CN1162297A - Boron nitride - Google Patents
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- CN1162297A CN1162297A CN 95196011 CN95196011A CN1162297A CN 1162297 A CN1162297 A CN 1162297A CN 95196011 CN95196011 CN 95196011 CN 95196011 A CN95196011 A CN 95196011A CN 1162297 A CN1162297 A CN 1162297A
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Abstract
A process for preparing boron nitride is as follows: heat treating BN powder at the rapid layer to reduce its oxygen content to 5-8% (meso- graphitic BN), washing the heat-treated powder, mixing it with 5-8% amorphism boron, molding the mixture, exploding and compacting the shaped body with the fluid dynamic method, reaction sintering the compacted shaped body to work out said produce. After that, the produce is embedded into a powder mixture of BN and SiC for heat treating to absorb the residual B2O3. And then, the produce is to impregnated into a low-viscosity oligomer (MW<1000) of silicon methyl alkanes, wherein the selected oligomer can generate high proportional SiC during its thermal decomposition; the produce suffers a heat treating, ensuring that the pore space thereof is full of SiC equably through its entire thickness.
Description
The present invention relates to a kind ofly particularly make the method for ceramic and comprise the goods made from this method by boron nitride (BN).The boron nitride goods are applied in the industry such as electronics, electrician, wireless, metallurgy, nuclear power and rocket, can be used as the structure unit of various devices, refractory and the gas turbine engine of boat, metal alloy, single crystal growing, vaporizer-pot, metal and the alloy melting of the synthetic and fusing usefulness of high-temperature dielectric insulation component, crucible, glass and cast usefulness.
Three main method of the fixed boron nitride of practical application at present are: the reaction sintering of pyrolysis method, pressure sintering and the biscuit of colding pressing.
Have high purity and high-density by halogenation boron with the pyrolitic boron nitride that vapour deposition process obtains, and have the highest quality, when 20 ℃ are heated to 1400 ℃, can remain and in fact constantly increase its intensity.Yet pyrolysis method is a method a kind of complexity and that expend the energy, comprises that expensive management is to remove deleterious waste gas.The actual (real) thickness of the maximum of the pyrolitic boron nitride goods that can make in addition, is about 5mm.
Pressure sintering-in the graphite pressing mold is 1800-2200 ℃ of moulding simultaneously and agglomerating method-be the more cheap methods of production boron nitride goods down.These goods have high-density and high strength, but contain the easy melt-phase of 10-15% boron oxide, and in fact they will lose entire infrastructure intensity more than 1000 ℃ in temperature.In addition, the hot pressed boron material also has highly anisotropic character, but than a little less than the pyrolysis material some.
The obvious a kind of boron nitride material of invention that needs makes it both have the intensity of pyrolitic boron nitride under hot conditions, keeps the advantages such as manufacturability of the economy of hot pressed boron, low pollution and thick sample simultaneously again.
The known sintering method of the biscuit of colding pressing of boron nitride that is to say as independent operation and then carries out sintering by moulding at first, is a step that steps towards this direction.The material that is produced demonstrates sizable porosity (until 40%) and intensity is not more than 10-20MPa, and this obviously is not enough for whole use range.
For this reason, Rusanova and Gorchakova propose [Soviet Powder Metallurgy (Soviet Union's powder metallurgy), 1989,28 (2) 108], and the sintering problem of boron nitride is directly relevant with its structure.The basic structural unit that boron nitride has is the plane layer that is made of the hexagonal rings that N and B atom alternative form with very strong basic covalent linkage; Layer with layer between the generation of bonding force mainly be the result of weak molecular interaction.Many layers are stacked and form flat thin slice, and are thick until 50nm, have the angle of rule.In such structure, only the particle on crystal face just has incomplete connection, does not in fact take place hexagonal connection on the angle.
Because the progress of rapids layer structure (turbostratic-structure) boron nitride synthetic method, disclosed method in USA Patent (United States Patent (USP)) 3241919 has for example become possibility from the production of bonding pottery (self-bonded ceramic).The turbostratic boron nitride has half non-crystal structure, and approximately parallel layer group is shifted at random in this structure, or is rotated with respect to normality.Above-mentioned investigators confirm that also the accumulation defective that exists is owing to causing at the interlayer aerobic in lamination.This fact has the meaning of particularly important in the technology with explosive compaction powder method moulded products, because the whole sintering potential energy that after blast, kept its whole oxygen and kept it therefrom by the goods of powder compression, it will be realized in the following manner: in the turbostratic boron nitride powder, cause the loss of nitrogen with the oxygen of boronation bonding, when temperature is elevated to when being enough to destroy the B-O key, oxygen will leave this structure, stay the outstanding key, " joint " of boron with the boron of six sides layer taken place by this key.For to this understanding by the goods sintering mechanism of rapids layer powder compression, Rusanova and Gorchakova (ibid) work out a kind of reaction sintering method, and this is the most approaching technology terms of settlement of the present invention, and is as described below.
The turbostratic boron nitride powder is mixed with amorphous boron by quality 10-50% in advance; Compression moulding under the pressure of 1-2 ton/centimetres 2.This has compressed powder at 1400-1800 ℃ of sintering in nitrogen, and required time should make nitrogenizing reaction finish [USSRInventor ' s Certificate (Soviet Union inventor certificate) No.635074, on August 7th, 1978] in whole integral body of goods.This method is effective in the production of fire resistive material product.
The problem of this method comprises: the difficulty of the complete nitrogenize of boron in the heavy wall product;
Remove the difficulty of boron oxide, this boron oxide is when the sintering of rapids layer boron nitride/boron mixture, contains in the structure owing to boron nitride that aerobic forms; With
Owing to the internal stress that the nitrogenize of a large amount of amorphous boron produces, skewness in rapids layer boron nitride matrix makes volume be increased to 2-3 doubly.Thereby the application of this method only limits to make the goods of certain size, and it is unwell to make and contains B
2O
3By quality less than 1% goods and wall thickness goods greater than 5-7mm.
Cold forming (oxygen containing) rapids layer boron nitride, at 1800-2000 ℃ of sintering to remove deoxidation and to produce pure as far as possible a kind of orderly hexagonal boron nitride, it has suitable intensity (be about pyrolitic boron nitride half), it keeps this intensity from 0 ℃ to 1400 ℃, all significantly is better than hot pressed boron under all temperature more than 500 ℃.
The present invention's imagination for the sintering process of activating boron nitride, adds the metal-powder of fine dispersion in the disordered structure of BN powder.
