CN110330344A - A method of high porosity silicon nitride ceramics is prepared based on selective laser sintering - Google Patents

A method of high porosity silicon nitride ceramics is prepared based on selective laser sintering Download PDF

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CN110330344A
CN110330344A CN201910532813.8A CN201910532813A CN110330344A CN 110330344 A CN110330344 A CN 110330344A CN 201910532813 A CN201910532813 A CN 201910532813A CN 110330344 A CN110330344 A CN 110330344A
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silicon nitride
sintering
selective laser
nano
nitride ceramics
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CN110330344B (en
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史玉升
程立金
马伊欣
吴甲民
陈双
魏正华
郭肖峰
陈安南
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Huazhong University of Science and Technology
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Huazhong University of Science and Technology
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Abstract

The invention discloses a kind of methods for preparing high porosity silicon nitride ceramics based on selective laser sintering, belong to increases material manufacturing technology and prepares inorganic non-metallic ceramics field, the method comprising the steps of: (1) preparing the uniformly mixed composite granule of sintering of nano-material auxiliary agent and the poly- hollow sphere of silicon nitride using mechanical mixing, or prepare the composite granule that sintering of nano-material auxiliary agent coats the poly- hollow sphere of silicon nitride by chemical coprecipitation；(2) Design CAD model saves as stl file after carrying out slicing treatment, imports in SLS former；(3) selective laser sintering is carried out to composite granule using SLS former, prepares pre-sintering silicon nitride ceramics；(4) after high temperature sintering, the porous silicon nitride ceramic of CAD model structure is prepared.After the method for the present invention prepares composite granule, pre-burning silicon nitride ceramics is prepared by selective laser sintering, and technique prepares high porosity silicon nitride ceramics after post treatment, it is high without dumping, formable labyrinth, drip molding porosity.

Description

A method of high porosity silicon nitride ceramics is prepared based on selective laser sintering
Technical field
The invention belongs to increases material manufacturing technologies to prepare inorganic non-metallic ceramics field, more particularly, to one kind based on sharp The method that the sintering of light constituency prepares high porosity silicon nitride ceramics.
Background technique
Silicon nitride is a kind of non-metallic inorganic compound with strong covalent bond, has high intensity, high rigidity, high resiliency mould Amount, low thermal coefficient of expansion, self-lubricating and the excellent performance such as wear-resistant, have obtained extensive concern.Wherein, porous silicon nitride is made pottery Porcelain also has light heat-resisting, specific surface area height, has some porosity characteristics such as selective penetrated property to gas or liquid, is " structure-function Can " integrated ceramic material.Future is expected to be applied on the radome material of aerospace craft.
Currently, the preparation of porous silicon nitride ceramic mainly uses foaming, underburnt method, pore creating material method, selective laser sintering Etc. modes.But the porous silicon nitride ceramic pore structure that foaming is prepared is uncontrollable；Underburnt method can not prepare internal structure Complicated porous silicon nitride ceramic；Although pore creating material method may be implemented the regulation of pore structure, but pore creating material mostly use it is organic Object needs to carry out dumping processing and is unfavorable for sintering densification and phase transition；Although selective laser sintering can shape labyrinth Silicon nitride ceramics, but mostly use the organic matter of low melting point as binder at present, need to carry out dumping processing, production procedure compared with It is long；And at present selective laser sintering technique in the complicated ceramic sample of preparation lattice structure etc. due to needing to carry out dumping Processing, is easy the problems such as making labyrinth sample be deformed, crack, collapse, it is difficult to 70% or more valid shaping porosity High porosity silicon nitride ceramics.
Therefore, for selective laser sintering technique, needing to find one kind can valid shaping labyrinth without binder High porosity silicon nitride ceramics method.
Summary of the invention
Aiming at the above defects or improvement requirements of the prior art, the present invention provides one kind is prepared based on selective laser sintering The method of high porosity silicon nitride ceramics, it is intended that without binder can valid shaping labyrinth high porosity (70% or more porosity) silicon nitride ceramics, 70% or more porosity can not be shaped by thus solving existing method selective laser sintering Silicon nitride ceramics, and need to carry out dumping processing, production procedure is longer, and makes pottery to the porous silicon nitride of the labyrinths such as dot matrix The technical issues of porcelain is also easy to produce deformation, cracks, collapses when shaping.
