TW200804228A - Molding die for glass hard disk substrate - Google Patents

Abstract

Disclosed is a molding die for glass hard disk substrates which is hardly reactive with glasses, while having high wear resistance and high durability. A glass molded therein can be easily released from the surface of the molding die. Specifically disclosed is a molding die for glass hard disk substrates, which contains a silicon carbide-carbon composite ceramic. The silicon carbide-carbon composite ceramic contains 15-50 parts by weigh of carbon per 100 parts by weight of silicon carbide, and the average particle diameter of the carbon is within the range of 0.3-100 μm.

Description

[Technical Field] The present invention relates to a molding die for a glass hard disk substrate, and more particularly to a molding die for a glass hard disk substrate containing a tantalum carbide-carbon composite ceramic. And a method of manufacturing a glass hard disk substrate using the same. [Prior Art] A glass hard disk substrate is suitable for a substrate for a magnetic recording medium used in an information recording device. Usually, the glass hard disk substrate is placed between the upper mold and the lower mold of the forming mold, and is formed into a desired shape by hot pressing, and further, the surface is polished to be processed as necessary. As a material for forming a molding die of the above-described glass hard disk substrate, since ceramics are excellent in thermal stability, various ceramics (JP 2002-230747) are used. On the other hand, JP 2004-67432 discloses a ceramic composite sintered body formed by blending a ceramic material of a specific particle size (such as tantalum carbide) with carbon of a specific particle size in a specific ratio, as a ceramic, glass, or the like. A raw material of a molding die when forming a metal or the like. However, in the manufacture of a glass hard disk substrate, the molding die material described in JP 2002-230747 has a surface that is easy to wear, and the glass component reacts with the surface of the molding die at a high temperature. Therefore, there is a problem that the surface precision of the formed glass is lowered. Further, in the ceramic composite sintered body described in JP 2004-67432, since the particle diameter of the carbon particles contained therein is small, the glass component and the surface of the molding die are strongly adhered to each other, and it is difficult to peel off from the molding die, so that it is difficult to continuously In the form of 121126.doc 200804228 shape. The present invention relates to a molding die for a glass hard disk substrate (hereinafter also referred to as "the molding die of the present invention"), which is a molding die containing a ruthenium carbide-carbon composite ceramic in which the above-described ruthenium carbide is- In the carbon composite ceramic, 15 parts by weight to 50 parts by weight of carbon particles are contained in parts by weight of the cerium carbide, and the average particle diameter of the stone antiparticles is in the range of 〇·3 μπι 1 to (4). The present invention relates to a method for producing a glass hard disk substrate, which comprises the steps of: arranging a glass raw material in a molding die, and subjecting the glass raw material to press forming, and the forming die is the glass of the present invention. A forming die for a hard disk substrate. [Embodiment] (Forming Die for Glass Hard Disk Substrate) As described above, the molding die of the present invention contains a ruthenium carbide-carbon composite ceramic (hereinafter also referred to as "composite ceramic"), and the ruthenium carbide-breaking composite ceramic is used. And 100 parts by weight of carbonized ruthenium containing 15 parts by weight to 50 parts by weight of carbon particles, and the average particle diameter of the carbon particles is in the range of 〇·3 μιη to 1〇〇μηι. As described above, in the above-mentioned composite ceramic, the above-mentioned composite ceramic contains 15 parts by weight to 50 parts by weight of the stone-reactive particles for 100 parts by weight of cerium carbide, and the prior art, for example, the above-mentioned Patent Document 1 The amount of carbon used as a sintering aid in the production of tantalum carbide composite taman is relatively large compared to the amount of carbon used as a sintering aid. By having the above content, the reactivity with the glass can be suppressed during the molding of the glass, whereby the molding die exhibits high abrasion resistance and durability. Further, it is also possible to ensure sufficient durability such as the patent document 2 for a carbon content of 121126.doc 200804228. In the molding die of the present invention, the average particle diameter of the carbon particles contained in the composite (four) is 0.3 μηι to 100 μηη, which is a very large particle size compared with the carbon particles in the ceramic of Patent Document 2. path. By using the above-mentioned large-sized carbon particles, the adhesion between the formed glass and the surface of the molding die can be lowered to achieve good mold release property.

