50results about How to "Reduce sintering shrinkage" patented technology

The invention relates to a ceramic rock plate and a preparation method thereof. A ceramic rock plate blank is composed of the following components in percentage by weight: 35-46.1% of mud; 50 to 60 percent of a water abrasive; 1-7% of a green body toughening material; 0.5 to 3 percent of a reclaimed material; and 0.1-0.8% of an additive. The preparation method comprises the following steps: preparing a green body, processing the green body, performing spray drying to prepare powder, performing dry pressing to form the green body (with a plane or concave-convex effect), drying, polishing the green body, blowing ash, spraying water, spraying white ink, spraying engobe, decorating patterns, decorating isolation glaze, decorating a transparent glaze layer, firing, polishing and edging.

The invention discloses a preparation method for an environment-friendly lead-free semiconductor ceramic capacitive electrode silver paste. The preparation method comprises the following steps of: (1) preparing glass powder, namely uniformly mixing the following components in percentage by mass: 20 to 30 percent of B2O3, 5 to 25 percent of SiO2, 50 to 70 percent of Bi2O3, 2 to 20 percent of Al2O3 and 1 to 2 percent of inorganic additive I, heating and ball-grinding until the particle size of the glass powder is less than 15 mu m, filtering and drying; (2) preparing an organic carrier; and (3) proportioning the following components in percent by mass: 50 to 75 percent of ultrathin silver powder, 4 to 10 percent of lead-free glass powder, 1 to 2 percent of inorganic additive II and 20 to 35 percent of organic carrier. The inorganic materials can meet a requirement of environment friendliness home and abroad; according to the adopted process, the stability and the consistency of the silver paste can be guaranteed; and the surface of a sintered silver layer is bright and compact, and has high continuity.

The invention provides silicon nitride ceramic slurry, a preparation method of the silicon nitride ceramic slurry and application of the silicon nitride ceramic slurry to preparation of a silicon nitride cast film. The preparation method comprises the following steps of mixing silicon nitride powder, a sintering aid, a dispersant and a solvent, performing first ball milling, then adding an adhesive and a plasticizer for secondary ball milling, and performing vacuum defoaming to obtain slurry, wherein the mass ratio of the silicon nitride powder, the sintering aid, the dispersant and the solvent is 100 to (5-15) to (49-67) to (2-3.5) to (10-20) to (10-40); and performing tape casting and drying on the slurry to obtain a smooth, uniform, dense, gentle and agreeable Si3N4 biscuit which is benefical to forming processing and sintering in a later period. The silicon nitride ceramic slurry obtained by the method is uniform, is low in viscosity, high in solid content, simple in preparation technology and liable to realize industrialization and is suitable for tape casting.

The invention discloses grout silver paste applied to a thick film circuit, which consists of 60 to 90 weight percent of conductive powder, 1 to 6 weight percent of frit and 10 to 35 weight percent of organic carrier, wherein the total weight of the conductive powder, the frit and the organic carrier is 100 percent. The conductive powder is the powder of gold, silver, palladium, copper, nickel, tungsten and manganese alloys or the mixed powder of the powder; and the grain diameter of the conductive powder is controlled to be 1 to 10mu m. The grout silver paste applied to the thick film circuit prepared by the invention has the characteristics of high electrical conductivity, low sintering shrinkage rate and good matrix matching performance and the using requirement of a grout process of the thick film circuit is met in the using process.

The invention relates to a method for preparing a molybdenum tube, in particular to a method for preparing a metal tube by a powder metallurgy method. The method is characterized by comprising the following steps: (1) evenly mixing a raw material molybdenum powder with water base adhesive solution; (2) placing the molybdenum powder and the water base adhesive solution in a centrifugal forming machine for forming; (3) drying a formed molybdenum tube blank; (4) degumming the dried molybdenum tube blank; (5) pre-sintering the degummed molybdenum tube blank; (6) sintering on the pre-sintered molybdenum tube at a high temperature; and (7) polishing the sintered molybdenum tube to obtain the molybdenum tube. By adopting the method of the invention, the preparation process of the molybdenum tubehas the advantages of easy control and simple, safe and reliable operation, thus being applicable to batch production; the preparation process can help flexibly control parameters such as diameter, wall thickness, length and the like of the molybdenum tube; and the prepared molybdenum tube has good uniformity, small sintered deformation quantity and small sintered shrinkage rate.

The invention relates to the technical field of ceramic part manufacturing, in particular to a sintering process for an automobile ceramic sparking plug. The sintering process comprises the five steps of isostatic compaction, abrasive machining, biscuit firing, glazing and high-pressure sintering. According to the sintering process, dry pressing molding is used for replacing a traditional slurry injection hot briquetting process, an isostatic press is used for conducting cold press molding on dry powder, and in the process engineering, the parameters such as the feeding amount of the dry powder, the heating temperature and time, the thickness of an enamel layer are continuously optimized. A formed sparking plug product is high in density, small in sintering shrinkage, stable in thermal performance, high in production efficiency and high in applicability.

