• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Disclosed is a method for manufacturing an object of silicon nitride. In the method, a body preformed from silicon nitride is surrounded with a casing which is permeable to gas. Upon heating, the casing is transformed into a layer which is impermeable to a pressure medium which is used during isostatic pressing of the preformed body while a pressure outside the casing is maintained which is at least as high as the pressure of the gas which is present in the pores of the preformed product. After the casing has been made impermeable to the pressure medium and the preformed body has been enclosed therein, the isostatic pressing is carried out while the body is simultaneously sintered.
    公开号:SU1011045A3
    申请号:SU792763350
    申请日:1979-04-28
    公开日:1983-04-07
    发明作者:Адлерборн Ян；Ларкер Ханс；Нильссон Ян
    申请人:Асеа Аб (Фирма)；
    IPC主号:
    专利说明:

    . /
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    0l / f.f. 11 The invention relates to methods of making products from nitride cream using isostatic pressing and can be used in the technology for producing high-temperature dense materials. A known method of manufacturing high density silicon nitride products by isostatic hot pressing of preformed blanks, placed in a shell that is made of molybdenum foil, is degassed and evacuated, after which hot pressing is carried out 1J. However, in this case, the shell is compacted during degassing, which leads to the appearance of defects in it. The closest to the proposed technical solution is the method of manufacturing products from nitride cream or isostatic hot pressing; preformed blanks using a pressure-transmitting gaseous medium. According to a known method, blanks are made of silicon nitride with a density of about 6S% of theoretical, placed in an ampoule made of vicore or quartz glass, degassing at R 0.1 Pa is carried out, and the ampoule is soldered at a temperature of about 125 ° C. an impermeable pressure transmitting medium for which nitrogen is used, and isostatic hot pressing is carried out at a pressure of 200-300 MPa and a temperature of 16001900 ° С 2. However, this method is rather laborious, requires the manufacture of ampoules Vani for insulating medium The relative preform. In addition, when using an ampoule of glass, which must be sufficiently refractory so as not to melt at high temperature. Sintering cannot be prevented when glass is hardening. It accumulates in cavities or on protruding parts of the workpiece, as a result of which, upon cooling, due to the difference in thermal expansion coefficient. Silicon nitride and glass on the protruding parts of the workpiece are cracked, so the known method is applicable only for the manufacture of products of simple form. jS2 The purpose of the invention is to simplify the process and ensure the possibility of manufacturing products of complex shape. This goal is achieved by the fact that according to the method of manufacturing products from silicon nitride by forming a preform of silicon nitride powder, placing it in. the glass shell, degassing the shell, followed by hot pressing using gas as the medium transmitting the pressure, the shell is gas-permeable, raising the temperature before the shell enters the gas-tight state at a gas pressure at least equal to the gas pressure in the pores of the workpiece, after bringing the temperature and pressure to the values required for hot pressing. In this case, the gas-permeable shell is made by dipping the blank into a suspension of glasses or by spraying or placing several glass elements around the blank. The shell can also be made two-layer, with the reflow temperature of the outer layer lower than the layer adjacent to the workpiece. The melting temperature is 600-1000 ° C for the outer layer, and 1200 TBBO for the layer adjacent to the workpiece. .. The proposed method, due to the fact that the product, for example, is dipped into a glass slurry, allows to create a shell of very small thickness, which exactly repeats all the bends of the molded workpiece, which eliminates the accumulation of glass in its recesses and cracking during cooling. Since the process of sintering silicon nitride takes place at 1BOO-1900 ° C and it is necessary to avoid the dissociation of silicon nitride with the release of nitrogen, a refractory porous layer is deposited from a slurry of low-melting glass, which becomes impermeable to the pressure transmitting medium, does not interfere with powder degassing blanks. Further, in the process of raising the temperature, the glass of the outer c; 1 ° reacts with the glass of the inner layer, becoming more refractory, with further heating of the inner layer also creates a shell that is impermeable to the medium, even before the outer layer begins to drain from the workpiece. 