CN1240891C - Procesxs for producing continuous silicon carbide fibre by skin and core double-composition fibre method - Google Patents
Procesxs for producing continuous silicon carbide fibre by skin and core double-composition fibre method Download PDFInfo
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- CN1240891C CN1240891C CN 02140433 CN02140433A CN1240891C CN 1240891 C CN1240891 C CN 1240891C CN 02140433 CN02140433 CN 02140433 CN 02140433 A CN02140433 A CN 02140433A CN 1240891 C CN1240891 C CN 1240891C
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Abstract
The present invention relates to a production technology for preparing continuous SiC fibers. In the technology, high molecular polymers are dissolved in a solvent to be prepared into skin liquid, and then a dispersing agent, high molecular polymers, SiC powder and a sintering aid are dissolved or dispersed in a solvent to be prepared into core liquid; the skin liquid and core liquid are extruded from the micropores of skin core composite spinning packs under pressure, and the skin liquid is coated on the external of the core liquid; the liquid stream lines are solidified by the wet method or dry method, and the obtained fibers are stretched, dried and coiled to obtain fibrils, wherein the core part is ceramic powder bonded by high molecules, and the skin part is pure high molecules; the fibrils are treated by low-temperature oxidation in the air and sintered at a high temperature in the atmosphere of highly pure Ar, and continuous fibers which have the core part of SiC fibers and the skin part of carbon fibers are obtained; carbon on the skin is removed through oxidation, and the continuous sintered SiC fibers are obtained, wherein the fiber diameter can decrease to be below 20 mum, the chemical component content is higher than 90% which approaches to SiC and alpha-SiC, and the relative density can reach as high as more than 98%.
Description
(1) technical field
The present invention relates to the production technology of a kind of continuous carbonization silicon (SiC) fiber.
(2) background technology
The SiC fiber has advantages such as high strength, excellent heat resistance, non-oxidizability and high temperature creep-resisting.Continuous SiC fiber is mainly used in the enhancing body of enhancing body, the especially CMC of metal or ceramic matric composite (CMC), to improve its intensity and toughness.Because the resistance to elevated temperatures that it is outstanding, the fibre-reinforced CMC of SiC becomes the critical material of Aero-Space, national defence weapon equipment, the parts of anti-nuclear radiation the and ceramic engine.Performance of composites depends on the performance of fiber to a great extent, so high-performance SiC fiber is the key of such composite of development.When strengthening body as CMC, generally to require the SiC fiber be continuous and have stitchability.
The technology of at present the most ripe preparation SiC fiber is based on Yajima (Chemical Letters, 1975:931; Chemical Letters, 1975:551) Yan Jiuhekaifa precursor method.This method is by the at first synthetic polysilane of the polymerization of organosilan, is re-combined into Polycarbosilane by macromolecular chain then; Polycarbosilane prepares fibrillation through melt spinning or dry spinning; Crosslinked or crosslinking with radiation carries out not melt processed to fibrillation through hot-air, at last (for example Ar or N under inert atmosphere
2) Pintsch process obtains the SiC fiber.Nicalon is the most ripe at present and commercial SiC fiber, is that Japanese Nippon Carbon company produces according to above-mentioned technology path.Because carbon surplus in the polycarbosilane precusor also contains excessive free carbon in the SiC fiber of being produced.The Ube company of Japan adopts the similar techniques route, but adds a spot of organo-metallic compound with the polysilane copolymerization when polymerization, the synthetic Polycarbosilane that contains metal ion, and the metallic element that is added generally is Al, Ti, Zr etc.This product has also been realized commercialization at present, and commodity are called Tyrrano.U.S. DowCorning company adopts polyamine silane, Polycarbosilane and organoboron compound reaction to produce novel precursor.It is reported that the fibre composition that utilizes this precursor preparation still contains a spot of nitrogen and boron near stoichiometric SiC.This fiber has been realized limited production at present, and commodity are called Sylramic.
The SiC fiber also can utilize the preparation of chemical vapor deposition (CVD) method, just deposits last layer SiC (US Patent 3433725) by cracking organic silicon alkane on carbon (C) fiber that heats or tungsten (W) silk (12.5 μ m) surface.The SiC fiber also commercialization at present of this method preparation.The diameter of fiber is generally greater than 100 μ m, so knitting property is relatively poor.