Moreover, from the viewpoint of ensuring better release property, the average particle diameter of the carbon particles contained in the composite ceramics is preferably 〇5 qing or more, more preferably 疋0.7 μηη or more, and further preferably i Ιιη or more. Similarly, from the viewpoint of ensuring better release properties, the average particle size of the carbon particles contained in the above composite ceramics is preferably 25 μC, and more preferably 5 or less. Specifically, the average particle diameter of the carbon particles is preferably 〇5 μιη to 25 pm, more preferably ~5 qing' and further preferably i(four) 〜5 _. The average particle diameter of the carbon particles is determined by the laser diffraction/scattering particle diameter, which is manufactured by the company, and the volume average particle diameter of the crucible is the same. Further, the molding die used in the production of the hard disk substrate of the present invention may be a substrate made of a hard glass substrate, but the glass hard disk substrate may be a non-crystalline glass. The glass (glass phantom substrate) is not particularly limited as long as it is a glass substrate. From the viewpoint of ensuring higher abrasion resistance and durability, the content of the carbon particles contained in the composite ceramic is preferably It is 15 parts by weight to 45 parts by weight, more preferably ～30 parts by weight, based on the weight of the cerium carbide. 121126.doc 200804228 As the raw material of the above-mentioned carbonized stone, it can be α, β The purity of the —-junction 碳 矽 并无 并无 并无 并无 并无 并无 并无 担 担 担 # # # # # # # # # # 处 处 处 处 处 处 处 处 更 更 更 更 更 更 更 更 更 更 更 更 更 更The flatness of the carbonaceous raw material (particles): the diameter is not particularly limited', but from the viewpoint of better sinterability, the above-mentioned raw material is preferably a powder of 10.10 „1~1〇^1111.

(4) The carbon particles contained in the noisy man are preferably carbon monomers, which are composed of a phase, an amorphous phase, or a mixed phase of a crystalline phase and an amorphous phase. The crystal phase of the specific monomer is preferably in the range of the spectrum measured by the Raman spectroscopy method, which is in the range of 1480::1 to 1700 ga. The crystal structure is not particularly limited, but is preferably a graphite-type planar hexagonal structure, a rhombohedral structure, etc. The amorphous phase is preferably obtained by laser Raman. The measurement spectrum obtained by the spectroscopic method has a peak of a crystal phase in the range of 1300 cm·i to 145 cm-i centered around 136 G W. The carbon particles contained in the composite ceramic are higher in ensuring From the viewpoint of abrasion resistance and durability, the peak area ratio (crystal phase 7 amorphous phase) of the laser Raman spectroscopic intensity of the crystal phase and the amorphous phase is higher from the viewpoint of achieving higher strength and fracture toughness. It is preferably 1 to 1 Torr, more preferably 1 to 5. In general, it is considered that the peak area ratio corresponds to the degree of graphitization of carbon, and if the value is in the above range, more excellent strength and fracture toughness can be achieved. Furthermore, the above spectrum can be measured using an argon laser Raman spectroscopic device (NEC Corporation). In order to achieve the above peak area ratio, it is also possible to better select a residual carbon ratio of 30% by weight to 95% by weight/〇 to better select a residual carbon ratio of 40% by weight to 90% by weight. Doc 200804228 Grease and coal tar pitch are used as carbon sources. Further, the carbon residue ratio refers to the weight percentage of fixed carbon in the carbon source measured according to JIS K 2425.

