Method for preparing oxygen-free passivated titanium or titanium-alloy powder product by means of gas-solid fluidization

Abstract

A method for preparing an oxygen-free passivated titanium or titanium-alloy powder product by means of gas-solid fluidization is provided. The new method includes placing the metal halide and the titanium powder which meet formula requirements into a gasifier and a fluidized bed reactor respectively; heating the gasifier to gasify the metal halide, and introducing dry argon and halide gas into the fluidized bed reactor; opening the fluidized bed, heating the fluidized bed, fluidizing the titanium powder after the introduction of the argon and the metal halide gas, and cooling the product to obtain the titanium powder subjected to oxygen-free passivation using metal chloride; molding the oxygen-free passivated titanium powder into a green body with powder metallurgy technology; and sintering the green body in vacuum or argon atmosphere according to the molding technology, and after temperature rise treatment, performing a densification sintering operation to obtain a high-performance titanium product component.

Claims

1. A method for preparing an oxygen-free passivated titanium or titanium-alloy powder product by means of gas-solid fluidization, comprising: 1) placing a metal halide and a titanium powder into a gasifier and a fluidized bed reactor respectively, wherein the titanium powder and the metal halide have a mass ratio of 80:20-98:2; 2) heating the gasifier to a first predetermined temperature to gasify the metal halide to obtain a metal halide gas, and introducing dry argon and the metal halide gas into the fluidized bed reactor in a volume ratio of 10:90-90:10 at a predetermined flow rate; 3) initiating the fluidized bed reactor, heating the fluidized bed reactor to a second predetermined temperature, fluidizing the titanium powder for 10-300 min after introducing the dry argon and the metal halide gas to obtain a product, and cooling the product to obtain a metal halide oxygen-free passivated titanium powder, wherein the second predetermined temperature is greater than the first predetermined temperature, and the titanium powder is fluidized by the fluidized bed reactor; 4) molding the metal halide oxygen-free passivated titanium powder obtained in step 3 into a green body with a powder metallurgy technology; and 5) sintering the green body obtained in step 4 in vacuum or an argon atmosphere according to a molding technology, and after a temperature rise treatment on the green body, performing a densification sintering operation on the green body with a sintering temperature of 1070-1400° C. and a heat preservation time of 0.5-5 h to finally obtain a titanium product component, wherein the metal halide in step 1 is one selected from the group consisting of anhydrous SnF.sub.4, anhydrous SnBr.sub.4, and anhydrous SnI.sub.4; and no liquid medium or organic solvent is used while performing steps 1 to 3.

2. The method according to claim 1, wherein the first predetermined temperature of the gasifier in step 2 is 50-400° C., and the predetermined flow rate is 100-300 ml/min.

3. The method according to claim 1, wherein the second predetermined temperature of the fluidized bed reactor in step 3 is 100-500° C.

4. The method according to claim 1, wherein the powder metallurgy technology in step 4 comprises a die forming technology, an isostatic pressing technology, a 3D printing technology, an injection forming technology, or a gel casting forming technology.

5. The method according to claim 1, wherein the temperature rise treatment in step 5 comprises: raising to a third predetermined temperature from room temperature to 100-650° C. at a temperature raising rate of 0.5-3° C./min, and keeping the third temperature for 120-240 min.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

First Embodiment

(1) 30-μm hydrogenation dehydrogenization (HDH) pure titanium powder and VCl.sub.4 have a mass ratio of 80:20, and a method includes:

(2) (1) placing the VCl.sub.4 and the HDH pure titanium powder which meet formula requirements into a gasifier and a fluidized bed reactor respectively;

(3) (2) heating the gasifier to 180° C. to gasify the VCl.sub.4, and introducing the VCl.sub.4 and dry argon into the fluidized bed reactor in a volume ratio of 20:80;

(4) (3) opening a fluidized bed, heating the fluidized bed to 300° C., fluidizing the titanium powder for 80 min after the introduction of the argon and the metal halide gas, and cooling the product to obtain the titanium powder subjected to oxygen-free passivation;

(5) (4) forming the oxygen-free passivated titanium powder obtained in step (3) into a green body using a polyoxymethylene binder system with an injection forming process; and

(6) (5) performing acid removal on the green body obtained in step (4) at 120° C., then heating the green body to 450° C. at a speed of 2° C./min, keeping the temperature for 120 min, then heating the green body to 1270° C., and keeping the temperature for 2.5 h, so as to obtain an injection-formed high-performance titanium component, wherein the whole process is performed in a vacuum debinding sintering furnace.

Second Embodiment

(7) 20-μm gas-atomized titanium alloy powder Ti-40Al and SnCl.sub.4 have a mass ratio of 92:8, and the performed whole operation and a device are located in argon protection atmosphere. A method includes:

(8) (1) placing the SnCl.sub.4 and the titanium powder Ti-40Al which meet formula requirements into a gasifier and a fluidized bed reactor respectively;

(9) (2) heating the gasifier to 120° C. to gasify the SnCl.sub.4, and introducing the SnCl.sub.4 and dry argon into the fluidized bed reactor in a volume ratio of 15:85;

(10) (3) opening a fluidized bed, heating the fluidized bed to 150° C., fluidizing the titanium powder for 50 min after the introduction of the argon and the metal halide gas, and cooling the product to obtain the titanium powder Ti-40Al subjected to oxygen-free passivation;

(11) (4) pressing the oxygen-free passivated titanium powder obtained in step (3) using an isostatic cool pressing technology; and

(12) (5) placing a green body obtained in step (4) into a vacuum furnace with a vacuum degree of 3-10 MPa, heating the green body to 350° C. at a speed of 2.5° C./min, keeping the temperature for 180 min, then heating the green body to 1400° C., and keeping the temperature for 2 h, so as to obtain a high-performance titanium-aluminum alloy component.

Third Embodiment

(13) −500-mesh ion-spheroidized powder TC4 and SnCl.sub.4 have a mass ratio of 95:5, and the performed whole operation and a device are located in argon protection atmosphere. A method includes:

(14) (1) placing metal halide and the powder TC4 which meet formula requirements into a gasifier and a fluidized bed reactor respectively;

(15) (2) heating the gasifier to 150° C. to gasify the SnCl.sub.4, and introducing the SnCl.sub.4 and dry argon into the fluidized bed reactor in a volume ratio of 10:90;

(16) (3) opening a fluidized bed, heating the fluidized bed to 500° C., fluidizing the titanium powder for 30 min after the introduction of the argon and the metal halide gas, and cooling the product to obtain the titanium powder subjected to oxygen-free passivation;

(17) (4) performing a gel casting forming operation on the oxygen-free passivated titanium powder obtained in step (3) by a low-molecular-weight gel system; and

(18) (5) in argon, heating a green body obtained in step (4) to 450° C. at a speed of 2° C./min, keeping the temperature for 140 min, then heating the green body to 1230° C., and keeping the temperature for 3 h, so as to obtain a high-performance TC4 titanium component.