According to the present invention, make the method for boron nitride ceramics goods by the mixture of the boron nitride powder of Jie's graphite and the reaction sintering agent except the pure boron powder, comprising this mixture is configured as shape of products, the mixture compacted that under pressure, will be shaped and with this mixture reaction sintering under the atmosphere of vacuum or inert or nitrogen of compacting, the boron nitride that it is characterized in that this Jie's graphite contains chemical bonding oxygen 5-10% by mass, described reaction sintering agent is equivalent to this chemical bonding oxygen at least by stoichiometric ratio, and this reaction sintering agent can with existing B, N and/or O be react with under sintering condition, adds the small portion volatile products of allowing to form suitable infusible compound.Be appreciated that " Jie's graphite " (" mesographitic ") is the transitional region that is described between the complete ordering graphite-structure of the complete unordered rapids layer structure of BN and BN.Should select such metal, promptly when it and sintering gaseous media and BN matrix interact, can produce infusible nitride, oxide compound and boride, these products have higher molecular volume than the component that is added in this mixture, this metal also should be such, i.e. its reaction is attended by perceptible exothermic effect.By utilizing volume to increase and the heat effect of reaction, under demulcent sintering condition relatively, promptly temperature is up to 1800 ℃ and nitrogen pressure and is not more than 0.06MPa, can obtain the gratifying material of structural strength.The quantity that adds the metal-powder in this mixture can be 5-50%, by quality.Their specific surface preferably is not less than 10m
2/ g.These metal-powders can be the powder of aluminium, titanium or silicon, or their mixture, also can comprise boron arbitrarily, perhaps can generate the compound of these metals in sintering process.This reaction sintering method can be applicable to obtain many various materials; By high-purity boron nitride, if boron is the metal that is added into, to containing the nearly matrix material of the complex construction of five kinds of different compounds.In addition, also according to the present invention, make the method for boron nitride ceramics goods by the mixture of the boron nitride powder of Jie's graphite and pure boron powder, comprising this mixture is configured as shape of products, the mixture compacted that under pressure, will be shaped and with this mixture reaction sintering in the atmosphere of vacuum or nitrogen of compacting, the boron nitride of wherein said Jie's graphite contains chemical bonding oxygen by mass from 5% to 10%, this pure boron is equivalent to this chemical bonding oxygen at least by stoichiometric ratio, also further comprise step with the silicoorganic compound dipping product of making, these silicoorganic compound itself are liquid or solution form (preferably anaerobic), its molecular weight is no more than 1000, and comprises and will flood product 600-1700 ℃ of heat treated step in vacuum or inert atmosphere.Described debulking methods can be hydrokinetic.In order to make the goods of complicated shape, for example crucible preferably adopts the hydrodynamic force compacting, for example in the hydraulic fluid of shaping mixt, hitting ripple in by blast, for example under 50-300MPa pressure, finish, but, adopt static compaction more suitable for making plate product.Also according to the present invention, make the method for boron nitride ceramics goods by the mixture of the boron nitride powder of Jie's graphite and pure boron powder, be configured as shape of products comprising this mixture, the mixture that has been shaped is with the compacting of hydrodynamic force mode, and the mixture of compacting reaction sintering in vacuum or nitrogen atmosphere, the boron nitride of wherein said Jie's graphite contains chemical bonding oxygen by quality from 5% to 10%, and this pure boron is equivalent to this chemical bonding oxygen at least by stoichiometric ratio.
Characteristics according to boron nitride reaction sintering of the present invention are, the matrix of the BN of this disordered structure is active, and the character of the pottery that is obtained on the lesser extent owing to the interaction between metal that is added and the sintering gaseous media, definition with regard to reaction sintering it is contemplated that, yet on the bigger degree owing in the BN matrix, be accompanied by removing of oxygen, the structural changes that takes place, and, inevitably, owing to the chemical reaction between BN and metal additive, its result generates oxide compound, boride, oxynitride and other compound.Therefore, the influence that the composition of finished product pottery and character are subjected to the structure type of initial BN powder fatefully and wherein contain oxygen quantity also is subjected to adding the influence of quantity, gaseous media and the sintering temperature of metal-powder.
According to the most generalized expression of the present invention, make the method for boron nitride ceramics goods by the mixture of the boron nitride powder of Jie's graphite and pure boron powder, be configured as shape of products comprising this mixture, the mixture that has been shaped compacting under pressure, and the mixture of compacting reaction sintering in vacuum or nitrogen atmosphere, it is characterized in that the boron nitride of this Jie's graphite contains chemical bonding oxygen by mass from 5% to 10%, and this pure boron is equivalent to this chemical bonding oxygen at least by stoichiometric ratio.This pure boron may be non-crystalline state or crystal form, preferably Powdered, its specific surface is at least 10m
2/ g, and the 5-8% that may account for this mixture, by mass.
In all cases, initial boron nitride is turbostratic preferably, with before pure boron or other reaction sintering agent mix, this boron nitride is preferably in the inert atmosphere or in a vacuum, in temperature under 1300 ℃ to 1500 ℃ condition, reach balance (for example 1 hour or longer) through thermal treatment, reduce its oxygen level, thereby partly boron nitride is converted into the structure of Jie's graphite from turbostratic preferably from～15% to 5-10%.Its specific surface is 100m at least preferably
2/ g.This boron nitride with before boron mixes preferably through washing (for example in water or alcohol or other suitable solvent), to remove boron oxide B
2O
3, preferably reach 1 % or following level by mass.
The present invention is based on the reaction sintering principle in the active matrix in general, that is to say the chemical reaction between this matrix and the reaction sintering agent, for example sintering of BN-B system (as previously described).Other example comprises BN-Al (and BN-Al-Si) system.Under the condition of heating, between the chemical bonding oxygen and (in this example) aluminium of BN, and between nitrogen and aluminium, will react, the result has BN-Al with generation
2O
3The fire-resistant composite ceramics of-AlN.
Various specific purposes for made pottery, the add-on of oxygen level among the BN and reaction sintering agent can be regulated, in vacuum, rare gas element or nitrogen, carry out sintering by different steps, might obtain to have the matrix material of required composition, comprising hexagonal boron nitride as main ingredient, and may be in varing proportions as nitride, oxide compound, boride, oxynitride and some more complicated [grand as matching (sialon) and mullite (mullite)] mutually of hotchpotch.
According to the present invention, comprise the half-dried shaping of oxygen containing BN powdered mixture with sintering activity by the method for boron nitride production ceramic, it is characterized in that, in order under the situation of not using the low melting point additive, to realize the effective low-temperature sintering of large-sized complicated shape, to keep isotropy and at high temperature stable physics-technical characteristic, the BN powder that contains the disordered structure of chemical bonding oxygen (contain structural bond contain oxygen reach 10% by weight) is heat-treated in inert atmosphere at temperature 1300-1500 ℃, in water or in the lower alcohol, wash afterwards, and mix with the reaction sintering agent, the latter is chemical element and/or compound form, at nitrogen, in rare gas element or the vacuum under the agglomerating condition, by with described oxygen generation chemical reaction from BN, can generate the infusible compound, comprise nitride, oxide compound, boride etc.This reaction sintering agent is pulverizing powder, or the metal boron powder of having pointed out, or the powder of other starting material such as aluminium, silicon, titanium, or the mixture of these powder, the hydride powder of above-mentioned metal, or their organic compound.These raw-material examples are: starting material are produced the composition BN+B BN BN+Al BN+Al of pottery
2O
3+ AlN+9Al
2O
32B
2O
3BN+Ti BN+TiB
2+ TiB+TiNBN+B+Al BN+Al
2O
3The grand BN+Ti+Al BN+AlN+Al of the grand BN+Al+B+Si BN+ match of+AlN+AlBBN+Al+Si BN+ match
2O
3+ TiB
2+ TiNBN+Ti+B BN+TiB
2+ TiBBN+TiH
2BN+TiB
2+ TiBBN+B
10H
122NH
3BNBN+meta-B
10C
2H
10(CH
2OH)
2(-the carborane glycol) the poly-carborane silane BN+SiC+Si of BNBN+
3N
4Or poly-carbon-boron-siloxanes
The reaction sintering process is preferably in the nitrogen carries out, and its pressure surpasses 0.03MPa (preferably surpassing 0.2MPa) sometimes at least, randomly adopts the pressure cycle variation, (mainly is B alternately to make gaseous product
2O
3) overflow and nitrogen is infiltrated in the mixture of compacting.