From the viewpoint of ensuring higher abrasion resistance and durability, the above-mentioned composite ceramics contains an average particle size of G3 _ or more. Similarly, from the viewpoint of ensuring higher wear resistance and durability, the average particle size of the carbon cut contained in the above composite ceramics is preferably (10) below, and more preferably 50 or less. It is 4 _ or less. Specifically, the average particle diameter of the carbonized stone is preferably G·3 handsome ~ (10) (four), more preferably 〇 3 μΓΠ ' and further preferably 〇 · 3 _ ~ 4 μιη. Further, the average particle diameter of the carbonized stone can be measured by the same method as the average particle diameter of the above carbon particles. The carbonized stone is a matrix in the above composite ceramic pot, and its crystal form may be either α or β. The above-mentioned composite (4) is preferably composed of the above-mentioned carbon cut and carbon. However, it may further contain an optional component such as a carbide other than the carbonaceous stone in the range which does not impair the effects of the present invention. The composite ceramic of the present invention contains carbon particles having a large particle diameter, and preferably contains a ruthenium carbide having a large diameter, thereby ensuring the strength of the composite ceramics, and it is preferable that the diameter of the void is small. The larger diameter of the larger void is preferably 鸠(4) or less, more preferably 0 is less than 100 (four), and further preferably 5 〇 μιη or less and more preferably 25 μπ1 or less. Further, the maximum void diameter can be measured as follows. In other words, for the void 1 on the surface of the composite pottery, the image of the void hole (photograph) can be obtained by the VH-8〇〇〇 type manufactured by Key: nce, and the obtained image can be analyzed. In the image analysis, the long axis diameter (mm) and the short (four) (job) of the randomly oriented void are measured, and the long axis 121126.doc 200804228 diameter + short axis diameter/2' is obtained and the above VH__ type magnification is obtained. The maximum value of each value obtained for each void hole in the field of view at the time of the double magnification is taken as the maximum void diameter. The long axis diameter and the short axis diameter are defined as follows. When the gap hole is held by two parallel lines, the width of the gap hole which minimizes the interval between the kick parallel lines is referred to as the short axis #, and on the other hand, when two holes are perpendicular to the parallel line When the wire is used to hold the void hole, the interval between the two parallel lines is referred to as a long axis diameter. Furthermore, it is molded and formed.

CIp (C〇LD IS〇STATIC PRESS, cold isostatic pressing), Hip (酣ISOSTATK: PRESS, hot isostatic pressing), etc., if formed by the pressure of 〇5 core 2, the largest compound ceramic scorpion The void diameter is _ or less. Since the mold of the present invention has high mold release property to glass, it is preferred that at least a part of the surface contacted by the glass during glass forming is composed of the above composite ceramics, and it is preferable that the contact surfaces are all The above composite Tao Jing constitutes. X, the entire molding die may be composed of the above composite ceramic. Specifically, when the molding die of the present invention is composed of a die and a punch, either or both of the die and the punch may be composed of the above composite ceramic. Further, for the mold or the punch, the part or the whole surface of the contact surface with the glass may be composed of the above composite ceramics. The shape of the molding die of the present invention may be exemplified as previously known. The shape of the forming die is the same. The molding die of the present invention is characterized in that it comprises the above composite ceramic, and as described above, if at least a part of the surface contacted by the glass contains the composite ceramic, the release property to the glass can be improved, and thus the shape is 121126. Doc 200804228 There are no restrictions. When the molding die of the present invention is used to form a glass hard disk substrate, the two moxibustion shapes of the contact surface with the glass in the molding die can be transferred to the surface of the formed glass (4). The contact surface is as smooth as possible. Specifically, from the viewpoint of the substrate polishing efficiency after molding and the smoothness of the above-mentioned contact surface, the average thickness Ra of the center line of the above-mentioned contact surface is higher.

