CN101871070B - Novel metal ceramic composite material and preparation method thereof - Google Patents

Abstract

The invention relates to a novel cermet composite material and a preparation method thereof. It is a cermet composite material with Al ₂ O ₃ ceramics as the matrix, Ti(C,N) ceramic hard particles and Fe metal as the dispersed phase. The mass percentage content of the main components of the material is: Al ₂ O ₃ : 50-70%; Ti(C, N): 20-30%; Fe: 5-20%; the rest are unavoidable impurities such as Mn, Si and Ca. Select Panzhihua ilmenite (FeTiO ₃ ) which is rich in reserves in China as raw material, and directly prepare low-cost Al ₂ O ₃ /Ti(C,N)/Fe cermets by hot pressing sintering process on the basis of carbothermal and aluminothermic reduction composite material. Compared with similar metal-ceramic composite materials, the composite material of the present invention has quite good comprehensive mechanical properties and excellent properties such as wear resistance, corrosion resistance, oxidation resistance and thermal shock resistance, the preparation process is simple, the cost is low, and it is rich in my country. Full and efficient use of resources opens up new avenues.

Description

A kind of metal-ceramic composite material and preparation method thereof

technical field

The invention relates to a metal-ceramic composite material, in particular to a metal-ceramic composite material with high hardness and high wear resistance and a preparation method thereof.

Background technique

Metal-ceramic composites are classified according to the different ceramic phases. Divided into oxide-metal composites, carbide-metal composites, nitride-metal composites, boride-metal composites, boron carbide-metal composites and silicide-metal composites. It has various varieties and different structures, all of which have different strength, hardness, wear resistance and oxidation resistance, and are widely used in electronic devices, metallurgy, chemical industry, aerospace and other fields.

Ti(C,N)/Al ₂ O ₃ cermets not only have high hardness, wear resistance, red hardness, excellent chemical stability, and extremely low friction coefficient between metals, but also have certain toughness and strength. . Compared with the usual cemented carbide, it has obvious advantages in the following aspects: higher cutting speed; better surface properties of the processed workpiece; higher wear resistance. However, Ti(C,N) powder, one of the raw materials for commercial production of such materials, is very expensive (700,000 yuan/ton), which hinders its wide application.

The ilmenite resource reserves are large and widely distributed, almost all over the world. According to the 1995 Mineral Products Summary of the U.S. Bureau of Mines, the proven reserves of ilmenite resources in the world are 20.7 billion tons, mainly distributed in Canada, Norway, South Africa, Australia, the United States, India, the former Soviet Union, and Sri Lanka. , Brazil, Finland and other countries, among which South Africa has the largest reserves, accounting for 23.4% of the world's total reserves. my country's ilmenite resources are very rich, covering 20 provinces and autonomous regions, including rock mines and placer mines, of which rock mines account for the majority. The total reserve of ilmenite in my country is about 30 million tons. At present, the total production capacity of ilmenite in my country is 300,000 tons per year. According to this calculation, ilmenite can be mined for 100 years. At present, the main utilization ways of ilmenite are as follows: (1) the ilmenite concentrate is smelted in an electric furnace to produce acid-soluble high-titanium slag, which is then used in the sulfuric acid process titanium dioxide production; (2) ilmenite concentrate After being enriched and processed into high-titanium slag (TiO ₂ above 90%) or artificial rutile (TiO ₂ above 96%), TiCl ₄ is prepared by boiling chlorination or molten salt chlorination; (3) used for sponge titanium Production. The above comprehensive utilization methods of ilmenite have problems such as high energy consumption, low comprehensive utilization of iron, or difficult treatment of waste acid mother liquor, which affects the efficiency of ilmenite utilization and the industrialization process of ilmenite. For this reason, it is urgent and necessary to develop new utilization approaches of ilmenite.

Contents of the invention

In view of this, the object of the present invention is to provide an alumina-based ceramic composite material with low cost and wide application range and improved utilization efficiency of ilmenite.

Another object of the present invention is to provide a method for preparing alumina-based ceramic composite materials that is suitable for industrial application, has a simple process, is easy to operate, and is suitable for the production of products with complex shapes.

