Metallic Glass Composite

Abstract

To provide a metal glass composite having heightened strength such as impact resistance and so on by suppressing air bubbles contained in glass, by preparing thermal spray glass powder having thermal expansion coefficient corresponding to a metal glass to be a target of thermal spray.SOLUTION: A metal glass composite comprises: a metal substrate portion composed of an iron material of a body-centered cubic crystal system and a thermal spray glass portion formed with a film thickness of 10 to 2000 μm on the metal substrate portion, wherein a glass material forming the thermal spray glass portion contains SiO2: 35-70 mass% as a first group component (A), 18-30 mass% of the total of B2O3: 9-15 mass%, Li2O: 5-9 mass% and Na2O: 4-10 mass% as a second group component (B), and 10-30 mass% of the total of BaO: 0-15 mass%, TiO2: 2-15 mass%, Al2O3: 0-8 mass% and ZnO: 0-15 mass% as a third component (C), and 90 mass% or more of a main component (D) as the sum of these.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a metallic glass composite, and more particularly to a metallic glass composite in which glass particles are thermally sprayed onto a metal surface and firmly adhered to the surface. [Background technology]

[0002] Thermal spraying is used to form a glassy coating on a metal substrate. When a glassy coating is applied to a metal substrate by thermal spraying, the glass adheres to the metal substrate more firmly than enamel, forming a coating. Therefore, thermal spraying is suitable for applications where durability is required.

[0003] In a thermal spraying device, a carrier gas is mixed with a material to be sprayed, such as glass or ceramics. A separately supplied gas and a high current generate plasma, which generates high heat and melts the sprayed glass powder, which is made up of glass particles. The molten sprayed glass powder is then ejected from the thermal spraying device toward the metal substrate to be sprayed (see Patent Documents 1 and 2, etc.).

[0004] The thermal expansion coefficient (linear expansion coefficient) of the metal substrate and the glassy material of the sprayed glass powder differ. Due to their specific heat relationships, the metal substrate cools faster. Because the rate of volumetric contraction differs between the metal substrate and the sprayed glass powder, control of the expansion coefficient is necessary, making spraying between dissimilar materials extremely difficult.

[0005] The inventors developed the thermal spray glass powder and thermal spraying method disclosed in Patent Document 1, as well as the thermal spraying apparatus disclosed in Patent Document 2. The inventors established strong thermal spraying between dissimilar materials, a metal substrate and the glassy substance of the thermal spray glass powder, and were able to manufacture a metallic glass composite. According to the disclosure of Patent Document 1, the surface of the metal substrate to be thermally sprayed is roughened by sandblasting or the like and then heated. Then, a coating of glassy substance derived from the sprayed glass powder melted by thermal spraying is formed on the surface. It is believed that the glassy substance derived from the sprayed glass powder penetrates into the surface of the roughened metal substrate in this way, improving adhesion between the metal substrate and the glassy substance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-216977 [Patent Document 2] Patent Publication No. 2021-130841 Summary of the Invention [Problem to be solved by the invention]

[0007] The inventors then conducted extensive research into the formation of glass by thermal spraying on the surface of a metal substrate. They discovered that, due to differences in thermal expansion coefficients depending on the type of metal substrate, it is necessary to adjust the thermal expansion coefficient of the sprayed glass powder depending on the type. They also discovered that bubbles inevitably form when the sprayed glass powder is melted by thermal spraying and applied to the metal substrate, reducing the impact resistance of the resulting glass in the metallic glass composite.

[0008] The present invention has been made in view of the above points, and provides a metallic glass composite in which a metal substrate and a glassy dissimilar material, a thermal spray glass powder, are integrated by thermal spraying. The thermal spray glass powder has a thermal expansion coefficient corresponding to the metal substrate to be thermal sprayed, and bubbles contained in the glassy material formed on the metal substrate after thermal spraying are suppressed, thereby improving strength such as impact resistance. [Means for solving the problem]

[0009] That is, the metallic glass composite of the embodiment has a metal substrate made of a body-centered cubic iron material and a sprayed glass portion formed on the metal substrate with a film thickness of 10 to 2000 μm, and the glass material forming the sprayed glass portion contains a first group component (A) of SiO2: 35 to 70 mass% and a second group component (B) of BO3: 9 to 15 mass%, Li2O: 5 to 9 mass%, and Na2O: 4 to 10 mass%, in total. The glass material contains 18 to 30 mass% of the first group component (A), 2 to 15 mass% of the second group component (B), 0 to 8 mass% of the third group component (C), and 10 to 30 mass% of the third group component (C) including 0 to 15 mass% of BaO, 2 to 15 mass% of TiO2, 0 to 8 mass% of Al2O3, and 0 to 15 mass% of ZnO in total. The glass material contains 90 mass% or more of the first group component (A), the second group component (B), and the third group component (A) in total as the main component (D). The linear expansion coefficient of the glass material from room temperature to 300°C is 9 to 11(×10 6 / °C), and the area ratio of bubbles of 1 μm or larger in the cross section in the thickness direction of the sprayed glass portion is less than 40%.

[0010] The metallic glass composite of the embodiment has a metal substrate made of a face-centered cubic iron material and a sprayed glass portion formed on the metal substrate with a film thickness of 10 to 2000 μm. The glass material forming the sprayed glass portion contains a first group component (A) of SiO2: 50 to 60 mass%, and a second group component (B) of BO3: 2 to 8 mass%, Li2O: 8 to 15 mass%, and Na2O: 8 to 20 mass%, totaling 2. The glass material contains 5 to 35 mass% of the first group component (A), 3 to 12 mass% of BaO, 4 to 15 mass% of TiO2, 0 to 5 mass% of Al2O3, and 0 to 5 mass% of ZnO as the third group component (C), totaling 10 to 20 mass% of the first group component (A), the second group component (B), and the third group component (A) together to contain 90 mass% or more of the main component (D), and the linear expansion coefficient of the glass material from room temperature to 300°C is 14 to 17 (×10 6 / °C), and the area ratio of bubbles of 1 μm or larger in the cross section in the thickness direction of the sprayed glass portion is less than 40%.

[0011] Furthermore, the difference between the linear expansion coefficient of the glass material of the metallic glass composite and the linear expansion coefficient of the metal substrate may be within 15%.

[0012] Furthermore, the metallic glass composite may have a molten solidified portion in which the sprayed glass portion is embedded in the metal substrate portion at the boundary between the metal substrate portion and the sprayed glass portion in the cross section, and the molten solidified portion may have a thickness of 0.3 μm or more.

[0013] Furthermore, the sprayed glass portion of the metallic glass composite may have an area ratio of bubbles of 1 μm or larger that exist within an area of ​​30% of the thickness of the sprayed glass portion starting from the boundary between the metal substrate portion and the sprayed glass portion in the cross section, of 50% or less.

[0014] Furthermore, the thickness of the sprayed glass portion of the metallic glass composite may be 10 to 100 μm, and the area ratio of bubbles of 1 μm or larger in size in a cross section in the thickness direction of the sprayed glass portion may be less than 10%.

