55results about How to "Prolong sintering time" patented technology

A preparation method of superfine crystal WC-Co hard alloys belongs to the field of high-performance functional materials. The powder mixture is composed of 8-11wt percent of Co, 0.001-0.7wt percent of VC, 0.001-0.8wt percent of Cr3C2, and WC with a grain size of 0.2-0.5 micron in balance. The powder mixture is weighed at the given weight ratio and then subjected to alloying treatment under such conditions that the ball-milling time is 15-60 min, the rotational speed of ball mill is 800-1400 r/min-1, the ratio of media-to-material is 5:1 to 10:1; and the level of ball milling media is 5-10 mm above the surface of the ball-milled material, so that the powder mixture is pre-formed to form a pre-forming blank with a density of 50-70 percent. The pre-forming blank is further processed into superfine WC-Co hard alloy by the ultra-high pressure sintering process in a six-face presser, under the following conditions: sintering voltage of 1.25-1.40V, sintering pressure of 10-12GPa, and sintering time of 60-120s. The method has the advantages that the powder is rapidly densified upon an extremely-high pressure and heating simultaneously; and the obtained produce has full density and high hardness (up to 93.1HRA) while the grain size of WC remains almost unchanged.

The invention discloses a preparation method of a porous film. The preparation method comprises the following steps: (1) acquiring a porous support body; (2) preparing a thick size containing raw material powder, a binder, a dispersant and a pore forming agent; (3) loading the size onto the porous support body, and drying to make a film billet; (4) sintering the film billet to make a porous film precursor; (5) removing the pore forming agent from the precursor to obtain a porous film with the thickness of 5-3,000 [mu]m, the average aperture of 0.05-100 [mu]m and the porosity of 40-90%. The preparation method has the following advantages: firstly, no chemical reaction occurs between the pore forming agent and the raw material powder, so that the ingredients of the porous film cannot be damaged; secondly, the pore forming agent is excellent in thermal stability and always occupies a certain space (place) in the sintering process; after sintering, the pore forming agent is removed, holes or pores are generated in situ; therefore, the whole technological process is simple, the hole structure of the porous film is easy to control, and the porosity is remarkably improved.

The invention discloses a porous film which comprises a filtering layer and a porous support, wherein the filtering layer is composed of dendritic metal substance powder and/or metal substance oxide powder. A preparation method for the porous film comprises the following steps: 1) acquiring the raw material powder and the porous support, wherein the raw material powder is the dendritic metal substance powder and/or the metal substance oxide powder; 2) preparing slurry; 3) loading the slurry on the surface of the porous support, drying and preparing into a film blank; 4) sintering the film blank and cooling, thereby acquiring the porous film. Firstly, the dendritic metal substance powder is stacked and formed into the pores of the porous film, the complex hole-forming process is avoided and the porosity is high and is easy to control; the filtering layer composed of the dendritic metal substance powder and/or the metal substance oxide powder is stable in physico-chemical property, long in service life and free from mutual reaction; the complex phase-forming process is avoided; the component of the porous film is easy to control.

The invention belongs to the technical field of material preparation and in particular relates to a preparation method of a WC-Co-cBN composite material. The preparation method of the WC-Co-cBN composite material comprises the following steps: firstly weighing WC, metal Co powder and cBN raw material in proportion, uniformly mixing, mixing by carrying out ball milling, drying the mixed raw materials in a drying oven at the temperature of 50-200 DEG C, then sieving with a sieve of 100-300 meshes, putting the dried raw materials into a mould, then placing the mould into a hot-pressing sintering furnace, heating the sintering furnace to 1200-1400 DEG C at a speed of 30-50 DEG C/min, insulating for 5-30 minutes, and maintaining pressure to be 20-50MPa, so that the WC-Co-cBN composite material is obtained. The preparation method of the WC-Co-cBN composite material has the advantages that the hot-pressing method is adopted, the sintering temperature is low, sintering time is short, and no phase transformation of cBN can be guaranteed while the WC-Co-cBN composite material has high shrinkage percentage and high volume density; meanwhile, hot pressing energy consumption is low, cost is low, operation is easy, and safety coefficient is high.

The invention discloses a nitride ceramic material microwave sintering method. According to the invention, a nitride ceramic blank is placed between graphite plates, and microwave sintering is carried out under a protective atmosphere in a microwave sintering device. A microwave frequency value range is 2.45GHz, a microwave sintering temperature is 500-3000 DEG C, and a temperature maintaining time is 0-50h. The protective atmosphere is composed of nitrogen gas or argon gas or a mixed gas of nitrogen and hydrogen. The pressure is normal pressure. Different from traditional convection, conduction or radiation heating method, according to the invention, heat is produced through the coupling of a special band of microwave and the basic structure of the material. With the medium loss of the material, the material is heated with an integral heating manner. The method has the advantages of low sintering temperature, short temperature maintaining time, low energy consumption, and the like. The sintered material has good performances and considerable economic benefit.