The invention discloses a warm-pressing process of powder metallurgy. The warm-pressing process comprises the following steps of: a, weighing an alloy powder raw material, a lubricating agent and an additive; mixing the alloy powder, the lubricating agent and the additive in a weight ratio of (10-30): 1: 1 to form a mixed material; b, pressing the mixed material into a pre-formed blank; carrying out warm-pressing treatment on the pre-formed blank; controlling the temperature to 130-150 DEG C and controlling the time to 10-12 hours, wherein the pressing density of warm-pressing forming treatment is 7.5-8g/cm<3>; putting into a furnace to be sintered, wherein the sintering temperature is 1200-1400 DEG C; c, de-burring the sintered pre-formed blank; cutting and machining to form a rough product; and d, carrying out immersing treatment on the rough product; and carrying out surface steam treatment at the temperature of 420-550 DEG C to obtain a finished-product part. The process disclosed by the invention has simple steps; the pressing density is improved by adopting a warm-pressing forming treatment process and the cost of the warm-pressing process is only 1.25; the surface smoothness is good and the sintering shrinking percentage is small; and the yielding strength and the impacting toughness are better than those of a traditional process.

The invention relates to a method for 3D printing of an aluminum oxide ceramic complex structure and discloses a method for 3D printing of a high-solid-content low-temperature co-fired aluminum oxide ceramic complex structure. The invention aims to solve the problems that the pH value of existing high-solid-phase-content aluminum oxide ceramic slurry needs to be adjusted, the prepared slurry is poor in stability and difficult to store for a long time, and high-speed and high-precision direct-writing type 3D printing is difficult to achieve. The method comprises the following steps: 1, weighing; 2, preparation of an organic colloid; 3, mixing of alumina powder and ceramic glass powder; 4, preparation of slurry; 5, heating for 3D printing; and 6, drying, glue discharging and sintering. The method is used for 3D printing of the high-solid-content low-temperature co-fired aluminum oxide ceramic complex structure.

The invention discloses a silica-based ceramic core and a preparation method thereof. The silica-based ceramic core is prepared from the following raw materials in parts by weight: 60-67 parts of silica glass powder, 30 parts of zircon sand and 3-10 parts of a SiO2 additive agent, according to a setting proportion, the raw materials are weighed, mixed and dried, and an elasticizer is added and stirred; compression moulding and demoulding of mixed slurry are conducted, a green body is obtained, and a compressed green body sample is embedded into calcination alpha-type aluminium oxide filler; and according to a set heating rate, the temperature rises for sintering, finally, the sintered sample is put into an ethyl silicate strengthening solution, after still standing, natural drying is conducted, and the core is obtained. According to the silica-based ceramic core and the preparation method thereof, sintering shrinkage of the silica-based ceramic core is low, high temperature bending strength is good, size control is good, the surface is smooth, during metal pouring, core-separating is easy, and abreuvage cannot be formed on the interfaces of metal and the core.

The invention aims at solving the problem that the liquidity of the aluminum oxide mould core slurry is poor in the prior art, and provides a method of improving aluminum oxide mould core slurry, belonging to the technical field of manufacturing of the aluminum oxide ceramic mould cores. The method comprises the following steps: adding spherical matrix powder with particle diameter of about 1 mu m into matrix powder electrically-fused corundum powder of normal particles and TiO2 to mix to obtain a mixture, and then adding a plasticizer into the mixture to obtain mould core slurry by stirring; controlling the temperature of a mould of a mould core injection-molding machine to 25-35 DEG C, controlling the temperature of the slurry to 95-105 DEG C and injecting the slurry into the injection-molding machine for pressing and molding to obtain the mould core, wherein the pressure holding time is 45-55 seconds. According to the method of improving the liquidity of aluminum oxide mould core slurry disclosed by the invention, a little spherical matrix micro fine powder is added to improve the liquidity of the mould core slurry, so that the liquidity of the slurry is improved, the mould core is prevented from being deformed during drawing and placing, the mould temperature is lowered, and the sintering shrinkage degree of the mould core is also reduced, and therefore, the product qualification rate of thin-wall directional blades and single crystal blades is increased.

The invention discloses a method for preparing aluminum oxide ceramic based on sinking type DLP photocuring 3D printing, and the method comprises the following steps of: mixing and stirring aluminum oxide powder, a first dispersing agent and an organic solvent, conducting drying, crushing and sieving to obtain modified aluminum oxide powder, adding graphene, a second dispersing agent and a defoaming agent into acrylic photosensitive resin, performing mixing, then adding modified aluminum oxide powder, carrying out ball milling and defoaming treatment to obtain aluminum oxide ceramic paste, carrying out photocuring 3D printing by adopting a sunken DLP photocuring method, and then carrying out sectional process degreasing treatment and sintering to obtain the aluminum oxide ceramic. The method disclosed by the invention is suitable for preparation and industrial production of the large-size aluminum oxide ceramic piece with low deformation, high precision and complex structure, and the prepared aluminum oxide ceramic has the advantages of few microdefects, high density, good mechanical and physical properties and the like.

