CN-121797938-B - Preparation method and application of molybdenum lanthanum alloy molybdenum powder

CN121797938BCN 121797938 BCN121797938 BCN 121797938BCN-121797938-B

Abstract

The invention belongs to the technical field of metal material preparation, and discloses a preparation method and application of molybdenum lanthanum alloy molybdenum powder. The scheme realizes the stable production of 4N-grade high-purity molybdenum powder through two solid-solid doping, segmented hydrogen reduction and a preparation process of a homogeneous molybdenum boat, and is characterized in that molybdenum dioxide and lanthanum oxide are firstly mixed according to (59-60): 1 and reduced for the first time, then are mixed with pure molybdenum powder for the second time, and are reduced for the second time after being mixed with the pure molybdenum powder for the second time, so that molybdenum-lanthanum alloy molybdenum powder with the lanthanum content of 0.1% -1.0% is obtained, and the special molybdenum boat is prepared by the molybdenum powder or the pure molybdenum powder and is used for carrying operation of a reduction furnace. The method improves the high-temperature strength and recrystallization resistance of the molybdenum powder by two solid-solid doping and sectional reduction processes, effectively inhibits impurity pollution, improves the purity and batch consistency of the molybdenum powder and the high-temperature service performance of the molybdenum boat, has fully independent and controllable process flow, does not need to rely on imported high-temperature alloy, reduces the cost of raw materials compared with the traditional process, and has remarkable comprehensive economic benefit.

Inventors

NIU PENG
SU YONG
MENG LI
ZHU FENG
HUANG LIFENG
GAO FENG
ZHAO FENG
ZHANG ZHIGUO
WANG WEI
MIAO BIN

Assignees

金堆城钼业光明（山东）股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260312

Claims (10)

1. The preparation method of the molybdenum lanthanum alloy molybdenum powder is characterized by comprising the following steps: carrying out primary solid-solid doping mixing on molybdenum dioxide powder and lanthanum oxide powder to obtain a first mixture; Placing the first mixture in a hydrogen atmosphere, preserving heat for 2-4 hours at 950-1050 ℃ and carrying out a reduction reaction to obtain a molybdenum-lanthanum alloy molybdenum powder matrix with the lanthanum oxide mass fraction of 1.64% -1.67%; Carrying out secondary solid-solid doping mixing on the molybdenum powder matrix of the molybdenum-lanthanum alloy and pure molybdenum powder, so that the mass fraction of lanthanum in a final product is controlled within the range of 0.1% -1.0%, and a second mixture is obtained; And placing the second mixture in a hydrogen atmosphere, preserving heat for 3-5 hours at 1000-1100 ℃ and carrying out secondary reduction reaction to obtain molybdenum lanthanum alloy molybdenum powder of the target component.
2. The method for preparing molybdenum-lanthanum alloy molybdenum powder according to claim 1, wherein the molybdenum dioxide powder has an oxygen content of 28.0% -30.0% and a fermi size of 1.5-2.5 μm, and the lanthanum oxide powder is pure lanthanum oxide and is calcined at 1000 ℃ to remove adsorbed water and carbonate impurities.
3. The method for preparing molybdenum lanthanum alloy molybdenum powder according to claim 1 or 2, wherein the first solid-solid doping mixing is performed by a three-dimensional mixer at a rotation speed of 30-50r/min for 4-6 hours, so that lanthanum oxide forms a uniform coating layer on the surface of molybdenum dioxide particles.
4. The method for preparing molybdenum-lanthanum alloy molybdenum powder according to claim 1, wherein lanthanum oxide is dispersed in the molybdenum grain boundary and the grain inside in the form of nano particles with average grain diameter of 20-50nm and volume fraction of 0.8% -1.2%.
5. The preparation method of the molybdenum lanthanum alloy molybdenum powder according to claim 1, wherein the pure molybdenum powder has a Fisher size of 2.0-3.0 μm and an oxygen content of less than 300ppm, the second solid-solid doping mixing is performed by a three-dimensional mixer at a rotating speed of 25-40r/min for 5-7 hours.
6. The method for preparing molybdenum lanthanum alloy molybdenum powder according to claim 1, wherein the primary reduction reaction and the secondary reduction reaction are carried out in a push boat type multitube reduction furnace, the hydrogen flow is 8-12m 3 /h per tube, the dew point is lower than-50 ℃, and the pressure in the furnace is maintained in a micro-positive pressure state of 5-15 Pa.
7. The use of molybdenum lanthanum alloy molybdenum powder, characterized in that the molybdenum lanthanum alloy molybdenum powder is prepared by the preparation method of molybdenum lanthanum alloy molybdenum powder according to any one of claims 1-6; The molybdenum boat is prepared from pure molybdenum powder or molybdenum-lanthanum alloy molybdenum powder containing 0.1% -1.0% of lanthanum through pressing, presintering, high-temperature sintering and multi-pass hot rolling/cold rolling, and is used for carrying molybdenum oxide raw materials in a hydrogen reduction furnace for reduction powder preparation operation.
8. The use of a molybdenum lanthanum alloy molybdenum powder according to claim 7, wherein the molybdenum boat is made by the process of: Pressing the powder into a slab with the thickness of 15-25 mm; Presintering for 2 hours at 1200-1300 ℃, and then sintering for 4-6 hours at a high temperature of 2000-2200 ℃ to obtain a sintered plate with a relative density of more than 92%; carrying out multi-pass hot rolling on the sintered plate, wherein the initial rolling temperature is 1400-1600 ℃, the final rolling temperature is more than 1000 ℃, and the accumulated rolling reduction is more than 70%; then an intermediate anneal is performed at 1100C x 1h, sub-cooled to a final thickness of 2.0-4.0mm, and stress relief annealed at 900C x 2h.
9. The application of the molybdenum lanthanum alloy molybdenum powder according to claim 7 or 8, wherein the molybdenum boat is of a rectangular structure and provided with reinforcing ribs at the bottom for a flat four-tube reduction furnace, and is of a boat-shaped structure and provided with a U-shaped groove in the middle and limit bosses at two ends for an eighteen-tube reduction furnace.
10. The use of molybdenum lanthanum alloy molybdenum powder according to claim 9, wherein the molybdenum boat is welded with a homogenous molybdenum material, and the weld is subjected to a 1200 ℃ vacuum annealing treatment, so that the molybdenum boat can be continuously used for more than 24 months in a 900-1200 ℃ hydrogen atmosphere without obvious plastic deformation.

