0037] Various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of this invention. Other embodiments of this invention will be apparent to those skilled in the art based on the practice of this invention disclosed in this specification. This specification and the examples disclosed herein should be considered illustrative only, and the true scope of this invention is defined by the appended claims and their equivalents.

Claims

1. A crucible clamp for gripping a platinum crucible (3), comprising a first clamping arm (1) and a second clamping arm (2), the first clamping arm comprising a first operating part (11) and a first clamping part (12) connected to each other via a first connecting part (13), the second clamping arm comprising a second operating part (21) and a second clamping part (22) connected to each other via a second connecting part (23), the first clamping arm (1) and the second clamping arm (2) being hinged to each other via pins (4) at the first connecting part and the second connecting part, such that the first and second clamping parts can be brought close together to grip the platinum crucible facing each other. The crucible tongs are characterized in that... Each of the first and second clamping portions includes a metal substrate (121) having a ceramic layer (122) for contacting the platinum crucible (3) on at least its clamping surface adapted to clamp the platinum crucible, and a transition layer (123) is provided between the ceramic layer and the metal substrate, which is bonded to both and has a material thermal expansion coefficient between the two.

2. The crucible tongs according to claim 1, characterized in that, The transition layer (123) is a transition coating formed on the metal substrate (121) by thermal spraying of metal material, and the ceramic layer (122) is a ceramic coating formed on the transition layer (123) by thermal spraying of ceramic material.

3. The crucible tongs according to claim 2, characterized in that, The transition layer (123) and the ceramic layer (122) are formed to cover the entire outer surface of the metal substrate (121), including the clamping surface.

4. The crucible tongs according to claim 2, characterized in that, The outer surface of the metal substrate (121) to which the transition layer (123) is formed has a micro-uneven structure formed by sandblasting, and the surface roughness Ra value is between 2 and 10.

5. The crucible tongs according to any one of claims 2 to 4, characterized in that, The ceramic material forming the ceramic layer (122) is yttrium-stabilized zirconium oxide or alumina.

6. The crucible tongs according to any one of claims 2 to 4, characterized in that, The thickness of the ceramic layer (122) is between 50 and 200 micrometers.

7. The crucible tongs according to any one of claims 2 to 4, characterized in that, The metal material forming the transition layer (123) is a nickel-chromium alloy or a nickel-chromium-aluminum-yttrium alloy.

8. The crucible tongs according to any one of claims 2 to 4, characterized in that, The thickness of the transition layer (123) is between 50 and 100 micrometers.

9. The crucible tongs according to any one of claims 2 to 4, characterized in that, The transition layer (123) and the ceramic layer (122) have pores inside, which are filled with solid particles formed by applying a sealing agent to the outer surface of the ceramic layer away from the transition layer and allowing the sealing agent to penetrate into the pores and then drying.

10. The crucible tongs according to claim 9, characterized in that, The solid particles are made of sodium silicate or silicon dioxide.

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