The object of the present invention is achieved in that a kind of alumina-based ceramic composite material is characterized in that, with Al ₂ O ₃ ceramics as matrix, Ti (C, N) ceramic hard particles and Fe metal as cermets of dispersed phase Composite material; wherein, the mass percentage content of the main component of the material is: Al ₂ O ₃ : 50-70%; Ti(C, N): 20-30%; Fe: 5-20%; unavoidable Mn, Si, Ca and other impurities.

Further, its main raw materials are ilmenite powder, aluminum powder and graphite powder, and the ratio satisfies the following formula:

FeTiO ₃ +xAl+(4-3x/2)C+yFe+(x/2)N ₂ →Ti(C,N)+(x/2)Al ₂ O ₃ +(y+1)Fe+CO, where, (0<x<2.7, 0≤y≤2);

The preparation method of the alumina-based ceramic composite material of the present invention is characterized in that it comprises the following steps:

The first step, the raw material ilmenite powder, aluminum powder and graphite powder are mixed with ball milling medium, surface active agent (bonding agent) and ball milled evenly, dry;

In the second step, the mixed powder treated in the first step is put into a hot-press furnace, and hot-pressed according to the shape of the mold under a nitrogen atmosphere.

The main parameters of the ball mill are: ball-to-material ratio 24:1～12:1; ball milling time 4～10h; rotating speed 300～500r/min;

Hot pressing process parameters: sintering temperature 1200~1500℃; sintering time: 15min~2h; pressure: 10~50MPa.

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

1. The main raw materials are the main components that are rich in resources and low in cost in my country, which can fully and effectively utilize resources, and open up a new way for the full and effective use of my country's rich resources.

2. In-situ synthesis, high interface bonding strength and excellent performance. Compared with similar metal-ceramic composite materials, the composite material of the present invention has quite good comprehensive mechanical properties and excellent performances such as wear resistance, corrosion resistance, oxidation resistance and thermal shock resistance. The Vickers hardness value of the cermet composite material of the invention reaches 17-19GPa, and the bending strength reaches 320-370MPa.

3. The process is simple. The invention utilizes the traditional hot-pressing sintering process, selects Panzhihua ilmenite (FeTiO ₃ ) which is rich in reserves in China as a raw material, adds aluminum powder and graphite powder, ball mills and mixes the materials, and then hot-pressing and sintering can directly prepare Al ₂ with excellent performance. O ₃ /Ti(C,N)/Fe cermet composite material. The equipment used in the preparation method is conventional general-purpose equipment, and the process is simple and easy to operate.

Description of drawings

Fig. 1 is the typical gold image microstructure photo of embodiment 1 metal-ceramic composite material of the present invention;

Fig. 2 is a typical scanning backscattered electron micrograph of the cermet composite material of the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific examples.

Example 1:

A kind of preparation technology of metal-ceramic composite material, its specific steps are as follows:

(1) Weigh 49.91 grams of ilmenite powder, 17.72 grams of aluminum powder and 3.94 grams of graphite according to the molar ratio of FeTiO3+2Al+C+0Fe on an electronic balance.

(2) Pour the mixed powder into a ball mill tank with a ball-to-material ratio of 12:1, and ball mill for 4 hours; then, put the ball-milled powder into a desiccator for drying.

(3) Put the mixture into a hot-pressed graphite mold, put it into a hot-pressed furnace, and pass nitrogen protection after vacuuming.

(4) Pre-press the powder once during the heating process, and then pressurize 21Mpa when it reaches 1400°C.

(5) Hold at 1400° C. for 30 minutes under pressure of 21 MPa, and finally cool to obtain metal-ceramic composite material A.

(6) The mechanical properties of the obtained composite material A are shown in Table 1, the chemical composition analysis is shown in Table 2, and the typical metal microstructure of the cermet composite material is shown in Figure 1 and Figure 2.

Example 2

A method for preparing a metal-ceramic composite material is prepared by ball milling technology and hot pressing technology, and the steps are as follows:

(1) The raw materials are ilmenite powder, aluminum powder, graphite and iron powder. Weigh 39.71 grams of ilmenite powder, 14.11 grams of aluminum powder, 3.13 grams of graphite and 14.63 grams of iron powder on an electronic balance according to the molar ratio of FeTiO3+2Al+C+1Fe.

(2) Pour the mixed powder into a ball mill tank with a ball-to-material ratio of 12:1, mill for 4 hours, and then put the ball-milled powder into a dryer for drying.