To achieve the above object, the present invention provides one kind prepares high porosity silicon nitride ceramics based on selective laser sintering Method, include the following steps:
(1) the uniformly mixed composite powder of sintering of nano-material auxiliary agent and the poly- hollow sphere of silicon nitride is prepared using mechanical mixing Body, or the composite granule that sintering of nano-material auxiliary agent coats the poly- hollow sphere of silicon nitride is prepared by chemical coprecipitation；
(2) Design CAD model saves as after carrying out slicing treatment to the CAD model comprising CAD model data information Stl file imports the stl file in selective laser sintering former；
(3) composite granule that step (1) obtains is layed in the powder cylinder of selective laser sintering (SLS) former, if Determine SLS forming parameters, in conjunction with the stl file imported in step (2), carries out selective laser sintering, successively print, prepare It is pre-sintered silicon nitride ceramics；
(4) the pre-sintering silicon nitride ceramics obtained to step (3) carries out high temperature sintering under protective atmosphere, prepares described The high porosity silicon nitride ceramics of CAD model structure.
Preferably, the sintering of nano-material auxiliary agent includes nano aluminium oxide, nano yttrium oxide, oxide nano rare earth and nanometer One or more of silica.
Preferably, the oxide nano rare earth includes lanthana, neodymia, cerium oxide and ytterbium oxide, and the nanometer is burnt Tying auxiliary agent includes one such or several oxide nano rare earths.
Preferably, by adjusting the additional amount and type of the sintering of nano-material auxiliary agent, to the porous silicon nitride being prepared The microstructure and properties of ceramics are regulated and controled.
Preferably, in step (1), the mass fraction that the sintering of nano-material auxiliary agent accounts for the composite granule is 5%~30%.
Preferably, in step (1), when using mechanical mixing, mixing time be 12~for 24 hours.
Preferably, in step (1), the chemical coprecipitation are as follows: by the poly- hollow sphere of the silicon nitride, quasi- generation institute is added It states and is mixed in the salting liquid of sintering of nano-material auxiliary agent, after ammonium hydroxide fully reacting is added, is filtered, dried, and 900~ 1200 DEG C carry out calcining and obtain composite granule.
Preferably, the SLS forming parameters are as follows: 3~15W of laser power, 10~300mm/s of scanning speed, layering 0.1~0.3mm of thickness, 0.01~0.3mm of sweep span.
Preferably, the technological parameter of the high temperature sintering are as follows: 5~20 DEG C/min of heating rate, sintering temperature be 1700~ 2000 DEG C, soaking time is 2~8h.
Preferably, the protective atmosphere is one or more of nitrogen, argon gas, hydrogen.
Preferably, the CAD model be honeycomb porous structure or Space expanding with internal intercommunicating pore structure or Complicated functional parts.
In general, through the invention it is contemplated above technical scheme is compared with the prior art, can obtain down and show Beneficial effect:
1, method provided by the invention combines sintering aftertreatment technology that can prepare complicated knot based on selective laser sintering work The high porosity silicon nitride ceramics of 70% or more the porosity of structure；This method prepares sintering of nano-material auxiliary agent-using mechanical mixing The poly- hollow sphere composite granule of silicon nitride, or by chemical coprecipitation prepare sintering aid coat the poly- hollow sphere of silicon nitride it is compound Powder is prepared by selective laser sintering technique and is pre-sintered silicon nitride ceramics, and further uses high temperature sintering, is prepared The controllable porous silicon nitride ceramic of microstructure and properties, it can be achieved that various structures and performance requirement porous silicon nitride ceramic； This method all has novelty on material prescription and porous ceramics preparation process, can valid shaping complexity knot without binder The high porosity silicon nitride ceramics of structure；Without carrying out dumping processing, porous ceramics preparation process flow is simplified, and effectively reduce The problem of deforming, crack, collapse when labyrinth forming.