According to further feature of the present invention, after reaction sintering, carry out next procedure (arbitrarily repeating), the goods of reaction sintering are encapsulated in granular (preferably infusible) medium comprising inciting somebody to action, the volatile oxidn of emitting when this medium can absorb heating product, this particle media comprises reductive agent or its precursor, and is heated at least 1400 ℃.Described reductive agent can be the silicon-containing compound of SiC or other infusible anaerobic, the latter does not preferably contain other element except Si, C, N and H, this particle media (" burying meal ") (" buryingmeal ") also can comprise refractory material, preferably BN.The B of the remnants that this absorbed is emitted from goods
2O
3
According to another feature of the present invention, after reaction sintering and the step that no matter whether has adopted " burying meal ", the goods of making by described method can carry out with silicoorganic compound soak, infiltration or the step of dipping in other words, these silicoorganic compound itself are liquid or solution form (preferably anaerobic), its molecular weight is no more than 1000, and the goods that flooded are heat-treated in vacuum or inert atmosphere at 600-1700 ℃.Produce inorganics residue by mass at least 70% when these silicoorganic compound are preferably in 1000-1200 ℃ of pyrolysis, these silicoorganic compound can be maybe to comprise oligomeric hydrogenated methyl thing silane (oligomethylhydridesilane); Can use the mixture of the silane low polymer of energy in-situ copolymerization, the molecular weight of these oligopolymer (MW) preferably is no more than 800, all keeps low viscosity.
The present invention also comprises aforesaid ceramic, as components and parts gasket ring, crucible and heating power, electric or structure, the thickness of these goods can reach with having no problem 20mm or more than.
The present invention can adopt quite cheap starting material, uses conventional equipment and does not need too high temperature.
Now the present invention is described with the method for giving an example.Feature 1
Boron nitride powder is to be synthesized by boron-nitrogen and oxygenatedchemicals according to the method that USA Patent 3241919 describes to obtain, in vacuum furnace, heated 30 hours in ammonia atmosphere with urea and boric acid, this boron nitride powder has unordered rapids layer structure, the content of chemical bonding oxygen is for pressing quality 15%, more unordered as fruit structure, then this content can highlyer (not considered with B
2O
3The oxygen that exists is because B
2O
3Can be removed by alcohols or other suitable solvent afterwards).Collect this powder and 1300-1500 ℃ of thermal treatment in inert atmosphere, treatment time answers sufficiently long no longer to change under chosen temperature until its structure, to reach the part greying of structure, just become Jie's graphite-structure from rapids layer structure, the content of oxygen is reduced to by quality 5-10% simultaneously.This structural changes is a successive, and described " Jie's graphite " structure is the intermediate of half amorphous between the hexagonal structure of rapids layer structure and strictness.Then water or technical grade alcohol wash this powder, to remove uncombined B
2O
3, make it be lower than 1 % by quality.This washing step can not carry out in advance, because boron nitride is very active before thermal treatment, it can react with washing water/alcohol.
Compound is shaped on metal-cored with the half-dried manufacturing process of hydrodynamic force (for example at explosive compaction under 30 to 500MPa), the boron nitride that this compound comprises disordered structure is 92-95% and reaction sintering agent 5-50% by mass by mass, comprise boron amorphous 5-8% by mass in this example, and add about 1% or 2%, by siccative weight, synthetic rubber, this synthetic rubber is dissolved in " sherwood oil " varsol, continues subsequent processing afterwards.With the product that has been shaped in nitrogen atmosphere at 1400 ℃ or 1500-1800 ℃ of sintering, must be enough to heat-up time make the nitrogenize of boron to run through whole integral body of product and the B that makes formation
2O
3Evaporate away fully.
Being added to the additive in the mixture, is boron in this example, and its consumption determines according to the oxygen level in the BN powder.The oxygen level of BN powder is big more, and the quantity that should be added to the boron in the compound is also big more, because part of boron is used to generate boron oxide, has only remainder and matrix and/or gas to react, and for example nitrogenization generates BN and makes ceramic dense.
Add boron amorphous 5-8% by mass, the heavy wall product is reached run through the complete nitrogenize of whole integral body, so that B
2O
3Content reduce to by quality below 0.2% or lower, avoiding producing stress, and production cost is reduced.In physical strength is not in the situation of key property, might adopt less boron, for example looks like crucible, Electric insulator or container etc. in the large size product.Yet, in all situations, must be equal to chemical bonding oxygen in this boron nitride at least with boron nitride blended boron.
Owing to use less boron result to cause lower intensity, to a large extent, can be compensated to produce higher density by suitable selection manufacturing process and parameter.Though can use hydrostatic pressing, hydrodynamic force be shaped, by its working fluid make in addition the product of bigger complicated shape pressurized is even everywhere, thereby make the shaping product reach the high homogeneity of high-density and density, and prevent to produce internal stress.Select hydrokinetic pressure, in the 50-300MPa scope, depend on the size of load,, make it help the diffusion process of during reaction sintering, then carrying out most to guarantee the tap density of particle.
Reaction sintering is in nitrogen atmosphere, reach under the 1.0MPa at pressure and carry out, and outlet temperature is 1500-1800 ℃.When the content of boron is low to moderate 5-8%, because the nitrogenizing reaction total heat of emitting is little, can not rely on this heat drive sintering process, so the lower limit of furnace temperature can not be lower than 1500 ℃ during sintering.Yet this can make sintering time shorter.Improve in the sintering oven working spaces nitrogen gas pressure to 0.03MPa or more than, will strengthen sintering process and promote the nitrogenize of boron to run through whole integral body of goods, when pressure was 0.2MPa, nitriding velocity in fact no longer depended on the thickness of goods wall.The B because such pressure can slow down
2O
3Overflow from goods at thickness range, so this pressure can be decreased to zero every now and then, for example pressure/vacuumize circulation once in 2 hours.The example 1 of feature 1
For large-sized heavy-walled goods that are shaped, wall thickness can reach 50mm, and such as gasket ring, the preparation compound is pressed quality 5%, its specific surface＞10m comprising the boron nitride powder that has washed by (or crystalline) boron powder of quality 95% and simple substance amorphous
2/ g, and this compound mixed with tackiness agent in a small amount, this tackiness agent are synthetic rubber solution of 2% in " sherwood oil " varsol.This boron nitride powder is synthetic in advance and 1500 ℃ of thermal treatments 1 hour, as previously mentioned.This moment it have the structure of Jie's graphite and wherein the content of oxygen for by quality 6-7%, promptly be less than can with the amount of whole pure borons reactions.The compound of above preparation is tamped around the surface of a powder metal core, and put a resilient overcoat thereon, so that compound keeps the shape of gasket ring.The shape of fuse determines the interior shape of these goods; In order to make goods obtain desired parameter, can add auxiliary foraminous packing at outside surface.