[0015] Furthermore, the components other than the main component (D) of the glass material of the metallic glass composite are auxiliary components (E), which are CaO, SrO, MgO, P2O5, K2O, V2O5, Cr2O3, MnO2, Fe2O3, Co3O4, NiO2, CuO, Y2O3, ZrO2, Nb2O2, MoO3, SnO2, Sb2O3, WO3, PbO, Bi2O3, La2O3, CeO2, Pr6O 11 Alternatively, it may be one or more of Nd2O3, Sm2O3, and Gd2O3. [Effects of the Invention]

[0016] The metallic glass composite of the present invention is a metallic glass composite in which a metal substrate and a glassy dissimilar material, a thermal spray glass powder, are integrated by thermal spraying. The thermal spray glass powder is prepared to have a thermal expansion coefficient that matches the metal substrate to be thermal sprayed, and air bubbles contained in the glassy material formed on the metal substrate after thermal spraying are suppressed, thereby increasing strength such as impact resistance. [Brief explanation of the drawings]

[0017] [Figure 1](A) A schematic cross-sectional view of a plate material, (B) a schematic cross-sectional view of a perforated plate material, (C) a schematic cross-sectional view of a pipe material, and (D) a schematic cross-sectional view of a bolt material, all relating to metallic glass composites. (E) A schematic view showing the compositional relationship of the glass materials. [Figure 2] FIG. 1A is a schematic diagram showing the compositional relationship of glass materials, and FIG. 1B is a cross-sectional schematic diagram showing the structure of a metallic glass composite. [Figure 3] 1A and 1B are cross-sectional photographs of the metallic glass composite of prototype number G1 at a magnification of 100 and 1000, respectively. [Figure 4] (A) is a 100x magnified cross-sectional photograph of the metallic glass composite of prototype number G2, and (B) is a 1000x magnified cross-sectional photograph. [Figure 5] 1A and 1B are cross-sectional photographs enlarged 100 times and 1000 times, respectively, of the glass material of the metallic glass composite of prototype number G6. [Figure 6] 1A and 1B are cross-sectional photographs enlarged 100 times and 1000 times, respectively, of the glass material of the metallic glass composite of prototype number G11. [Figure 7] 1A and 1B are cross-sectional photographs enlarged 100 times and 1000 times, respectively, of the glass material of the metallic glass composite of prototype number G13. [Figure 8] 1A and 1B are cross-sectional photographs enlarged 100 times and 1000 times, respectively, of the glass material of the metallic glass composite of prototype number G19. [Figure 9] (A) is a 100x magnified cross-sectional photograph of the glass material of the metallic glass composite of prototype example number H5, and (B) is a 1000x magnified cross-sectional photograph. [Figure 10] 1 is a graph showing the relationship between the area ratio of all bubbles and the height of a falling ball. [Figure 11] 1 is a graph showing the relationship between the area ratio of bubbles in a boundary portion and dielectric strength. DETAILED DESCRIPTION OF THE INVENTION

[0018] The metallic glass composite of the embodiment is a metal-glass composite in which a glassy coating is formed on the entire or part of the surface of various types of metal by thermal spraying. The glassy material is prepared in a powder form such as frit and supplied to a thermal spraying device. The glassy powder is then instantaneously melted by plasma spraying in the thermal spraying device and sprayed toward the target metal substrate. As a result, the molten glassy material adheres to the metal substrate and cools, and the glassy material adheres to the metal and becomes integrated.

[0019] 1A to 1D are schematic diagrams of metallic glass composites 1A, 1B, 1C, and 1D in which a sprayed glass portion 20 is formed on (the surface of) a metal substrate portion 10. FIG.

[0020] FIG. 1(A) shows a metallic glass composite 1A in which a sprayed glass portion 20 is formed on the surface of a sheet metal-like metal substrate 11 (10). The sprayed glass portion 20 is formed by spraying on the surface of a metal substrate 11 such as a steel plate. As a result, the impact resistance, corrosion resistance, etc. of the steel plate are imparted. FIG. 1(B) shows a metallic glass composite 1B in which a sheet metal-like metal substrate 12 (10) is prepared having a hole 15 that allows for fastening with bolts, rivets, etc. and for connecting other components, and the sprayed glass portion 20 is formed on the surface of the metal substrate 12. The sprayed glass portion 20 is also attached to the hole 15 and the area surrounding the hole 15, thereby improving resistance to wear, corrosion, and other issues caused by contact between metals.

[0021] FIG. 1(C) shows a metallic glass composite 1C in which a sprayed glass portion 20 is formed on the surface of a metal substrate portion 13 (10) of a pipe material. In the case of the metallic glass composite 1C, it can be combined with another cylindrical electrode to form an electrode for silent discharge (see Patent Document 1, etc.). The insulating properties due to the glassy nature of the sprayed glass portion 20 are utilized. In FIG. 1(D), a bolt is used as the metal substrate portion 14 (10). By forming the sprayed glass portion 20 on the surface of the bolt, the corrosion resistance of the bolt is improved, and the resistance to breakage of the bolt due to weakening caused by corrosion is increased. Of course, the metallic glass composite disclosed in FIG. 1 is only one example, and the metallic glass composite is not limited to the illustrated embodiment.

[0022] In the metallic glass composite of the embodiment, the thickness of the sprayed glass portion 20 is in the range of 10 to 2000 μm. If the thickness of the sprayed glass portion 20 is less than 10 μm, the molten glass material is likely to form stripes or spots on the surface of the metal substrate portion 10. This makes it difficult to achieve a uniform deposition of the glass material. Furthermore, if the thickness of the sprayed glass portion 20 exceeds 2000 μm, the thickness of the sprayed glass portion 20 becomes too large, and cracks and peeling are likely to occur due to the difference in thermal expansion coefficients between the metal substrate portion 10 and the sprayed glass portion 20. In particular, it becomes more difficult to control bubbles contained in the sprayed glass portion 20, as described below.

[0023] In preparing the metallic glass composite of the embodiment, the composition of the glass material constituting the sprayed glass portion is determined by the difference in thermal expansion coefficient (linear expansion coefficient) depending on the type of metal in the metal substrate, particularly the type of iron material (iron alloy).The metallic glass composite of the embodiment mainly uses body-centered cubic iron material and face-centered cubic iron material as the metal substrate.

[0024] Body-centered cubic iron materials include martensitic stainless steel, ferritic stainless steel, etc., such as stainless steels SUS409, SUS420, SUS430, etc., and general structural rolled steels such as SS400. In the examples described below, SUS409 and SS400 are used. Face-centered cubic iron materials include austenitic stainless steel, such as SUS304, SUS310, SUS316, etc. In the examples described below, SUS304 is used.

[0025] The composition of the glass material constituting the sprayed glass portion must be adjusted to accommodate the type of metal in the metal substrate. The schematic diagram in Figure 2(A) shows an overview of the composition of the glass material constituting the sprayed glass portion. First, the main component (D) is composed of the first group component (A), the second group component (B), and the third group component (C). The main component (D) accounts for 90 mass% or more of the glass material per unit weight. The remaining components of the glass material are the auxiliary component (E). Of course, unavoidable impurity components may be mixed into the glass material. Hereinafter, mass% and weight% are treated as synonyms. The mass% ratios of the first group component (A), the second group component (B), and the third group component (C) vary depending primarily on whether the iron material is a body-centered cubic iron material or a face-centered cubic iron material.

[0026] The first group component (A) is SiO2. SiO2 of the first group component (A) is the main component of the glass material that constitutes the sprayed glass portion, and mainly increases corrosion resistance, hardness (abrasion resistance), stain resistance, electrical insulation, voltage resistance, etc. In the case of a metal substrate made of a body-centered cubic iron material, the SiO2 content in the glass material is 35 to 70 mass %. In the case of a metal substrate made of a face-centered cubic iron material, the SiO2 content in the glass material is 50 to 60 mass %.

[0027] If the SiO2 content of the first group component (A) is below its respective lower limit, the corrosion resistance and other properties of the final sprayed glass part are reduced. Furthermore, the sprayed glass part is more likely to undergo changes over time, such as whitening. If the SiO2 content of the first group component (A) is above its respective upper limit, the surface of the sprayed glass part formed after spraying is less likely to be flat. During spraying, the metal substrate to be sprayed is heated to a temperature above its heat distortion temperature (1000°C or higher). As the amount of SiO2 increases, the fire resistance of the glass material itself increases, and its melting property during plasma spraying decreases. This increases the load on the spraying equipment and makes it more difficult to achieve a smooth sprayed glass part after melting.

