CN103722176A - Method for doping rare earth lanthanum in nano molybdenum powder - Google Patents

Abstract

The invention provides a method for doping rare earth lanthanum in nano molybdenum powder, and belongs to the field of rare earth materials. The method includes the following steps that (1) ammonium paramolybdate, rare earth lanthanum nitrate and complexing agent citric acid are doped in a solution mode, the pH value of the solution is adjusted through HNO3 and NH3 water to be 1-3, complexing is performed on citrate ions, molybdate ions and rare earth ions to obtain a stable compound, water bath is performed on the solution at the temperature of 70-90 DEG C to obtain transparent faint yellow sol, and the transparent faint yellow sol is dried at the temperature of 100-120 DEG C to obtain xerogel; (2) the xerogel is sintered for 6 hours at the temperature of 560 DEG C, then in a four-tube sintering reduction furnace, two-step reduction is performed with hydrogen as a reducing agent to obtain doped MoO3 powder and doped Mo powder respectively, the reduction temperatures of the two-step reduction are 540 DEG C and 980 DEG C respectively, the doped nano rare earth molybdenum powder which is round and normal in particle and even in distribution is prepared, the size of doping phase is below 100nm, and the size of doped molybdenum powder particles is 300-500nm. According to the method, the nano molybdenum powder doped with the earth lanthanum evenly is prepared, and meanwhile chemical reaction sediments in the liquid-liquid doping process are eliminated.

Description

A kind of method of nano rare earth lanthanum doped molybdenum

Technical field

the invention belongs to rare earth material field, be specifically related to a kind of method of nano rare earth lanthanum doped molybdenum.

  

Background technology

molybdenum and molybdenum alloy have that fusing point is high, elevated temperature strength is high, heat-conductivity conducting performance is good, thermal coefficient of expansion is low and the advantage such as refractory salt and liquid light metal corrosion, are widely used in electronics industry, chemical industry, metallurgical industry and aerospace industry.But the drawbacks limit such as recrystallization temperature is low, fragility is ruptured in processing during deformation and high-temperature oxidation resistance is poor the extensive use of pure molybdenum as structural material.Doped with rare-earth elements is the effective ways of putting forward High-Purity Molybdenum recrystallization temperature, and rare earth doped molybdenum materials not only has good elevated temperature strength, creep-resistant property, and after high temperature recrystallization annealing, has good plasticity under normal temperature.More ripe and be applied to industrial doping process for solid solid doping and liquid-solid doping at present.Gu but solid doping and liquid-solid doping easily cause doped chemical segregation, doped chemical content is unstable, causes prepared molybdenum materials not reach desirable performance requirement.The doping of liquid liquid is a kind of new technology and technique, there be limited evidence currently of research and report.The employing liquid liquid methods such as Zhou Meiling and sol-gel technique have been prepared nano level doped molybdenum, but to concrete doping process, as pH value of solution value, complexing agent addition, one-tenth adhesive process, drying mode, heat treatment temperature and time etc. are not carried out elaborate report.In said method preparation process, there is chemical reaction sediment simultaneously.

  

Summary of the invention

In order to prepare the rear earth lanthanum doping nano Mo powder of uniform doping, eliminate the chemical reaction sediment in liquid liquid doping process simultaneously, the present invention proposes a kind of method of nano rare earth lanthanum doped molybdenum.

The method of a kind of nano rare earth lanthanum of the present invention doped molybdenum, according to following steps, carry out:

(1) ammonium paramolybdate, rare earth lanthanum nitrate and complexing agent citric acid are mixed in the mode of solution, use HNO ₃and NH ₃water regulator solution pH value is 1 ~ 3, makes the compound of citrate ion and molybdenum acid ion and rare earth ion network synthesizing stable, and solution water-bath at 70 ~ 90 ℃ becomes transparent faint yellow colloidal sol, after drying, obtains xerogel at 100 ~ 120 ℃;

(2) by xerogel at 560 ℃ of sintering 6h, then in four pipe sintering and reducing stoves, take hydrogen as reducing agent carries out two step reduction, obtain respectively the MoO that adulterates ₃powder and Mo powder, the reduction temperature of two step reduction is respectively 540 ℃ and 980 ℃, the mixed nanometer rare earth molybdenum powder of preparing particle rounding and being evenly distributed, doping phase size is below 100 nm, and doped molybdenum particle size is at 300 ~ 500 nm.

The present invention adopts sol-gal process to prepare nano rare earth doped molybdenum, and the regulation and control of pH value of solution value and the addition of citric acid are the keys of technique.When the mass ratio of pH=1, citric acid and the ammonium paramolybdate of initial soln is controlled at 1.5:1, the mixed nanometer rare earth molybdenum powder that can prepare particle rounding and be evenly distributed, doping phase size is below 100 nm, and doped molybdenum particle size is in 500 nm left and right.

