The invention discloses a preparation method of a B4C nanosheet and the B4C nanosheet. The preparation method comprises: 1) taking boric acid, coal dust and sodium carbonate or sodium bicarbonate to conduct ball-milling to obtain mixed powder, wherein the adding mass of sodium carbonate or sodium bicarbonate accounts for 3%-10% of the total mass of boric acid and coal dust; 2) subjecting the obtained mixed powder to pre-press molding, and then performing cold isostatic pressing to obtain flake object; and 3) imbedding the obtained flake object into quartz sand to conduct microwave sintering, thus obtaining the B4C nanosheet. According to the method, boric acid, coal dust and sodium carbonate or sodium bicarbonate are subjected to ball-milling mixing, pre-press molding and cold isostatic pressing are carried out, then the product is subjected to microwave sintering, by utilizing the excellent wave-absorbing properties of carbon and the plasma effect of gas during microwave sintering, the method realizes rapid synthesis of B4C nanosheet. The obtained B4C nanosheet has good crystallinity, small thickness, and high yield and purity; the sintering time is short, the sintering temperature is low, and a lot of energy is saved. The process is simple, is convenient to operate, and is suitable for industrial rapid production, thus having broad application prospects.

Preparation method of B4C nanosheet and B4C nanosheet

The invention discloses a microwave experimental furnace. The microwave experimental furnace comprises a furnace body, a hollow thermal-insulation module and a crucible, wherein the hollow thermal-insulation module is arranged inside the furnace body, and the crucible is arranged inside a cavity in the thermal-insulation module and used for containing a material. Temperature measurement holes areformed in the crucible and the thermal-insulation module, a high-temperature infrared thermometer and a low-temperature infrared thermometer are installed on the furnace body at the same time, and receive infrared rays generated by the surface of the material through the temperature measurement holes, and axes of the receiving ends of the two infrared thermometers are intersected on one point of the surface of the material. According to the microwave experimental furnace, the high-temperature infrared thermometer and the low-temperature infrared thermometer are installed on the microwave furnace body at the same time for temperature measurement, and therefore the requirement for full-temperature section continuous temperature control can be met.

Microwave experimental furnace

The invention discloses a preparation method of boron nitride-boron carbide composite ceramic. The method includes the following steps: (1) mixing boric acid and urea in a ratio of a certain amount ofsubstances, adding anhydrous ethanol, performing ball milling for 6-8 h, and placing the mixture in nitrogen atmosphere at 950-1200 DEG C for heat preservation for 2-4 h to obtain boron nitride powder; (2) adding boron carbide powder into the boron nitride powder, evenly mixing the boron carbide powder and the boron nitride powder, adding anhydrous ethanol, and preforming ball milling for 8-10 hto obtain boron nitride-boron carbide composite powder; and (3) placing the boron nitride-boron carbide composite powder in a vacuum sintering furnace and placing the composite powder in nitrogen atmosphere at 700-1000 DEG C for 2-10 h to obtain the boron nitride-boron carbide composite ceramic. The boron nitride-boron carbide composite ceramic prepared by the method in the invention has the advantages of high flexural strength, high fracture toughness, good machinability and the like.

Preparation method of boron nitride-boron carbide composite ceramic

The invention relates to a silicon nitride ceramic material, a preparation method and application thereof, and a bulletproof flashboard. The silicon nitride ceramic material is prepared from the following raw materials in percentage by mass: 80 to 90 weight percent of silicon nitride powder, 1 to 6 weight percent of elemental carbon, 1 to 10 weight percent of diboron trioxide powder, 1 to 10 weight percent of nitride whiskers and carbide whiskers, 1 to 10 weight percent of rare earth oxide and 1 to 6 weight percent of an adhesive. Specific components and proportions are adopted, the bending strength and fracture toughness of the silicon carbide ceramic material can be enhanced through the combined action of nitride whiskers, carbide whiskers and rare earth oxide on silicon nitride powder,and the bulletproof performance of the silicon carbide ceramic material can also be improved through cooperation of the nitride whiskers and the carbide whiskers. Meanwhile, the elemental carbon and the diboron trioxide powder can form a discontinuous boron carbide whisker component in the silicon nitride matrix under the catalysis of the rare earth oxide, so that the surface density of the material is reduced, and the hardness and the elasticity modulus of the material are improved.

