7results about "Tungsten halides" patented technology

The invention discloses a synthesis process of tungsten hexafluoride, and relates to the technical field of special gas synthesis. The process comprises the following steps: mixing ammonium fluoride and hydrofluoric acid to prepare an activation solution, carrying out ultrasonic activation treatment on tungsten powder to obtain pretreated tungsten powder, and reacting the pretreated tungsten powder with fluorine gas at a certain temperature and pressure to prepare a liquefied crude product tungsten hexafluoride; the preparation method comprises the following steps: by taking aluminum sec-butoxide and the like as raw materials, carrying out sol-gel and ethanol supercritical drying and calcining to prepare highly porous activated aluminum oxide; gasifying the crude tungsten hexafluoride, adsorbing with activated aluminum oxide, and rectifying to obtain purified tungsten hexafluoride liquid; and finally, dissolving in liquid sulfur dioxide, treating under illumination with the wavelength of 395nm, and carrying out distillation separation to obtain high-purity tungsten hexafluoride. According to the method, the activation pretreatment is combined with multi-stage purification, so that the purity and the synthesis efficiency of tungsten hexafluoride are remarkably improved.

This invention discloses a process for preparing chlorides by reducing chlorination with rare metal oxides, comprising the following steps: S1, in an inert atmosphere, a mixture containing rare metal oxide powder, a reducing agent, and a chloride salt is subjected to a reduction reaction at a predetermined temperature 1; S2, the temperature is lowered to a predetermined temperature 2, oxygen is introduced, and the concentration of oxygen in the mixed gas is adjusted to carry out a chlorination reaction, and the chlorinated product is condensed and collected. This invention eliminates the need for gaseous chlorinating agents such as chlorine or hydrogen chloride, avoiding the leakage risks of liquid chlorine and compressed hydrogen chloride during storage and transportation; the raw materials can be directly rare metal oxides, with a wide range of sources, good process adaptability, and significantly reduced production costs.

The invention relates to the technical field of chemical engineering, in particular to a preparation method of tungsten pentachloride, which comprises the following steps: S1, feeding tungsten hexachloride into a fluidized bed reactor through gravity and inert gas flow, continuously introducing inert gas into the fluidized bed reactor, keeping the tungsten hexachloride in the fluidized bed reactor to be fluidized, preheating and preserving heat; s2, introducing mixed gas of nitrogen or inert gas and hydrogen into the fluidized bed reactor, and reacting in the fluidized bed reactor; and S3, collecting tungsten pentachloride. The equipment and operation are simple, continuous production of high-quality tungsten pentachloride can be achieved, the technological process is simple, the operation unit is small, daily operation and maintenance are simple, and automatic control is facilitated.

A device which can be exposed to chemical vapors, such as a molybdenum vapor, a tungsten vapor, or any combination thereof, which has a coating covering at least a portion thereof. The coating reduces or inhibits mass change at an outer surface of the device from exposure to the vapor. In certain situations, the mass change is a mass gain, and the coating reduces or inhibits the mass gain of equal to or less than 1 x 10-5 g mm-2.

The application discloses a preparation method of rare metal chloride, which comprises the following steps: in an inert atmosphere, a mixture containing rare metal powder, a chlorine salt and an auxiliary material is heated to a predetermined temperature, oxygen is introduced, the concentration of oxygen in the mixed gas is adjusted, a chlorination reaction is carried out, and a chlorination product is condensed and collected to obtain the rare metal chloride. The application avoids the safety production risk caused by the use of chlorine or hydrogen chloride in the traditional production, and the production process avoids the leakage risk of liquid chlorine and compressed hydrogen chloride in the storage and transportation process. Since the reaction process is a double decomposition reaction, the reaction rate is controllable, the reaction does not have obvious heat release, and is safe and reliable. The chlorine content in the production tail gas is extremely low, and the environmental pollution problem caused by a large amount of chlorine-containing tail gas in the traditional chlorination process is avoided.

This application provides a method for preparing metal chlorides. This method and apparatus solve the problem of inaccurate flow metering of chlorides as reactants in existing chemical vapor deposition (CVD) processes. The method includes: installing a dedicated chlorine flow meter at the inlet of a chlorine gas inlet pipe; adding bulk metal to a reaction vessel and sealing the vessel; purging the reaction vessel containing the bulk metal with an inert protective gas, heating to remove water and oxygen; heating to a specified temperature, shutting off the inert protective gas, and starting the chlorine gas reaction. This invention precisely controls the flow rate of the chlorine gas to generate a fixed amount of metal chloride. Under the action of a reducing gas, a uniformly deposited, high-strength metal / carbide coating is obtained on the substrate surface. This coating is virtually free of impurities, and the deposited substrate can be used in industries such as semiconductors and medicine. This method is low-cost, produces stable products, and is easy to scale up.

Methods and related systems are provided for removing impurities from a precursor. A method includes at least one thermal cycle. The at least one thermal cycle includes one or more of the following steps: heating a vessel including a precursor and at least one impurity to a temperature for a duration sufficient to vaporize at least a portion of the at least one impurity; measuring a vapor pressure within the vessel to obtain a measured vapor pressure and comparing the measured vapor pressure to a set vapor pressure; and removing at least a portion of the vapor including the at least one impurity from the vessel when the measured vapor pressure is higher than or within the setpoint vapor pressure. Other methods and systems are provided herein.