阅读说明：本技术 一种石墨部件表面钛金属化改性的制备工艺 (Preparation process for titanium metallization modification of surface of graphite component ) 是由 楼华山 王大红 陈文勇 楼江燕 宋东福 陈冬玲 李宏军 莫文锋 蔡英 高茂涛 韦 于 2018-08-22 设计创作，主要内容包括：本发明涉及一种石墨部件表面钛金属化改性的制备工艺,所述石墨部件表面钛金属化的制备方法是结合了溶胶凝胶、氧化、还原以及真空烧结技术,首先以乙基纤维素、松油醇、蓖麻油、纳米TiO<Sub>2</Sub>粉体为原料制备纳米TiO<Sub>2</Sub>油膏,并均匀涂覆在石墨部件表面,随后,采用加热氧化彻底脱除有机成分,接着,在石墨表面氢气还原出纳米Ti颗粒层。最后,利用真空烧结技术,使石墨部件表面具备金属属性。本发明的工艺合理,操作简便,获得的表面金属改性石墨部件材料与铝合金亲和性高,并具有优异的耐铝合金腐蚀性能,在铝合金行业具有良好的推广应用前景。(The invention relates to a preparation process for the surface titanium metallization modification of a graphite component, which combines the sol-gel, oxidation, reduction and vacuum sintering technologies, and firstly adopts ethyl cellulose, terpineol, castor oil and nano TiO 2 Preparation of nano TiO by using powder as raw material 2 The ointment is evenly coated on the surface of a graphite component, then, organic components are thoroughly removed by heating and oxidation, and then, a nano Ti particle layer is reduced on the surface of the graphite by hydrogen. Finally, the surface of the graphite component is provided with metal properties by using a vacuum sintering technology. The method has the advantages of reasonable process and simple and convenient operation, and the obtained surface metal modified graphite part material has high affinity with aluminum alloy, excellent aluminum alloy corrosion resistance and good popularization and application prospects in the aluminum alloy industry.)

1. A preparation process for the surface titanium metallization modification of a graphite component is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: stock preparation

Firstly, preparing the following raw materials in percentage by mass: 2.4-2.7 wt.% of ethyl cellulose, 72-81 wt.% of terpineol, 5.6-6.3 wt.% of castor oil and nano TiO₂10-20 wt.% of powder;

step two: TiO 2₂Ointment preparation

Mixing ethyl cellulose, terpineol and castor oil uniformly, heating in a water bath at the temperature of 80-100 ℃, and stirring until the mixture of the ethyl cellulose, the terpineol and the castor oil is dissolved into a uniform and transparent terpineol carrier solution; then adding nano TiO₂Adding the powder into terpineol carrier solution, and stirring to obtain nanometer TiO₂Uniformly dispersing the powder in terpineol carrier solution, stopping heating, and cooling to obtain nano TiO₂An ointment;

step three: graphite surface impregnation ointment

Placing a graphite component into the modulated nano TiO₂Heating the ointment in a water bath to 80-100 ℃, preserving heat for 60-120 min, taking out the graphite part, and standing and drying in the shade;

step four: terpineol carrier oxidation

Putting the dried graphite component into an aerobic furnace, heating the graphite component from room temperature to 165-185 ℃ at a heating rate of 4-6 ℃/min, preserving heat for 60-120 min, heating the graphite component to 200-240 ℃ at a heating rate of 4-6 ℃/min, preserving heat for 360-600 min, heating the graphite component to 350-450 ℃ at a heating rate of 4-6 ℃/min, preserving heat for 50-70 min, and finally cooling the graphite component to room temperature in a furnace cooling mode to obtain a graphite dispersion member after the terpineol carrier is removed through oxidation;

step five: nano TiO 2₂Reduction of

Putting the graphite dispersion piece into a hydrogen reduction furnace, introducing hydrogen, heating to 640-660 ℃ from room temperature at the heating rate of 5-7 ℃/min, preserving heat for 60-120 min, then heating to 780-820 ℃ at the heating rate of 5-7 ℃/min, preserving heat for 60-120 min, and then cooling to room temperature in a furnace cooling mode;

step six: ti metallization of graphite surface

Taking the graphite dispersion member out of the hydrogen reduction furnace, rapidly putting the graphite dispersion member into a vacuum furnace, vacuumizing, heating from room temperature to 780-800 ℃ at a heating rate of 9-11 ℃/min, preserving heat for 60-120 min, heating to 1500-1700 ℃ at a heating rate of 9-11 ℃/min, preserving heat for 90-360 min, cooling to 700-800 ℃ at a cooling rate of 9-11 ℃/min, preserving heat for 60-120 min, and finally cooling to room temperature in a furnace cooling mode to obtain the graphite member with the Ti metalized surface.