3, argon, helium, and nitrogen are used as the gas used to create the pressure. At the same time, as the gas used in the process of transition of the shell into a gas-tight state, nitrogen is the most preferred. A porous layer from a suspension of glass or during sputtering is preferably applied with a layer of 0.05-1 mm, and the particles of the material from which the layer is created have a size of 0.1-100 microns. It is also possible to make a layer of individual glass elements placed around the shell, which, as the temperature rises, merge with each other and eventually the alloy. The material of the refractory shell can be a glass Vikor containing 96.7 wt. SiO, 2.9 and 0, AB.O-j. Quartz glass is also possible to use refractory metals / M W /. The material of the shell of the outer layer can be glass Aprex, contents -. mass 1: SiOi80,3; 12.2; Ag2.03 2.8; A,); K, 0 Q, k, CaO 0.3, and also aluminum silicate (58% SiDi, 20 Ae2.0c, 9 ,, 5 CaO and 8 HgO) or other StO mixtures. with oxides. The pressure during sintering of nitride depends on whether additives that promote the sintering process (MDO) are added to the composition and can be / 100 MPa (200-300 MPa) without additives or y / 20 MPa if additives are present. Sintering temperature 1600-1990 FIG. 1-6 clarify the proposed set. . Example 1. A silicon nitride powder with a particle size of 7 µm, containing about 0.5 free Cru and about 0.1 magnesium oxide, is packed in an elastic capsule at a pressure of about 600 MPa. A billet 1, having, for example, a cylinder with disc-shaped ends (Fig. 1), is immersed in a suspension of vykor glass, dried to form layer 2, and placed in a high-temperature furnace equipped with a gas exhaust tube. The billet is degassed for 2 hours, after which the furnace is filled with nitrogen and the temperature is raised until the pressure is maintained, after 2 hours the temperature is gradually (within 3 hours) raised from 1200 to, argument. however, the pressure of nitrogen to 0.7 MPa, and the pressure outside the shell support, at least equal to the pressure in the pores of the workpiece. When the envelope becomes impermeable to nitrogen and nitrogen or helium is additionally introduced into the furnace, up to P 200-300 MPa, after which the temperature is raised to and maintained for 2 hours. After cooling, the product is removed by breaking the glass. Example 2. A briquetted cylindrical preform 1 is placed between two glass elements 2 (Fig. 2) of the same composition as in Example 1. Next, the process is carried out as in Example 1, and during the temperature increase from 1200 to while increasing the pressure plate the glass softens and changes its shape (fig. 3) to become gas-tight. Example 3. Briquetted billet of the same shape as Example 1 (FIG.) Is covered with a porous layer 2 of refractory glass and a layer 3 of glass with a lower melting point by successively immersing it in a suspension of vikor glass and Pyrex glass. and drying after each immersion. The billet is degassed as in Example 1 /, the furnace is filled with nitrogen to atmospheric pressure and the temperature is raised to 2 hours. Then the temperature is raised from 600 to 1000 C nfjH for 3 hours while simultaneously introducing nitrogen in the amount necessary to create a pressure of 0.7. MPa, and the pressure outside the shell all the time support, at least equal to the pressure of residual gases in the pores of the workpiece. At 10. the outer layer becomes impermeable to nitrogen and an additional amount of nitrogen or gels up to P 100 MPa is introduced into the furnace. The temperature is then slowly raised until a second gastight layer is formed before the first (external) starts to melt. Sintering is then carried out as in Example 1. Example 4. The preform 1 is covered with a layer 2 of refractory glass and placed between two 3 5 elements of more low-melting glass (FIG. 5 is placed in an oven and the process is carried out as in Example 3) and during the process the plate 3 changes shape and joins bottom plate (Fig. 6).
    v
    2
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    JSftof.J
    J g
    / /
    FUG. 10110 5 ") If a temporary joint of 950 cm (methylcellulose, cellulose nitrate, etc.) is used in the molding of the preform, it is removed before or after applying a porous layer, usually by heating the preform to 00-70b C.
    fug. four
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    权利要求:
    Claims (4)
    [1]
    1. METHOD FOR PRODUCING PRODUCTS FROM SILICON NITRIDE by molding a workpiece from silicon nitride powder, placing it in a glass shell, degassing the shell, followed by isostatic hot pressing using gas as a pressure transmitting medium, characterized in that, in order to simplify the process and ensure the possibility of manufacturing products of complex shape, the shell is gas-permeable, the temperature is raised until the shell transitions to a gas-tight state at a gas pressure of at least yes the appearance of the pelvis in the pores of the workpiece, after which the temperature and pressure are raised to the values necessary for hot pressing.
    [2]
    2. The method according to p. Characterized in that the gas-permeable shell is performed by dipping the preform in a glass suspension or by spraying, or by placing several glass elements around the preform. g
    [3]
    3. The method according to PP. 1 and 2, characterized in that the shell on the workpiece is double-layer, and the fusion temperature of the “outer layer is lower than that of the layer adjacent to the workpiece.”
    [4]
    4. The method according to p. 3, with the fact that the melting temperature of the outer layer is 600-1000 / a of the layer adjacent to the workpiece, 1200-
    I 1’65 (HS.