Afterwards this molectron (fuse, powder mixture and resilient overcoat) is put into the container of hydrodynamic force machinery, this container is full of fluid working medium (in this example for water), in this container with the pressure of explosion of 300MPa with the product compacting.
The product that has been shaped is removed overcoat, and dry down at 100 ℃ to remove the varsol that is used for rubber.For carrying out reaction sintering this product is embedded in the ground boron nitride powder waste material afterwards.(this BN powder scrap not can with this product sintering that is shaped because it does not contain can acceleration of sintering impurity or reagent.Other powder in theory also can be used, but none is successful as BN so far, keeps selected powder firmly in mind and must absorb oxygen.) reaction sintering be in vacuum resistance furnace in nitrogen atmosphere under the 0.05MPa pressure heating finish, outlet temperature is 1600 ℃, keeps 10 hours.
Resulting goods have 30% porosity and high resistance～10
12Ω m; B in this material
2O
3Content be no more than 0.5%, by quality; Its bending strength is 25-40MPa.These goods have anti-thermal shock stability, can withstand temperature range and be 20-2000 ℃ cold cycling repeatedly, do not lose its performance characteristics.The example 2 of feature 1
The goods that have the 10mm wall thickness in order to be shaped, for example crucible adopts boron nitride by quality 92% and the compound of boron by quality 8% composition.This boron nitride powder at 1300 ℃ through thermal treatment in advance; It has the tangible rapids layer structure of the graphite that tends to be situated between and contains aerobic until 10%, by quality.Be shaped and the method and the above-mentioned example 1 of compacting similar, in the container of hydrodynamic force machinery under the pressure of 150MPa.That describes in reaction sintering method therefor and the example 1 was similar, but under the 0.03MPa nitrogen pressure, and outlet temperature is 1500 ℃, through 10 hours.
The total content of metallic additions is no more than 10% in the pottery that makes, by quality; B
2O
3Content is not more than 0.2%, by quality; Bending strength is 30-50MPa, and reaches 1400 ℃ at least and do not reduce.Prepared crucible has anti-thermal shock stability, and contacting molten metal or glass also are stable; Its high thermal conductivity and isotropic character have guaranteed the fast whole and uniform heating of processome.This crucible still keeps its performance characteristics in order to melt titanium even after having used 10 times.The example 3 (BN+Al) of feature 1
A kind of BN powder of disordered structure wherein contains oxygen by quality～9%, with itself and the particulate lead powder (3-5m that presses quality 30%
2/ g) mix.This compound is pressed into the shape of the separating ring of horizontal cast steel machine with half-dried moulding method, and (diameter can reach 250mm; Thickness can reach 25mm), carry out sintering afterwards, in a vacuum to 1200 ℃ and in nitrogen atmosphere to 1500 ℃.
The composition of the ceramic of being made, the minimizing order of pressing composition: BN, Al
2O
3, AlN, 9Al
2O
3 *2B
2O
3BN content is about 60% by quality.These goods have physical strength 40-60MPa, the high and refractory body erosion of thermostability.It is suitable in inertia or the medium-term and long-term use of low oxidative medium.The example 4 (BN+Al) of feature 1
The BN powder of disordered structure wherein contains oxygen by quality～5%, with fine aluminum powder (3-5m by quality 80%
2/ g) mix mutually by quality 20%.This mixture is pressed into the shape of electrical isolation pad or protective guard with aforesaid hydrodynamic force moulding method.This product in nitrogen atmosphere to 1450 ℃ of sintering.
The composition of prepared ceramic, by composition successively decrease the order: BN, AlN, Al
2O
3The content of BN is about 70% by quality.The physical strength of these goods is 40-80MPa, resistance～10
nΩ m, n～10 wherein, high and the corrosion-resistant and refractory body of thermostability corrodes.That these goods are suitable in inertia or low oxidative medium falling in violent temperature and with condition that metal melt contacts under life-time service.The example 5 (BN+Al+B) of feature 1
The BN powder of disordered structure is pressed quality 70%, wherein contain oxygen by quality～6%, with fine aluminum powder (3-5m
2/ g) by quality 25% and particulate boron powder (5-10m
2/ g) mix mutually by quality 5%.This mixture is pressed into the shape of packing ring, ring or fuse with the hydrodynamic force moulding method.This product in nitrogen atmosphere to 1550 ℃ of sintering.
The composition of prepared ceramic, by composition successively decrease the order: BN, AlN, AlB
2, Al
2O
3The content of BN is about 70% by quality.The physical strength of these goods is 70-80MPa, resistance～10
10Ω m, density 1.7g/cm
3More than, high and the corrosion-resistant and refractory body erosion of thermostability.These goods are suitable in inertia or low acidic medium long-term as structural element, for example protective sleeve of thermopair under the condition that violent temperature is fallen.The example 6 (BN+Ti) of feature 1
With the BN powder of disordered structure, wherein contain oxygen by quality～8%, with particulate ti powder (10-15m
2/ g) mix mutually by quality 15%.This compound is pressed into the shape of boat, crucible or vaporizer-pot with the hydrodynamic force moulding method, afterwards in nitrogen atmosphere to 1600 ℃ of sintering.
The composition of the ceramic of being made, by composition successively decrease the order: BN, TiB
2, TiN.The content of BN is about 80% by quality.High and the anti-molten aluminium of this goods thermostability corrodes.It is suitable at inert atmosphere or vacuum medium-term and long-term as the anti-corrosion element in the aluminum evaporation device.The example 7 (BN+Ti+Al) of feature 1
With the BN powder of disordered structure, wherein contain oxygen by mass～8%, with particulate ti powder (10-15m
2/ g) by mass 10% and fine aluminum powder (3-5m
2/ g) mix mutually by quality 10%.Is tubing or sheet material with this mixture with hydrodynamic force moulding method press forming, afterwards in nitrogen atmosphere to 1550 ℃ of sintering.
The composition of prepared ceramic successively decreases in proper order by composition: BN, AlN, Al
2O
3, TiN, TiB
2The content of BN is about 70% by quality.The thermostability height and the mechanical bending strength of these goods are 20-30MPa.These goods have anti-thermal shock stability and anti-molten aluminium corrodes.It is suitable in inert atmosphere or the medium-term and long-term use of vacuum, as the protection overcoat that is inserted in the transmitter that carries out metallurgical monitoring in the metal melting body.Example 8 (the BN+TiH of feature 1
2)
With the BN powder of disordered structure, wherein contain oxygen by mass～8%, with particulate titanium hydride powders (10-15m
2/ g) 15% mixing mutually by mass.Is boat, crucible or vaporizer-pot with this mixture with hydrodynamic force moulding method press forming, afterwards in nitrogen atmosphere to 1600 ℃ of sintering.