Ok, please call 1 _~10, and better _ μΓη~9.5 (4), and then 0.02 is good. Furthermore, the average thickness of the center line can be obtained by using m B 〇 651. The average thickness of the center line can be set to the above range by increasing the density of the sintered body. Therefore, the following calcined powder (combined ceramics *) can be used. (Manufacturing method of composite ceramic) The composite ceramic in the molding die for a glass hard disk substrate of this month can be prepared as follows. The above composite ceramics can be produced by forming a raw material mixture containing cerium carbide and a carbon source into a desired shape after firing according to the necessity of firing. As will be described below, when the composite mold of the present invention is constituted by the composite ceramic, it can be formed into a desired shape of a molding die, and when the composite ceramic is used as a part of the molding die of the present invention, it can be formed into a molding die part. The desired shape. The above composite ceramic is preferably a monomer containing carbon as described above, but the monomer of the carbon is preferably produced by a suitable carbon source in the production process. Specifically, the cerium carbide, the following carbon source, and the previously known additives as required may be subjected to wet mixing and then sintered. In the sintering step, the carbon of the carbon 121126.doc -12-200804228 is usually converted to a monomer. The mixing ratio of each of the above-mentioned raw materials can be appropriately set to [10 parts by weight of carbonaceous stone in the composite ceramic material obtained, and contains 15 parts by weight to 50 parts by weight of carbon particles. The above-mentioned additives are not particularly limited, and examples thereof include sintering aids such as a well-known boron compound, a titanium compound, and a silver oxide compound. The above-described fishing type σ can be mixed using a ball mill, a vibrating ball mill, a planetary ball mill or the like. The solvent to be used for the wet mixing is not particularly limited. It is preferably a solvent such as benzene, toluene or di-f-benzene, or an alcohol-based solvent such as methanol or ethanol; and a ketone solvent such as methyl ethyl ketone. Organic solvents. As the other solvent, water, a mixed solvent of water and the above organic solvent, or the like can be used. The pseudo-sintering of the mixture after the wet mixing is not particularly limited and can be carried out by a previously known method, but from the viewpoint of more fully converting the carbon source used to a carbon monomer' and maintaining good dispersibility, Preferably, the heat treatment is carried out at 150 C to 800 ° C under an n-% gas (ambient gas such as nitrogen or argon). The above carbon source is not particularly limited, and it can be used for wet mixing in which the organic solvent is soluble or dispersible, and can be converted into carbon under the above-mentioned calcination conditions. When the carbon source is a solid powder, it is preferably a material having an average particle diameter of about 1 μm to about 1 Å from the viewpoint of dispersibility. Further, in order to convert the carbon source into a carbon after the calcination, the conversion rate is high, and therefore, the aromatic hydrogen halide is preferably used, and specific examples thereof include a furan resin, a phenol tree, and a coal tar pitch. More preferably, the resin and coal tar are blue. Further, the above-mentioned substance after the sinter can be used as a carbon source. 12I126.doc -13- 200804228: The anti-chemical raw material (particle), as described above, may be any crystal form of α or β. In addition, there is no particular limitation on the purity of the raw materials of the sub-&, ^ children, but from the higher density, &, #f, ^, 、, σ, to improve wear resistance and longevity Fortunately, 90% by weight or more, more preferably 95% by weight or more. The average particle diameter of the carbonaceous material (particles) is not particularly limited, but a powder of G.1 μπι to 1G μπι is preferable from the viewpoint of better sinterability. In addition, the average particle diameter of the two materials (particles) is measured by the laser diffraction/scattering light particle size distribution, and is measured by f, and quotient (commercial nu*LA72〇, manufactured by Horiba, Ltd.). Volume average particle diameter D5. (the same below). + The mixture of the two people after the rice is granulated as needed, and formed into a shape. The molding method is not particularly limited as long as it is formed by a die forming method, an injection, a two-P (cold isostatic pressing) method, or the like, and it is necessary to machine the above-mentioned block to form a molded body having a desired shape. Then, the obtained molded body is supplied to the firing step. The calcination method is particularly limited to the method which can be well known, but it is preferred that it is in the case of [monthly % gas or vacuum, ^ 18 〇 (rc~23〇 (rCT is performed = in i) When the treatment is carried out at the firing temperature, the sintered body is dense, and the mechanical properties such as strength and hardness are further improved. In order to achieve higher density, the upper: firing method is preferably hot pressing or HIP (hot isostatic). Pressure method