2, method provided by the invention is pre-sintered porous silicon nitride ceramic based on the preparation of selective laser sintering technique, passes through The additional amount and type and aftertreatment technology parameter of adjustment sintering of nano-material auxiliary agent, to the porous silicon nitride ceramic being prepared Microstructure and properties are regulated and controled, and have the characteristics that macroporous structure and micropore structure are controllable, it can be achieved that various knots The porous silicon nitride ceramic of structure and performance requirement.
3, method provided by the invention, can porous silicon nitride ceramic valid shaping to labyrinths such as dot matrix, such as The functional parts (cooling fin etc.) of honeycomb porous structure or Space expanding or complexity with internal intercommunicating pore structure, have The problem of effect is deformed, is cracked, collapsing when reducing the forming of these labyrinths.
4, method provided by the invention is not necessarily to mold, reduces manufacturing cost；Due to reducing without carrying out subsequent dumping Environmental pollution.
Detailed description of the invention
Fig. 1 is the method flow diagram provided by the invention that high porosity silicon nitride ceramics is prepared based on selective laser sintering；
Fig. 2 is octahedra Space expanding CAD model example provided by the invention；
Fig. 3 is the honeycomb porous structure CAD model example that inside provided by the invention has intercommunicating pore structure；
Fig. 4 (a) is the microscopic appearance low power figure that silicon nitride ceramics is pre-sintered prepared by the embodiment of the present invention 1；
Fig. 4 (b) is the microscopic appearance high power figure that silicon nitride ceramics is pre-sintered prepared by the embodiment of the present invention 1；
Fig. 5 (a) is the microscopic appearance low power figure of porous silicon nitride ceramic prepared by the embodiment of the present invention 1；
Fig. 5 (b) is the microscopic appearance high power figure of porous silicon nitride ceramic prepared by the embodiment of the present invention 1.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and It is not used in the restriction present invention.As long as in addition, technical characteristic involved in the various embodiments of the present invention described below Not constituting a conflict with each other can be combined with each other.
The present invention provides a kind of methods for preparing high porosity silicon nitride ceramics based on selective laser sintering, specially make Use sintering of nano-material auxiliary agent as binder and sintering aid, based on the slice of data information of SLS forming technology combination CAD model, Near-net-shape prepares pre-sintering porous silicon nitride ceramic, post-processes forming porous silicon nitride ceramics part through oversintering.Such as Fig. 1 institute Show, step includes:
(1) the uniformly mixed composite powder of sintering of nano-material auxiliary agent and the poly- hollow sphere of silicon nitride is prepared using mechanical mixing Body, or the composite granule that sintering of nano-material auxiliary agent coats the poly- hollow sphere of silicon nitride is prepared by chemical coprecipitation.
The poly- hollow sphere of silicon nitride, full name in English Si3N4Poly-hollow microspheres, is detailed in paper (Preparation of porous Si3N4ceramics via tailoring solid loading of Si3N4slurry and Si3N4poly-hollow microsphere content[J].Journal of Advanced Ceramics,2015,4(4):260-266.)。
The present invention can control the microcosmic knot of porous ceramics biscuit by adjusting the type and additional amount of sintering of nano-material auxiliary agent Structure and performance；Due to sintering aid in silicon nitride ceramics sintering process densification and phase transition can have an impact, such as be sintered Promoter addition is more, then phase transition and densification rate may improve, and increases the density of silicon nitride ceramics, but corresponding high Warm mechanical property may decline.It therefore, can be by the additional amount and type of adjusting sintering of nano-material auxiliary agent finally to silicon nitride The microstructure and properties of ceramic part are regulated and controled.Wherein, sintering aid is preferably nano aluminium oxide, nano yttrium oxide, receives One or more of rice rare earth oxide (lanthana, neodymia, cerium oxide, ytterbium oxide etc.) and nano silica.
Specifically, mechanical mixing preparation SLS forming composite granule, it is total that sintering of nano-material promoter addition accounts for composite granule The 5%~30% of quality, mixing time be 12~for 24 hours.