The composition of resulting product, by composition successively decrease the order: BN, TiB
2, TiN.The content of BN is about 80% by quality.High and the anti-molten aluminum of the thermostability of these goods corrodes.It is adapted at inert atmosphere or the medium-term and long-term use of vacuum, as the protecting component in the aluminum evaporation device.The example 9 (BN+Si+Al) of feature 1
Prepare a compound and prepare the usefulness of shaping, this compound comprises silica flour (3-5m
2/ g) by quality 4.2%, aluminium powder (5-10m
2/ g) press quality 1% by quality 82.3% and rubber cement by quality 12.5%, rapids layer boron nitride powder.This boron nitride powder at 1500 ℃ through thermal treatment in advance with contain oxygen by quality 6-7%.Prepared mixture is seated in the model carrying out half-dried cold stamping die, the 0.5-1 ton/centimetre
2Press forming is the parallelepiped of 7 * 7 * 70mm under the pressure.
From model, take out the product that has been shaped, be placed in the granule medium of boron nitride to carry out reaction sintering.Carry out sintering in vacuum resistance furnace in nitrogen atmosphere under the 0.05MPa pressure, last sintering temperature was 1600 ℃, through 10 hours.
The goods that obtained have high resistance, and～10
11Ω m; Show that by the X-ray analysis and the chemical analysis of phase this material is formed B in this material by the match of the boron nitride of 75% hexagonal structure and 20-25% is grand
2O
3Content is no more than 0.5% by quality; Its mechanical bending strength is 20-30MPa.These goods have anti-thermal shock stability, are able to take thermal cycling repeatedly between 20 ℃ and 2000 ℃ in inert media, do not lose its performance characteristics simultaneously.The example 10 (BN+Si+Al+B) of feature 1
Prepare the usefulness that a compound is prepared as moulding, this compound comprises silica flour (3-5m
2/ g) by quality 5.5%, aluminium powder (5-10m
2/ g) by quality 16.6%, boron amorphous powder (3-5m
2/ g) press quality 1% by quality 60.2% and rubber cement by quality 16.6%, rapids layer boron nitride powder.This boron nitride powder at 1500 ℃ through thermal treatment in advance with contain oxygen by quality 6-7%.Prepared mixture is seated in the model carrying out half-dried cold stamping die, the 0.5-1 ton/centimetre
2Press forming is the parallelepiped of 7 * 7 * 70mm under the pressure.
From model, take out the product that has been shaped, be placed in the granule medium of boron nitride to carry out reaction sintering.Carry out sintering in vacuum resistance furnace in nitrogen atmosphere under the 0.05MPa pressure, last sintering temperature was 1600 ℃, through 10 hours.
The goods that obtained have high resistance, and～10
10Ω m; Show that by the X-ray analysis and the chemical analysis of phase this material is formed B in this material by the match of the boron nitride of 70% hexagonal structure and 25-30% is grand
2O
3Content is no more than 0.5% by quality; Its mechanical bending strength is 30-45MPa.These goods have anti-thermal shock stability, are able to take thermal cycling repeatedly between 20 ℃ and 2000 ℃ in inert media, do not lose its performance characteristics simultaneously.Example 11 (the BN+B of feature 1
10H
12 *2NH
3)
With 85 parts of boron nitride, this boron nitride at 1 500 ℃ through thermal treatment in advance with contain oxygen, and by 15 parts of diamino Decaboron tetradecahydride (molecular formula: B of quality by quality 6-7%
10H
12 *2NH
3, by Decaboron tetradecahydride B
10H
12Obtain with ammonia react, add purification) mix mutually, the latter adds with the acetonitrile solution form of 5-10%.This compound stirred 0.5-1 hour at 60-70 ℃, added benzene (half of diamino Decaboron tetradecahydride liquor capacity) afterwards.After stirring 10 minutes, under 100 ℃ and vacuum condition, solvent evaporation is fallen.The resulting boron nitride powder that adds the diamino Decaboron tetradecahydride that has is put into crucible, in vacuum electric furnace, in the atmosphere of argon gas or helium, be heat-treated to 700 ℃.Resulting powder mixed with rubber cement by quality 1% in gasoline and dry.The compound of preparing is seated in the model carrying out half-dried cold stamping die, the 0.5-1 ton/centimetre
2Press forming is the parallelepiped of 7 * 7 * 70mm under the pressure.
From model, take out the product that has been shaped, be placed in the granule medium of boron nitride to carry out reaction sintering.Carry out sintering in vacuum resistance furnace in nitrogen atmosphere under the 0.05MPa pressure, last sintering temperature was 1600 ℃, through 10 hours.
The goods that obtained have high resistance ,～1013 Ω m; Show that by the X-ray analysis and the chemical analysis of phase this material is the boron nitride of pure hexagonal structure, B in this material
2O
3Content is no more than 0.5% by quality; Its mechanical bending strength is 30-40MPa.These goods have anti-thermal shock stability, and it is able to take between 20 ℃ and 2000 ℃ thermal cycling repeatedly in inert media, do not lose its performance characteristics simultaneously.The example 12 of feature 1 (between BN+-B
10C
2H
10(CH
2OH)
2)
With 85 parts of boron nitride, this boron nitride 1500 ℃ through thermal treatment in advance with contain oxygen by quality 6-7%, and by between 15 parts of quality-carborane glycol (meta-B
10C
2H
10(CH
2OH)
2) mix mutually, the latter adds with 10% benzole soln form.After stirring 10 minutes, under 100 ℃ and vacuum condition, solvent evaporation is fallen.With resulting have add between-boron nitride powder of carborane glycol puts into crucible, be heat-treated to 900 ℃ in the atmosphere of argon gas or helium in vacuum electric furnace.The gained powder mixed with rubber cement by quality 1% in gasoline and dry.The compound of preparing is seated in the model carrying out half-dried cold stamping die, the 0.5-1 ton/centimetre
2Press forming is the parallelepiped of 7 * 7 * 70mm under the pressure.
From model, take out the product be shaped, be placed in the granule medium of boron nitride to carry out reaction sintering.Carry out sintering in vacuum resistance furnace in nitrogen atmosphere under the 0.05MPa pressure, last sintering temperature was 1600 ℃, through 10 hours.
The goods that obtained have high resistance, and～10
13Ω m; Show that by the X-ray analysis and the chemical analysis of phase this material is the boron nitride of pure hexagonal structure, B in this material
2O
3Content is no more than 0.5% by quality; Its mechanical bending strength is 30-40MPa.These goods have anti-thermal shock stability, and it is able to take between 20 ℃ and 2000 ℃ thermal cycling repeatedly in inert media, do not lose its performance characteristics simultaneously.The example 13 of feature 1 (BN+ gathers the carborane silicane) (we show a base polymer with poly-carborane silicane (poly-carboranosilanes) vocabulary, and its main chain comprises silane chain (silane links)-Si-NH-Si-NH-, with insert-B
10C
2H
10The carborane fragment alternative of-type connects.)