In addition to the ease of processing, the web H is dependent on the characteristics required for the forming mold to which the problem to be solved by the present invention is:::: contribution, which is specifically relative to The high temperature glass is stabilized (oxidation resistance, resistance to life, inert to glass) or abrasion resistance 121126.doc 200804228

Further, in the case of niobium carbide, it is preferred to adjust the residual carbon of the carbon raw material within the range to dissolve the raw material. The firing conditions are adjusted to increase the crystallinity, and the particles are appropriately grown. (Manufacturing Method of Forming Die of the Present Invention) Next, a preferred manufacturing method of the forming die of the first invention will be described. However, the method of producing the forming die of the present invention is not limited to these methods. When the entire composite mold of the present invention is composed of the above composite ceramics, the pseudo-fired mixture can be formed into a desired mold shape and fired in the k-step of the composite ceramic. Further, when the composite mold of the present invention constitutes a part of the forming mold of the present invention, as described above, a component composed of a composite ceramic can be produced and assembled as a part of the forming mold to manufacture the present invention. Forming die. Preferably, the molding die of the present invention has a smooth surface as described above in contact with the glass in the manufacture of a glass hard disk substrate. Therefore, it is preferred to grind the contact surface with the above glass as needed. The polishing method is not particularly limited. However, when the composite ceramic is a high-hardness material, since the time required for polishing with an abrasive other than diamond is long, it is preferred to use a diamond abrasive for polishing. From the viewpoint of sufficiently ensuring the surface smoothness of the contact surface with the glass in the molding die of the present invention, the average particle diameter of the diamond abrasive to be used is preferably 2 μm or less. When the above composite ceramic constituting the molding die of the present invention is fired by the HIP method 121126.doc • 15 - 200804228, a sintered body of a very high density can be obtained. Since the surface of the formed glass is imparted with better smoothness, the relative density of the forming mold is preferably higher. Specifically, the relative density of the forming die is preferably 95% or more, more preferably 98% or more. The relative density can be calculated by dividing the bulk density by the theoretical density (true specific gravity), which can be measured in accordance with JIS R1634. Further, when the ceramic is composed of a plurality of components, the theoretical density X of each component is calculated (% by weight of 100%, and the sum of the calculated values of the obtained components is used as the theoretical density of the entire ceramic. (Manufacturing Method of Glass Hard Disk Substrate) As described above, the method for producing a glass hard disk substrate of the present invention includes the steps of disposing a glass raw material in a forming mold and, if necessary, under heating conditions. The step of press molding the glass raw material, wherein the forming die is a molding die for a glass hard disk substrate of the present invention. As described above, in the manufacturing method of the present invention, if the molding die of the present invention is used as a molding die, Other steps, processing conditions, and the like are not limited. An example of a method for producing a glass hard disk substrate of the present invention will be described with reference to Fig. 1. However, the present invention is not limited thereto. Fig. 1 is a view showing the glass hard of the present invention. A cross-sectional view of an example of a forming die for a disk substrate. As shown in the figure, the forming die has a facing upper die i 〇a and a lower die 10b, and the upper die and the lower die The outer peripheral portion 12, 101a can be connected to the processing surface (contact surface with the glass) of the upper mold l〇a, and the processing surface (contact surface with the glass) of the lower mold 10b can be moved up and down. In the forming mold, at least the processing surface 10a and the lower surface 1b of the upper mold 10a are formed of the above composite ceramic. Further, the forming mold may not have the outer circumference 121126.doc - 16- 200804228 Department.