The SiC fiber also can be loaded with SiO by heating under inert atmosphere
2The viscose preparation (JP Patent58/91823,1983) of powder.In the heating process, the viscose carbonization provides carbon source, and carbon is at the same SiO of high temperature
2Reaction generates SiC.Similarly method is polyacrylonitrile (PAN) fiber production (JP Patent55/085472,1980) the SiC fiber that heating is loaded with silicon (Si) powder under inert atmosphere.In the heating process, the PAN carbonization provides carbon source, and carbon generates SiC at high temperature with the Si reaction.
At high temperature during (＞1200 ℃) long term exposure, intensity can produce remarkable decline to the SiC fiber of precursor method preparation.The deterioration of this intensity not only appears in the oxidizing atmosphere, even also be so under inert atmosphere, although intensity underspeeds slower under inert atmosphere.By contrast, though the block SiC of sintering more than 1500 ℃ during long term exposure, any reduction also appears in intensity hardly.
The research that the SiC fiber high temperature intensity for preparing for the precursor method reduces is system and extensive very.Sum up document institute results reported objectively, generally believed two main causes (J.Amer.Ceram.Soc., 1998:2109), first fiber contains aerobic and free carbon, discharge CO and SiO in the two reaction of high temperature (more than 1100 ℃), destroyed the globality of fiber; It two is that fiber has microstructure on crystal structure, contain relatively large noncrystalline phase and partially crystallizable phase, and the crystalline size of crystalline phase is generally below 20nm.This to be organized in high temperatures poor, and the crystal coarsening rate is fast, and degree of crystallinity improves, and becomes the principal element that elevated temperature strength reduces.The oxidized activating of low-crystallinity SiC can be also lower, oxidation easily.In addition, even the present different precursor fiber type of best performance, for example Hi-Nicalon-s has composition gradient in the fibre diameter direction, and the top layer is near stoichiometric SiC, and core contains excessive free carbon, so oxidation resistance is relatively poor.
In Tyranno and Sylramic series fiber, in precursor is synthetic, introduce a spot of Al, N, B, Zr, elements such as Ti.This fiber generally needs in preparation process through high-temperature process (1500～1800 ℃), these elements promoted the densification of fiber and formed solid solution with SiC this moment, thereby the microstructure of stable fibers suppresses the growth of crystallite in the fiber under the high temperature, reaches the purpose that improves high-temperature stability.According to research reports, Tyranno S A and the Sylramic elevated temperature strength conservation rate in Ar atmosphere is than the fiber height of Nicalon type.But present business-like product still by very tiny crystallite (＜30nm) form, more than 1400 ℃ during long-time the military service, intensity and creep resistance are obviously not enough.
CVD method SiC fiber significantly descends in intensity more than 1200 ℃.For SiC (W) fiber, the W core reacts with SiC under the high temperature, make intensity reduce (Proc.Int.Conf.on SiC, Miami, 1973:386).And for SiC (C) fiber, because the thermal coefficient of expansion of C and SiC differs greatly, high temperature produces bigger interfacial stress down, makes intensity reduce (J.Composite Materials 1975:73).The oxidation resistance of CVD method SiC fiber is poor, because C or W core will produce severe oxidation more than 500 ℃, fibre strength is reduced significantly.
Above-mentioned two kinds of methods, promptly the viscose carrier adds SiO
2Add the Si powder method in the method for powder and the PAN fiber carrier, performance indications such as the SiC fibre strength of preparation are very low, still can't use as the enhancing body of composite at present.
Except the method for front, the SiC fiber also can be by the powder sintered method preparation of SiC.Early phase Frechette etc. (US Patent 4908340,1990) just proposes to utilize sintered powder technique to produce single-phase SiC fiber in the early 1990s, and multinomial patent open in succession (European Patent, EP 0363-054-A2 are arranged again soon; European Patent, EP0341-025-A2).
Adopting the SiC sintered powder technique to prepare the SiC fiber generally is that α-SiC or β-same sintering aid of SiC powder (for example B, C) are mixed, and the macromolecule with Polymer Solution or fusion mixes then; The plasticity group material that mixes utilizes double screw extruder to extrude from aperture, and dry then or cooling obtains fibrillation (green fiber); Fiber level is placed, and to obtain with α-SiC be the sintered sic fiber of main phase to sintering under 1900～2200 ℃ high-purity Ar atmosphere.SiC fiber with the method preparation is discontinuous staple fibre, and density can reach more than 98% of solid density, and fibre diameter is at 100 μ m～500 μ m.Because diameter is excessive, the fiber pliability is very poor, does not possess knitting property.