Silicon nitride ceramic material, preparation method and application thereof, and bulletproof flashboard

The invention discloses microwave curing equipment for a beach surface of a uranium tailing pond. The microwave curing equipment comprises a microwave heating system, a lifting device, an exhaust gastreatment system, a power supply system and a moving device, the microwave heating system moves to the beach surface of the uranium tailing pond needing to be treated through the lifting device and the moving device, microwaves output by the microwave generator can directly act on the beach surface, and the purposes of high-temperature sintering and solidification of the beach surface of the uranium tailing pond are achieved. According to the invention, during microwave treatment of the beach surface of the uranium tailing pond, the microwave heating system is used for carrying out layering, direction dividing and solidification treatment on the beach surface of the uranium tailing pond, and finally sintering treatment of the whole beach surface is achieved. In addition, the volume reduction effect is achieved through sintering treatment, sintering is conducted in a microwave heating mode, the interior and the exterior of the material can be heated at the same time and warmed at the same time without any heat conduction process, the heating speed is high and uniform, and the equipment has characteristic of being high in temperature increasing speed, short in sintering time, high inpenetrability, high in energy utilization rate, less in generated secondary waste and the like.

Microwave curing equipment for beach surface of uranium tailing pond

The invention discloses a preparation method of B4C whiskers The preparation method comprises the following steps: 1) dissolving boric acid in water to obtain a solution, adding coal powder into the solution according to principle that the molar ratio of C to B is (1 to 2):(1 to 2), mixing uniformly, and drying to obtain compound powder of coal powder wrapped with boric acid; 2) pressing the compound powder into sheets; 3) embedding the sheets into quartz sand, and carrying out microwave sintering: preheating at a temperature rise rate of 5 to 20 DEG C per minute, heating to 1300 to 1800 DEG C at a temperature rise rate of 20 to 200 DEG C per minute, keeping the temperature for 1 to 30 min, and cooling to obtain the B4C whiskers The preparation method has the advantages that due to utilization of superior wave absorbing property of carbon, the B4C whiskers can be synthesized fast; the obtained B4C whiskers are high in crystallinity, small in diameter, large in length-diameter ratio, and high in yield and purity; the sintering time is short, and the sintering temperature is low, so that a large quantity of energy is saved; the technology is simple, the operation is convenient, suitability for industrial fast production is high, and the application prospect is wide

Preparation method of B4C whiskers

The utility model provides an industry dual -frenquency microwave sintering equipment, includes furnace body, control system, vacuum pump, variable frequency motor, cooling device, high temperature microwave source and low temperature microwave source, and the furnace body is double -deck hollow structure, and the furnace body front end is equipped with the furnace gate, is equipped with switch handle on the furnace gate, is equipped with single currenting direction inside in the double -deck hollow interlayer of furnace body, and the furnace body bottom left and right sides is equipped with water inlet and the delivery port of connecting single currenting direction inside respectively, furnace body top middle part is arranged in proper order and is equipped with low temperature infrared radiation thermometer, high temperature infrared radiation thermometer and micropore camera. The utility model discloses to the material of different microwave absorption characteristics, select different single microwave source sintering, the microwave sintering of dual -band perhaps carries out simultaneously, have more extensive application, the furnace body is opened has vacuum connection and atmosphere interface, has stronger pertinence, among the sintering process, two high low temperature infrared radiation thermometers detect material temperature simultaneously, and variable attenuator feedback microwave reflectance data has higher stability.

Yang Bingquan

Papers

Preparation method of B4C whiskers

Industry dual -frenquency microwave sintering equipment