First, a glass material 11 is disposed between the upper mold 〇a and the lower mold 〇b (for example, disposed on the processing surface (7) of the lower mold 10b). Next, the upper mold 10a and the lower mold 10b are moved to pressurize the glass material η, and thereafter, it is cooled to be formed into a glass hard disk substrate. Then, the formed glass hard disk substrate was released from the molding die to obtain a glass hard disk substrate. Further, the manufacturing method of the molding die for a glass hard disk substrate of the present invention is characterized by using the molding die of the present invention, and the temperature and the weighting conditions are not limited, and can be set as previously known. In the glass material 11, the unheated glass raw material (at room temperature or so) can be disposed between the upper mold 10a and the lower mold 10b, and can be pressurized while being heated, or the glass raw material can be smashed in advance! The glass is heated to a specific temperature to be molten glass, and flows from the molten glass tank through the outflow pipe to the processing surface of the lower mold lb. The temperature of the heat treatment is not particularly limited, but from the viewpoint of formability, it is preferably 2 Å. 〇~15〇〇〇c, more preferably 400°C~1500°C, and even better 50(rc~14〇(rc, and more preferably 峨~1400...and the temperature of the molten glass) The glass raw material may be melted, and it is not particularly limited, but from the viewpoint of moldability, it is preferably 200 ° C to 1500 ° C, more preferably 400. 〇 15 15 ° < t, and further 500. 〇 1400. (:, and further preferably 6 〇 (rc 〜 14 〇 (rc. 疋. The pressure applied during pressurization is not particularly limited, but preferably 0.2 MPa to 50 MPa, Since the pressurization time can be further shortened, it is more preferably 0.3 MPa to 40 MPa, and further preferably 〇4 Mpa to 3 〇Mpa. Further, = moving both the upper mold 10a and the lower mold 10b Pressurize, as shown in the previous figure, 121126.doc -17- 200804228, pressurize the upper mold 1 (^ pressure is applied. There is no restriction on the type of the above-mentioned glass raw materials, but it can be formed. The material in the form of amorphous glass may be a raw material in the form of crystallized glass (glass ceramic) after molding. (Information recording medium) According to the present invention, it is possible to provide The information recording medium of the glass hard disk substrate. In this case, the glass hard disk substrate produced by the above method may be used, and other configurations of the information recording medium and the like are not limited. [Examples] The carbon source shown in 1 and the average particle diameter of 05 p_barium carbide particles (purity: 98% by weight) and the sintering aid b4C (2% by weight) were wet-mixed in ethanol in a vibratory ball mill, and dried. Sintering 2% by % under 5 ' generation and polymerizing the smoltar by wet pulverization with ethanol: granulating the slurry with a spray dryer to obtain granules. Using i particles to CIP The method is formed into a block, and the obtained block is processed by a c〇r〇i) adding machine to form a glass forming mold and then fired at 2200T: for 4 hours in a chlorine atmosphere. The carbonized stone-carbon composite ceramic of the present invention is formed by the firing. For the forming mold after firing, the surface of the fish glass contact is ground with a diamond abrasive having an average particle diameter of 2 mm, and finally the broken surface is obtained. The glass hard disk substrate is used to open the > mold. Again, The amount of carbon after firing was measured with respect to 1 part by weight of niobium carbide in the following Table 1. The properties of the obtained molding die were evaluated by the following measurement methods. 121126.doc 200804228 The results are shown together in the following table i. (1) Laser Raman ratio The so-called laser Raman ratio refers to the peak area ratio of the laser Raman splitting intensity of the crystalline phase and the amorphous phase of the carbon particles (crystalline phase /Amorphous phase, which was measured by an argon laser Raman spectroscopic device (manufactured by NEC Corporation). (2) The surface roughness was measured using a roughness meter (developed by Kogyo Co., Ltd.), and the above-mentioned forming mold was measured in accordance with JIS B 0651. The centerline average roughness Ra of the surface in contact with the glass. (3) Mold release property Using the formed mold, the hard disk substrate was produced under the following conditions, and the mold release property of the hard