Chemical coprecipitation cladding process prepare SLS forming use composite granule, method particularly includes: will based on powder quality 5%~ The silicon nitride ceramics powder that the 30% corresponding salting liquid of sintering of nano-material auxiliary agent is 70~95% with corresponding mass score is mixed It closes, after ammonium hydroxide fully reacting is added, is filtered, dried, and carry out calcining at 900~1200 DEG C and obtain composite granule-cladding Silicon nitride ceramics powder.
(2) CAD (the Computer Aided of the porous silicon nitride ceramic of optimization design labyrinth according to demand Design, CAD) model, it saves as after carrying out slicing treatment to the CAD model comprising CAD model data information Stl file, import selective laser sintering former in.The CAD model that the present invention is applicable in does not limit shape, structure and ruler It is very little, the internal honeycomb porous structure or octahedron, dodecahedron with intercommunicating pore structure can also be optimized for according to application demand Equal Space expandings or the functional device with labyrinth, such as heat shield.As Fig. 2 give one it is application-oriented excellent The octahedra Space expanding CAD model example of change, as the inside for giving an application-oriented optimization Fig. 3 has intercommunicating pore The honeycomb porous structure CAD model example of structure.
STL is normative document type applied by most rapid prototyping systems.STL is to show three-dimensional with triangle gridding CAD model.
(3) SLS forming parameters are selected, according to the stl file data information imported in step (2), carry out laser choosing Area's sintering, successively prints, prepares the pre-sintering porous silicon nitride ceramic of corresponding CAD structure.
Specifically, SLS forming parameters are preferred are as follows: laser power is 3~15W, and scanning speed is 10~300mm/s, Layering thickness is 0.1~0.3mm, and sweep span is 0.01~0.3mm.
(4) after carrying out high temperature sintering processing to the pre-sintering porous silicon nitride ceramic that step (3) is prepared, CAD is prepared With the porous silicon nitride ceramic part of special pore structure designed by model.
Specifically, high-sintering process parameter is preferred are as follows: 5~20 DEG C/min of heating rate, sintering temperature be 1700~ 2000 DEG C, soaking time is 2~8h, and protective atmosphere is one or more of nitrogen, argon gas, hydrogen.
The present invention carries out mechanical mixture or change using the poly- hollow sphere of silicon nitride as raw material and pore creating material, with sintering of nano-material auxiliary agent It learns co-precipitation cladding and prepares composite granule, pre-burning silicon nitride ceramics is prepared by the sintering of Direct Laser constituency, and after warp Treatment process prepares silicon nitride ceramics, has without dumping, formable labyrinth, drip molding porosity height, dimensional accuracy The features such as high.
High porosity silicon nitride pottery is prepared based on selective laser sintering to provided by the invention below in conjunction with attached drawing and example The method of porcelain is described in more detail.
Embodiment 1:
(1) the poly- hollow sphere of silicon nitride and sintering of nano-material auxiliary agent are carried out chemical coprecipitation cladding, preparation cashier by the present embodiment The composite granule of the rice sintering aid cladding poly- hollow sphere of silicon nitride；Specifically,
The salting liquid that the poly- hollow sphere of 93g silicon nitride and 15g aluminum nitrate, 17g yttrium nitrate are made into is mixed, ammonium hydroxide is added It to fully reacting, filtered, dried, and carried out calcining at 1000 DEG C and obtain uniformly mixed composite granule, that is, coated Silicon nitride ceramics powder, it is 7% that wherein sintering of nano-material auxiliary agent, which accounts for the mass fraction of composite granule,；
(2) the octahedra Space expanding CAD model of application-oriented optimization is designed, and to the CAD model slicing treatment It is converted into stl file, which is imported into SLS former；
(3) on SLS former, following SLS forming parameters forming porous silicon nitride ceramics biscuits are selected, i.e., in advance Sintered silicon nitride ceramic: laser power 9W, scanning speed 50mm/s, layering thickness are 0.15mm, sweep span 0.15mm；This Shown in the microscopic appearance figure such as Fig. 4 (a) and Fig. 4 (b) for being pre-sintered silicon nitride ceramics prepared by embodiment.
(4) the porous silicon nitride ceramic biscuit that step (3) obtains is subjected to high temperature sintering, high temperature sintering in nitrogen atmosphere Technological parameter is 5 DEG C/min, is warming up to 1750 DEG C, keeps the temperature 2h, finally prepares the porous Si that porosity is 75%3N4Ceramics zero Part.