[0028] The thermal expansion coefficient of SiO2 is smaller than that of the other components described below. Increasing the amount of SiO2 reduces the thermal expansion coefficient of the entire glass material. It also results in low melting and high viscosity during plasma spraying. Therefore, SiO2 is used in consideration of adjusting the thermal expansion coefficient of the metal substrate of body-centered cubic iron material or the metal substrate of face-centered cubic iron material, as well as corrosion resistance and ease of spraying and melting. The amount of SiO2 added to the glass material is determined based on the composition of the metal substrate, taking into account the adjustment of the thermal expansion coefficient.

[0029] The second group component (B) is a component that mainly adjusts the melting property and low viscosity of the glass material during melting, and includes B2O3, Li2O, and Na2O. The total amount of the second group component (B) and the amount of each component included in the second group component (B) are adjusted and blended in order to bring the thermal expansion coefficient of the glass material closer to that of the metal substrate.

[0030] B2O3 promotes the melting and low viscosity of glass materials during plasma spraying. Therefore, it is essential for adjusting the effects of SiO2 and other components. The thermal expansion coefficient of B2O3 is small, just like SiO2. However, contrary to SiO2, B2O3 reduces corrosion resistance, hardness (abrasion resistance), electrical insulation, and voltage resistance, and accelerates changes over time. For this reason, increasing the amount of B2O3 impairs the properties of the sprayed glass part. B2O3 is easily volatilized by heating during spraying, and the amount of volatilization is not easy to control. As B2O3 volatilizes, the thermal expansion coefficient of the glass material changes from the original design.

[0031] In the case of a metal substrate made of a body-centered cubic iron material, the glass material contains 9 to 15 mass% of B2O3. In the case of a metal substrate made of a face-centered cubic iron material, the glass material contains 2 to 8 mass% of B2O3. If the B2O3 content exceeds the upper limit, peeling and penetration (cracks) of the glass coating of the sprayed glass formed on the surface of the metal substrate are likely to occur. If the B2O3 content falls below the lower limit, the glass material will not be able to fully melt and have low viscosity during plasma spraying, making it impossible to produce a suitable glass material.

[0032] Li2O promotes the melting and viscosity reduction of glass materials during plasma spraying, making it an essential component for adjusting the effects of SiO2 and other components. At the same time, Li2O is relatively resistant to volatilization during plasma spraying and has the highest thermal expansion coefficient compared to other components. Therefore, Li2O acts as a buffer to adjust the thermal expansion coefficients of other components and achieve the desired glass coating properties of the sprayed glass. Li2O reduces corrosion resistance against acids and alkalis and hardness (abrasion resistance). Furthermore, glass materials are more likely to recrystallize (to form lithium silicate crystals) during spraying. While recrystallization improves corrosion resistance, it also reduces the thermal expansion coefficient of the resulting glass coating. This decrease in the thermal expansion coefficient is difficult to control and can ultimately lead to cracking (cracking) on ​​the surface of the substrate.

[0033] In the case of a metal substrate made of body-centered cubic iron material, the Li2O content in the glass material is 5 to 9 mass%. In the case of a metal substrate made of face-centered cubic iron material, the Li2O content in the glass material is 8 to 15 mass%. If the Li2O content exceeds the upper limit, problems such as peeling described above occur, and the deterioration of electrical insulation, voltage resistance, corrosion resistance, etc. becomes significant. If the Li2O content is below the lower limit, the melting property and low viscosity during plasma spraying are not achieved.

[0034] Depending on the amount of Na2O in the glass material, it enhances the meltability of the glass material during plasma spraying and simultaneously increases its viscosity during melting. This facilitates adhesion of the glass material sprayed onto the surface of the metal substrate to be sprayed, enhancing the adhesive strength between the sprayed glass material and the surface of the metal substrate. Furthermore, the increased viscosity of the glass due to Na2O somewhat reduces the fluidity of the molten glass material adhered to the surface of the metal substrate, thereby suppressing the movement of bubbles entrained during spraying (the bubbles becoming larger due to fluidity) (see the examples below). Na2O significantly contributes to improving the smoothness of the sprayed glass portion after plasma spraying and reducing its film thickness, while also enhancing its electrical insulation and voltage resistance. Furthermore, when Na2O is used in a mass ratio (weight ratio) equivalent to that of Li2O, it enhances electrical insulation and voltage resistance, providing excellent functionality.

[0035] Because Na2O has the second-highest thermal expansion coefficient after Li2O, it is easy to engineer the thermal expansion coefficient of the glass material to match that of the metal substrate (body-centered cubic iron material or face-centered cubic iron material) to be sprayed. In this case, the amount of Na2O added depends on the ratio to the amount of Li2O. It is also worth noting that the viscosity of the melt developed by adding Na2O differs from that of the melt developed by adding Al2O3 or CaO, as described below. In the case of Na2O, the viscosity of the melt tends to increase linearly with increasing addition. In contrast, the viscosity of Al2O3 and CaO changes suddenly with the addition of these elements. Therefore, Na2O is suitable for easily controlling the viscosity of melted glassy materials.

[0036] However, like B2O3, Na2O is easily volatilized by plasma spraying, and the amount of volatilization is greater than that of Li2O. Na2O has a significantly different thermal expansion coefficient from B2O3. Therefore, in the case of a metal substrate made of body-centered cubic iron material, the glass material contains 4 to 10 mass% of Na2O. In addition, in the case of a metal substrate made of face-centered cubic iron material, the glass material contains 8 to 20 mass% of Na2O.

[0037] The upper limit of the Na2O content is determined by taking into account the thermal expansion coefficient of the metal substrate of the body-centered cubic iron material to be sprayed or the individual metal substrate of the face-centered cubic iron material. In particular, if the Na2O content is 20 mass% or more, the composition of the sprayed glass portion itself changes significantly after spraying due to the volatilization of Na2O, which can cause the sprayed glass portion to peel off or crack from the surface of the metal substrate. Furthermore, the glass material melts and becomes filamentous in the spraying device described below, hindering uniform spraying. Furthermore, sprayed glass portions formed from glass materials with a high Na2O content are prone to deterioration in corrosion resistance and hardness (wear resistance). Furthermore, if the Na2O content is below the lower limit, the characteristics of increasing the meltability of the glass material and simultaneously increasing the viscosity during melting are not observed, making it impossible to obtain the desired electrical insulation and voltage resistance.

[0038] The components B2O3, Li2O, and Na2O included in the second group component (B) are relatively easily volatilized when the glass material is heated during plasma spraying. When a sprayed glass portion derived from the molten glass material is formed on the surface of the metal substrate, the entrapment of bubbles is unavoidable. Therefore, the characteristics of the glass material used in the metallic glass composite of the embodiment require the utilization of the functions attributable to the second group component (B), the convergence of the glass material composition to take into account the thermal expansion coefficient of the material of the metal substrate, and the suppression of the amount of bubbles generated in the sprayed glass portion. If the amount of bubbles in the sprayed glass portion is excessive, the density of the sprayed glass portion itself will be lost, easily leading to a partial decrease in strength. Furthermore, the fluctuation in the dielectric constant of the sprayed glass portion will make it more susceptible to dielectric breakdown.

[0039] Therefore, in the glass material used in the metallic glass composite of the embodiment, when the second group component (B) is lumped together, in the case of a metal substrate made of a body-centered cubic iron material, the second group component (B) is blended in a total of 18 to 30 mass% in the glass material, and in the case of a metal substrate made of a face-centered cubic iron material, the second group component (B) is blended in a total of 25 to 35 mass% in the glass material.

[0040] The third group component (C) is a component that is blended mainly for the purpose of assisting in the formation of glass in the sprayed glass portion that occurs after thermal spraying. The third group component (C) includes BaO, TiO2, Al2O3, and ZnO.