disk substrate forming mold of the hard disk substrate was evaluated as follows. In the above-mentioned molding die, a glass clot (G〇b block) (viscosity logr|: 1 to 4) as a raw material was placed, and a pressure of 20 MPa was applied to produce a glass hard disk substrate. Further, one glass hard disk substrate was continuously produced by using the same molding die, and the mold release property of each glass disk substrate was evaluated in accordance with the following evaluation criteria. (Production conditions of hard disk substrate) Glass composition: Si〇2, Li2〇, A1203, B2〇3, Na20, K20 Glass temperature immediately before pressurization: ^(^^~^(^^(measured by radiation thermometer) Pressurization method: The temperature of the molten glass of a specific weight is cooled to the molding temperature region (1 〇 § = 7 〜 1 〇) by a direct press method, and the glass block is press-formed by a molding die. · During the pressurization, the heat exchange fluid (water) is used to absorb the heat of the pressurized product 121126.doc -19 - 200804228. By this, the 'pressure surface is cooled, so that the glass quality of the south quality and the efficiency can be transmitted. (Evaluation Criteria) ◎: Indicates that 1000 pieces are all released well 〇: indicates that one of the 1000 pieces has a mold release defect △ ·· indicates that there are 2 to 4 pieces of die release in 1000. X: 5 out of 1000 In the above mold release failure, "good mold release" means that the pressurization product does not move even when the mold is removed from the press mold after pressurization, and the mold release is good. When the upper mold of the forming mold leaves the pressing product, the pressing product moves, or the pressing product adheres to the upper portion. (4) Durability of the durable molding die is a visual observation of the surface appearance and the thickness thereof after the mold release test of the above (3), and the measurement of the center line average roughness Ra, and The evaluation was carried out according to the following evaluation criteria: The center line average roughness Ra was measured at one of the center portion and the outer peripheral portion of the contact surface (pressure surface) of the molding die (upper mold) with the glass, and two measurements were determined. The difference between the values. The upper mold of the forming mold is schematically shown in Fig. 2. In Fig. 2, Fig. 2(A) is a cross-sectional view of the upper mold of the forming mold, and Fig. 2(B) is a plan view of the upper mold of the forming mold. As shown in Fig. 2(B), in the center portion, 2 (centered arrow χ) centered on the center of the pressing surface of the forming die (upper die) is measured, and the outer peripheral portion is measured from the outer periphery (this In Fig. 2(B), the solid line on the flash side is 2 mm on the inner side of the inner side 〇mm (the arrow γ in the figure). In the following evaluation criteria, the "thickness change" means the center portion and the outer peripheral portion. The difference in thickness is 121126.doc 200804228, that is, the difference between the center portion and the outer portion is before and after the release test. In addition, when the durability evaluation of the forming mold is high, the abrasion resistance is also considered to be good. (Evaluation criteria) ◎: No change in thickness 〇: There are some roughness changes Ra Δ10% The following △: It is considered that there is a change in roughness Ra Δ20% or less X: It is considered that there is a large thickness change Ra Δ30% or less (Table 1) Carbon source Carbon carbide 矽 Ceramic content Weight part average particle size μιη Laser Raman ratio Weight fraction average particle size μιη Maximum void diameter La (pm) before mold release test Demolding property Comparative example 1 Phenolic resin 25 0.25 0.6 100 0.05 11 0.03 X Δ Example 1 Phenolic resin 25 0.4 1.1 100 0.2 5 0.03 〇 ◎ Example 2 Phenolic resin 25 U 1.5 100 0.7 13 0.05 ◎ ◎ Example 3 Phenolic resin 25 3.7 1.9 100 3.9 17 0.2 ◎ ◎ Example 4 Coal tar pitch 25 9.9 2.8 100 38 29 0.9 ◎ 0 Example 5 酴Resin 25 28 2.1 100 5 93 1.1 〇〇 Example 6 Phenolic resin 25 71 1.7 100 1.7 210 3.3 〇〇 Comparative Example 2 Phenolic resin 25 150 1 100 13.5 15 0.02 Δ X Comparative Example 3 Phenolic resin 25 1.1 1.5 100 110 355 11.7 Δ X Example 7 Phenolic Resin 17 5.3 1.7 100 0.7 19 0.1 ◎ ◎ Example 8 Phenolic Resin 48 69 1.8 100 0.7 39 0.5 〇〇 Comparative Example 4 Phenolic Resin 15 0.1 0.4 100 0.05 49 0 Δ Δ Comparative Example 5 Phenolic Resin 52 7.7 1.1 100 0.7 420 16.9 Δ X Comparative Example 6 Resin 8 1.6 1.2 100 1.3 14 0.09 Δ Δ Example 9 Coal tar pitch 25 27 5.8 100 0.7 77 8.9 〇〇