In doping MoO3 powder, lanthanum exists with La2O3 or La-Mo composite oxides form, and rare earth particle sticks to MoO3 particle surface.In the reduction process of doping MoO3 powder, La-Mo composite oxides decompose, and in the assorted molybdenum powder of Erbium-doped, lanthanum exists with the form of La2O3.

The present invention adopts liquid liquid doping new technology and sol-gal process to prepare the assorted molybdenum powder of Rare Earth Lanthanum Erbium-doped, not only prepares the rear earth lanthanum doping nano Mo powder of uniform doping, eliminates the chemical reaction sediment in liquid liquid doping process simultaneously.

  

The specific embodiment

embodiment 1

A method for nano rare earth lanthanum doped molybdenum, according to following steps, carry out:

(1) ammonium paramolybdate, rare earth lanthanum nitrate and complexing agent citric acid are mixed in the mode of solution, use HNO ₃and NH ₃water regulator solution pH value is 1, makes the compound of citrate ion and molybdenum acid ion and rare earth ion network synthesizing stable, and solution water-bath at 90 ℃ becomes transparent faint yellow colloidal sol, after drying, obtains xerogel at 120 ℃;

(2) by xerogel at 560 ℃ of sintering 6h, then in four pipe sintering and reducing stoves, take hydrogen as reducing agent carries out two step reduction, obtain respectively the MoO that adulterates ₃powder and Mo powder, the reduction temperature of two step reduction is respectively 540 ℃ and 980 ℃, the mixed nanometer rare earth molybdenum powder of preparing particle rounding and being evenly distributed, doping phase size is below 100 nm, and doped molybdenum particle size is at 300 nm.

  

embodiment 2

A method for nano rare earth lanthanum doped molybdenum, according to following steps, carry out:

(1) ammonium paramolybdate, rare earth lanthanum nitrate and complexing agent citric acid are mixed in the mode of solution, use HNO ₃and NH ₃water regulator solution pH value is 1, makes the compound of citrate ion and molybdenum acid ion and rare earth ion network synthesizing stable, and solution water-bath at 70 ℃ becomes transparent faint yellow colloidal sol, after drying, obtains xerogel at 100 ℃;

(2) by xerogel at 560 ℃ of sintering 6h, then in four pipe sintering and reducing stoves, take hydrogen as reducing agent carries out two step reduction, obtain respectively the MoO that adulterates ₃powder and Mo powder, the reduction temperature of two step reduction is respectively 540 ℃ and 980 ℃, the mixed nanometer rare earth molybdenum powder of preparing particle rounding and being evenly distributed, doping phase size is below 100 nm, and doped molybdenum particle size is at 500 nm.

  

embodiment 3

A method for nano rare earth lanthanum doped molybdenum, according to following steps, carry out:

(1) ammonium paramolybdate, rare earth lanthanum nitrate and complexing agent citric acid are mixed in the mode of solution, use HNO ₃and NH ₃water regulator solution pH value is 1, makes the compound of citrate ion and molybdenum acid ion and rare earth ion network synthesizing stable, and solution water-bath at 80 ℃ becomes transparent faint yellow colloidal sol, after drying, obtains xerogel at 110 ℃;

(2) by xerogel at 560 ℃ of sintering 6h, then in four pipe sintering and reducing stoves, take hydrogen as reducing agent carries out two step reduction, obtain respectively the MoO that adulterates ₃powder and Mo powder, the reduction temperature of two step reduction is respectively 540 ℃ and 980 ℃, the mixed nanometer rare earth molybdenum powder of preparing particle rounding and being evenly distributed, doping phase size is below 100 nm, and doped molybdenum particle size is at 400 nm.

  

Claims (1)

1. a method for nano rare earth lanthanum doped molybdenum, is characterized in that carrying out according to following steps:

(1) ammonium paramolybdate, rare earth lanthanum nitrate and complexing agent citric acid are mixed in the mode of solution, use HNO ₃and NH ₃water regulator solution pH value is 1 ~ 3, makes the compound of citrate ion and molybdenum acid ion and rare earth ion network synthesizing stable, and solution water-bath at 70 ~ 90 ℃ becomes transparent faint yellow colloidal sol, after drying, obtains xerogel at 100 ~ 120 ℃;

(2) by xerogel at 560 ℃ of sintering 6h, then in four pipe sintering and reducing stoves, take hydrogen as reducing agent carries out two step reduction, obtain respectively the MoO that adulterates ₃powder and Mo powder, the reduction temperature of two step reduction is respectively 540 ℃ and 980 ℃, the mixed nanometer rare earth molybdenum powder of preparing particle rounding and being evenly distributed, doping phase size is below 100 nm, and doped molybdenum particle size is at 300 ~ 500 nm.