Get 1 part, by quality ,-carborane glycol B
10C
2H
10(CH
2OH)
2Be dissolved in by 2 parts, by quality, oligomeric hydrogenated methyl thing silane (molecular weight about 800) in 20% the solution, stirs this mixture and evaporates fully until gas in benzene.With resulting poly-carborane solution of silane and 20 parts, by quality, boron nitride is mixed, this boron nitride at 1500 ℃ through thermal treatment in advance with contain oxygen by quality 6-7%.After stirring 10 minutes, solvent is evaporated under 100 ℃ and vacuum condition.The resulting boron nitride powder that has outer addition polymerization carborane silane is seated in the model so that carry out half-dried cold stamping die, the 0.5-1 ton/centimetre
2Press forming is the parallelepiped of 7 * 7 * 70mm under the pressure.
From model, take out the product be shaped, be placed in the granule medium of boron nitride to carry out reaction sintering.Carry out sintering in vacuum resistance furnace in nitrogen atmosphere under the 0.05MPa pressure, last sintering temperature was 1600 ℃, through 10 hours.
The goods that obtained have high resistance, and 10
10Ω m; Show that by the X-ray analysis and the chemical analysis of phase this material is to have the boron nitride that total amount reaches the hexagonal structure of 5% carbide and silicon nitride, B in this material
2O
3Be no more than 0.5% by quality; Its mechanical bending strength is 30-40MPa.These goods have anti-thermal shock stability and be able to take between 20 ℃ and 2000 ℃ repeatedly thermal cycling in inert medias, and the while does not lose its performance characteristics.Feature 2
As everyone knows, in the example 1 of feature 1, also address, the boron nitride ceramics product can be buried among the BN " meal " (" meal ") in order to burn till.So bury and have many technological merits.At first, the high thermal conductivity of BN has guaranteed good thermal conduction, thereby also makes by the thermograde of product integral body little.Secondly, owing to should absorb by " meal " height in process furnace, make ceramic objects itself avoid oxidation to the oxygen in the technical grade nitrogen atmosphere, moisture and other impurity.Simultaneously, the more important thing is, be somebody's turn to do the volatile constituent that from product, discharges when " meal " can be absorbed in reaction sintering.This sintering process can be improved the intensity and the purity of product, but does not influence its porosity.
This boron nitride sintered process directly is attended by residual oxygen with B
2O
3The form of steam escapes into its surface from each particle body of BN, and the surface that escapes into product subsequently.The process of discharging boron oxide from ceramic objects would rather be carried out lentamente, particularly under the situation of heavy wall product., it is highly important that for this reason, bury ceramic objects and carry out the discharge that agglomerating " meal " should be able to promote this residual oxygen therein.
Be used for the pure BN of this boron nitride sintered kind " meal " and absorb B
2O
3The performance of steam is fine.Yet, bury B in " meal " at this
2O
3Absorption-desorption be reversing process, thereby should " meal " can make positive B
2O
3Vapour pressure raises, and this situation can make the discharge of boron oxide from ceramic objects slow down conversely again.Viewpoint is seen thus, and re-using a kind of second then, to bury " meal " be favourable, and it should be able to cause a kind of reducing atmosphere, and the B-O key is replaced by the B-N key, can remove any remaining B thus
2O
3, be beneficial to high purity and high strength.
For this reason, except that in above-mentioned reaction sintering boron nitride ceramics product, removing boron oxide,, use second then and bury " meal " to promote its reinforcement according to eigen of the present invention, as mentioned below.Intergranular point of contact is the higher position of concentration of residual oxygen, to a great extent, B takes place here
2O
3Reduction reaction, stronger B-N key replaces the B-O key, this can promote the further sintering and the reinforcement of ceramic objects.Thereby this sintering has the character of cohesive strength between the BN particle that increase contacted, yet do not make this powder densification.
These two kinds " meal " can not merge, and can react with any additives that is applied to second meal because be present in the pure boron of first meal in the stage.
According to eigen of the present invention, further sintering process in reducing atmosphere, in fact can finish by the product that sintering is buried in this second " meal ", this second " meal " is made up of the silicon compound (ROSC) of SiC or other infusible anaerobic, or uses separately or use with other granule medium.Prepare a kind of compound that comprises boron nitride " meal " and ROSC (SiC) powder.This compound of burying has the ventilation property that high heat conductivity is become reconciled, and for the product surface provides extra protection, so as not in the gas atmosphere of process furnace by impurity contamination.
Silicon carbide is the efficient reductive agent that is suitable for this purposes, as other ROSCs, is used for (just in the scope of SiO temperature stability) more than 1400 ℃.This reduction process can be summarised in (is example with SiC) in the following reaction formula:
[SiC gas] represents gas phase in this case, and it occurs on the SiC surface in nitrogen atmosphere and evenly expansion, and it not only comprises SiC steam itself, and its degradation production (Si) and the reaction product (C of it and nitrogen in addition
2N
2, CN ...).
Although SiC is the best ROSC that is intensity enhancing, still obtained a kind of this mixture of burying of substituted type, method is to flood boron nitride " meal " with silicon compound, and these silicon compounds produce during pyrolysis by the SiC of quality 10% above output and other ROSC.Use the local depletion that these compounds can guarantee not have Si.The molecular weight of these compounds is unimportant.
Should point out once more, to carry out sintering in " meal " be an independently technological operation containing burying of SiC (ROSC) or its precursor according to eigen, it can not be overlapping with reaction sintering, reason is, pointed out briefly the front, contain the Si steam will participate in furnace charge in the boron react with of nitrogenize not as yet, generate undesirable silicon boride.Nitrogenization does not take place in silicon boride under sintering condition, in this case, ceramics strength will sharply reduce, and its dielectric properties will be irreversibly weakened.The example 1 of feature 2
Make the product of (comprising reaction sintering) according to the example 1 of feature 1 and be buried in the SiC powder (particle diameter is 5-20 μ m), simultaneously in nitrogen atmosphere at 1700 ℃ through 2 hours sintering.Resulting goods bending strength is 50-60MPa at 20 ℃, and ℃ remains this value with identical straight horizontal to 1500.By quality B
2O
3Content be 0.2-0.3%.The other technologies characteristic of these goods as resistance and anti-thermal shock stability, keeps and former identical level.The example 2 of feature 2
The product of making (comprising reaction sintering) according to the example 2 of feature 1 in the 5% oligomeric impregnated boron nitride of hydrogenated methyl thing solution of silane " meal " in nitrogen atmosphere 1700 ℃ of sintering 2 hours.Oligomeric hydrogenated methyl thing solution of silane will further describe in feature 3, but the scope of its broad can be applicable to eigen 2.
Resulting goods have the bending strength of 60-70MPa.B
2O
3Content is 0.2-0.3% by quality.Feature 3
Eigen is in order to make full dense structure ceramic composite.
Boron nitride powder particulate lamella shape causes the isotropic pottery by its making to have high pore texture inevitably, even also is like this when sintering carries out under extreme temperature.The open porosity of this material by volume can reach 35-40%, and the result causes intensity lower.
The most effective method of improving these agglomerated material character is, floods these materials with organic element compound, carries out pyrolysis processing afterwards until generating useful inorganic residues.With the purposes of material, can use the impregnation compound of wide region routinely as requested; Selected compound preferably contains the element of forming required inorganic residues with the highest as far as possible ratio, for example can be silicoorganic compound (OSC), wherein includes Si-O-Si, Si-N-Si and Si-C key.Because the existence of these keys, these compounds can be thermal decomposited and be SiO
2, Si
3N
4And SiC, these inorganic residues cause these agglomerated materials to be gained in strength and protect these materials with anti-oxidation.