The porous Si that porosity prepared by the present embodiment is 75%3N4Microscopic appearance figure such as Fig. 5 (a) and Fig. 5 of ceramics (b) shown in.Embodiment 2:
(1) the poly- hollow sphere of 70g silicon nitride, 30g nano lanthanum oxide are subjected to mechanical mixture and obtain composite granule for 24 hours, wherein Sintering of nano-material promoter addition is the 30% of total composite granule quality；
(2) inside for establishing application-oriented optimization has the honeycomb porous structure CAD model of intercommunicating pore structure, and to this CAD model slicing treatment is converted into stl file, which is imported SLS former；
(3) on SLS former, following SLS forming parameters forming porous silicon nitride ceramics biscuits are selected, i.e., in advance Sintered silicon nitride ceramic: laser power 12W, scanning speed 100mm/s, layering thickness are 0.3mm, sweep span 0.20mm；
(4) the porous silicon nitride ceramic biscuit that step (3) obtains is subjected to high temperature sintering, high temperature sintering in argon atmosphere Technological parameter is 20 DEG C/min, is warming up to 1700 DEG C, keeps the temperature 8h, finally prepares the porous Si that porosity is 73%3N4Ceramics zero Part.
Embodiment 3:
(1) the poly- hollow sphere of 95g silicon nitride, 5g nano silica are subjected to mechanical mixture 12h and obtain composite granule, wherein Sintering of nano-material promoter addition is the 5% of total composite granule quality；
(2) inside for establishing application-oriented optimization has the honeycomb porous structure CAD model of intercommunicating pore structure, and should CAD model slicing treatment is converted into stl file, which is imported SLS former；
(3) on SLS former, following SLS forming parameters forming porous silicon nitride ceramics biscuits are selected, i.e., in advance Sintered silicon nitride ceramic: laser power 3W, scanning speed 10mm/s, layering thickness are 0.1mm, sweep span 0.3mm；
(4) the porous silicon nitride ceramic biscuit that step (3) obtains is subjected to high temperature sintering, high temperature sintering in argon atmosphere Technological parameter is 10 DEG C/min, is warming up to 2000 DEG C, keeps the temperature 4h, finally prepares the porous Si that porosity is 80%3N4Ceramics zero Part.
Embodiment 4:
(1) the poly- hollow sphere of 93g silicon nitride, 64g aluminum nitrate, 72g yttrium nitrate wiring solution-forming are mixed, ammonium hydroxide is added extremely It after fully reacting, filtered, dried, and carried out calcining at 1200 DEG C and obtain composite granule, is i.e. sintering of nano-material auxiliary agent coats nitrogen The composite granule of the poly- hollow sphere of SiClx, the additional amount of sintering of nano-material auxiliary agent accounts for the 30% of composite granule quality after cladding；
(2) the octahedra Space expanding CAD model of application-oriented optimization is established, and by the CAD model slicing treatment It is converted into stl file, which is imported into SLS former；
(3) on SLS former, following SLS forming parameters forming porous silicon nitride ceramics biscuits: laser are selected Power 15W, scanning speed 300mm/s, layering thickness are 0.20mm, sweep span 0.01mm；
(4) the porous silicon nitride ceramic biscuit for obtaining step (3) carries out high temperature burning in hydrogen/argon gas mixed atmosphere Knot, high-sintering process parameter are 15 DEG C/min, are warming up to 1800 DEG C, keep the temperature 6h, finally prepare porosity be 70% it is more Hole Si3N4Ceramic part.
Embodiment 5:
(1) the poly- hollow sphere of 90g silicon nitride, the nano oxidized ytterbium of 5g and 5g nano yttrium oxide are subjected to mechanical mixture 18h acquisition Composite granule；
(2) the octahedra Space expanding CAD model of application-oriented optimization is established, and by the CAD model slicing treatment It is converted into stl file, which is imported into SLS former；
(3) on SLS former, following SLS forming parameters forming porous silicon nitride ceramics biscuits are selected, i.e., in advance Sintered silicon nitride ceramic: laser power 5W, scanning speed 30mm/s, layering thickness are 0.10mm, sweep span 0.05mm；
(4) the porous silicon nitride ceramic biscuit that step (3) obtains is subjected to high temperature sintering, high temperature sintering in nitrogen atmosphere Technological parameter is 5 DEG C/min, is warming up to 1900 DEG C, keeps the temperature 3h, finally prepares the porous Si that porosity is 83%3N4Ceramics zero Part.