[0041] BaO is a component that aids in the formation of SiO2 glass in glass materials. The greater the BaO content, the greater the melting property of the glass material and the lower the softening temperature of the glass material during thermal spraying. While the effect is less than the viscosity increase caused by Na2O, the inclusion of BaO does enhance the adhesion strength of the glass material sprayed onto the surface of the metal substrate. Therefore, BaO improves the smoothness of the glass coating on the sprayed glass portion formed after plasma spraying. Therefore, BaO contributes to reducing the film thickness of the sprayed glass portion and also improves the electrical insulation, voltage resistance, and dielectric constant of the sprayed glass portion. When BaO is added in the same amount as alkaline components such as Li2O and Na2O, its electrical insulation and voltage resistance are superior to those of Li2O and Na2O.

[0042] Therefore, in the case of a metal substrate made of a body-centered cubic iron material, the BaO content in the glass material is 0 to 15 mass%. Furthermore, in the case of a metal substrate made of a face-centered cubic iron material, the BaO content in the glass material is 3 to 12 mass%. If the BaO content in the glass material exceeds the upper limit, the viscosity of the glassy sprayed glass portion becomes extremely high when the glass material is plasma sprayed. As a result, the molten glass material melts and becomes thread-like in the spraying device described below, hindering uniform spraying. The coating of the sprayed glass portion formed after spraying may have reduced corrosion resistance and become brittle over time. In the case of a metal substrate made of a body-centered cubic iron material, the lower limit of the BaO content may be zero (0 mass%). Preferably, the lower limit of the BaO content is 3 mass%, similar to the case of a metal substrate made of a face-centered cubic iron material. Although it depends on the amount of other components added, this is because it is expected to improve the electrical insulation, voltage resistance, dielectric constant, etc. of the sprayed glass portion formed, and to improve the adhesive strength of the glass coating on the surface of the substrate.

[0043] TiO2 is a component that assists in the glass formation of SiO2 in glass materials. The more TiO2 is added, the more the hardness (wear resistance) of the glass coating of the sprayed glass portion increases. TiO2 also improves corrosion resistance, electrical insulation, and voltage resistance. TiO2 increases the viscosity of the glass material after spraying. Therefore, in the case of a metal substrate made of body-centered cubic iron material, the glass material should contain 2 to 15 mass% TiO2. In addition, in the case of a metal substrate made of face-centered cubic iron material, the glass material should contain 4 to 15 mass% TiO2.

[0044] If the TiO2 content exceeds the upper limit, crystallization of the glass occurs when the glass material melted by heating during plasma spraying cools (slowly cools) to form the sprayed glass part. In other words, the thermal expansion coefficient decreases, making it more likely to peel off. Crystallization of the glass drastically reduces hardness, corrosion resistance, etc. If the TiO2 content falls below the lower limit, it becomes difficult to improve the electrical insulation, voltage resistance, dielectric constant, etc. of the sprayed glass part formed, and to achieve meltability during plasma spraying, depending on the amounts of other components.

[0045] Al2O3 is a component that aids in the formation of a glassy SiO2 in glass materials. Al2O3 improves the corrosion resistance, hardness (abrasion resistance), electrical insulation, and voltage resistance of the glassy coating formed by the molten glass material, and prevents recrystallization. The inclusion of Al2O3 is desirable because of the improved recrystallization of the glassy coating in the sprayed glass material due to the inclusion of Li2O. Therefore, in the case of a metal substrate made of a body-centered cubic iron material, the glass material contains 0 to 8 mass% of Al2O3. In addition, in the case of a metal substrate made of a face-centered cubic iron material, the glass material contains 0 to 5 mass% of Al2O3. If the Al2O3 content exceeds the upper limit, the meltability of the glass material during plasma spraying is reduced and the viscosity is significantly increased. The lower limit of the Al2O3 content may be zero (0 mass%), and is preferably 2 mass%. The inclusion of Al2O3 improves the corrosion resistance of the sprayed glass and prevents recrystallization.

[0046] ZnO is a component that aids in the formation of SiO2 glass in glass materials. Like BaO, increasing the amount of ZnO increases the meltability of glass materials and lowers the softening temperature of the glass material during thermal spraying. While this effect is less than the viscosity increase caused by Na2O, the addition of ZnO does enhance the adhesion strength of the sprayed glass portion on the surface of the metal substrate. Therefore, like BaO, ZnO improves the smoothness of the glass coating formed on the sprayed glass portion after plasma spraying and contributes to reducing the thickness of the glass coating. Additionally, it enhances the electrical insulation, voltage resistance, and dielectric constant of the sprayed glass portion. When used in the same amount as alkaline components such as Li2O and Na2O, ZnO has superior electrical insulation and voltage resistance to Li2O and Na2O.

[0047] In the case of a metal substrate made of a body-centered cubic iron material, the ZnO content in the glass material is 0 to 15% by mass. In the case of a metal substrate made of a face-centered cubic iron material, the ZnO content in the glass material is 0 to 5% by mass. If the ZnO content exceeds the upper limit, the viscosity of the molten glass material increases when plasma spraying the glass material. As a result, the molten glass material melts and becomes filamentous in the thermal spraying device described below, hindering uniform spraying. Even in the glassy portion of the sprayed glass formed after thermal spraying, crystallization of the glass may occur, reducing the thermal expansion coefficient and potentially inducing peeling. As a result, the corrosion resistance of the glassy coating of the sprayed glass portion decreases and it becomes brittle over time. In particular, the crystallization of the glassy portion cannot be controlled. The lower limit of the ZnO content may be zero (0% by mass) regardless of whether the metal substrate is made of a body-centered cubic iron material or a face-centered cubic iron material. It is preferably 2% by mass. Depending on the amount of other components added, this tends to contribute to improving the electrical insulation, voltage resistance, dielectric constant, etc. of the glassy material in the sprayed glass portion formed after thermal spraying, and to improving the adhesion strength of the glassy material on the surface of the substrate.

[0048] The purpose of the third group component (C) is to improve the glass quality of the sprayed glass portion formed after thermal spraying. Therefore, depending on the application, function, etc. of the metallic glass composite, it is acceptable to not incorporate any of the components included in the third group component (C), as described above. The blending ratio of the third group component (C) is adjusted to balance with the first group component (A) and the second group component (B) and to adjust the thermal expansion coefficient. Therefore, in the glass material used in the metallic glass composite of the embodiment, when the third group component (C) is lumped together, in the case of a metal substrate made of a body-centered cubic iron material, the blending ratio of the third group component (C) in the glass material is 10 to 30 mass%. In the case of a metal substrate made of a face-centered cubic iron material, the blending ratio of the third group component (C) in the glass material is 10 to 20 mass%.

[0049] In the glass material used in the metallic glass composite of this embodiment, the main component (D) is the total blend of the first group component (A), the second group component (B), and the third group component (C). The blending ratio of the main component (D) in the glass material is 90 mass% or more. The entire glass material, excluding unavoidable impurities, can be made up of only the main component (D). Furthermore, in consideration of the application and durability of the metallic glass composite, an auxiliary component (E) is further blended with the main component (D).

[0050] The auxiliary component (E) is blended into a glass material composed of the oxide species of the main component (D) described above for the purposes of facilitating thermal spraying, improving the glassy quality when the glass material is melted, and stabilizing the properties of the glassy coating of the sprayed glass portion, as well as enhancing or adding functionality. To achieve compositional balance, the auxiliary component (E) is contained in the glass material at 0 to 10 mass %. The compositional components included in the auxiliary component (E) are listed below by function.