2. The preparation process of the graphite component with the surface modified by titanium metallization according to claim 1, is characterized in that: the technological parameters in the hydrogen reduction furnace include hydrogen pressure of 0.02-0.05 MPa and flow rate of 2.5-5.5 mL/min.

3. The preparation process of the graphite component with the surface modified by titanium metallization according to claim 1, is characterized in that: sintering process parameters in a vacuum furnace, vacuum degree: 1X 10^-2～1×10^-3 Pa。

4. The preparation process of the graphite component with the surface modified by titanium metallization according to claim 1, is characterized in that: nano TiO 2₂The particle size of the powder is 10-20 nm.

Technical Field

The invention relates to a preparation technology for activating the surface performance of a graphite component, in particular to a preparation technology for the surface of the graphite component with certain metal properties.

Background

The graphite has excellent performances of high melting point, low density and the like, and is a selected material of the stirring impeller when aluminum alloy is smelted. In order to fully exploit the properties of aluminum alloys and further improve the melting quality of aluminum alloys, it is necessary to develop a novel graphite member. The graphite component is designed into a multi-size hole structure, and during working, the multi-size holes are processed to play a role in shunting the aluminum alloy melt so as to change the position and the size between adjacent aluminum alloy melts, thereby increasing the surface area of the diffusion of the microstructure of the aluminum alloy, shortening the diffusion distance of the microstructure and finally achieving the effect of uniformly mixing the aluminum alloy melt.

However, graphite has a high surface energy and has poor wettability with liquid aluminum alloys. When the graphite component with the porous structure is rotated and stirred, the aluminum alloy melt is difficult to overcome the permeation resistance of the microporous structure, so that permeation is generated. If active Ti element is added on the surface of graphite, it reacts with the surface of graphite to form TiC interface layer. By utilizing the metal property of the TiC interface layer, the wettability between the graphite surface and the liquid aluminum alloy can be improved, and the spreading of an aluminum alloy solution on the inner wall of the hole structure of the graphite part is facilitated.

The traditional graphite surface metallization modification process mainly adopts an ion plating mode, and the process is not suitable for surface plating of a hole structural member. In view of the fact that the wettability between the graphite surface (particularly the inner wall of the hole) and the aluminum alloy melt plays a critical role in the preparation of homogeneous aluminum alloy materials; therefore, a surface activation process suitable for a graphite component with complex holes is developed, the affinity between the inner wall of the hole and the aluminum alloy melt is enhanced, the aluminum alloy melt effectively flows through the microporous pore channel of the graphite component, and the method has important significance for preparing homogeneous aluminum alloy materials.

Disclosure of Invention

The invention aims to provide a preparation method suitable for surface titanium metallization of a graphite part with a porous structure aiming at the defects of the existing ion plating technology, the surface metallization of the graphite part is realized through good combination of a titanium plating layer and a graphite matrix, and early bedding work is well done for preparing a homogeneous aluminum alloy material.

The purpose of the invention is realized by the following technical scheme:

a preparation process for titanium metallization modification of the surface of a graphite component combines sol-gel, oxidation, reduction and vacuum sintering technologies to enable the surface of the graphite component to have metal properties.

The process uses the catalyst containing activating agent-nano TiO₂Coating nano TiO on the surface of the graphite component by taking terpineol solution as a carrier₂The ointment comprises the following specific components in percentage by mass: 2.4-2.7 wt.% of ethyl cellulose, 72-81 wt.% of terpineol, 5.6-6.3 wt.% of castor oil, TiO₂ 10～20 wt.%。

Subsequently, organic components are removed by heating and oxidizing, and the specific heat treatment process is divided into 3 stages: 1) keeping the temperature for 60-120 min at the room temperature of 165-185 ℃; 2) heating to 200-240 ℃ at 165-185 ℃, and keeping the temperature for 360-600 min; 3) keeping the temperature at 200-240-350-450 ℃ for 50-70 min.

