31results about How to "Small sintering shrinkage" patented technology

The invention provides a low-temperature preparation method of high-strength mullite ceramic. Kaolin, aluminum sol and aluminum oxide are taken as raw materials, under the action of a mineralizing agent and sintering aids, mullite porous ceramic with needle-shaped crystal whiskers is firstly synthesized under low temperature, space is provided for the growth of the crystal whiskers by using internal pores of the materials to allow the crystal whiskers grow fully, mullite precursors with higher reaction activities are soaked, and finally the high-strength mullite ceramic is obtained through secondary low-temperature sintering. The method has the advantages that the prices of the raw materials are cheap, sources of the raw materials are extensive and easy to obtain, the costs are lower, andthe preparation temperature is lower, so that production consumption is greatly reduced, the process is simple, equipment demands are low, the improvement of material strength and toughness are achieved simultaneously by the in-situ growing crystal whiskers, during the sintering process, the shrinkage of products is less, and net size shaping can be achieved.

The invention discloses a bionic lamellar thermal insulation material which simulates a fireproof, corrosion-resistant and excellent-thermal-insulation-performance American redwood bark multi-thin-layer laminated and thin-layer microporous structure, adopts low-thermal-conductivity microporous powder as a main raw material, and is supplemented with a reinforcing agent, a plasticizer and a pore-forming agent to form a microporous thin-layer unit, and the thin-layer units are boned to prepare the lamellar thermal insulation material. The heat conductivity coefficient of the finished product is as low as 0.02-0.05 W / m.k, and the finished product is good in heat-insulating property and mechanical property, can be used within the temperature range of 1000 DEG C or below, has better heat-insulating and energy-saving effects and toughness compared with common heat-insulating materials, remarkably reduces the thickness of the heat-insulating layer, and is suitable for large-scale popularization and application. The material can be widely applied to the fields of industrial kilns, thermotechnical devices, heat preservation pipelines and the like.

The invention provides a preparation method of a large-size zirconia-based heat insulation material, and the heat insulation prepared by adopting the method. The preparation method comprises the following steps: 1, mixing deionized water, organic monomers and a cross-linking agent, adding alpha-Al2O3 powder, ZrO2 powder and a dispersant, and carrying out ball milling by adopting a zirconium dioxide ball to obtain a slurry; 2, adding an initiator and a catalyst to the slurry obtained in step 1, stirring, injecting the obtained mixture to a die, solidifying, and cooling to obtain a wet green body; and 3, drying the wet green body obtained in step 2, and sintering. The preparation method comprises special blank molding treatment according to the formula of specific powder, so the problem of adverseness of too large shrinkage in the zirconia sintering process to pore maintenance is effectively solved, the deformation and cracking problems appearing in the drying process of gel injection molded large-size green body are avoided, and the obtained green body has the advantages of high uniformity and small drying shrinkage.

The invention provides a method for preparing high-performance sintered heat insulating bricks, which comprises the following steps: step 1, sludge from urban domestic sewage treatment plants or paper mill sludge is concentrated, filtered and dried; step 2, clay, sludge Carry out natural drying, crushing, crushing and sieving; step 3, mix the raw materials evenly to obtain the dry mixture, add water and stir evenly; step 4, carry out aging treatment on the wet mixture, and the aging time should exceed 24h; step 5 1. The brick blanks are molded to obtain bricks; step 6, the bricks are dried naturally at room temperature and then sent to the tunnel drying kiln for drying; step 7, after drying, the bricks are directly sent to the tunnel sintering kiln, the sintering temperature is 950 ~ 1100 ℃, The holding time of the brick body at the highest sintering temperature is 1 to 3 hours. The invention overcomes the disadvantages of poor mechanical properties and high thermal conductivity of traditional thermal insulation bricks, and realizes the production of high-performance thermal insulation bricks with a large amount of sludge; the source of raw materials is wide, the cost is low, and various production and domestic sludges are consumed in large quantities.

