CN111004956A

CN111004956A - TiB2Preparation method of (E) -Fe-Co-Ni-Cr aluminum liquid corrosion resistant material

Info

Publication number: CN111004956A
Application number: CN201910978289.7A
Authority: CN
Inventors: 尹付成; 尚岩松; 王鑫铭; 欧阳雪枚; 易华清; 谢小龙; 刘克
Original assignee: Xiangtan University
Current assignee: Xiangtan University
Priority date: 2019-10-15
Filing date: 2019-10-15
Publication date: 2020-04-14

Abstract

The invention discloses a preparation method of TiB2 _- Fe _- Co-Ni-Cr aluminum liquid corrosion resistance material, which uses TiB2 powder, Fe powder, Co powder, Ni powder and Cr powder as raw materials. The steps include: Step 1: Mixing ball milling step, step ₂ : drying step; step 3: sintering step; the proportion of each component is: TiB ₂ powder, Fe powder, Co powder, Ni powder and Cr powder. 70‑88%, Fe powder 2.97‑7.43%, Co powder 3.14‑7.84%, Ni powder 3.12‑7.81%, Cr powder 2.77‑6.92%. The preparation method of the TiB ₂ ‑Fe‑Co‑Ni‑Cr aluminum liquid corrosion resistance material is easy to implement, and the prepared material has excellent aluminum industry corrosion resistance properties.

Description

TiB2Preparation method of (E) -Fe-Co-Ni-Cr aluminum liquid corrosion resistant material

Technical Field

The invention belongs to the field of aluminum liquid corrosion resistant materials, and particularly relates to a TiB₂A preparation method of an-Fe-Co-Ni-Cr molten aluminum corrosion resistant material.

Background

At present, aluminum and its alloy are widely used in the fields of traffic, energy, electronics, etc. But the aluminum liquid is one of the most corrosive metal liquids, so that equipment directly contacting the aluminum liquid is greatly corroded in a smelting, casting and hot-dip aluminizing production line, and the service life of the equipment is greatly shortened. And the dissolution of the materials in the aluminum liquid may pollute the aluminum liquid, so that the product quality is low, and the production efficiency is influenced. In a hot-dip aluminum plating production line, equipment such as an aluminum liquid loading tank, an immersion roller and the like needs to be soaked in aluminum liquid for a long time, so that the service life of the hot-dip aluminum plating production equipment is shortened, the quality of a plating layer is reduced, the energy consumption is increased, the production efficiency is reduced and other adverse effects are caused. Therefore, the aluminum liquid corrosion resistance of the material is improved, and a series of corrosion problems such as aluminum liquid pollution, corrosion perforation of an aluminum liquid containing container, aluminum sticking of an aluminum forming die and the like can be effectively solved.

Therefore, it is necessary to design a new preparation method of the molten aluminum corrosion resistant material.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a TiB₂A preparation method of an-Fe-Co-Ni-Cr molten aluminum corrosion resistant material, namely the TiB₂The Fe-Co-Ni-Cr aluminum liquid corrosion resistant material has excellent aluminum liquid corrosion resistance.

The technical solution of the invention is as follows:

a preparation method of a TiB2-Fe-Co-Ni-Cr molten aluminum corrosion resistant material comprises the following steps:

step 1: mixing and ball milling:

weighing TiB according to preset mass percentage₂Putting the powder, Fe powder, Co powder, Ni powder and Cr powder into a ball mill for ball milling;

TiB₂the powder comprises the following components in percentage by mass:

TiB₂70-88% of powder, 2.97-7.43% of Fe powder, 3.14-7.84% of Co powder, 3.12-7.81% of Ni powder and 2.77-6.92% of Cr powder.

Step 2: and (3) drying:

putting the ball-milled powder into a vacuum drying box for drying;

and step 3: sintering:

and putting the dried mixed powder into a mould for spark plasma sintering.

The ball mill in the step 1

The method is characterized in that the wet ball milling is carried out, absolute ethyl alcohol is used as a ball milling medium, and the ball: the mixing powder ratio is 3:1, the grinding balls and the mixing powder are added according to the mass ratio of 3:1-5:1 (preferably 3:1), the rotating speed is 150-. The ball milling tank and the milling balls are made of hard alloy.