(Amer.Ceram.Soc.Bull. 1991:424) is the improvement that extrusion molding is made the SiC fibre technology to suspension spining technology (VSS).With extrusion molding relatively, prepared fibrillation is continuous, has good pliability, and it can be produced ceramic fibre with the sintered powder technique combination.VSS method preparation process can be described below simply: SiC powder and sintering aid are dispersed in the macromolecule spinning solution (or fusion macromolecule), and spinning obtains fibrillation.Macromolecule decomposes the back volatilization in the heating process, and then SiC powder high temperature sintering obtains fine and close polycrystalline Si C fiber.
No matter adopt the extruding technology spining technology that still suspends, a common shortcoming is all arranged, can't produce continuous ceramic fibre exactly.The key issue that hinders the preparation continuous SiC fiber is to be used to bond after the macromolecule of SiC powder decomposes (＜500 ℃), and the SiC powder loses most of binding agent, and one section temperature range (250～1900 ℃) intensity of fiber before SiC is powder sintered is very low.The production requirement fiber of continuous fibers is subjected to tension always in the continuous reeling process, avoid fiber bending.If there is a low-intensity district, can produce fracture of wire in the winding process, can't prepare continuous fiber.Fibre diameter is excessive in addition, and knitting property is very poor, greatly limits its application.
(3) summary of the invention
It is continuous that purpose of the present invention aims to provide a kind of SiC fiber, and diameter is less than 50 μ m, and the sheath/core bicomponent fiber legal system of fibrage function admirable is equipped with the production technology of continuous SiC fiber.
The processing step that sheath/core bicomponent fiber legal system provided by the present invention is equipped with continuous SiC fiber is as follows:
1) macromolecular material is dissolved in makes skin liquid in the solvent, said macromolecular material is that high molecular polymer is polyacrylonitrile (PAN) or viscose glue, molecular weight Mw=35000～95000 of PAN, said solvent are dimethylformamide (DMF) or dimethylacetylamide (DMA) or dimethyl sulfoxide (DMSO) (DMSO).When high molecular polymer was PAN, PAN concentration was 14%～35% in the skin liquid, was preferably 18%～20%, and when high molecular polymer was viscose glue, the falling ball viscosity of viscose glue was 30～350s, and NaOH content is 4%～7%, and degree of ripeness is 6～10ml 10%NH
4Cl;
2) preparation core liquid, at first dispersant is dissolved in the used solvent of core macromolecule, adds SiC powder and sintering aid and ball milling again, ceramic powders is uniformly dispersed, then the Polymer Solution for preparing is joined in the ceramic size, continue ball milling and obtain uniform core liquid.Said dispersant is NP-10 (nonyphenol polyethylene glycolether), JA-28 (polyphosphate ester); The SiC powder is sintered purity greater than 98.5% α-SiC or β-SiC powder, and average powder size is 0.02～1 μ m, is preferably 0.1～0.35 μ m; Sintering aid is particle mean size 0.1～1 μ m, is preferably B powder or particle mean size 0.02～0.5 μ m of 0.1～0.35 μ m, is preferably the Al of 0.02～0.1 μ m
2O
3And Y
2O
3Mixed-powder, Al
2O
3And Y
2O
3Weight ratio be 1/ (0.5～1.5); Macromolecule in the core liquid is complementary with the macromolecule in the skin liquid, selects PAN for use as pericarp liquid, and the macromolecule of core liquid is a molecular weight at 15000～22000 PAN or cellulose acetate, and solvent is DMF, DMA or DMSO, and Polymer Solution concentration is 5%～25%; Select viscose glue for use as pericarp liquid, the macromolecule of core liquid is a viscose glue, polyvinyl alcohol (PVA) or polyvinyl acetate (PVAC), and solvent is a water, Polymer Solution concentration is 5%～25%, is preferably 10%～20%.
The weight of dispersant is 1% of core SiC powder weight in the core liquid, and the weight of B powder is 0.2%～0.8% of SiC powder weight, is preferably 0.25%～0.5%, Al
2O
3And Y
2O
3Mixed-powder weight be 5%～20% of SiC powder weight, be preferably 8%～10%, the weight of high molecular polymer is 5%～15% of SiC powder weight, the content of solid in the core liquid (SiC, sintering aid and macromolecule) accounts for 40%～70% of total solution weight, is preferably 45%～55%.