Then, hydrogen is reduced to obtain a Ti element film layer, and the specific reduction process is divided into 2 stages: 1) keeping the temperature for 60-120 min at the room temperature of 640-660 ℃; 2) and keeping the temperature at 640-660-780-820 ℃ for 60-120 min.

Finally, the vacuum sintering technology is utilized to fuse the Ti and the graphite component surface into a whole, and the specific sintering process is divided into 3 stages: 1) keeping the temperature for 60-120 min at the room temperature of 780-800 ℃; 2) maintaining the temperature at 780-800 ℃ to 1500-1700 ℃ for 90-360 min; 3) 1500-1700 ℃ to 700-800 ℃, and keeping the temperature for 60-120 min.

The preparation process for the titanium metallization modification of the surface of the graphite component comprises the following specific steps and process conditions: the method comprises the following steps: stock preparation

Firstly, preparing the following raw materials in percentage by mass: 2.4-2.7 wt.% of ethyl cellulose, 72-81 wt.% of terpineol, 5.6-6.3 wt.% of castor oil and nano TiO₂10-20 wt.% of powder;

step two: TiO 2₂Ointment preparation

Mixing ethyl cellulose, terpineol and castor oil uniformly, heating in a water bath at the temperature of 80-100 ℃, and stirring until the mixture of the ethyl cellulose, the terpineol and the castor oil is dissolved into a uniform and transparent terpineol carrier solution; then adding nano TiO₂Adding the powder into terpineol carrier solution, and stirring to obtain nanometer TiO₂Uniformly dispersing the powder in terpineol carrier solution, stopping heating, and cooling to obtain nano TiO₂An ointment;

step three: graphite surface impregnation ointment

Placing a graphite component into the modulated nano TiO₂Heating the ointment in a water bath to 80-100 ℃, preserving heat for 60-120 min, taking out the graphite part, and standing and drying in the shade;

step four: terpineol carrier oxidation

Putting the dried graphite component into an aerobic furnace, heating the graphite component from room temperature to 165-185 ℃ at a heating rate of 4-6 ℃/min, preserving heat for 60-120 min, heating the graphite component to 200-240 ℃ at a heating rate of 4-6 ℃/min, preserving heat for 360-600 min, heating the graphite component to 350-450 ℃ at a heating rate of 4-6 ℃/min, preserving heat for 50-70 min, and finally cooling the graphite component to room temperature in a furnace cooling mode to obtain a graphite dispersion member after the terpineol carrier is removed through oxidation;

step five: nano TiO 2₂Reduction of

Putting the graphite dispersion piece into a hydrogen reduction furnace, introducing hydrogen, heating to 640-660 ℃ from room temperature at the heating rate of 5-7 ℃/min, preserving heat for 60-120 min, then heating to 780-820 ℃ at the heating rate of 5-7 ℃/min, preserving heat for 60-120 min, and then cooling to room temperature in a furnace cooling mode;

step six: ti metallization of graphite surface

Taking the graphite dispersion member out of the hydrogen reduction furnace, rapidly putting the graphite dispersion member into a vacuum furnace, vacuumizing, heating from room temperature to 780-800 ℃ at a heating rate of 9-11 ℃/min, preserving heat for 60-120 min, heating to 1500-1700 ℃ at a heating rate of 9-11 ℃/min, preserving heat for 90-360 min, cooling to 700-800 ℃ at a cooling rate of 9-11 ℃/min, preserving heat for 60-120 min, and finally cooling to room temperature in a furnace cooling mode to obtain the graphite member with the Ti metalized surface.

The technological parameters in the hydrogen reduction furnace include hydrogen pressure of 0.02-0.05 MPa and flow rate of 2.5-5.5 mL/min.