In the drying step in the step 2, the drying temperature is 70-90 ℃, the vacuum degree is 0.09MPa to-0.1 MPa, the preferred vacuum degree is-0.1 MPa, and the drying time is 8-12 hours, and the preferred time is 12 hours.

The sintering adopted by the invention is spark plasma sintering: and (3) placing the dried mixed powder into a mold, heating to the temperature T at the temperature T of 1300-1400 ℃ at the heating rate of 300 ℃/min of 200 ℃/min-300 ℃/min, and preserving the heat for 5-10 minutes in the temperature T environment at the pressure of 50-60 MPa.

The heating rate is 200 ℃/min, 250 ℃/min or 300 ℃/min;

t is 1300 ℃, 1350 ℃ or 1400 ℃, and the heat preservation time is 5, 7, 8, 9 or 10 minutes.

The sintering can be completed by pressureless sintering, hot-pressing sintering, spark plasma sintering and the like; however, the use of Spark Plasma Sintering (SPS) has the following advantages over conventional sintering processes (pressureless sintering, hot pressed sintering, etc.): the method has the characteristics of high heating rate, low sintering temperature, short sintering time and the like, can prepare high-density materials at a lower temperature, is commonly used for preparing ceramic materials difficult to sinter, generates discharge plasma when the electrode is introduced with direct-current pulse current in the sintering process, purifies the surfaces of particles, and enables each particle to uniformly generate Joule heat per se and activate the surfaces of the particles. Therefore, the sintering can be completed quickly and efficiently, the energy is saved, the production cost is reduced, and the production efficiency is improved.

The spark plasma sintering can be carried out by FAS-10015Y spark plasma sintering equipment or other equipment manufactured by Shanghai Kangshi electric furnace equipment Co.

Description of the technical idea of the invention TiB₂Has a plurality of excellent performances such as high hardness, high wear resistance, good high-temperature oxidation resistance and the like. But TiB₂Poor high-temperature toughness, low diffusion coefficient and poor sintering property, so that the pure TiB₂Sintering preparation of the material is difficult. Therefore, the characteristics of excellent toughness and low melting point of the metal binding phase can be utilized to improve TiB₂Poor toughness and difficult sintering. But TiB₂The wettability with most metals is poor, so it is necessary to select one with TiB₂The metal with good wettability is used as a binding phase. The related literature is consulted to find that only Fe, Co, Ni and TiB₂Has better wettability, so the elements Fe, Co and Ni are selectively added to improve the TiB₂The addition of Cr element has a good strengthening effect, and the addition of metal element can improve TiB₂The brittleness and the toughness of the steel are improved.

Has the advantages that:

the invention discloses a TiB₂The invention relates to a preparation method of-Fe-Co-Ni-Cr-Ti aluminum liquid corrosion resistant metal ceramic integral material, which is characterized in that TiB is added₂The ceramic powder is added with metal simple substance as a binding phase, thereby obviously reducing TiB₂The sintering temperature of the alloy improves TiB₂Sintering property of (2). In addition, compared with the traditional sintering process, the spark plasma sintering process has great advantages, can obviously reduce the sintering temperature and the sintering time, and has low temperature, high speed and high efficiencyIs characterized in that. Meanwhile, the preparation process is simple, the price is low, the excellent corrosion resistance is shown in the aluminum liquid, and the preparation method has important application value in industry.

TiB₂As the only stable compound of the transition group metal elements Ti and B, having a close-packed hexagonal C32 type crystal structure, TiB₂Meanwhile, the wear-resistant steel has strong Ti-B ionic bonds and B-B covalent bonds, so that the wear-resistant steel has high hardness, high wear resistance and good high-temperature oxidation resistance. But TiB₂Poor high-temperature toughness, low diffusion coefficient and poor sintering property, so that the pure TiB₂Sintering preparation of the material is difficult. Therefore, the characteristics of excellent toughness and low melting point of the metal binding phase can be utilized to improve TiB₂Poor toughness and difficult sintering. But TiB₂The wettability with most metals is poor, so that it is necessary to select a metal having good wettability with the metal as a binder phase. Therefore, a new metal system is designed as a binding phase, and a new sintering process is designed to improve TiB₂The material has the defect of difficult sintering, has excellent aluminum liquid corrosion resistance, low price of raw materials, simple preparation process and considerable industrial application prospect.