(3) Put the mixed material into a hot-pressed graphite mold, put it into a hot-pressed furnace, and ventilate nitrogen protection after vacuumizing;

(4) Pre-press the powder once during the heating process, and then pressurize 21MPa when it reaches 1200°C;

(5) Hold at 1200° C. under pressure of 21 MPa for 30 minutes, and finally cool to obtain metal-ceramic composite material B.

(6) The mechanical properties of the obtained composite material B are shown in Table 1, and the chemical composition analysis is shown in Table 2.

Table 1 Mechanical properties of metal-ceramic composites

(Vickers hardness value Hv20, flexural strength σav, fracture toughness Kic)

Material Hv20 σav(Mpa) Kic(Mpa*M(1/2)) A 1779 339 5.32 B 1826 260 5.57

Table 2 Composition of cermet composites

Material Al ₂ O ₃ Ti(C,N) Fe A 60.05 28.59 10.80 B 62.35 25.77 11.17

The cermet composite material of the present invention belongs to Ti(C, N), which is a continuous solid solution Ti(C _1-x , N _x ) formed by TiC and TiN. The properties of Ti(C _1-x , N _x ) vary with the change of x. TiC has higher hardness, while TiN has better toughness. Generally speaking, as the x value increases, the hardness of the material decreases and the toughness increases. Ti(C,N) cermets not only have high hardness, wear resistance, red hardness, excellent chemical stability, and extremely low friction coefficient between metals, but also have certain toughness and strength. Compared with the usual cemented carbide, it has obvious advantages in the following aspects: higher cutting speed; better surface properties of the processed workpiece; higher wear resistance. Ti(C,N) cermet has good performance. Compared with WC-based cemented carbide, it shows higher red hardness, similar strength, lower corrosion, thermal conductivity and friction coefficient in processing, and has Higher life or higher cutting speed can be used under the same life, and the workpiece has better surface finish. Therefore, Ti(C,N) cermets can successfully replace WC-based cemented carbide in many processing occasions, filling the gap between WC-based hard Ti(C,N) alloys and ceramics.

Titanium carbonitride is a non-oxide ceramic material with excellent performance and wide application. It has the advantages of both TiC and TiN. It has high melting point, high hardness, wear resistance, oxidation resistance, corrosion resistance and other characteristics, and has good thermal conductivity. It has a wide range of applications in many fields such as machinery, chemical industry, automobile manufacturing and aerospace.

The present invention combines the resource characteristics of our country, selects ilmenite (FeTiO3) produced in Panzhihua, which is rich in reserves in my country and contains two main elements of Fe and Ti, as a raw material (~1000 yuan/ton), and prepares a new type of Al2O3 by hot pressing process /Ti(C,N)/Fe cermet. Due to the low cost of raw materials, the composite material fully utilizes two main elements in ilmenite, the process is simple, the performance is excellent, and the composite material has great application value and broad market prospect. Therefore, the present invention has very important significance for promoting the effective utilization of ilmenite resources in my country and accelerating the development of cermets and metal matrix composite materials in my country.

Claims (1)

1. Alumina-based ceramic composite material is characterized in that: Al ₂ O ₃ ceramics are matrix, Ti(C, N) ceramic hard particles and Fe metal are as cermet composite material of dispersed phase; material main component mass percentage The content is: Al ₂ O ₃ : 50-70%; Ti(C, N): 20-30%; Fe: 5-20%; the rest are unavoidable Mn, Si, Ca impurities; The main raw materials of alumina-based ceramic composite materials are ilmenite powder, aluminum powder and graphite powder, and the ratio satisfies the following formula: FeTiO ₃ +xAl+(4-3x/2)C+yFe+(x/2)N ₂ →Ti(C,N)+(x/2)Al ₂ O ₃ +(y+1)Fe+CO, where, (0<x<2.7, 0≤y≤2); Prepared according to the following method, specifically comprising the following steps: In the first step, the raw material ilmenite powder, aluminum powder, graphite powder and ball milling medium are mixed and ball milled evenly, and dried; In the second step, the mixed powder treated in the first step is added into a hot-press furnace, and hot-pressed according to the shape of the mold under a nitrogen atmosphere; The main parameters of the ball mill are: ball-to-material ratio 24:1～12:1; ball milling time 4～10h; rotating speed 300～500r/min; Hot pressing process parameters: sintering temperature 1200~1500℃; sintering time: 15min~2h; pressure: 10~50MPa.