    SU „„ 1011,045
    k =pl_ f-2 iri
    fg / g f
    类似技术:
    公开号 | 公开日 | 专利标题
    US4112143A|1978-09-05|Method of manufacturing an object of silicon nitride
    US4381931A|1983-05-03|Process for the manufacture of substantially pore-free shaped polycrystalline articles by isostatic hot-pressing in glass casings
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    US4351858A|1982-09-28|Process for the manufacture of substantially pore-free shaped polycrystalline articles by isostatic hot-pressing
    US4455275A|1984-06-19|Method of manufacturing bodies of silicon nitride
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    KR970001557B1|1997-02-11|Method of manufacturing an object of powdered material by isostatic pressing
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    KR960002413B1|1996-02-17|Method of manufacturing an object of powdered material by isostatic pressing
    US4478789A|1984-10-23|Method of manufacturing an object of metallic or ceramic material
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    US4209478A|1980-06-24|Method of sintering ceramics
    CA1148772A|1983-06-28|Method of manufacturing an object ofmetallic or ceramic material
    KR960004427B1|1996-04-03|Method for the manufacture of an object of a powdered material by isostatic pressing
    GB1564851A|1980-04-16|Method of manufacturing an object of silicon nitride
    US4199339A|1980-04-22|Method for the manufacture of a molded member from a ceramic material
    US4812272A|1989-03-14|Process by compacting a porous structural member for hot isostatic pressing
    US4230745A|1980-10-28|Method of encapsulating a molded ceramic member
    US4952353A|1990-08-28|Hot isostatic pressing
    SE414920C|1982-03-04|SET TO MAKE A FORM OF A MATERIAL IN THE FORM OF A POWDER THROUGH ISOSTATIC PRESSING OF A POWDER-FORMATED BODY
    US5039629A|1991-08-13|Hybrid ceramic composition and process for its manufacture
    SE425360B|1982-09-27|SET TO ISSTATIC PRESSURE OF POWDER FOR THE PREPARATION OF FORMAL OF CERAMIC OR METALLIC MATERIAL
    JP2708245B2|1998-02-04|Hot isostatic pressing method
    同族专利:
    公开号 | 公开日
    DE2916223A1|1979-11-08|
    SE414922B|1980-08-25|
    AU4648779A|1979-11-08|
    CA1133683A|1982-10-19|
    US4505871A|1985-03-19|
    DE2916223C2|1987-09-24|
    GB2024255A|1980-01-09|
    FR2424890A1|1979-11-30|
    FR2424890B1|1984-05-18|
    JPS6220152B2|1987-05-06|
    IT1112737B|1986-01-20|
    AU521280B2|1982-03-25|
    SE7804990L|1979-11-03|
    ZA792082B|1980-05-28|
    JPS54144412A|1979-11-10|
    IT7922131D0|1979-04-24|
    GB2024255B|1982-09-15|
    BE875963A|1979-08-16|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    SE348961C|1971-03-15|1982-04-19|Asea Ab|PROCEDURE FOR PREPARING A SINTERED POWDER BODY|
    DE2349277A1|1973-10-01|1975-04-24|Feldmuehle Anlagen Prod|Silicon nitride components with high density - esp. turbine blades, made by injection moulding followed by isostatic pressing|
    AU507155B2|1976-01-29|1980-02-07|Aktiebolag Asea|Silicon nitride article|
    US4112143A|1977-01-18|1978-09-05|Asea Aktiebolag|Method of manufacturing an object of silicon nitride|
    SE414920C|1978-05-02|1982-03-04|Asea Ab|SET TO MAKE A FORM OF A MATERIAL IN THE FORM OF A POWDER THROUGH ISOSTATIC PRESSING OF A POWDER-FORMATED BODY|
    DE3040771A1|1980-10-29|1982-05-27|Elektroschmelzwerk Kempten GmbH, 8000 München|METHOD FOR THE PRODUCTION OF PRACTICALLY PORE-FREE, POLYCRYSTALLINE MOLDED BODIES BY ISOSTATIC HOT PRESSING IN GLASHUELLES|JPS6146431B2|1980-12-19|1986-10-14|Kobe Steel Ltd|
    SE426815B|1981-03-10|1983-02-14|Asea Ab|WAY TO MAKE FORMS OF CERAMICS|
    GB8926455D0|1989-11-23|1990-05-30|T & N Technology Ltd|Manufacture of shaped articles from sinterable powder|
    SE469467B|1990-12-21|1993-07-12|Asea Cerama Ab|SETTING IN ISOSTATIC PRESSING TO ENSURE A PORO'S BODY WITH A GLASS COVER AND IMPROPER LAYER|
    SE9100396D0|1991-02-08|1991-02-08|Sandvik Ab|SET FOR PREPARATION OF A COMPONENT BODY|
    SE9103065D0|1991-10-21|1991-10-21|Sandvik Ab|METHOD FOR PREPARING CERAMIC BODY|
    US5503926A|1995-01-11|1996-04-02|Saint-Gobain/Norton Industrial Ceramics Corporation|Hipped silicon nitride having a reduced reaction layer|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE7804990A|SE414922B|1978-05-02|1978-05-02|SET TO MAKE A FORMULA OF SILICON NITRIDE THROUGH ISOSTATIC PRESSING OF A SILICON NITRID POWDER FORMATED BODY WITH A GAS PRESSURE MEDIUM|
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