At present, the average corrosion rate of the cast iron material commonly used in the production industry in molten aluminum at 700 ℃ is 8.5 multiplied by 10^-1The average corrosion rate of mm/h, 316L stainless steel in aluminum liquid at 700 ℃ is 1.1 multiplied by 10^-1mm/h. In the first embodiment of the invention, the average corrosion rate of the material is 5.13 multiplied by 10^-3mm/h, compared with the common cast iron and 316L stainless steel in the current industrial production, the aluminum liquid corrosion resistance is greatly improved, and the test proves that TiB in the material₂The higher the content is, the better the corrosion resistance of the material is, and the material has good industrial application prospect.

Drawings

FIG. 1 shows TiB in the first embodiment of the present invention₂SEM image of the mixed powder of-Fe-Co-Ni-Cr after ball milling.

FIG. 2 shows TiB prepared in the first embodiment of the present invention₂SEM image of-Fe-Co-Ni-Cr cermet bulk Material

FIG. 3 shows a second embodiment of the present inventionPrepared TiB₂SEM image of Fe-Co-Ni-Cr cermet monolith.

FIG. 4 shows TiB prepared in the third embodiment of the present invention₂SEM image of Fe-Co-Ni-Cr cermet monolith.

FIG. 5 is a graph of etch depth versus time for three different materials in an embodiment of the present invention.

FIG. 6 is an SEM image of a corrosion interface of the material after 2, 4, 6, 8 and 10 days of corrosion in molten aluminum at 700 ℃ in the first embodiment of the invention.

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the following specific embodiments.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Example 1:

the first embodiment is as follows: TiB₂The preparation method of the Fe-Co-Ni-Cr aluminum liquid corrosion resistant metal ceramic integral material comprises the following steps:

(1) sample preparation: mixing TiB₂Fe, Co, Ni and Cr powder are weighed according to the following mass percent: TiB₂70% of powder, 7.43% of Fe powder, 7.84% of Co powder, 7.81% of Ni powder and 6.92% of Cr powder. The TiB₂The purity of the powder was 99.5%, particle size<35 microns; the purity of the Fe powder, the Co powder, the Ni powder and the Cr powder>99.9% by weight, particle size<15 microns.

(2) Ball milling: and (3) putting the weighed mixture into a ball milling tank, and weighing the required balls and putting the balls into the ball milling tank according to the ball-to-mixture mass ratio of 3: 1. And (3) adopting a wet ball milling process, and pouring a proper amount of absolute ethyl alcohol into the ball milling tank to cover the powder. The rotating speed of the ball mill is 200r/min, and the ball milling time is 1 hour. FIG. 1 is an SEM image of the mixed powder after ball milling. It can be seen from the figure that after the ball milling of the mixed powder, the metal powder is uniformly dispersed in the mixed powderTiB₂In the powder.

(3) And (3) drying: and (3) putting the mixed slurry subjected to ball milling into a vacuum drying oven for drying, wherein the temperature of the drying oven is 70-90 ℃, the vacuum degree is-0.1 MPa, and the drying time is 12 hours. The dried powder was taken out for further use.

(4) And (3) sintering: the sintering equipment used in this example was spark plasma sintering, and the dried powder was placed in a cylindrical graphite mold and then sintered in the sintering equipment, and the sintering process was set as follows: heating from room temperature to 1400 deg.C at 300 deg.C/min, maintaining at 1400 deg.C for 5 min, and pressurizing at 50-60MPa during sintering. And cooling along with the furnace after sintering is finished, and then demoulding to obtain a sample. FIG. 2 is a microscopic topography of a sample under a Scanning Electron Microscope (SEM). From the SEM image, it can be seen that the dark gray is TiB₂Hard phase, light gray is metal binding phase distributed in TiB₂Around the hard phase, TiB is filled₂The surrounding void.