The invention relates to a method for preparing mullite porous ceramics by a freeze-drying method. The method comprises the following steps: (1) adding modified opoka, alpha-alumina and sintering aidsinto an agate jar, and ball milling at a rate of 300 revolutions per minute for 2 hours by using a planetary ball mill so as to obtain uniformly mixed powder; (2) mixing the uniform powder and water,and preparing ceramic slurry having the starch content of 6-10 vol%; (3) rapidly pouring the prepared ceramic slurry into a mold of a certain shape for casting and molding, performing vacuum degassing, removing bubbles in the slurry, placing the sample in a cryogenic refrigerator, enabling the sample to be completely frozen, and demolding; (4) performing freeze drying on the sample in a vacuum freeze drier at the temperature of 30 DEG C below zero at a vacuum degree of 10 Pa for 36 hours; (5) sintering, and cooling, thereby obtaining the mullite porous ceramics. According to the method disclosed by the invention, the opoka serves as the main ingredient and a pore forming material, so that the void ratio of the mullite ceramics can be effectively improved, the usage amount of the adhesiveis reduced, and the strength of the product is further improved.

The invention discloses a spinel-magnesium-based ceramic core and a preparation method thereof, and belongs to the field of ceramic core preparation in the field of precision casting. Raw materials of the spinel-magnesium-based ceramic core comprise a powder raw material and a binder, and the powder raw material comprises the following components in percentage by mass: 50%-90% of spinel powder, 0%-30% of zirconium oxide powder, 0%-5% of titanium dioxide powder and the balance of magnesium oxide powder; and the mass of the binder accounts for 15-25% of the mass of the powder raw material. The preparation method of the spinel-magnesium-based ceramic core comprises the following steps: mixing powder according to the ratio, preparing a binder, mixing the preheated mixed powder and the binder to prepare slurry, carrying out compression molding on the slurry by adopting a hot-press injection molding method, and sintering to obtain the spinel-magnesium-based ceramic core. The spinel-magnesium-based ceramic core has the advantages of being high in strength, small in shrinkage rate and easy to remove, and meanwhile the thermal shock resistance is improved.

The invention relates to the technical field of preparation of sagger kiln furniture, and particularly relates to a forming method of a sagger for a lithium battery cathode material. The forming method comprises the following steps of powder pretreatment, die filling and prepressing, drying, die filling and forming, wherein the forming specifically comprises the following steps of putting an elastic die which is tightly coated with a semi-finished sagger blank and is sealed into a high-pressure cylinder, and suspending the elastic die in the high-pressure cylinder by using a high-pressure-resistant rope; covering a high-pressure cylinder sealing cover; and continuously injecting liquid between the inside of the high-pressure cylinder and the elastic die for pressurization, when the internal pressure reaches 5,000kgf/cm <2>, maintaining the pressure for 12 hours, discharging the liquid, slowly releasing the pressure, taking out the sagger blank after the pressure is released, opening the sagger blank, and removing the elastic die to obtain a finished sagger blank. The sagger blank obtained by pressing by the method has the advantages of uniform tissue structure, high density, low sintering shrinkage and low die cost; and the method has high production efficiency, can be used for forming slender products with complex shapes, large-size products and precise-size products, and is suitable for automatic operation.

The invention provides a low-temperature co-fired ceramic raw material belt and a preparation method thereof. The preparation method comprises the following steps: mixing CBS-1 microcrystalline glasspowder and BBZ glass powder to obtain glass mixed powder, and preparing glass mixed slurry on the basis of the glass mixed powder; mixing ceramic powder and CBS-2 glass powder, mixing the ceramic powder and ZBS glass powder or mixing the ceramic powder, the CBS-2 glass powder and the ZBS glass powder to obtain ceramic-glass mixed powder, and preparing ceramic-glass mixed slurry based on the ceramic-glass mixed powder; and forming a lower material layer on the surface of a base film based on the glass mixed slurry, forming an intermediate material layer on the surface of the lower material layer based on the ceramic-glass mixed slurry, and forming an upper material layer on the surface of the intermediate material layer based on the glass mixed slurry to prepare the raw material belt. According to the invention, the problem of large sintering shrinkage rate in the X-axis direction and the Y-axis direction after the existing LTCC raw material belt material is sintered is solved.

The invention provides a low-temperature co-fired ceramic raw material belt and a preparation method thereof. The preparation method comprises the following steps: mixing CBS microcrystalline glass powder and BBZ glass powder to obtain glass mixed powder, and obtaining glass mixed slurry on the basis of the glass mixed powder; preparing ceramic slurry based on the ceramic powder; and forming a lower material layer on the surface of the base film based on the glass mixed slurry, forming an intermediate material layer on the surface of the lower material layer based on the ceramic slurry, and forming an upper material layer on the surface of the intermediate material layer based on the glass mixed slurry to prepare the raw material belt. According to the invention, the problem of large sintering shrinkage rate in the X-axis direction and the Y-axis direction after the existing LTCC raw material belt material is sintered is solved.