The invention belongs to the technical field of gas (oil) exploitation auxiliaries and discloses a fracturing propping agent for shale gas exploitation and a preparation method of the fracturing propping agent. The fracturing propping agent is composed of, by weight, 43-55% of bauxite, 43-55% of shale, 1-3% of barium carbonate and 1-2% of boric acid, wherein BaCO3 is added as a fluxing agent and a binding agent to prevent sintering by lowering the sintering temperature, a certain quantity of monoclinic celsian excellent in acid resistance is generated by Al2O3 and SiO2 to form a protective film on the surface of the propping agent, and accordingly the propping agent can be protected from corrosion of acidic and alkaline substances of rock stratums. The calcination temperature can be lowered by the boric acid, mullite in growth can be slowly wrapped by celsian melts by prolonging of sintering time, and accordingly porosity of blanks can be guaranteed to further improve compressive strength of the propping agent. In addition, corrosion resistance of the propping agent is improved owing to own acid resistance of the boric acid, and adverse effects of K2O, Na2O and the like in raw materials on acid solution can be reduced.

The utility model provides microwave sintering of an ultra-fine grain titanium carbonitride group cermet. A 300MHz to 8GHz microwave frequency medium is used as a heat source to enable a billet of the ultra-fine grain titanium carbonitride group cermet to absorb microwave energy to complete the sintering process. During the sintering process, vacuum and atmosphere protection microwave heating and sintering techniques are adopted respectively according to the ratio of carbon to nitrogen of the billet of the ultra-fine grain carbon titanium nitride cermet. The 300MHz to 8GHz microwave frequency is used to heat and sinter the billets of the titanium carbonitride group cermet with different ratio of carbon to nitrogen and vacuum microwave sintering and atmosphere protection microwave sintering technological proposals are used respectively for the billets of the titanium carbonitride group cermet with the different ratio of carbon to nitrogen, which overcomes the defects of the prior vacuum or atmosphere protection sintering techniques, such as low heating efficiency, long sintering time, large energy consumption, serious environment pollution and oversized grains, and the like. The microwave sintering can be widely applied to sintering other ceramics, ceramic matrix composites and intermetallic compound materials with stronger microwave absorbing capacity.

The invention discloses a quick change method of a converter tap hole. The quick change method is mainly used for solving the technical problems that in the prior art, the replacement time of a converter tap hole is long, the replacement operation is complex, and the replacement quality is poor. According to the technical scheme, the quick change method of the converter tap hole comprises the steps of preparing a mounting hole for the new tap hole; mounting the new tap hole; filling a gap between the new tap hole with a refractory material and the mounting hole of the new tap hole in a converter body; and after 5-8 minutes since grouting is completed, returning the converter to a zero position, so that replacement of the new tap hole is completed. By means of the method, rapid replacementof the converter tap hole is achieved, and the replacement quality is controllable.

The invention discloses a preparation method of a ceramic device, which comprises the steps of S1, adding a binding agent to a powder raw material and performing internal mixing and granulation to form a granule, S2, performing molding on the granule obtained in Step S1 to form a body, S3, performing degreasing treatment on the body obtained in Step S2, and S4, performing hot press sintering on the body obtained in Step S3 to form the ceramic device, wherein the degreasing treatment comprises the steps of placing the body in a solvent, performing solvent degreasing, and then performing hot degreasing on the body subjected to the solvent degreasing.

The invention relates to a barium strontium titanate-based dielectric ceramic material as well as a preparation method and application thereof. The composition formula of the barium strontium titanate-based dielectric ceramic material comprises the following components: aBaTiO3+bSrTiO3+cTiO2+dBiO5+e MgO+fAl2O3+gCaO+hSiO2, wherein a, b, c, d, e, f, g and h are molar percentages of the components; 20 < = a < = 50 mol%; 15 < = b < = 30 mol%, 10 < = c < = 20 mol%, 0 < = d < = 10 mol%, 0 < = e < = 35 mol%, 0 < = f < = 6 mol%, 0 < = g < = 6 mol%, 0 < = h < = 1 mol%, and a + b + c + d + e + f + g + h= 100 mol%.