And cutting the prepared sample into cuboid samples with the size of 4 multiplied by 5 multiplied by 10mm by using an electric spark numerical control wire cutting machine, and cutting 5 samples, wherein the cutting position is preferably the central position of the sample. And (4) polishing the surface of the sample by using sand paper, and removing an oxide film on the surface of the sample. And then measuring the thickness of the sample before corrosion by using a micrometer, then putting the sample into a graphite crucible filled with aluminum liquid at 700 ℃ for a corrosion experiment, heating and preserving heat by using a well-type resistance furnace, respectively corroding for 2 days, 4 days, 6 days, 8 days and 10 days, then taking out, analyzing the texture of a corrosion interface by using a Scanning Electron Microscope (SEM), and measuring the phased chemical components by using an energy spectrometer (EDS).

The corrosion depth and the corrosion rate of the sample at different time are calculated, the corrosion rate is measured by using a depth method in the experiment, and the calculation formula is as follows: v ═ a-b)/2 t.

And a is the thickness of the sample before corrosion, b is the thickness of the sample after corrosion, t is corrosion time, the thickness a before corrosion is accurately measured by a micrometer before a corrosion experiment, then the structural observation is carried out on the cross section of the sample after corrosion under a scanning electron microscope, and the residual thickness b of the sample after corrosion is measured by Smile View software.

Example two: compared with the first embodiment, the method of the second embodiment is the same except that the step (1) is different; step (1) of example two, sample preparation: mixing TiB₂Fe, Co, Ni and Cr powder are weighed according to the following mass percent: TiB₂88% of powder, 2.97% of Fe powder, 3.14% of Co powder, 3.12% of Ni powder and 2.77% of Cr powder. The other steps are the same as in the first embodiment. FIG. 3 is a SEM microstructure of sintered sample of this example. The erosion depth of this material as a function of time is shown in FIG. 5.

Example three: compared with the method in the first embodiment, the method in the third embodiment is the same except that the step (1) is different; step (1) of example three, sample preparation: mixing TiB₂Fe, Co, Ni and Cr powder are weighed according to the following mass percent: TiB₂80% of powder, 4.95% of Fe powder, 5.23% of Co powder, 5.21% of Ni powder and 4.61% of Cr powder. The other steps are the same as in the first embodiment. FIG. 4 is a SEM microstructure of sintered sample of this example. The erosion depth of this material as a function of time is shown in FIG. 5.

FIG. 5 is a graph showing the erosion depth of three materials of the first, second and third embodiments as a function of time. It can be seen from the figure that the etch depth of this material increases with the time of etching, but the etch rate decreases with time. The average corrosion rate of the cermet material in the first example was calculated as: 5.13X 10^-3mm/h; the average corrosion rate of the cermet material in example two was: 2.901X 10^-3mm/h; the average corrosion rate of the cermet material in example three was: 7.883X 10^-3mm/h. Compared with the corrosion rate of cast iron in molten aluminum of 0.85mm/h, the corrosion rate of the molten aluminum resistance of the integral material is greatly improved.

FIG. 6 is SEM images of corrosion interfaces of the material after 2, 4, 6, 8 and 10 days of corrosion in molten aluminum at 700 ℃ in the first embodiment (corresponding to FIGS. 6(a) - (e), respectively). The substrate, the corrosion layer and the aluminum layer are sequentially arranged from left to right. The picture after 2 days of corrosion shows that the aluminum liquid begins to corrode the matrix, and the preferential corrosion is the metal binding phase, TiB₂The ceramic phase is present in the molten aluminum without being corroded. With decayThe etching time is increased and the depth of the corrosion layer is increased. A diffusion layer which is denser than the matrix is found between the corrosion layer and the matrix, EDS analysis shows that the aluminum content of the diffusion layer is obviously less than that of the corrosion layer, and the aluminum content is lower at the position closer to the matrix, which indicates that the diffusion layer effectively slows down the corrosion of aluminum liquid to the matrix. Through comparing the electron microscope photos after 2, 4, 6, 8 and 10 days of corrosion, the wettability of the external aluminum liquid and the material is poor in the early stage of corrosion, a gap exists between the aluminum liquid and the corrosion layer, the gap between the aluminum liquid and the corrosion layer is reduced along with the prolonging of corrosion time, and the picture after 10 days of corrosion shows that the aluminum liquid and the corrosion layer are tightly combined. And in experiments, the aluminum liquid corrodes the material, but the corrosion layer is not separated from the matrix and is dissociated in the aluminum liquid, and the material still maintains the original shape.