Description

Preparation method and application of molybdenum lanthanum alloy molybdenum powder Technical Field The invention belongs to the technical field of metal material preparation, and relates to a preparation method and application of molybdenum lanthanum alloy molybdenum powder. Background Molybdenum and its alloy powder are used as key basic raw materials of high-end hard alloy, electronic functional material and high-temperature structural component, and its purity, grain size distribution and microstructure consistency directly determine the upper limit of the performance of the end product. In the technical field of powder metallurgy reduction powder preparation, the industrialized preparation of high-purity molybdenum powder depends on a process path of hydrogen reduction of molybdenum trioxide or molybdenum dioxide for a long time. Nickel-base superalloy (such as Inconel series) is commonly adopted as a material boat material by main flow production enterprises in China, has certain oxidation resistance and mechanical strength in a reducing atmosphere of 900-1200 ℃, and effectively supports the preliminary development of molybdenum powder industry in the production stage with low productivity and low purity requirements in early stage. Under the variable load working condition of 900-1200 ℃, low-melting-point metal components (the melting points are about 1538 ℃ and 1455 ℃ respectively) such as Fe, ni and the like contained in the nickel-based alloy can be selectively diffused and surface segregated, and particularly under the strong reducing environment of hydrogen reducing atmosphere, the metal elements are more likely to migrate in an atomic state or a suboxide form and permeate into adjacent molybdenum powder particle gaps. The process not only directly introduces metal impurities which are difficult to remove by the subsequent process, so that the oxygen content and the total metal impurities of the final product are out of control, but also the pollution has high randomness and time variability, so that the quality fluctuation of the molybdenum powder in different furnace times and even in different areas of the same furnace is obvious, and the process consistency necessary for producing the high-purity material is destroyed. Under the action of repeated thermal circulation and mechanical load, the problem of plastic deformation of the nickel-based alloy material boat caused by high-temperature creep and phase change is also difficult to avoid, the problem of boat buckling and clamping stagnation on the inner wall of the reduction furnace tube is often caused, the problem of boat blocking is caused, the production line is forced to be frequently stopped and overhauled, the utilization rate of equipment is greatly reduced, the balance of a thermal field is disturbed due to unplanned interruption, and the discreteness of the distribution of molybdenum particle diameters and the oxygen content is further aggravated. Disclosure of Invention In order to achieve the aim of the invention, the invention provides a preparation method and application of molybdenum lanthanum-molybdenum alloy powder. According to the method, through constructing an integrated process system of twice solid-solid doping-hydrogen reduction-sintering rolling forming-special boat body application, the technical bottlenecks of poor batch stability and structural failure caused by introducing metal impurities in the preparation process of the high-purity molybdenum powder of the existing nickel-based superalloy material boat are solved, and the high-efficiency, stable and large-scale production of the high-purity molybdenum powder of grade 4N (99.99%) and above is realized. The preparation method of the molybdenum lanthanum alloy molybdenum powder comprises the following steps of firstly carrying out primary solid-solid doping mixing on molybdenum dioxide powder and lanthanum oxide powder according to a mass ratio of 59:1 to 60:1 to obtain a first mixture, then placing the first mixture in a hydrogen atmosphere, carrying out primary reduction reaction under the conditions that the temperature range is 950-1050 ℃ and the heat preservation time is 2-4 hours to obtain a molybdenum lanthanum alloy molybdenum powder matrix containing 1.64% -1.67% of lanthanum oxide, secondly carrying out secondary solid-solid doping mixing on the molybdenum lanthanum alloy molybdenum powder matrix and pure molybdenum powder with purity of more than 99.95% according to a set proportion to accurately control the mass fraction of lanthanum element in a final product within a range of 0.1% -1.0%, and then placing the second mixture in the hydrogen atmosphere, carrying out secondary reduction reaction under the conditions that the temperature range is 1000-1100 ℃ and the heat preservation time is 3-5 hours to obtain a molybdenum lanthanum alloy molybdenum powder containing target components, and finally carrying out secondary reduction reaction on the molybdenu