Embodiment 6:
(1) the poly- hollow sphere of 93g silicon nitride, 11g aluminum nitrate, 12g yttrium nitrate wiring solution-forming are mixed, ammonium hydroxide is added extremely It after fully reacting, filtered, dried, and carried out calcining at 900 DEG C and obtain composite granule, that is, the silicon nitride ceramic coated Body, the additional amount of sintering aid is the 5% of total composite granule quality after cladding；
(2) the octahedra Space expanding CAD model of application-oriented optimization is established, and to the CAD model slicing treatment It is converted into stl file, which is imported into SLS former；
(3) on SLS former, following SLS forming parameters forming porous silicon nitride ceramics biscuits: laser are selected Power 8W, scanning speed 200mm/s, layering thickness are 0.30mm, sweep span 0.10mm；
(4) the porous silicon nitride ceramic biscuit that step (3) obtains is subjected to high temperature sintering, high temperature sintering in nitrogen atmosphere Technological parameter is 10 DEG C/min, is warming up to 1850 DEG C, keeps the temperature 6h, finally prepares the porous Si that porosity is 85%3N4Ceramics zero Part.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to The limitation present invention, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should all include Within protection scope of the present invention.

Claims (10)

1. a kind of method for preparing high porosity silicon nitride ceramics based on selective laser sintering, which is characterized in that including walking as follows It is rapid:
(1) the uniformly mixed composite granule of sintering of nano-material auxiliary agent and the poly- hollow sphere of silicon nitride is prepared using mechanical mixing, or Person prepares the composite granule that sintering of nano-material auxiliary agent coats the poly- hollow sphere of silicon nitride by chemical coprecipitation；
(2) Design CAD model saves as the STL text comprising CAD model data information after carrying out slicing treatment to the CAD model Part imports the stl file in selective laser sintering former；
(3) composite granule that step (1) obtains is layed in selective laser sintering former powder cylinder, setting SLS shapes work Skill parameter carries out selective laser sintering, successively prints in conjunction with the stl file imported in step (2), prepares pre-sintering nitridation Silicon ceramics；
(4) the pre-sintering silicon nitride ceramics obtained to step (3) carries out high temperature sintering under protective atmosphere, prepares the CAD The high porosity silicon nitride ceramics of model structure.
2. a kind of method that high porosity silicon nitride ceramics is prepared based on selective laser sintering according to claim 1, It is characterized in that, the sintering of nano-material auxiliary agent includes nano aluminium oxide, nano yttrium oxide, oxide nano rare earth and nanometer titanium dioxide One or more of silicon.
3. a kind of method that high porosity silicon nitride ceramics is prepared based on selective laser sintering according to claim 2, It is characterized in that, the oxide nano rare earth includes lanthana, neodymia, cerium oxide and ytterbium oxide, the sintering of nano-material auxiliary agent Including one such or several oxide nano rare earths.
4. a kind of method that high porosity silicon nitride ceramics is prepared based on selective laser sintering according to claim 2 or 3, It is characterized in that, by adjusting the additional amount and type of the sintering of nano-material auxiliary agent, to the high porosity silicon nitride being prepared The microstructure and properties of ceramics are regulated and controled.
5. a kind of method that high porosity silicon nitride ceramics is prepared based on selective laser sintering according to claim 1, It is characterized in that, in step (1), the mass fraction of the sintering of nano-material auxiliary agent is 5%~30%.
6. a kind of method that high porosity silicon nitride ceramics is prepared based on selective laser sintering according to claim 5, Be characterized in that, in step (1), when using mechanical mixing, mixing time be 12~for 24 hours.