As described above, the molding die for a glass hard disk substrate according to the present invention has less reactivity with glass and is excellent in abrasion resistance durability, and the release property of the glass after molding from the surface of the molding die is good. Therefore, even if the molding die of the present invention is used continuously and for a long period of time, it is possible to suppress the roughening or mold release failure of the surface of the molding die, and to manufacture the glass hard disk substrate at a high frequency. Moreover, the yield of the glass hard disk substrate obtained by -21 · 121126.doc 200804228 is also improved, so that the surface smoothness which is substantially unnecessary after polishing can be realized. Therefore, according to the molding die of the present invention, the forming cost of the glass hard disk substrate can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an example of a molding die for a glass hard disk substrate of the present invention. Fig. 2 is a cross-sectional view of the upper mold of Fig. 2A, and Fig. 2B is a plan view of the upper mold, in a forming mold for a glass hard disk substrate according to an embodiment of the present invention. [Description of main component symbols] Upper die Lower die material Outer peripheral part Processing surface Processing surface

10 a 10b 11 12 101a 101b 121126.doc -22-

Claims (1)

200804228 X. Patent application scope: 1 . A molding die for a glass hard disk substrate, which comprises a cerium carbide-carbon composite ceramic, wherein the carbonized cerium-carbon composite ceramic has 10 () parts by weight of carbonized fossil eve And containing 15 to 50 parts by weight of carbon particles, and the carbon particles have a flat average particle diameter ranging from 0·3 μηι to 100 μιη. 2. The molding die for a glass hard disk substrate according to claim 1, wherein the average particle diameter of the niobium carbide in the niobium carbide-carbon composite ceramic is in the range of 〇3 μηι to 1〇〇 μηΐ2 _. 3. The molding die for a glass hard disk substrate according to claim 1 or 2, wherein a peak area ratio (crystalline phase/amorphous phase) of the laser Raman spectral intensity of the crystal phase of the carbon particles to the amorphous phase is 1 ~10. 4. The molding die for a glass hard disk substrate according to claim 1 or 2, wherein the composite ceramic has a maximum void diameter of 300 μη or less. 5. The molding die for a glass hard disk substrate according to claim 2 or 2, wherein in the surface of the forming die which is in contact with the glass during molding of the glass hard disk substrate, the mean diameter of the core line is "0.001 μ? The above-mentioned method of manufacturing a glass hard disk substrate includes a glass forming step of disposing a glass raw material in a molding die and press-molding the glass raw material, and the above-mentioned forming die request item A molding die for a glass hard disk substrate according to any one of the above-mentioned items. ^ 7. The method for producing a glass hard disk substrate according to claim 6, wherein the above-mentioned = 〇 ^. The glass raw material is heated to a temperature of 200 ° C to 1500 C, and a pressure of 〇 2 to 50 MPa is applied to the glass raw material to form.