Should be taken into account, although in agglomerating BN pottery high porosity, by volume, the size in hole is little, typical " effective radius " (" effective radius ") is 1000-1500A.Therefore, thickness carries out full degree of depth dipping greater than the sample of 10-12mm with high molecular OSC solution (MW=2000), says it is difficult in principle.The high molecular weight component that exists in tar is formed has increased the viscosity of solution greatly and has caused the tendency of the inhomogeneous dipping of product, the low molecule resultant that has can infiltrate to very dark part by the micropore of pottery, but can equally easily pour off afterwards, and the polymer resultant concentrates at upper layer.
According to eigen, use low molecule anaerobic oligopolymer (MW is in～1000 scopes), they have distribution of low molecular weight, and polymerization takes place in their before pyrolysis, the useful resistates that their produce when pyrolysis (for example SiC, Si
3N
4) productive rate be at least 70%, can make prepared stupalith avoid ununiformity.Oligomeric hydrogenated methyl thing silane (OMHS) can be used as an example of this compound.Its lower molecular weight (600-650) and do not have high molecular component in it is formed makes it might realize the even dipping of being satisfied with in large-sized BN product (wall thickness can reach 60mm), with and pyrolysis cause the gratifying high yield of inorganic residues; Under 1000-1400 ℃ situation, surpass 80-85% (when generating SiC or SiC in pyrolysis by quality
xN
yDuring intermediate), when pyrolysis to 1600 ℃ with when above, by quality 40-45% (when in the composition of SiC at by product in the highest flight the time).This high yield is necessary, guarantees again with the high-density that promptly guarantees product that the deleterious inside of gas emits in product and cuts to bone.
Can realize that in thermal treatment more than 1600 ℃ an example of the compound of high yield is a kind of mixture of oligopolymer, the main oligopolymer of some of them is: [CH
2=CHSi (NH)
1.5]
3[CH
3HSi (NH)
1.5]
1[(CH
3)
3Si (NH)
0.5]
3[CH
2=CHSi (NH)
1.5]
6[CH
3HSi (NH)
1.5]
2[(CH
3)
3Si (NH)
0.5]
4Usually based on following structure:
Molecular-weight average is～800.This is a kind of low viscous and more stable compound of character.Can flood with quite dense form solution with 80-90% in light hydrocarbon such as pentane, hexane for example with this compound.After ℃ pyrolysis of T 〉=1600, the productive rate height of inorganic residues, near theoretical maximum, silicon carbide can reach 50-53% by quality.
If steeping process need be enhanced to greatest extent, can use the mixture of this or similar oligopolymer and " reactive thinner ".Have living oligomer MW300-600, that can play copolyreaction with the main ingredient of this mixture, can be used as this reactive thinner.For example, this specific oligopolymer can be pressed quality, oligomeric hydrogenated methyl thing silane chemical combination with 25%:
N～5-6 (M～450-470) wherein
Copolyreaction can take place more than 100 ℃ in similar this mixture in ceramic hole, the multipolymer that is generated has the required inorganic residues of high yield.(polyreaction is necessary, because after oligopolymer has permeated whole product, they should still be retained in original position (and not flowing away) during thermolysis then.)
Similarly, the low molecular weight polycaprolactone carbon silane that structure is following
N 〉=m wherein, MW
Mean value～400-600 can be used for identical purpose, and identical result is arranged.The example 1 of feature 3
The wall thickness of making according to the example 1 of feature 1 is the reaction sintering product of 50mm, with the oligomeric hydrogenated methyl thing silane of MW mean value～650 by the gasoline solution impregnation of quality 80% 72 hours.With the product that flooded 100 ℃ of dryings, thermal treatment in nitrogen afterwards, temperature slowly rises to 1400 ℃.This step at first is to make oligomeric hydrogenated methyl thing polymerizable silane, to be fixed in position, afterwards with its thermolysis, is full of micropore equably on the whole thickness of product by forming the infusibility resistates that approaches SiC.The time length of heating is depended on the thickness of product, because for the time that meets the demands, requires the centre also must reach 1400 ℃, is 48 hours in this case, is included in 1400 ℃ and keeps 4 hours.
It is 70-90MPa in the time of 20 ℃ that resulting goods have bending strength, is 80-100MPa at 1500 ℃.Specific volume resistance is 10
13Ω m.Oxidizability is according to 1/5 of 1 prepared material of example of feature 1 at 1300 ℃.In low oxidative medium (that is, the natural gas liquid products of combustion), under the condition of heat erosion, the life-span of these goods is 10 times of pure boron nitride in the time of 1500-2000 ℃.The example 2 of feature 3
Making wall thickness according to the example 2 of feature 1 is 10 or product-crucible of 100mm, be used in the mixture described in last the 3rd section of feature 3, comprising the oligopolymer of MW mean value～800 and the oligomeric hydrogenated methyl thing silane of MW mean value～450, mixed with 3: 1, this mixture is dissolved in the solution that formation connects quality 90% in lower boiling " sherwood oil " hydrocarbon mixture, above-mentioned product-crucible was flooded 48 hours in this solution.After 100 ℃ of dryings, with the slowly heating in nitrogen atmosphere of this crucible,, need with 30 hours until 1600 ℃, be included in 1600 ℃ and kept 10 hours.It is 70-90MPa in the time of 20 ℃ that the crucible of being made has bending strength, is 80-100MPa at 1500 ℃.With the material compared of making according to the example 2 of feature 1, its open porosity reduces 45-50%.This crucible is able to take the melting (at boiling temperature) of 10-15 secondary aluminium, and the crucible of pure boron nitride only can be used for melting 2-3 time.
Although be not frequent needs, feature 3 can be applied to the material made according to feature 1+2 after all.
Claims (28)
1. one kind by the method for the boron nitride powder of Jie's graphite with the mixture manufacturing boron nitride ceramics goods of reaction sintering agent except the pure boron powder, comprising this mixture is configured as shape of products, the mixture compacted that under pressure, will be shaped and with this mixture reaction sintering under the atmosphere of vacuum or inertia or nitrogen of compacting, the boron nitride that it is characterized in that this Jie's graphite contains chemical bonding oxygen by quality from 5% to 10%, described reaction sintering agent is equivalent to this chemical bonding oxygen at least by stoichiometric ratio, and this reaction sintering agent can with existing B, N and/or O be react with under sintering condition, adds the small portion volatile products of allowing to form suitable infusible compound.
2. according to the process of claim 1 wherein that described reaction sintering agent comprises metal-powder, as Al, Si or Ti with randomly also have boron, or their powdered hydride or their organic compound.
