107results about How to "High nitriding efficiency" patented technology

The invention discloses a method for producing zirconium nitride powder, which comprises the following steps of: crushing sponge zirconium into granules with the granularity of less than 3mm, putting the crushed sponge zirconium granules into a vacuum furnace, supplying power for raising the temperature when the vacuum degree is 5 to 40Pa, keeping the temperature at the pre-nitrogenization temperature, stopping vacuumizing, and introducing nitrogen into the furnace for a pre-nitrogenization reaction; after the pre-nitrogenization, cutting off the power for reducing the temperature to 80 DEG C, and discharging; crushing the pre-nitrogenized materials into powder with the granularity of less than 0.075mm, putting the powder into the vacuum furnace, supplying power for raising the temperature to between 500 and 700 DEG C within 2 to 5 hours when the vacuum degree is 5 to 40Pa; stopping vacuumizing, introducing nitrogen into the furnace continuously raising the temperature to the nitrogenization temperature within 3 to 6 hours, and continuously introducing the nitrogen for nitrogenization; after the nitrogenization, cutting off the power for reducing the temperature, continuously introducing the nitrogen in the process of reducing the temperature, and discharging a zirconium nitride clinker when the temperature is reduced to 80 DEG C; and crushing the zirconium nitride clinker so as to prepare the zirconium nitride powder.

This invention relates to an oriented silicon steel and its processing method and equipment. It comprises of 0.035~0.060% of C, 2.5~3.5% of Si, 0.08~1.8% of Mn, 0.005~0.010% of S, 0.015~0.035% of Al, 0.0050~0.0090% of N, 0.01~0.15% of Sn, 0.010~0.030% of P and 0.05~0.12% of Cu, with the rest iron. The processing method includes: a) smelting; b) hot rolling. Billets are heated to 1100~1200 deg.C and rolling temperature is lower than 1200 deg.C with a finishing temperature of above 850 deg.C and a coiling temperature of below 650 deg.C; c) normalizing. Hot-rolled boards are normalizing annealed at 1050~1180 deg.C for 1~20 seconds and 850~950 deg.C for 30~200 seconds and then cooled quickly; d) cold rolling. Boards are rolled to product thickness by one-off cold rolling or repetitious cold rolling with intermediate annealing; e) nitriding, decarbonization and high-temperature and hot-leveling annealing with boards coated with high-temperature annealing isolation agents mainly made of MgO.

A zirconium nitride powder which has a specific surface area of 20 to 90 m2 / g as measured by a BET method, has a peak corresponding to zirconium nitride but does not have a peak corresponding to zirconium dioxide, a peak for lower zirconium oxide or a peak corresponding to lower zirconium oxynitride in an X-ray diffraction profile, and the light transmittance X at 370 nm is at least 18%, the lighttransmittance Y at 550 nm is 12% or less and the ratio (X / Y) of the light transmittance X at 370 nm to the light transmittance Y at 550 nm is 2.5 or more in the transmission spectra of a dispersion that contains the powder at a concentration of 50 ppm.

The present invention is fluidized bed apparatus and process for preparing silicon nitride directly. The fluidized bed has the features of strong gas-solid reaction, high heat transfer and mass transfer effect and homogeneous temperature. In a high temperature fluidized bed at 1000-1650 deg.c, silicon powder is nitrided directly to produce silicon nitride powder. The reacted silicon powder of diameter before sintering smaller than 10 micron and average diameter after sintering in 300-500 micron is fed to the fluidized bed directly. The fluidized bed gas consists of nitrogen in 10-100 vol%, hydrogen in 0-60 vol% and Ar in the balanced amount. The silicon powder fluidizing bed is fluidized in sound forced mode. The present invention can produce homogeneous silicon nitride powder of high quality in high efficiency, and has wide industrial application foreground.

The invention supplies a method used to produce orientation silicon steel by low temperature heating. It includes the following steps: heating the plate blank under 1280 degree centigrade; hot rolling; once or double cold rolling to gain finished product sheet thickness; nitriding treatment; decarburizing annealing; coating insulator; high temperature annealing. In the nitriding technology, heating area dew point is controlled at -15-40 degree centigrade. The invention has the advantages of high nitriding efficiency, no influence from the surface oxide film, excellent MgO coat formula which makes the magnesium silicate substrate have good magnetic property, ensure the implementation for the next hot leveling annealing and insulating coating.

The invention relates to a low-temperature plasma nitriding preparation method of iron nitride magnetic powder. The invention uses atomized iron powder, hydroxyl iron powder or reduced iron powder with an average particle size of 2-80 μm as the raw material; feeds O2 and oxidizes at 300-400 °C for 1-10 hours to obtain iron oxide powder; feeds hydrogen, Restore at 300~400°C for 4-20h to regain iron powder; low-temperature plasma nitriding, control temperature at 120~200°C, nitriding for 1~30h; cool down, cool to room temperature with the furnace, and take out the sample. The method uses low-temperature nitrogen plasma for nitriding, which solves the bottleneck problem of low ammonia gas decomposition efficiency in the ammonia gas nitriding method, and effectively improves the nitriding efficiency.