Skin liquid that 3) will prepare and core liquid are after passing through spinning pump respectively, filter with candled filter respectively, the filtering accuracy of skin liquid screen pack is 2 μ m, the filtering accuracy of core liquid screen pack is 10 μ m, skin liquid and core liquid after will filtering then carry out spinning by the core-skin composite spinneret pack, the temperature of skin liquid is 30～50 ℃ during spinning, and the temperature of core liquid is 30～100 ℃, and spinning pressure is 0.2～20Mpa; The aperture of spinnerets is preferably 80～165 μ m less than 1mm, and the hole count of spinnerets is 1～200, is preferably 20～80.
4) liquid fluid line that pushes out from spinning pack adopts wet spinning or dry-spinning to be prepared into fibrillation, wet spinning is to make the liquid fluid line that comes out from spinneret orifice enter the coagulating bath that non-solvent is housed, because the counterdiffusion mutually of solvent and non-solvent makes polymer precipitation come out to form as-spun fibre.When skin liquid macromolecule was selected PAN for use, coagulating bath was the water of room temperature and the mixing material of DMF or DMA or DMSO, and the volume ratio of the two is (20～60)/(80～40).When skin liquid macromolecule was selected viscose glue for use, coagulating bath was for containing 40～350g/LNa
2SO
4, 0.3～100g/LZnSO
4With 20～120g/LH
2SO
4The aqueous solution, temperature is 25～50 ℃.The fiber that comes out from coagulating bath stretches stretch bath, to reduce fibre diameter, improve the fibre diameter uniformity and to improve the intensity of fiber.Said stretch bath medium is a boiling water, and draw ratio is 2～12 times, is preferably 5～10 times.The back fiber dry back coiling in 165 ℃ of hot-airs that stretches obtains fibrillation.
Dry spinning is to allow liquid fluid line carry out hot-stretch through 165 ℃ hot-air and in hot-air, and draw ratio is 2～12 times, is preferably 5～10 times.With the fiber roll after stretching around obtaining fibrillation.
Fibrillation has skin-core structure, and core is the ceramic powders that is bondd by macromolecule, and skin zone is pure macromolecule.
5) fibrillation is handled through low-temperature oxidation, in follow-up heating process, bondd (doubling), and improve the mechanical property of fiber to avoid fiber.It is to heat 10～60min in 200～230 ℃ of air that low-temperature oxidation is handled.During K cryogenic treatment, fiber is operation continuously in tube furnace, and feeding roller (roller) speed is 0.01～0.2m/min, and Wound-up roller speed is higher by 1%～5% than feeding roller speed, makes fiber be subjected to certain force of strain, avoids fiber bending.
6) fiber after low-temperature oxidation is handled enters and carries out continuous sintering in the high temperature process furnances.Logical high-purity Ar gas in the boiler tube is to prevent fiber oxidation.The boiler tube two ends utilize mercury seal, enter to prevent air.The feeding roller speed is 0.001～0.05m/min, and Wound-up roller speed is than feeding roller speed low 10%～20%.This is because fiber can produce 10%～20% axial shrinkage in sintering process, fiber is not stressed in sintering process or is subjected to very little tension by above speeds match, avoids fiber bending.High-temperature temperature district in the boiler tube is 1850～2250 ℃.Fiber is 5～60min by the time of high-temperature region, is preferably 10～40min, is not less than 95% with the sintered density that guarantees core SiC fiber.
7) fiber behind the sintering is made up of the SiC fiber of core sintering and the carbon fiber of skin zone, and the carbon fiber layer through air heat oxidation removal outside obtains continuous SiC fiber.The carbon elimination oxidizing temperature is 550～750 ℃, and the time is 20～60min.
Technology provided by the invention can significantly reduce fibre diameter (to 20 μ m) and solve sintering process and prepares in the SiC fiber sintering process the low excessively problem of the interval fibre strength of transition temperature.In the core-skin fibrillation, core with the fiber-like of VSS method preparation seemingly, but the outside utilizes the carbon element macromolecule to coat.In the spinning stage, therefore the tensile property excellence of macromolecule cortex can significantly reduce the core-skin fibre diameter, improves the diameter uniformity and improve fibriilar intensity.In sintering process, after macromolecule decomposed, core was made up of SiC powder and sintering aid, and crust carbon element macromolecule decomposes the residual high-strength carbon fiber layer down in back, supports core SiC fiber smoothly by the low-intensity district by carbon fiber.
Prepared SiC fiber microscopic structure on whole cross section is even, and crystal grain is 0.1～0.5 μ m, does not have component gradient, is made up of single-phase SiC through the XRD detection fibers, and these SiC fibers with precursor method or the preparation of CVD method are obviously different.In addition, fiber is continuous, and diameter is less than 50 μ m, and this SiC fiber with former powder sintering preparation is obviously different.