The invention discloses a process for producing high-purity magnesia by adopting a double-layer sintering spray gun vertical kiln and relates to the technical field of preparation of high-purity magnesia. The process comprises the following specific steps: firstly performing grinding treatment on a caustic-burned magnesia powder with a particle size of 150-200 mm, grinding by adopting a ball mill,ending grinding after the material fineness of 95 percent of the caustic-burned magnesia powder is less than 325 meshes, then ball-pressing by adopting a ball press machine, health-preserving and drying after the end of ball-pressing, then enabling a dried magnesium ball to enter the kiln, preheating the temperature of the vertical kiln to 800-1000 DEG C, opening a first-layer spray gun to calcine till the sintering zone temperature is 1200-1500 DEG C, opening a second-layer spray gun to calcine till the sintering zone temperature is 1800-2000 DEG C after the end of calcination by the first-layer spray gun, finally cooling to 150-200 DEG C through a cooling zone and going out of the kiln by adopting a furnace discharge conveyer to prepare the high-purity magnesia. The process disclosed bythe invention has the benefits that a double-layer sintering spray gun structure is adopted, the sintering time is prolonged, and the purpose of producing the high-density and high-purity magnesia isachieved.

The invention belongs to the technical field of tantalum capacitor preparation and particularly relates to a preparation method of a high-voltage ultra-small-capacity non-solid electrolyte tantalum electrolytic capacitor. The method is characterized in that pressing density is improved, a molding mode is changed, the increasing sintering temperature and sintering time are increased, so the strength of a tantalum core is enhanced, tantalum cores are not easy to fall off and have unfilled corners, impurities in tantalum powder are effectively removed, a tantalum core with excellent electrical performance is obtained through an improved forming method, aging process treatment is combined, so the voltage of the prepared non-solid electrolyte tantalum capacitor can reach 180V, the capacitance can reach 0.047 mu F, and the non-solid electrolyte tantalum capacitor has the characteristics of high voltage and ultra-small capacitance.

A method for producing CdS-based photocatalyst for hydrogen generation and a method for producing hydrogen in the presence of CdS. Dissolve the compound containing Cd and M in water, after the M value reaches 0.001-20.00, add H to it ₂ S or Na ₂ S any reactant, stir to get Cd[M]S precipitate, wash the precipitate with water, and vacuum dry the washed precipitate in a nitrogen (flow) atmosphere at a temperature of 105-150 ℃ for 1.5-3.0 Hours later, add a liquid phase m-containing compound to the dried Cd[M]S precipitate for doping treatment, so that the m content in the entire photocatalyst reaches 0.10 to 5.00% by weight, and the photocatalyst with the following formula I is produced. m(a)/Cd[M(b)]S(I) (in the above general formula, m represents the metal doped as an electron acceptor, which is made from Ni, Pd, Pt, Fe, Ru, Co or their oxides One or more substances selected from; a represents the weight % of m, and its value is 0.10 to 5.00. M is a promoter selected from V, Cr, Al, P, As, Sb, Pb, and b represents M/ (Mole % of (M+Cd), its value is 0.001~20.00.) Make the above-mentioned photocatalyst, contact with the water that adds 0.05~1.0 mole sodium sulfite reducing agent and 0.05~1.0 mole sodium sulfide electron donor to suspend it, while stirring While irradiating the light in the visible light region adjusted by the filter and sunlight, it reacts to generate hydrogen.

The invention belongs to the technical field of iron ore sintering, and particularly relates to an iron ore sintering method capable of simultaneously improving sinter reducibility and reducing nitrogen oxide emission. The method comprises the steps of batching, primary mixing, secondary mixing, distributing, ignition and sintering, wherein low-carbon alcohol is added in the secondary mixing step.The inventor found through research that adding an appropriate amount of the low-carbon alcohol into the secondary mixing can adjust the sintering temperature during the sintering process and prolongthe sintering time. The sinter reducibility can be improved and also the nitrogen oxide emission is significantly reduced. Particularly, compared with a blank test, the content of ferrous oxide in the sinter can be reduced from 11% to 9.6%, and the sinter reducibility is significantly improved; at the same time, compared with the blank test, the total concentration of nitric oxide and nitrogen oxide in sintering flue gas is decreased.

The invention provides a microwave ferrite magnetic sheet, a preparation method and applications thereof. The raw materials of the magnetic sheet comprise a main raw material and an auxiliary raw material, wherein the main raw material comprises an oxide of a Fe element and an oxide of a Y element, and the auxiliary raw material comprises Ca element, Sn element, Mn element and In element. The preparation method comprises the following steps: 1) mixing the raw materials according to the formula ratio, and carrying out first crushing to obtain a first crushing material; 2) pre-sintering the first crushing material to obtain a pre-sintered material; 3) carrying out second crushing on the pre-sintered material to obtain a second crushing material; and (4) granulating and molding the second crushing material, and sintering to obtain the microwave ferrite magnetic sheet. According to the microwave ferrite magnetic sheet provided by the invention, the saturation magnetization intensity of thematerial is improved by adjusting the formula, so that the size of an isolator is reduced, and the high saturation magnetization intensity can increase the bandwidth of a device.