7. a kind of method that high porosity silicon nitride ceramics is prepared based on selective laser sintering according to claim 5, It is characterized in that, in step (1), the chemical coprecipitation are as follows: by the poly- hollow sphere of the silicon nitride, the quasi- generation nanometer is added Mixed in the salting liquid of sintering aid, be added ammonium hydroxide fully reacting after, filtered, dried, and 900~1200 DEG C into Row calcining obtains composite granule.
8. -7 any a kind of side for preparing high porosity silicon nitride ceramics based on selective laser sintering according to claim 1 Method, which is characterized in that the SLS forming parameters are as follows: 3~15W of laser power, 10~300mm/s of scanning speed are layered layer Thickness 0.1~0.3mm, 0.01~0.3mm of sweep span.
9. -7 any a kind of side for preparing high porosity silicon nitride ceramics based on selective laser sintering according to claim 1 Method, which is characterized in that the technological parameter of the high temperature sintering are as follows: 5~20 DEG C/min of heating rate, sintering temperature be 1700~ 2000 DEG C, soaking time is 2~8h.
10. -7 any described a kind of preparing high porosity silicon nitride ceramics based on selective laser sintering according to claim 1 Method, which is characterized in that the protective atmosphere is one or more of nitrogen, argon gas, hydrogen.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111057928A (en) * 2020-01-03 2020-04-24 合肥工业大学 WC-Co-Y with excellent comprehensive mechanical properties2O3Hard alloy and preparation method thereof

Citations (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3084998A (en) * 1960-12-20 1963-04-09 Union Carbide Corp Method of making foamed silicon nitride
CN102500748A (en) * 2011-10-25 2012-06-20 中南大学 Method for preparing aluminum silicon carbide composite material
CN102635479A (en) * 2012-04-23 2012-08-15 常州联德电子有限公司 Preparation method of automobile silicon nitride ceramic glow plug
CN103496999A (en) * 2013-09-18 2014-01-08 清华大学 Method for preparing porous ceramics from hollow ceramic ball
CN103922748A (en) * 2014-03-14 2014-07-16 河海大学 Preparation method for porous silicon nitride ceramic
CN105294160A (en) * 2015-09-29 2016-02-03 洛阳暖盈电子技术有限公司 Method for preparing porous silicon nitride ceramics through gel casting and microwave sintering
CN105777180A (en) * 2016-03-01 2016-07-20 贵州师范大学 Method for preparing porous silicon nitride through three-dimensional printing
CN106316440A (en) * 2016-08-19 2017-01-11 华中科技大学 Selective laser sintering based preparation method of complex-structure porous ceramic
CN106674828A (en) * 2016-11-28 2017-05-17 安徽省春谷3D打印智能装备产业技术研究院有限公司 3d printing silicon nitride ceramic material and preparation method thereof
CN106673662A (en) * 2016-12-26 2017-05-17 上海工程技术大学 Silicon carbide ceramic part and preparation method thereof
CN107032798A (en) * 2017-05-31 2017-08-11 清华大学 A kind of preparation method of the porous ceramic film material based on photocureable rapid shaping
CN107056320A (en) * 2017-04-12 2017-08-18 广东工业大学 A kind of cordierite honeycomb ceramic and its application
CN107200597A (en) * 2017-05-26 2017-09-26 华中科技大学 A kind of Direct Coagulation Casting preparation method of the complicated porous ceramics of high porosity
CN107353036A (en) * 2017-08-21 2017-11-17 广东工业大学 A kind of porous silicon nitride ceramic based on increases material manufacturing technology, its preparation method and its application
CN107500781A (en) * 2017-09-28 2017-12-22 上海应用技术大学 A kind of preparation method of porous ceramics
CN107602130A (en) * 2017-10-17 2018-01-19 哈尔滨理工大学 The method that porous SiC ceramics are prepared based on 3D forming techniques
US20180111881A1 (en) * 2016-10-24 2018-04-26 The Boeing Company Precursor Material for Additive Manufacturing of Low-density, High-porosity Ceramic Parts and Methods of Producing the Same