(4) specific embodiment
The invention will be further described below by embodiment.
Embodiment 1
1, with 100g PAN (mean molecule quantity M
w=42000) be dissolved in 400g fully and analyze among the pure DMF, make 20% solution as skin liquid.Adopt the external heat mode to remain on 80 ℃ skin liquid.
2,2g dispersant NP-10 is dissolved among the 180g DMF, adds 200g β-SiC powder (average grain diameter 0.1 μ m, maximum particle diameter 0.25 μ m) and the unformed boron powder of 0.6g (average grain diameter 0.6 μ m, maximum particle diameter 1.0 μ m) then.With resulting mixture ball milling 1h, add the DMF solution (M of PAN of the PAN of 120g 20% then
w=20000), continue ball milling 3h (100 ℃ of ball milling temperature), obtain uniform core liquid.Adopt the external heat mode to remain on 80 ℃ core liquid.
3, skin liquid and core liquid are respectively through independently entering the core-skin composite spinneret pack behind spinning pump and the candle filter.The filtering accuracy 2 μ m of skin liquid screen pack, the filtering accuracy 10 μ m of core liquid screen pack, the spinneret orifice number of spinning pack is 40, the diameter in each hole is 150 μ m.
4, the fiber that comes out from composite spinneret pack enters the coagulating bath, and the composition of solidification liquid is that volume ratio is 30/70 water and DMF, and the temperature of solidification liquid is 20 ℃.
5, as-spun fibre enters the boiling water stretch bath behind 45% negative stretch in coagulating bath, and fiber is through 600% stretching in the boiling water stretch bath, and the fiber after the stretching is reeled behind 165 ℃ of hot-air dries and obtained fibrillation.
6, fibrillation oxidation processes in 225 ℃ of air, the time is 30min.Oxidation processes is carried out in continuous tube furnace.The feeding roller speed is 0.3m/min, and Wound-up roller speed is 0.31m/min.
7, the fiber after the oxidation processes is by continuous tubular type high temperature sintering furnace.Sintering temperature is 2100 ℃, and fiber is 30min in the time that this temperature section passes through.The feeding roller speed is 0.005m/min, and Wound-up roller speed is 0.0043m/min.Pass to high-purity Ar gas in the boiler tube.
8, fiber is made up of the SiC fiber of core and the carbon fiber of skin zone behind the sintering.Heat 30min in 700 ℃ of air, the carbon fiber layer on oxidation removal surface obtains continuous SiC fiber.
The average diameter of SiC fiber is 32 μ m, and relative density is 94.6% (is Medium Measurement with mercury).After being embedded in fiber in the epoxy resin and utilizing diamond paste polishing, it is 0.12 μ m that scanning electronic microscope (SEM) is observed the average dimension that shows crystal grain, and no crystal grain is grown up unusually.The fiber of above-mentioned preparation is carried out XRD analysis, and other diffraction maximum beyond the no SiC occurs, and illustrates on the fiber it is single-phase SiC, and the content of α-SiC is greater than 90%.Analysis of chemical elements shows that Si content is 68.4% in the fiber, and C content is 30.8%, and B content is 0.26%, and the content of other element all is lower than 0.1%, with stoichiometric SiC composition basically identical.
Embodiment 2
With embodiment 1, different is to utilize dry spinning to prepare fibrillation, just distinguishes in embodiment 1 step 4 and 5.The fiber that comes out from composite spinneret pack enters heating clamber to be made solvent evaporates and forms fiber, and heating-up temperature is 165 ℃.Stretch simultaneously in the heating process, extensibility is 1000%, with the fiber roll after stretching around obtaining fibrillation.
Obtain continuous SiC fiber behind the sintering, average diameter is 29 μ m, and relative density is 95.8%.The average dimension of crystal grain is 0.12 μ m, and no crystal grain is grown up unusually.The XRD analysis display fibers is single-phase SiC, and the content of α-SiC is greater than 90%.Analysis of chemical elements shows that fiber is stoichiometric SiC substantially.
Embodiment 3
With embodiment 1, different is that skin liquid high molecular polymer is a viscose glue, and the falling ball viscosity of viscose glue is 120s, and NaOH content is 5.5%, and degree of ripeness is 7ml 10%NH
4Cl, the temperature of skin liquid is 30 ℃ during spinning.