[0051] CaO improves corrosion resistance, hardness (wear resistance), etc. CaO also increases the melting point of the glass material during thermal spraying and lowers the softening temperature of the glass material during thermal spraying. This increases the adhesive strength of the glass material sprayed onto the surface of the metal substrate. In the presence of BaO, a small amount of CaO improves the transparency of the glass coating of the sprayed glass. However, although this depends on the blending ratio with other alkaline components, if the amount of CaO is too large, it reduces corrosion resistance and hardness and also deteriorates the melting point during thermal spraying.

[0052] SrO increases the melting property of the glass material during thermal spraying and lowers the softening temperature of the glass material during thermal spraying. This increases the adhesive strength of the glass material sprayed onto the surface of the metal substrate. Although SrO does not volatilize easily during thermal spraying, adding a large amount can induce crystallization during slow cooling of the sprayed glass, causing peeling.

[0053] MgO, P2O5, K2O, V2O5, MnO2, Fe2O3, Co3O4, NiO2, CuO, MoO3, SnO2, PbO, BiO2, and Lu2O3 increase the melting point of the glass material during thermal spraying and lower the softening temperature of the glass material during thermal spraying. This increases the adhesion strength of the glass material sprayed onto the surface of the metal substrate. However, depending on the amount, corrosion resistance, hardness (abrasion resistance), electrical insulation, and voltage resistance may decrease, or the viscosity of the glass material may suddenly increase during thermal spraying.

[0054] Cr2O3, ZrO2, and WO3 increase the hardness (wear resistance) of the glass coating on the sprayed glass part. Of these, ZrO2 improves corrosion resistance, electrical insulation, and voltage resistance. Sb2O3 reduces and shrinks the amount of bubbles in the glass material that is sprayed onto the surface of the metal substrate. However, depending on the amount added, ZrO2 and Sb2O3 can suddenly increase the viscosity of the glass when melted.

[0055] Y2O3, Nb2O5, Ta2O3, Bi2O3, La2O3, CeO2, Pr6O 11Nd2O3, Sm2O3, and Gd2O3 improve the electrical insulation and voltage resistance of the sprayed glass formed on the surface of the metal substrate. However, depending on the content, the melting temperature of the glass material increases, reducing its melting ability during spraying. They can also cause a sudden increase in the viscosity of the glass material during melting.

[0056] The metallic glass composites 1A, 1B, 1C, and 1D shown in the schematic diagrams (A) to (D) of FIG. 1 are generally produced in the following order: First, a metal substrate to be sprayed is prepared. Then, the surface of the metal substrate is blasted. During the blasting, fine particles such as Al2O3 (alundum) and SiC (carborundum) are sprayed onto the surface of the metal substrate. The surface of the metal substrate is roughened by sandblasting, which enhances thermal conduction to the metal substrate during heating, as described below. Note that the blasting is optional and is selected depending on the shape of the metal substrate and the area to be sprayed.

[0057] The surface temperature of the metal substrate is heated to 200 to 1000°C, preferably 500 to 1000°C, and more preferably 700 to 1000°C. An electric furnace or the like is used for heating. The heating is performed to maintain the molten state of the glass material prior to the thermal spraying described below. Note that if the metal substrate is at room temperature, the adhesion of the molten glass material to the metal substrate will be extremely reduced.

[0058] For thermal spraying, a plasma spraying device such as that described in Patent Document 2 is used. The glass material is a glassy powder (frit) containing the aforementioned compositional components. The glass material is supplied as a powder to the plasma spraying device, where it is instantaneously melted in the presence of a carrier gas, and sprayed onto the surface of a heated metal substrate, where it adheres to the surface. The thickness of the glassy coating on the sprayed glass portion is adjusted by adjusting the amount sprayed onto the surface of the metal substrate and the number of sprays. In the examples described below, argon gas or dry air was used as the carrier gas.

[0059] The thickness of the glass coating on the sprayed glass portion can be set over a wide range, from 10 to 2000 μm. For example, the thickness of the glass coating on a printing roll is 1000 to 2000 μm. Furthermore, in the case of an electrode for silent discharge, the thickness of the glass coating is 300 to 1500 μm. Furthermore, in the case of a bolt, the thickness of the glass coating is 10 to 100 μm. Of course, these thicknesses are merely examples, and the thickness may be increased or decreased depending on the application, durability, etc.

[0060] After thermal spraying, the sprayed glass formed on the surface of the metal substrate is slowly cooled or air-cooled. Then, if necessary, the surface is polished, ground, or otherwise smoothed to a smooth finish. In this way, metallic glass composites 1A, 1B, 1C, 1D, etc., as shown in the schematic diagrams (A) to (D) of Figure 1, are produced.

[0061] In order to maintain a strong bond between the metal substrate and the sprayed glass portion, it is necessary to match the thermal expansion coefficients of the metal substrate and the sprayed glass portion as closely as possible. As mentioned above, both the metal substrate and the sprayed glass portion undergo volumetric shrinkage during cooling after spraying. However, due to differences in expansion coefficients, the degree of volumetric shrinkage differs, resulting in poor adhesion, such as gaps between the metal substrate and the sprayed glass portion or cracks in the sprayed glass portion.

[0062] For the metal substrate of body-centered cubic iron material, for example, the linear expansion coefficient of SUS409 is 9.9 (×10 6 / ℃), and the linear expansion coefficient of SS400 is 12(×10 6 / °C). Therefore, in order to make the glass material used for the sprayed glass part correspond to the linear expansion coefficient of the metal substrate of the body-centered cubic iron material, the linear expansion coefficient of the glass material from room temperature to 300°C should be 9 to 11 (×10 6 / ℃).

[0063] For the metal substrate of face-centered cubic iron material, for example, the linear expansion coefficient of SUS304 is 17.3 (×10 6 / °C). Therefore, in order to make the glass material used for the sprayed glass part correspond to the linear expansion coefficient of the metal substrate of face-centered cubic iron material, the linear expansion coefficient of the glass material from room temperature to 300°C is set to 14 to 17 (×10 6 / ℃).

[0064] When adjusting the thermal expansion coefficients of the metal substrate and the sprayed glass portion (glass material), in addition to adjusting according to the type of metal substrate as described above, adjustments are made to minimize the difference in the linear expansion coefficients of the metal substrate and the sprayed glass portion (glass material). Specifically, the difference between the linear expansion coefficient of the glass material and the linear expansion coefficient of the metal substrate is set to within 15%. Theoretically, it is possible to achieve a perfect match (0% difference) between the linear expansion coefficients of both. However, in the case of a metal substrate with a curved surface or other shape, the contraction force of the sprayed glass portion formed after plasma spraying is utilized, allowing the sprayed glass portion to adhere more firmly to the surface of the metal substrate.

[0065] Examples of metallic glass composites suitable for different types of metal substrates are as follows: Iron-based materials include conveyor rolls and plywood for construction materials; stainless steel alloys include water rollers for printing equipment, zinc plating bath rollers, various rolls and rollers used at room temperature, various rolls and rollers for heating furnaces, electrodes for ozone-generating silent dischargers, and electrodes for plasma generation; nickel alloys include metal setters for firing various sintered bodies; and chromium-molybdenum steel alloys (e.g., SCM435, etc.) include automotive bolts (especially for fastening dissimilar metals and parts that generate sparks due to friction or static electricity), bolts for fastening various wind power generation parts (especially bolts for fastening offshore wind power generation), and bolts for general mechanical equipment.

[0066] In the metallic glass composite of the embodiment, as shown in the cross-sectional schematic diagram of FIG. 2(B), a molten solidified portion 40 is formed at a boundary 30 between the metal substrate portion 10 and the sprayed glass portion 20 in the cross section, where the sprayed glass portion is embedded in the metal substrate portion. The molten solidified portion 40 is formed to a thickness of 0.3 μm or more. Bubbles 21 exist in the sprayed glass portion 20, and residual glass 22 exists within the metal substrate portion 10 in the molten solidified portion 40. The symbol T30 in the figure is a mark indicating a 30% region in the thickness direction of the sprayed glass portion 20, starting from the boundary portion 30.

