10 results about "Microwave sintering" patented technology

The application discloses an anti-thermal shock alumina fiber reinforced phosphate high-temperature-resistant composite material and a preparation method thereof, and belongs to the technical field of ceramic matrix composites. The material is composed of gradient modified alumina fiber reinforcement, composite phosphate matrix and multi-scale composite filler. The fiber surface is provided with a nano yttrium oxide-yttrium phosphate gradient interface layer, and the matrix is an aluminum phosphate-zirconium phosphate-yttrium oxide composite system. The preparation method comprises fiber degumming, gradient interface modification, slurry preparation, impregnation and curing and microwave sintering. Through gradient interface regulation and composite matrix design, the application solves the problems of poor thermal shock resistance and insufficient high-temperature stability of the existing materials. Tests show that the material has no macroscopic cracking after 10 times of water cooling at 1300 DEG C, the strength retention rate is greater than or equal to 88%, the room temperature bending strength is greater than or equal to 280 MPa, and the material has excellent high-temperature mechanical properties and thermal shock stability, and is suitable for aerospace thermal protection and high-temperature structural parts.

This invention discloses a rapid, high-strength microwave bonding method for ceramics and cemented carbide, belonging to the field of ceramic material bonding technology. The method includes the following steps: preparing a metal solder; grinding, polishing, and cleaning the bonding surfaces of the ceramic and cemented carbide respectively; loading the prepared metal solder into a mold and pressing it under uniaxial pressure to obtain a metal solder sheet; placing the ceramic, metal solder sheet, and cemented carbide in a stacked structure in a microwave sintering furnace for microwave sintering to achieve the bonding of the ceramic and cemented carbide. Compared with traditional brazing and diffusion welding, this ceramic-cemented carbide microwave bonding method increases the heating / cooling rate by 6-10 times, improves the single-furnace bonding efficiency by 5-9 times, allows for mass production, and yields ceramic-cemented carbide bonding interfaces with high strength. This invention significantly improves production efficiency, reduces energy consumption, and has widespread application value.

The application provides a kind of silicon carbide ceramic material based on gradient activation sintering and nanocomposite reinforcement and its preparation method and application, the preparation method includes: silicon carbide raw materials are mixed and ball milled to obtain sintering raw materials, the sintering raw materials are sequentially subjected to magnetic field strengthening sintering, pressure sintering and microwave sintering, SiC nanowires grow in the pressure sintering, and finally obtain silicon carbide ceramic material. The preparation method provided by the application is subjected to segmented sintering under the intensification of magnetic field, pressure and microwave respectively, the sintering powder is activated, particle arrangement and growth are promoted by using specific intensification means in different sintering stages, the densification of silicon carbide ceramic is improved, and SiC nanowires grow in the sintering process, so that the mechanical properties and thermal properties of silicon carbide ceramic material are significantly improved.

The application discloses an aluminum nitride ceramic substrate of a composite sintering aid and a preparation method thereof, and relates to the technical field of ceramic materials. The sintering aid is prepared by compounding zirconium boride whiskers, rare earth oxides and rare earth fluorides. The whisker structure advantage is utilized to improve the bending strength of the substrate. The sintering aid can be used as a liquid phase promoter in the sintering process, so that the diffusion activation energy of aluminum nitride particles is reduced. Meanwhile, the zirconium boride and the aluminum nitride can form a uniform interface through chemical bonding, so that the compactness of the substrate is increased, and the thermal conductivity and the mechanical properties are improved. In the discharge plasma sintering or the microwave sintering, the rapid heat transfer characteristics of the zirconium boride whiskers are highly matched with the heating mechanism of the pulse current or the microwave field, so that the performance of the aluminum nitride substrate is further enhanced.

This invention provides a nano-multiphase ceramic spring, the raw materials of which include inorganic powder and molding aids; the inorganic powder includes nano-α-silicon nitride powder, nano-α-alumina powder, nano-silicon carbide powder and / or aluminum nitride powder, rare earth oxides, and zirconium oxide. The molding aids include mixed sol binder, organic additives, dispersants, and plasticizers. This invention also proposes a method for preparing the above-mentioned ceramic spring, including slurry preparation, near-net-shape forming, debinding, microwave sintering, and post-treatment steps. This invention utilizes irregularly distributed long columnar β-silicon nitride to form a complex three-dimensional interlocking structure, thereby greatly enhancing the toughness of the ceramic material. Silicon nitride and alumina, as the main materials, are inherently stable, and the grain boundary phases formed by the rare earth oxides can absorb and accommodate irradiation defects, exhibiting excellent corrosion resistance and radiation resistance. Microwave sintering with a uniform temperature field ensures high grain uniformity and improves the product yield.

The present invention relates to the technical field of the preparation of ceramic rollers. Disclosed are a microwave sintering method and microwave sintering equipment for a ceramic roller. The microwave sintering method of the present invention comprises the following steps: conducting microwave sintering by using a microwave sintering kiln, wherein the microwave sintering kiln comprises a sintering cavity and an outer cavity surrounding the sintering cavity, the outer cavity is provided with a focusing reflector, and a heating zone, a sintering zone and a cooling zone are sequentially formed in the sintering cavity from top to bottom; starting a microwave source, and adjusting the working frequency and power of the microwave source to make the temperature of the sintering zone be 1200-1600ºC; placing an auxiliary heating base in the sintering cavity; and enabling the ceramic roller to enter and pass through the sintering cavity at the speed V1 to undergo microwave sintering while maintaining a rotary motion, so as to obtain a microwave sintered ceramic roller. The microwave sintering method and microwave sintering equipment for a ceramic roller of the present invention can achieve effective microwave sintering of an aluminum oxide ceramic roller, the temperature for the microwave sintering of the ceramic roller reaches 1200ºC or higher, and the ceramic roller can be heated more evenly by means of dynamic continuous sintering.

The invention relates to the technical field of microwave high-temperature sintering, and discloses a high-power microwave sintering furnace for high-temperature uniform batch sintering of high-performance ceramic parts, which comprises a front-end pre-excitation area, a middle main heating area and a rear-end compensation excitation area which are axially divided on the sintering furnace; the feed port assembly comprises 15 feed ports, four feed ports are arranged on the front-end pre-excitation area, six feed ports are arranged on the middle main heating area, and five feed ports are arranged on the rear-end compensation excitation area; the bearing assembly comprises a rotary lifting part and a rotary disc, the rotary lifting part is arranged at the bottom end of the sintering furnace, one end of the rotary lifting part is fixedly connected with the rotary disc, and a temperature measuring part and a monitoring part are arranged on the sintering furnace and used for measuring the temperature of the sintering sample in real time and monitoring the smoke concentration in the sintering furnace and the state change of the sintering sample in real time. According to the invention, it is ensured that a large batch of samples are placed in an area with optimal and uniform microwave field intensity, synchronous, stable and uniform high-temperature sintering is realized, and the quality consistency of microwave sintering of the samples and the safety of the sintering process are realized.