With embodiment 1, different is in the 2nd of embodiment 1 2g dispersant JA-281 to be dissolved in the 180g distilled water, add 200g β-SiC powder (average grain diameter 0.1 μ m then, maximum particle diameter 0.25 μ m) and the unformed boron powder of 0.6g (average grain diameter 0.6 μ m, maximum particle diameter 1.0 μ m).With resulting fluid-mixing ball milling 1h, add 120g then with the same viscose solution of skin liquid, continue ball milling 3h (80 ℃ of ball milling temperature), obtain uniform core liquid.
With embodiment 1, the composition of different is solidification liquid in the 4th of embodiment 1 is 220g/L Na
2SO
4, 13g/LZnSO
4With 46g/L H
2SO
4The aqueous solution, the temperature of solidification liquid is 50 ℃.
Obtain continuous SiC fiber behind the sintering, average diameter is 32 μ m, and relative density is 95.2%.The XRD analysis display fibers is single-phase SiC, and the content of α-SiC is greater than 90%.
Embodiment 4
With embodiment 1, different is in the 2nd of embodiment 1, with the DMF solution (M of PAN of the PAN of 120g 20%
w=20000) change into the DMF solution of the cellulose acetate of 120g 30%.Obtain continuous SiC fiber behind the sintering, average diameter is 32 μ m respectively, and relative density is respectively 94%, and the XRD analysis display fibers is single-phase SiC, and the content of α-SiC is greater than 90%.
Embodiment 5～6
With embodiment 1, different is in the 3rd of embodiment 1, and the orifice diameter of combination spinning pack is 80 μ m and 120 μ m.Obtain continuous SiC fiber behind the sintering, average diameter is respectively 19.8 μ m and 24 μ m, and relative density is respectively 93.8% and 94.2%, and the content of α-SiC is greater than 90%.
Embodiment 7～8
With embodiment 1, different is in the 2nd of embodiment 1, and it is α-SiC of 0.6 μ m that the SiC powder is respectively β-SiC and the average grain diameter that average grain diameter is 0.5 μ m.Obtain continuous SiC fiber behind the sintering, average diameter is respectively 31 μ m and 32 μ m, and relative density is respectively 95.5% and 97.1%, and the content of the former α-SiC is greater than 90%, and the content of latter α-SiC is greater than 95%.
Embodiment 9～10
With embodiment 1, different is that the addition of Polymer Solution is respectively 80g and 100g in the 2nd of embodiment 1.Obtain continuous SiC fiber behind the sintering, average diameter is respectively 36 μ m and 34 μ m, and relative density is respectively 97.2% and 96.5%, and the content of α-SiC is greater than 90%.
Embodiment 11～12
With embodiment 1, different is that extensibility is respectively 400% and 800% in the 5th of embodiment 1.Obtain continuous SiC fiber behind the sintering, average diameter is respectively 36 μ m and 28 μ m, and relative density is respectively 97.0% and 96.1%, and the content of α-SiC is greater than 90%.
Embodiment 13
With embodiment 1, different is that the α-SiC with 0.6 μ m replaces β-SiC in the 2nd of embodiment 1.
With embodiment 1, different is to change the B powder into 12g Y in the 2nd of embodiment 1
2O
3(average grain diameter 0.45 μ m, maximum particle diameter 0.9 μ m) and 8g Al
2O
3(average grain diameter 0.05 μ m, maximum particle diameter 0.1 μ m).
With embodiment 1, different is that sintering temperature is 1900 ℃ in the 7th of embodiment 1, and fiber is 8min in the time that this temperature section passes through.Obtain continuous SiC fiber behind the sintering, average diameter is respectively 30.5 μ m, and relative density is respectively 98.4%, and the content of α-SiC is greater than 90%.
Embodiment 14,15
With embodiment 1, different is in the 7th of embodiment 1, and sintering temperature is respectively 2050 ℃ and 2150 ℃.Obtain continuous SiC fiber behind the sintering, average diameter is respectively 33 μ m and 31 μ m, and relative density is respectively 92.2% and 98.2%, and the content of α-SiC is greater than 90%.