3. method of making the boron nitride ceramics goods by the mixture of the boron nitride powder of Jie's graphite and pure boron powder, comprising this mixture is configured as shape of products, the mixture compacted that under pressure, will be shaped and with this mixture reaction sintering in the atmosphere of vacuum or nitrogen of compacting, the boron nitride of wherein said Jie's graphite contains chemical bonding oxygen by quality from 5% to 10%, this pure boron is equivalent to this chemical bonding oxygen at least by stoichiometric ratio, also further comprise step with the silicoorganic compound dipping product of making, these silicoorganic compound itself are liquid or solution form (preferably anaerobic), its molecular weight is no more than 1000, and will flood product 600-1700 ℃ of heat treated step in vacuum or inert atmosphere.
4. according to the method for the arbitrary claim in front, wherein said debulking methods is hydrokinetic.
5. method of making the boron nitride ceramics goods by the mixture of the boron nitride powder of Jie's graphite and pure boron powder, comprising this mixture is configured as shape of products, with the mixture that has been shaped in the hydrodynamic force mode in compacting under the pressure with this mixture reaction sintering in the atmosphere of vacuum or nitrogen of compacting, the boron nitride of wherein said Jie's graphite contains chemical bonding oxygen by quality from 5% to 10%, and this pure boron is equivalent to this chemical bonding oxygen at least by stoichiometric ratio.
6. according to the method for the arbitrary claim in front, wherein said reaction sintering agent or pure boron powder form described mixture by quality from 5% to 50%.
7. according to claim 1; Or claim 2; Or claim 4, except when be subordinated to claim 3; Or claim 5; Or the method outside during claim 6, wherein further comprise the product that to be obtained step with the silicoorganic compound dipping, these silicoorganic compound itself are the forms (preferably anaerobic) of liquid or solution, its molecular weight is no more than 1000, and will flood product 600-1700 ℃ of heat treated step in vacuum or inert atmosphere.
8. according to claim 4,5,6 or 7, when being subordinated to 4, method, wherein said hydrodynamic force compacting is carried out under 50-300MPa.
9. according to claim 4,5,6,7, when being subordinated to 4, or 8 o'clock method, wherein said hydrodynamic force compacting is to finish by hitting ripple in the blast in the hydraulic fluid that surrounds shaping mixt.
10. according to the method for the arbitrary claim in front, wherein said reaction sintering is to surpass in the nitrogen of 0.03MPa to carry out when having at least.
11. according to the method for the arbitrary claim in front, wherein said pure boron or other reaction sintering agent are powder types, its specific surface is 10m at least
2/ g.
12. according to the method for claim 11, wherein said pure boron is an amorphous.
13. according to arbitrary method of claim 2 to 12, wherein said pure boron form described mixture by quality 5-8%.
14. according to the method for the arbitrary claim in front, wherein said raw material boron nitride is the turbostratic boron nitride, with before described pure boron or other reaction sintering agent mix, this boron nitride is issued to balance through thermal treatment in advance for from 1300 to 1500 ℃ in temperature.
15. according to the method for claim 14, the heat treated boron nitride of wherein said process has specific surface 100m at least
2/ g.
16. method according to the arbitrary claim in front, wherein further comprise, after described reaction sintering, the product of reaction sintering is encapsulated in step (arbitrarily multiple) in granular (preferably infusible) medium, described granule medium can be absorbed in the volatile oxidn that discharges when product is heated, this granule medium comprises reductive agent or its precursor, and comprises the step that is heated at least 1400 ℃.
17. according to the method for claim 16, wherein said reductive agent is silicon-containing compound or its precursor of silicon carbide or other infusible anaerobic.
18. according to the method for claim 17, wherein said compound or precursor include only and are selected from: the atom among Si, C, N, B and the H.
19. according to claim 16,17 or 18 method, wherein said granule medium also comprises a kind of infusibility material, preferably boron nitride.
20. according to the method for claim 19, wherein said granule medium is that boron nitride adds a kind of infusibility anaerobic silicon-containing compound or its precursor.
21. according to claim 3 or 7 or any method that directly or indirectly is subordinated to 3 or 7 claim, wherein said silicoorganic compound are a kind ofly can produce the compound of inorganic residues by quality at least 70% when 1000-1200 ℃ of thermolysis.
22. according to claim 3,7 or 21 method, the polymerization before its thermolysis of wherein said silicoorganic compound.
23. according to claim 3,7,21 or 22 method, wherein said silicoorganic compound are or comprise oligomeric hydrogenated methyl thing silane.
24., wherein use the mixture of the silane low polymer of energy in-situ copolymerization according to the method for claim 23.
25. according to the method for claim 22 or 23, the MW that wherein said or every kind of silane low polymer has is no more than 800.
26. the ceramic of making according to the method for the arbitrary claim in front.
27., be gasket ring, crucible or heat, components and parts shape electricity or structure according to the ceramic of claim 26.
28., be that 20mm is thick at least according to the ceramic of claim 26 or 27.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95196011 CN1162297A (en) | 1994-09-07 | 1995-08-25 | Boron nitride |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| RU94032296 | 1994-09-07 | ||
| CN 95196011 CN1162297A (en) | 1994-09-07 | 1995-08-25 | Boron nitride |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1162297A true CN1162297A (en) | 1997-10-15 |
Family
ID=5083078
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| CN 95196011 Pending CN1162297A (en) | 1994-09-07 | 1995-08-25 | Boron nitride |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101003696B (en) * | 2006-01-06 | 2012-11-07 | 通用电气公司 | Enhanced boron nitride composition and compositions made therewith |
| CN101715611B (en) * | 2007-05-28 | 2014-07-30 | 塞拉姆氢技术公司 | Method of activating boron nitride |
| CN111825465A (en) * | 2020-06-01 | 2020-10-27 | 福州派尔盛陶瓷有限公司 | Preparation method of high-purity boron nitride for sintering aluminum nitride substrate |
| CN112675803A (en) * | 2020-11-19 | 2021-04-20 | 江苏大学 | Preparation and use methods of three-dimensional boron nitride nanosheet foam |
| CN116323052A (en) * | 2020-10-28 | 2023-06-23 | 住友电工硬质合金株式会社 | Cubic boron nitride sintered body, tool provided with cubic boron nitride sintered body, and method for producing cubic boron nitride sintered body |
-
1995
- 1995-08-25 CN CN 95196011 patent/CN1162297A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101003696B (en) * | 2006-01-06 | 2012-11-07 | 通用电气公司 | Enhanced boron nitride composition and compositions made therewith |
| CN101715611B (en) * | 2007-05-28 | 2014-07-30 | 塞拉姆氢技术公司 | Method of activating boron nitride |
| CN111825465A (en) * | 2020-06-01 | 2020-10-27 | 福州派尔盛陶瓷有限公司 | Preparation method of high-purity boron nitride for sintering aluminum nitride substrate |
| CN116323052A (en) * | 2020-10-28 | 2023-06-23 | 住友电工硬质合金株式会社 | Cubic boron nitride sintered body, tool provided with cubic boron nitride sintered body, and method for producing cubic boron nitride sintered body |
| CN112675803A (en) * | 2020-11-19 | 2021-04-20 | 江苏大学 | Preparation and use methods of three-dimensional boron nitride nanosheet foam |
| CN112675803B (en) * | 2020-11-19 | 2023-03-24 | 江苏大学 | Preparation and use methods of three-dimensional boron nitride nanosheet foam |
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