Sintering process parameters in a vacuum furnace, vacuum degree: 1X 10^-2～1×10^-3 Pa。

Nano TiO 2₂The particle size of the powder is 10-20 nm.

The principle of the preparation process of the graphite surface titanium metallization modified coating is as follows: uniformly dispersing nano TiO by using terpineol carrier solution₂Powder and form nanometer TiO with good fluidity₂Ointment. Putting nano TiO into graphite component₂After the factice is taken out, the factice can automatically level on the surface of the graphite component, so that a uniform factice film layer is formed. Then the ointment film layer attached to the surface of the graphite component is oxidizedThe organic components (ethyl cellulose, terpineol and castor oil) are fully volatilized and oxidized (as shown in figure 1), so that only nano TiO is remained on the surface of the graphite part₂Coating (as shown in fig. 2). Then, the nano TiO₂The thickness coating of the TiC film layer is reduced by hydrogen to form a metal Ti layer covering the surface of the graphite component, and reacts with the surface of the graphite component in the subsequent vacuum heating treatment to generate the TiC film layer (as shown in fig. 3 and 4). The generation and diffusion processes of the TiC film layer on the graphite surface can be regulated and controlled by setting the sintering temperature and the sintering time, so that the thickness of the TiC film layer and the bonding performance of the TiC film layer and the graphite surface are controlled, and the titanium metal graphite part with excellent performance can be obtained.

Compared with the prior art, the invention has the following advantages:

1. the preparation process for the titanium metallization modification of the graphite part surface has the advantages of simple processing process and convenient operation, and the thickness of the modified TiC film layer of the titanium metallization graphite part is controllable, so that the preparation process is particularly suitable for the Ti metallization modification treatment of the graphite part surface with a complex porous structure.

2. Because the hydrogen reduction-vacuum sintering technology is adopted, the nano Ti particles can be directly attached to the graphite surface, the contact area of the nano Ti particles and the graphite is increased, and further, the full reaction of the nano Ti particles and the graphite is facilitated in the subsequent sintering, and the nano Ti particles are diffused to the graphite surface, so that the TiC film prepared by the method disclosed by the invention is well combined with the graphite surface (as shown in figure 5), and has excellent comprehensive mechanical properties such as high plasticity, high strength and the like.

3. The surface Ti metallized graphite component prepared by the method has good aluminum alloy corrosion resistance and good affinity with aluminum alloy (as shown in figure 6), basically meets the application requirements of serving as a novel aluminum alloy stirring component material, and has wide popularization and application prospects in the aluminum alloy industry.

Drawings

FIG. 1 shows a nano TiO compound of the present invention₂And (3) an infrared test data curve graph of the ointment after the terpineol carrier is removed by oxidation. The infrared test data show that the nano TiO is coated₂The graphite matrix of the ointment is adopted by the inventionAfter the oxidation treatment, no organic components were detected.

FIG. 2 shows the present invention of nano TiO₂A Raman test data curve chart of the ointment after the terpineol carrier is removed by oxidation. Raman test data shows that the component of the substance attached to the graphite matrix is TiO₂。

FIG. 3 is a XRD detection data chart of Ti metallization on the graphite surface according to the invention. The detection data show that a TiC new phase is generated on the surface of the graphite matrix after sintering.

FIG. 4 is a BSEM photograph of Ti metallization on the graphite surface of the present invention. BSEM photographs reveal that the TiC metal film coated on the surface of the graphite substrate has the characteristics of uniformity and continuity.

FIG. 5 is an SEM photograph of a TiC/C interface of the present invention. The high-magnification SEM photograph reflects that the TiC film and the graphite matrix are integrated, and indirectly shows that the TiC film and the graphite matrix have good bonding performance.

FIG. 6 is an SEM photograph of the surface Ti-metallized graphite of the present invention after being impregnated with an aluminum alloy melt. The SEM photograph clearly reflects that the surface of irregular TiC particles (metal film composition units) is completely wrapped by the aluminum alloy after being impregnated by the aluminum alloy melt, which indicates that the TiC and the aluminum alloy have good wetting performance.

Detailed Description

The present invention is described in further detail by the following examples and the accompanying drawings, but the embodiments of the present invention are not limited thereto.