Claims (9)
1, the sheath/core bicomponent fiber legal system is equipped with the production technology of continuous carbofrax fibre, it is characterized in that processing step is as follows:
1) macromolecular material is dissolved in makes skin liquid in the solvent, said macromolecule is high molecular polymer polyacrylonitrile (PAN) or viscose glue, molecular weight Mw=35000～95000 of PAN, said solvent is dimethylformamide DMF or dimethylacetylamide DMA or dimethyl sulfoxide (DMSO) DMSO, when high molecular polymer is PAN, PAN concentration is 14%～35% in the skin liquid, when high molecular polymer is viscose glue, the falling ball viscosity of viscose glue is 30～350s, NaOH content is 4%～7%, and degree of ripeness is 6～10ml 10%NH
4Cl;
2) preparation core liquid is dissolved in dispersant in the used solvent of core high molecular polymer, adds the SiC powder again and becomes ceramic size with sintering aid and ball milling, then core liquid is joined in the ceramic size with Polymer Solution, continues ball milling and obtains uniform core liquid; Said dispersant is NP-10, JA-28; Sintering aid is B powder or Al
2O
3And Y
2O
3Mixed-powder, Al
2O
3And Y
2O
3Weight ratio be 1/ (0.5～1.5); Select PAN for use as pericarp liquid, macromolecule is a molecular weight at 15000～22000 PAN or cellulose acetate in the Polymer Solution of core liquid, and solvent is DMF, DMA or DMSO, and Polymer Solution concentration is 5%～25%; As skin liquid high molecular polymer is viscose glue, and high molecular polymer is viscose glue, PVAC polyvinylalcohol or polyvinyl acetate PVAC in the Polymer Solution of core liquid, and solvent is a water, and Polymer Solution concentration is 5%～25%;
The weight of dispersant is 1% of core SiC powder weight in the core liquid, and the weight of B powder is 0.2%～0.8% of SiC powder weight, Al
2O
3And Y
2O
3Mixed-powder weight be 5%～20% of SiC powder weight, the weight of high molecular polymer is 5%～15% of SiC powder weight, the content of solid accounts for 40%～70% of total solution weight in the core liquid;
Skin liquid that 3) will prepare and core liquid are after passing through spinning pump respectively, filter with candled filter, skin liquid and core liquid after will filtering then carry out spinning by the core-skin composite spinneret pack, the temperature of skin liquid is 30～50 ℃ during spinning, the temperature of core liquid is 30～100 ℃, and spinning pressure is 0.2～20Mpa; The aperture of spinnerets is less than 1mm, and the hole count of spinnerets is 1～200;
4) liquid fluid line that pushes out from spinning pack adopts wet spinning or dry-spinning to be prepared into fibrillation;
5) fibrillation is heated 10～60min in 200～230 ℃ of air and carry out the low-temperature oxidation processing, during K cryogenic treatment, fiber is operation continuously in tube furnace, and the feeding roller speed is 0.01～0.2m/min, and Wound-up roller speed is higher by 1%～5% than feeding roller speed;
6) fiber after the oxidation processes enters and carries out continuous sintering in the high temperature process furnances, logical Ar gas in the boiler tube, boiler tube two ends mercury seal, high-temperature temperature district in the boiler tube is 1850～2250 ℃, fiber is 5～60min by the time of high-temperature region, feeding roller speed 0.001～0.05m/min, Wound-up roller speed is than feeding roller speed low 10%～20%;
7) fiber behind the sintering obtains continuous SiC fiber through the carbon fiber layer of air heat oxidation removal outside, and the carbon elimination oxidizing temperature is 550～750 ℃, and the time is 20～60min.
2, sheath/core bicomponent fiber legal system as claimed in claim 1 is equipped with the production technology of continuous carbofrax fibre, and the concentration that it is characterized in that PAN in the skin liquid is 18%～20%.
3, sheath/core bicomponent fiber legal system as claimed in claim 1 is equipped with the production technology of continuous carbofrax fibre, it is characterized in that SiC powder in the core liquid is sintered purity greater than 98.5% α-SiC or β-SiC powder, average powder size 0.02～1 μ m; Sintering aid is the B powder of particle mean size 0.1～1 μ m or the Al of particle mean size 0.02～0.5 μ m
2O
3And Y
2O
3Mixed-powder, skin zone is a carbon fiber.
4, sheath/core bicomponent fiber legal system as claimed in claim 1 is equipped with the production technology of continuous carbofrax fibre, it is characterized in that the average powder size of SiC powder is 0.1～0.35 μ m; B powder mean particle sizes 0.1～0.35 μ m; Al
2O
3And Y
2O
3The particle mean size of mixed-powder is 0.02～0.1 μ m.
5, sheath/core bicomponent fiber legal system as claimed in claim 1 is equipped with the production technology of continuous carbofrax fibre, it is characterized in that polymer concentration is 10%～20% in the core liquid, and the weight of B powder is 0.25%～0.5% of SiC powder weight, Al
2O
3And Y
2O
3Mixed-powder weight is 8%～10% of SiC powder weight, and the content of solid accounts for 45%～55% of total solution weight in the core liquid.