[0067] A notable phenomenon in the metallic glass composite of the embodiment is that the molten glass material sprayed onto the metal substrate does not simply adhere (deposit) onto the surface of the metal substrate. Specifically, in the surface layer of the metal substrate (the boundary between the two), the heated metal substrate and the molten glass material are mixed together, and some of the molten glass material penetrates into the metal substrate. This was confirmed by observation with a scanning electron microscope (SEM) (see electron microscope photographs from Figure 3 onwards). As a result, after cooling, a molten solidified portion is formed in which the sprayed glass portion is embedded in the metal substrate.

[0068] In the metallic glass composite of the embodiment, at the boundary between the metal substrate and the sprayed glass portion, the sprayed glass portion not only adheres to the metal substrate but also penetrates moderately, forming a region where both materials are mixed. Therefore, the sprayed glass portion penetrates into the metal substrate, improving the adhesion strength between them compared to the simple adhesion by conventional spraying. Specifically, durability can be confirmed by the ball drop height test described below.

[0069] The reason why a molten solidified portion is formed in the metallic glass composite of the embodiment is thought to be due to the conditions of plasma spraying, in which the glass material is melted and sprayed onto the heated metal substrate. Because the molten glass material itself is at a high temperature, the surface layer of the metal substrate is further heated by its own heating and the heat generated by the molten glass material, which is thought to cause metal melting also in the surface layer of the metal substrate. Then, the molten glass material collides with the surface layer of the metal substrate with the spraying force (velocity, pressure) from the plasma spraying. Since both are in a molten state within a very limited range, they tend to mix with each other, and ultimately a molten solidified portion is thought to be formed.

[0070] In the case of the aforementioned Patent Document 1 (JP 2013-216977 A), a molten glass material penetrates into the surface of a metal substrate that has been roughened by blasting. In contrast, the metallic glass composite of the embodiment is structurally different in that it forms a molten solidified portion.

[0071] The electron microscope photographs in Figure 3 and subsequent figures are cross-sections of prototype metallic glass composites. Measurements based on the photographs at increased magnification, particularly (B) in each figure, confirmed that the molten solidified portion had a thickness of 0.3 μm or more. The upper limit of the molten solidified portion cannot exceed the total thickness of the sprayed glass portion. Therefore, the upper limit of the molten solidified portion is considered to be approximately 1 μm or less. As can be seen from each photograph, in the metallic glass composite of the embodiment, the boundary portion is the interface where the sprayed glass portion contacts the metal substrate portion. The molten solidified portion is a region where glass material is trapped and scattered within the metal substrate portion, and is the depth from the boundary between the metal substrate portion and the sprayed glass portion to the range where the trapped glass material is present.

[0072] The above explanations disclose the composition, thermal expansion coefficient relationship, and characteristics of the molten and solidified zone that occurs at the boundary between the sprayed glass portion (glass material) and the metal substrate. In addition, a specification is required after the sprayed glass portion is formed on the surface of the metal substrate. Specifically, the amount of bubbles present in the sprayed glass portion must be controlled. Therefore, the area ratio of bubbles 1 μm or larger in the cross section of the sprayed glass portion in the thickness direction of the finished metallic glass composite is suppressed to less than 40%. To measure the bubbles, the metallic glass composite is cut in the thickness direction of the sprayed glass portion to expose the cut surface. The cut surface is then enlarged using a scanning electron microscope (SEM), and the area of ​​bubbles 1 μm or larger in diameter on the exposed cut surface is determined. The total area of ​​bubbles 1 μm or larger in diameter is then calculated. The area ratio of bubbles 1 μm or larger is calculated as the total area of ​​bubbles in the cross section of the sprayed glass portion. That is, the area ratio of bubbles of 1 μm or more is calculated as "area ratio (%) of bubbles of 1 μm or more" = {(total area of ​​bubbles of 1 μm or more on the cut surface) / (total area of ​​the cut surface)}×100.

[0073] When the amount of bubbles increases in the sprayed glass portion of a metallic glass composite, the sprayed glass portion becomes more spongy, losing its density and reducing its structural strength. As shown in the ball drop height test described below, the greater the area fraction of bubbles in the cross section, the lower the impact strength. Therefore, since this is an index that directly affects the durability of the metallic glass composite, the area fraction of bubbles 1 μm or larger in the cross section in the thickness direction of the sprayed glass portion should be less than 40%, preferably 30% or less, and more preferably 20% or less.

[0074] Furthermore, if the metallic glass composite is intended for use as an electrode, a high bubble area ratio can easily cause insulation breakdown in the sprayed glass when current is applied. This can cause damage to the device in which the metallic glass composite is installed. Therefore, it is important to minimize the bubble area ratio. As explained in the glass material components section, when the glass material melts due to heating during spraying, the second group component (B) is easily volatilized, and this gasification generates bubbles. Furthermore, during spraying, the molten glass material is instantly applied to the surface of the metal substrate and adheres to that surface. The bubbles that form in the molten glass material cannot move, and remain trapped in the sprayed glass as it cools, remaining in the sprayed glass.

[0075] The blending ratios of the first group component (A), the second group component (B), and the third group component (C) of the glass material are necessary to adjust the thermal expansion coefficient of the metal substrate and to control the durability of the glass. Therefore, the second group component (B) is blended regardless of gasification. As can be seen from this, the composition of the glass material of the embodiment is established in a balance that adjusts the thermal expansion coefficient of the metal substrate while suppressing residual bubbles for durability reasons.

[0076] In the metallic glass composite of the embodiment, the basic presence region and area ratio are further specified in detail. Specifically, at the boundary between the metal substrate portion and the sprayed glass portion in a longitudinal cross section of the metallic glass composite, it is desirable that the area ratio of bubbles 1 μm or larger that exist within an area of ​​30% of the thickness of the sprayed glass portion from the boundary be suppressed to 50% or less. Furthermore, it is desirable that the thickness of the sprayed glass portion be in the range of 10 to 100 μm, and that the area ratio of bubbles 1 μm or larger in the cross section of the sprayed glass portion in the thickness direction be less than 10% in the sprayed glass portion.

[0077] As mentioned above, when spraying a glass material, the compositional components volatilize and gasify due to the heat of the spraying. Then, because the molten glass material is sprayed before the volatilized gases can diffuse, they are left behind as bubbles. In particular, in metallic glass composites, the deep regions of the sprayed glass portion, in other words, the regions close to the metal substrate, tend to inevitably have many bubbles. Furthermore, to increase the adhesive strength between the sprayed glass portion and the metal substrate, it is desirable for the sprayed glass portion to be dense, i.e., to have as few bubbles as possible.

[0078] Therefore, in order to make it possible to grasp the shape of the sprayed glass part, the area ratio of bubbles of 1 μm or more is suppressed to 50% or less, preferably 40% or less, in the region starting from the boundary and extending up to 30% (including within 30%) of the thickness of the sprayed glass part. By suppressing the amount of bubbles near the boundary of the sprayed glass part, the density of the sprayed glass part near the boundary increases, making it easier to increase its strength.

[0079] Furthermore, the thickness of the sprayed glass portion of a metallic glass composite can be adjusted by changing the amount of spraying depending on the application. However, a thicker sprayed glass portion results in an increase in glassiness, which may lead to cracks after cooling and reduced durability during use. In particular, for purposes such as corrosion protection and insulation, the thinner the thickness, the better. For this reason, the thickness of the sprayed glass portion is usually finished in the range of 10 to 100 μm.