The invention relates to a method for using zirconia to sinter full-ceramic tooth, which uses zirconia powder to be sintered at 1500-1900Deg. C to obtain the zirconia ceramic powder, to be grinded into powder or pulp, then adds some sintering agent and flexibilizer, to be sintered in mold secondary to obtain the full-ceramic tooth. The invention has simple process, less contraction, high strength, and low cost as 2% of foreign product.

The present invention relates to a low-sintering temperature power type piezoelectric ceramic material, which has a chemical general formula of Pb1-xMx(Ni1 / 2W1 / 2)y(Mn1 / 3Sb2 / 3)z(ZreTif)1-y-zO3+awt%Fe2O3+bwt% Sm2O3+cwt%MnO2+dwt%CuO, wherein M is Sr<2+> and / or Ba<2+>, x is 0.02-0.1, y is 0-0.1, z is 0.01-0.1, e is 0.40-0.60, f is 0.40-0.60, the sum of e and f is 1, a is 0.01-0.4, b is 0.01-0.4, C is 0.01-0.4, and d is 0.1-0.4. The low-sintering temperature power type piezoelectric ceramic material of the present invention has advantages of low sintering temperature, high piezoelectric performance, high mechanical quality factor, high electromechanical coupling coefficient, moderate dielectric constant, and low dielectric loss.

The invention provides a stemming utilizing a waste refractory material and a preparation method thereof. The stemming comprises the following raw materials: silicon carbide particles or fine powder, high-temperature fine asphalt powder, Jilin fine clay powder, coke particles, industrial grade corundum particles or fine powder, wherein recovered aluminum and magnesium material particles or fine powder used for an electric furnace is added; and tar serves as a bonding agent. The preparation method comprises the following steps of: preparing the raw materials according to a proportion; after uniformly stirring particle materials in a stirring machine for 1 to 10 minutes, adding 20 to 30 percent of the tar; stirring for 5 to 10 minutes; adding fine powder materials; stirring for 5 to 15 minutes; adding the remaining tar and stirring for 25 to 40 minutes; and extruding by using a stemming extruder and packaging. The stemming has the following advantages: high operating performance, low stemming sintering shrinkage, rapid sintering property, high scour resistance and slag iron erosiveness. The invention provides a way for regenerating and utilizing the waste refractory material, and contributes to saving resources and protecting environment.

The invention discloses a method of preparing a superhard alloy bar by using WC-Co composite powder as a raw material through dry bag isostatic pressing and low-pressure sintering. The method is characterized in that the nanometer WC-Co composite powder is used as a raw material, firstly the raw material is put in a dry bag isostatic pressing equipment mold cavity so as to suffer compression molding, and then low-pressure sintering furnace equipment is used for sintering so as to obtain the superhard alloy bar. The method has the beneficial effects that working procedures such as material mixing by wet milling, drying by alcohol volatilization, granulation by blending a forming agent and pressed blank drying in the process of preparing the superhard alloy bar by using low-Co fine-crystalline grain WC as raw materials are omitted, the technological process is short, the equipment operation is simple, and large-sized long bars can be produced.

The invention relates to a F-Ca-Lu-doped aluminum nitride composite ceramic green body with high thermal conductivity and a casting process thereof. The ceramic green body is prepared by a casting process, and organic solvents, binders, nitriding Aluminum powder, sintering aid, dispersant, anti-sedimentation agent, plasticizer and other raw materials are uniformly dispersed and stirred, and sand-milled to obtain casting slurry, and the slurry is subjected to vacuum defoaming, casting plate making, isostatic pressing and other processes The multi-phase ceramic green body with high flatness and small sintering shrinkage can be obtained through advanced processing, and at the same time meet the industrial needs of rapid, large-scale, and stable quality manufacturing of green bodies; the obtained aluminum nitride ceramic substrate is widely used in the field of integrated circuits, high-power devices and Optoelectronic engineering fields such as high-power LED lighting have broad application prospects.