6, sheath/core bicomponent fiber legal system as claimed in claim 1 is equipped with the production technology of continuous carbofrax fibre, and the filtering accuracy that it is characterized in that skin liquid screen pack in the candled filter is 2 μ m, and core liquid filtering accuracy is 10 μ m.
7, sheath/core bicomponent fiber technology as claimed in claim 1 prepares the production technology of continuous carbofrax fibre, it is characterized in that aperture 80～165 μ m of spinnerets, and the hole count of spinnerets is 20～80.
8, sheath/core bicomponent fiber legal system as claimed in claim 1 is equipped with the production technology of continuous carbofrax fibre, it is characterized in that wet spinning is to allow the liquid fluid line that comes out from spinneret orifice enter the coagulating bath that non-solvent is housed, when being PAN as skin liquid macromolecule, coagulating bath is the water of room temperature and the mixing material of DMF or DMA or DMSO, and the volume ratio of the two is (20～60)/(80～40); When skin liquid macromolecule was viscose glue, coagulating bath was for containing 40～350g/LNa
2SO
4, 0.3～100g/LZnSO
4With 20～120g/LH
2SO
4The aqueous solution, temperature is 25～50 ℃; The fiber that comes out from coagulating bath stretches stretch bath, and draw ratio is 2～12 times, reels and obtain fibrillation in the back fiber dry back in 165 ℃ of hot-airs that stretches.
9, sheath/core bicomponent fiber legal system as claimed in claim 1 is equipped with the production technology of continuous carbofrax fibre, it is characterized in that dry-spinning is to allow liquid fluid line through 165 ℃ hot-air, and in hot-air, carry out hot-stretch, 2～12 times of draw ratios, with the fiber roll after stretching around obtaining fibrillation.
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| CN 02140433 CN1240891C (en) | 2002-07-04 | 2002-07-04 | Procesxs for producing continuous silicon carbide fibre by skin and core double-composition fibre method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02140433 CN1240891C (en) | 2002-07-04 | 2002-07-04 | Procesxs for producing continuous silicon carbide fibre by skin and core double-composition fibre method |
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| CN1465549A CN1465549A (en) | 2004-01-07 |
| CN1240891C true CN1240891C (en) | 2006-02-08 |
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Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100333670C (en) * | 2004-10-15 | 2007-08-29 | 湖南中烟工业公司 | Inorganic spinning additive and its application method |
| CN101280474B (en) * | 2008-05-27 | 2010-10-06 | 厦门大学 | Method for preparing silicone carbide fibre by thermochemical crosslinking and crosslinking apparatus therefor |
| CN101994169B (en) * | 2010-09-14 | 2014-04-02 | 苏州赛力菲陶纤有限公司 | Continuous silicon carbide fiber preparation method and production device |
| CN102515723B (en) * | 2011-12-31 | 2013-10-16 | 中国电子科技集团公司第十三研究所 | Refined white ceramic material and preparation method thereof |
| CN102807369A (en) * | 2012-08-27 | 2012-12-05 | 中国科学院化学研究所 | Method for preparing continuous silicon carbide fiber |
| CN104460533A (en) * | 2014-11-03 | 2015-03-25 | 镇江奥立特机械制造有限公司 | Constant-linear-velocity control system for ceramic fiber preparation |
| CN106337211B (en) * | 2016-08-29 | 2018-08-28 | 浙江惠侬丝针织内衣有限公司 | Processing method of ceramic health-care yarn |
| CN107140985A (en) * | 2017-06-01 | 2017-09-08 | 北京化工大学 | A kind of high performance ceramic material preparation method based on increasing material manufacturing technique |
| CN107117982A (en) * | 2017-06-01 | 2017-09-01 | 北京化工大学 | A kind of material model of space in-situ carburization Material reinforcement ceramics and preparation method thereof |
| CN108218435B (en) * | 2018-01-16 | 2020-09-11 | 贵州师范大学 | Preparation method of skin-core structure silicon carbide ceramic fiber |
| CN109851363B (en) * | 2019-01-31 | 2021-08-27 | 中南大学 | Heterogeneous element-containing SiC fiber with gradient interface layer and preparation method and equipment thereof |
| CN110565194B (en) * | 2019-09-25 | 2020-04-24 | 安徽省华瑞网业有限公司 | Composite fiber, short fiber and filter material |
| CN115522270B (en) * | 2022-10-26 | 2023-04-28 | 山东金冠网具有限公司 | Conductive polymer fiber with sheath-core structure and preparation method thereof |
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| CN1465549A (en) | 2004-01-07 |
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