[0080] In a sprayed glass portion of this thickness, the presence of bubbles directly contributes to a decrease in performance such as durability and insulation, so it is desirable to reduce the number of bubbles even further than the above conditions. Therefore, the area ratio of bubbles 1 μm or larger in the sprayed glass portion (entire cross section) is suppressed to less than 10%, preferably less than 7%. [Example]

[0081] [Type of metal substrate] In producing the metallic glass composite, the following three types of metal substrate plates (100 mm x 30 mm, 1.2 mm thick) were used. SUS409, SUS430, and SS400 were used as metal substrates made of body-centered cubic iron material. SUS304 was used as metal substrates made of face-centered cubic iron material. For reference, the metal composition (mass%) and linear expansion coefficient (×10 -6 / °C) are shown in Table 1. Since each metal in the table is an iron-based alloy, Fe is shown as the balance.

[0082] [Table 1]

[0083] [Treatment of metal substrate] The plate-shaped metal substrates listed in Table 1 were sandblasted with #60 or #80 alundum, and the surfaces were air-washed to remove dust. Prior to thermal spraying, the plate-shaped bodies were heated to approximately 700 to 1000°C in an electric furnace, and thermal spraying was carried out under the conditions described below before the temperature was lowered.

[0084] [Glass composition] Each component was blended according to the composition shown in Table 2 below to prepare glass materials of prototypes 1 to 16, which were then pulverized into frit (powder). The frit was classified to the desired average particle size. In the table, each component is shown as mass % of the entire glass material. For ease of understanding, the total of the second group components (B) and the total of the third group components (C) in the entire glass material are also shown. In addition, the linear expansion coefficient (α) (unit: × 10 -6 / ℃).

[0085] [Table 2]

[0086] [Thermal spraying equipment and conditions] For plasma spraying, the spraying equipment used was a Praxair Model SG-100 Plasma Spray Gun (manufactured by Praxair Technology, Inc.). Additionally, the equipment used to control the supply of electricity, cooling water, gas, and spraying material was the Praxair Model 3710 Plasma Control Console. The glass material supply device was the Praxair Model 1264 Powder Feeder. The power supply was the Praxair Model PS-1000 Plasma Power Source. The high-frequency generator was the Praxair Model HF-2200.

[0087] The same method was used for spraying the frit of the glass material in Prototype Examples 1 to 16. However, the scanning speed of the plate-shaped metal substrate during spraying was increased or decreased to adjust the amount of coating that was sprayed onto the surface. Thermal spraying conditions Voltage: 30~50V Current: 700~1000A Heating temperature of metal substrate: 700-1000℃

[0088] For each thermal spraying condition, if the lower limit is exceeded, the effect of insufficient heat is so great that the glass material does not melt on the surface of the metal substrate, making it impossible to ensure adhesion.If the upper limit is exceeded, the melting of the metal substrate becomes too intense, causing deformation of the metal substrate itself.

[0089] The raw material supply conditions were the following gas species and flow rates. The raw material carrier gas was dry air or argon. When the flow rate is Fa (NL / min) and the raw material supply rate is Fb (g / min), "Fb / Fa" was controlled to 0.4 or less. If "Fb / Fa" exceeds 0.4, melting of the base material becomes difficult even if the above-mentioned thermal spraying conditions are met.

[0090] [Characteristics of metallic glass composites] Prototypes G1 to G21 were fabricated as metallic glass composites with a metal substrate made of body-centered cubic iron material, and prototypes H1 to H8 were fabricated as metallic glass composites with a metal substrate made of face-centered cubic iron material. The results for prototypes G1 to G21 are shown in Table 3, and the results for prototypes H1 to H8 are shown in Table 4.

[0091] Tables 3 and 4 list, in order, the prototype number, the type of glass material disclosed in Table 2, the type of metal substrate, the heating temperature (°C) of the metal substrate, the amount of current (A) during spraying, the thickness (μm) of the sprayed glass portion of the final metallic glass composite, the area ratio (%) of bubbles 1 μm or larger in the entire sprayed glass portion, the area ratio (%) of bubbles 1 μm or larger that exist in a region within 30% of the thickness of the sprayed glass portion starting from the boundary, the thickness of the molten and solidified portion (μm), the maximum diameter (μm) of bubbles present in the sprayed glass portion, the ball drop height (cm), and the dielectric strength test (MV / m).

[0092] To observe and measure thickness and bubbles, each metallic glass composite was cut lengthwise and observed using a scanning electron microscope (SEM). Figure 3 shows electron microscope photographs of prototype G1, Figure 4 shows prototype G2, Figure 5 shows prototype G6, Figure 6 shows prototype G11, Figure 7 shows prototype G13, Figure 8 shows prototype G19, and Figure 9 shows prototype H5. (A) in each figure is a 100x magnified photograph, and (B) in each figure is a 1000x magnified photograph.

[0093] The ball drop height was evaluated by freely dropping a 150g steel ball from directly above onto the sprayed glass portion (exposed glass surface) of each metallic glass composite. The height (vertical length from the sprayed glass portion to the steel ball) at which the impact of the falling steel ball caused visible abnormalities in the sprayed glass portion, such as cracks, fissures, or chips, was defined as the ball drop height for that sample. The plot graph (scatter diagram) in Figure 10 shows the relationship between the total bubble area fraction (%) in the sprayed glass portion of each metallic glass composite and the ball drop height (cm) for each sample.

[0094] A dielectric strength test was conducted in accordance with the test method of JIS C 2110 (2016) (IEC 60243-1:2013), and the metallic glass composite of each prototype was measured. The plot graph (dispersion diagram) in Figure 11 shows the relationship between the bubble area ratio (%) at the boundary of the sprayed glass part of the metallic glass composite of each prototype and the dielectric strength (MV / m). For the dielectric strength test, a Nippon Technart HP-5110DS was used, and the presence or absence of leakage was evaluated by applying 10 kV for 1 minute.

[0095] For the metallic glass composites of prototypes G1 to G19 in Table 3, the thermal spraying device travel speed was 31 mm / sec. For prototypes G1 to G18, the metal substrate was sprayed five times, while prototype G19 was sprayed once. For prototype G20, the thermal spraying device travel speed was 52 mm / sec, and the metallic substrate was sprayed once. For prototype G21, the thermal spraying device travel speed was 125 mm / sec, and the metallic substrate was sprayed once.

[0096] For the metallic glass composites of prototypes H1 to H8 in Table 4, the moving speed of the thermal spraying device was set to 31 mm / sec, and the metal substrate was thermally sprayed five times.

[0097] For the metallic glass composites of prototype examples H9 to H16 in Table 5, the movement speed of the spraying device was 125 mm / sec and the metal substrate was sprayed once; for the metallic glass composites of prototype examples H17 to H21, the movement speed of the spraying device was 52 mm / sec and the metal substrate was sprayed once; and for the metallic glass composites of prototype examples H22 to H24, the movement speed of the spraying device was 31 mm / sec and the metal substrate was sprayed five times.

[0098] [Table 3]

[0099] [Table 4]

[0100] [Table 5]

[0101] [Results and Discussion] As shown in Table 3, the metallic glass composite of Prototype G6 used the glass material of Prototype 4. Prototype 4 had a high proportion of the volatile component, Group 2 component (B) (32% by mass in total). This resulted in an increased bubble area ratio. The increased voids due to the increased bubble content led to a deterioration in the ball drop height. In contrast, the metallic glass composite of Prototype G5 used the glass material of Prototype 3. The proportion of Group 2 component (B) in the glass material of Prototype 3 was 29% by mass in total. A decrease in the total bubble area ratio of Prototype G5 was confirmed, and an increase in the ball drop height was also evident. Therefore, for a metal substrate made of a body-centered cubic iron material, such as SUS409, the upper limit for the proportion of Group 2 component (B) is estimated to be 30% by mass.

[0102] The metallic glass composites of prototypes G19 to G21 are examples in which the glass film thickness of the sprayed glass portion was thinned to 100 μm or less. For prototypes G19 to G21, the glass materials of prototypes 1 and 16, which have a low proportion of the second group component (B), were used. This is thought to have suppressed the amount of volatilization during spraying and reduced the generation of bubbles. The results of the falling ball height confirmed the formation of an extremely strong sprayed glass portion.