CN108002842A (en) * 2017-11-16 2018-05-08 华中科技大学 A kind of preparation method of complicated shape nitride porous silicon member
CN108046779A (en) * 2017-12-19 2018-05-18 华中科技大学 The method that labyrinth hollow ball ceramic part is prepared using selective laser sintering
CN108585886A (en) * 2018-06-11 2018-09-28 哈尔滨工业大学 A kind of porous ceramic film material and preparation method thereof that porosity change is controllable

Patent Citations (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3084998A (en) * 1960-12-20 1963-04-09 Union Carbide Corp Method of making foamed silicon nitride
CN102500748A (en) * 2011-10-25 2012-06-20 中南大学 Method for preparing aluminum silicon carbide composite material
CN102635479A (en) * 2012-04-23 2012-08-15 常州联德电子有限公司 Preparation method of automobile silicon nitride ceramic glow plug
CN103496999A (en) * 2013-09-18 2014-01-08 清华大学 Method for preparing porous ceramics from hollow ceramic ball
CN103922748A (en) * 2014-03-14 2014-07-16 河海大学 Preparation method for porous silicon nitride ceramic
CN105294160A (en) * 2015-09-29 2016-02-03 洛阳暖盈电子技术有限公司 Method for preparing porous silicon nitride ceramics through gel casting and microwave sintering
CN105777180A (en) * 2016-03-01 2016-07-20 贵州师范大学 Method for preparing porous silicon nitride through three-dimensional printing
CN106316440A (en) * 2016-08-19 2017-01-11 华中科技大学 Selective laser sintering based preparation method of complex-structure porous ceramic
US20180111881A1 (en) * 2016-10-24 2018-04-26 The Boeing Company Precursor Material for Additive Manufacturing of Low-density, High-porosity Ceramic Parts and Methods of Producing the Same
US20180305262A1 (en) * 2016-10-24 2018-10-25 The Boeing Company Precursor Material for Additive Manufacturing of Low-Density, High-Porosity Ceramic Parts and Methods of Producing the Same
CN106674828A (en) * 2016-11-28 2017-05-17 安徽省春谷3D打印智能装备产业技术研究院有限公司 3d printing silicon nitride ceramic material and preparation method thereof
CN106673662A (en) * 2016-12-26 2017-05-17 上海工程技术大学 Silicon carbide ceramic part and preparation method thereof
CN107056320A (en) * 2017-04-12 2017-08-18 广东工业大学 A kind of cordierite honeycomb ceramic and its application
CN107200597A (en) * 2017-05-26 2017-09-26 华中科技大学 A kind of Direct Coagulation Casting preparation method of the complicated porous ceramics of high porosity
CN107032798A (en) * 2017-05-31 2017-08-11 清华大学 A kind of preparation method of the porous ceramic film material based on photocureable rapid shaping
CN107353036A (en) * 2017-08-21 2017-11-17 广东工业大学 A kind of porous silicon nitride ceramic based on increases material manufacturing technology, its preparation method and its application
CN107500781A (en) * 2017-09-28 2017-12-22 上海应用技术大学 A kind of preparation method of porous ceramics
CN107602130A (en) * 2017-10-17 2018-01-19 哈尔滨理工大学 The method that porous SiC ceramics are prepared based on 3D forming techniques
CN108002842A (en) * 2017-11-16 2018-05-08 华中科技大学 A kind of preparation method of complicated shape nitride porous silicon member
CN108046779A (en) * 2017-12-19 2018-05-18 华中科技大学 The method that labyrinth hollow ball ceramic part is prepared using selective laser sintering
CN108585886A (en) * 2018-06-11 2018-09-28 哈尔滨工业大学 A kind of porous ceramic film material and preparation method thereof that porosity change is controllable

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PETER MERCELIS 等: "Binding Mechanisms in Selective Laser Sintering and Selective Laser Melting", 《RAPID PROTOTYPING JOURNAL》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111057928A (en) * 2020-01-03 2020-04-24 合肥工业大学 WC-Co-Y with excellent comprehensive mechanical properties2O3Hard alloy and preparation method thereof
CN111057928B (en) * 2020-01-03 2021-04-02 合肥工业大学 WC-Co-Y with excellent comprehensive mechanical properties2O3Hard alloy and preparation method thereof

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