TiB₂Has high melting point, high hardness, high wear resistance and good high-temperature oxidation resistance, has poor wettability with aluminum liquid and does not react with the aluminum liquid. It can be found by the examples that the aluminium liquid will preferentially corrode the metal binding phase, TiB₂The phases are not corroded by the molten aluminum and still exist in the matrix. As the corrosion time increases, a diffusion layer denser than the matrix is found between the corrosion layer and the matrix, and EDS analysis shows that the aluminum content of the diffusion layer is obviously less than that of the corrosion layer, and the aluminum content is lower at the position closer to the matrix, which indicates that the diffusion layer effectively slows down the corrosion of aluminum liquid to the matrix, and the corrosion rate is also determined as follows: as the etch time increases, the etch rate decreases.

The embodiments are only for the purpose of facilitating understanding of the technical solutions of the present invention, and do not constitute a limitation to the scope of the present invention, and any simple modification, equivalent change and modification made to the above solutions without departing from the contents of the technical solutions of the present invention or the technical spirit of the present invention still fall within the scope of the present invention.

Claims

1. a preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion-resistant material, is characterized in that, comprises the following steps:

Step 1: Mixing Ball Milling Steps:

Weigh _TiB powder, Fe powder, Co powder, Ni powder and Cr powder according to the preset mass percentage, and put them into a ball mill for ball milling;

The composition of TiB ₂ powder, Fe powder, Co powder, Ni powder and Cr powder in terms of mass percentage is as follows:

TiB ₂ powder 70-88%, Fe powder 2.97-7.43%, Co powder 3.14-7.84%, Ni powder 3.12-7.81%, Cr powder 2.77-6.92%.

Step 2: Drying Step:

Put the ball-milled powder into a vacuum drying oven for drying;

Step 3: Sintering Step:

The above-mentioned dried mixed powder is put into a mold for spark plasma sintering.

2. the preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion resistance material according to claim 1, is characterized in that, in described step 1, ball milling

For wet ball milling, anhydrous ethanol is used as the ball milling medium. The ball: mixed powder ratio is 3:1. The grinding ball and the mixed powder are added according to the mass ratio of 3:1-5:1. -3 hours.

3. the preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion resistance material according to claim 1, is characterized in that,

In the drying step in step 2, the drying temperature is 70-90° C., the vacuum degree is 0.09 MPa～-0.1 MPa, and the drying time is 8-12 hours.

4. the preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion resistance material according to claim 1, is characterized in that,

In the sintering step: the dried mixed powder is placed in the mold, and the temperature T is 1300°C-1400°C at a temperature rise rate of 200°C/min-300°C/min of 300°C/min, and the temperature T is in the environment of temperature T. Incubate for 5-10 minutes under the pressure of 50-60MPa.

5 . The preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion resistant material according to claim 4, characterized in that the heating rate is 200°C/min, 250°C/min or 300°C/min.

6. The preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion-resistant material according to claim 5, characterized in that, T is 1300 ℃, 1350 ℃ or 1400 ℃, and the holding time is 5, 7, 8, 9 or 10 minutes.

7. The preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion resistant material according to claim 1, wherein,

The purity of the TiB ₂ powder is >99.5%, and the particle size is <35 microns;

The purity of the Fe powder, Co powder, Ni powder and Cr powder are all >99.9%, and the particle size is all <15 microns.

8 . The preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion resistant material according to claim 1 , wherein the TiB ₂ powder is 80-88% and the Fe powder is 2.97-4.95%. 9 .

9 . The preparation method of TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion resistant material according to claim 1, wherein the Co powder is 3.14-5.23%, the Ni powder is 3.12-5.21%, and the Cr powder is 3.14-5.23%. was 2.77-4.61%.

10 . The preparation method of the TiB ₂ -Fe-Co-Ni-Cr liquid aluminum corrosion-resistant material according to any one of claims 1-9, wherein the sintering adopts spark plasma sintering.