[0103] When producing each prototype metallic glass composite, the spraying environment using a plasma spraying device is in a temperature range that melts the outermost surface of the metal substrate, which serves as the base for the spraying. Therefore, the heat during spraying makes it easier for the compositional components of the glass material to volatilize. In particular, the linear expansion coefficient of body-centered cubic iron materials is lower than that of metals made of face-centered cubic iron materials, so it is more important to control the thermal expansion coefficient (linear expansion coefficient) and to limit the upper limit of the easily volatilized second group component (B). Therefore, based on the results of the prototypes, the blending ratio of the second group component (B) in the glass material is 10 to 30 mass%, preferably 20 to 30 mass%.

[0104] The metallic glass composites of prototypes H1 to H24 are examples of metal substrates (SUS304) made of face-centered cubic iron material. Face-centered cubic iron material has a larger linear expansion coefficient than body-centered cubic iron material, so the restrictions on the blending ratio of the second group component (B) are relaxed. Furthermore, the amount of bubbles is generally small, and the ball drop height is good. For this reason, the blending ratio of the second group component (B) in the glass material is 25 to 35 mass%.

[0105] When preparing the glass material of the prototype example, if the SiO2 content of the first group component (A) in the glass material exceeds 70% by mass, the viscosity of the molten glass material becomes excessive during thermal spraying, resulting in significant residual bubbles. Furthermore, if it is less than 35% by mass, it becomes difficult to adjust the linear expansion coefficient. Therefore, in the case of body-centered cubic iron materials, the SiO2 content of the first group component (A) in the glass material is 35 to 70% by mass. For the same reason, in the case of face-centered cubic iron materials, the SiO2 content of the first group component (A) in the glass material is 50 to 60% by mass.

[0106] The third group component (C) is a component that affects the viscosity of the molten glass material. From the results of the glass material and metallic glass composite of each prototype, in the case of body-centered cubic iron material, the total content of the third group component (C) in the glass material is 10 to 30 mass%, and in the case of face-centered cubic iron material, the content of SiO2, the first group component (A), in the glass material is 10 to 20 mass%.

[0107] Considering the results of the falling ball height and dielectric strength of the metallic glass composites of prototypes G1 to G19 and H1 to G24, the area ratio of bubbles 1 μm or larger in the cross section of the thickness direction of the sprayed glass portion is less than 40%, preferably 30% or less. In addition, the area ratio of bubbles 1 μm or larger present in a region within 30% of the thickness direction of the sprayed glass portion from the boundary is also preferably 50% or less. Furthermore, in the metallic glass composites of prototypes G19 to G21 where the thickness of the sprayed glass portion is 100 μm or less, the area ratio of bubbles 1 μm or larger present in the thickness direction of the sprayed glass portion can be reduced to an extremely low 10% or less, resulting in improved performance in the falling ball height and dielectric strength.

[0108] The relationship between the total bubble area ratio (%) and the falling ball height (cm) is shown as a plot graph in Figure 10. As the total bubble area ratio increases, the falling ball height value tends to decrease. This indicates that the strength of the sprayed glass part decreases due to the increase in bubbles. The relationship between the bubble area ratio (%) at the boundary and the dielectric strength (MV / m) is shown as a plot graph in Figure 11. Dielectric strength is maintained so long as the bubble area ratio at the boundary is up to 40%. However, once the bubble area ratio at the boundary exceeds 40%, the decrease in dielectric strength becomes noticeable. From this trend, the range of the bubble area ratio mentioned above is determined. [Explanation of symbols]

[0109] 1A, 1B, 1C, 1D Metallic glass composite 10,11,12,13,14 Metal base material part 20 Thermal Spray Glass Section 21 Bubbles 22 Residual vitreous 30 Boundary 40 Melting and solidification area T30 30% of the thickness of the sprayed glass

Claims

1. a metal substrate made of a body-centered cubic iron material, and a sprayed glass portion formed on the metal substrate with a film thickness of 10 to 2000 μm; The glass material forming the sprayed glass portion is As the first group component (A), SiO ２ : 35 to 70% by mass, As the second group component (B), B ２ O ３ : 9 to 15 mass%; Li ２ O: 5 to 9 mass%; Na ２ O: 4 to 10% by mass, and the total amount is 18 to 30% by mass, As the third group component (C), BaO: 0 to 15 mass%; TiO ２ : 2 to 15 mass%; Al ２ O ３ : 0 to 8 mass%; ZnO: 0 to 15% by mass, totaling 10 to 30% by mass, the first group component (A), the second group component (B), and the third group component (A) together constitute 90 mass% or more of a main component (D); The coefficient of linear expansion of the glass material from room temperature to 300°C is 9 to 11 (×10 ６ / °C), The area ratio of bubbles of 1 μm or more in the cross section in the thickness direction of the sprayed glass portion is less than 40%. A metallic glass composite comprising:

2. a metal substrate made of a face-centered cubic iron material, and a sprayed glass portion formed on the metal substrate with a film thickness of 10 to 2000 μm; The glass material forming the sprayed glass portion is As the first group component (A), SiO ２ : 50 to 60% by mass, As the second group component (B), B ２ O ３ : 2 to 8 mass%; Li ２ O: 8 to 15 mass%; Na ２ O: 8 to 20% by mass, totaling 25 to 35% by mass, As the third group component (C), BaO: 3 to 12 mass%; TiO ２ : 4 to 15 mass%; Al ２ O ３ : 0 to 5 mass%; ZnO: 0 to 5 mass%, and the total amount is 10 to 20 mass%, the first group component (A), the second group component (B), and the third group component (A) together constitute 90 mass% or more of a main component (D); The coefficient of linear expansion of the glass material from room temperature to 300°C is 14 to 17 (×10 ６ / °C), The area ratio of bubbles of 1 μm or more in the cross section in the thickness direction of the sprayed glass portion is less than 40%. A metallic glass composite comprising:

3. 3. The metallic glass composite according to claim 1, wherein a difference between the linear expansion coefficient of the glass material and the linear expansion coefficient of the metal substrate is within 15%.

4. The metallic glass composite according to claim 1 or 2, wherein the metallic glass composite has a molten solidified portion in which the sprayed glass portion is embedded in the metallic substrate portion at the boundary between the metallic substrate portion and the sprayed glass portion in the cross section, and the molten solidified portion has a thickness of 0.3 μm or more.

5. 3. The metallic glass composite according to claim 1, wherein the area ratio of bubbles having a size of 1 μm or more that are present in an area within 30% of the thickness of the sprayed glass portion from the boundary between the metal substrate portion and the sprayed glass portion in the cross section is 50% or less.

6. 3. The metallic glass composite according to claim 1, wherein the thickness of the sprayed glass portion is 10 to 100 μm, and the area ratio of bubbles of 1 μm or larger in a cross section in the thickness direction of the sprayed glass portion is less than 10%.

7. The component other than the main component (D) of the glass material is an auxiliary component (E), The auxiliary component (E) is CaO, SrO, MgO, P ２ O ５ , K ２ O.V. ２ O ５ , Cr ２ O ３ , MnO ２ , Fe ２ O ３ , Co ３ O ４ , NiO ２ , CuO, Y ２ O ３ , ZrO ２ , Nb ２ O ２ , MoO ３ , SnO ２ , Sb ２ O ３ , W.O. ３ , PbO, Bi ２ O ３ , La ２ O ３ , CeO ２ , Pr ６ O １１ , Nd ２ O ３ , Sm ２ O ３ , Gd ２ O ３ 3. The metallic glass composite according to claim 1, wherein the metallic glass composite is one or more of the following:

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