CN1061330C - Wear resistant sintered zirconium boule composite and manufacture thereof - Google Patents

Abstract

The present invention relates to a wear resistant sintered zirconium corundum composite material and producing method thereof. In the producing method of the wear resistant sintered zirconium corundum composite material, Al2O3 and ZrSiO4 are used as main raw materials, a certain additive agent is added, the excess proportioning process and the high-temperature reaction in-situ process of Al2O3 and ZrSiO4 are carried out, main crystal phase corundum as a reaction product is toughened by ZrO4 as a decomposed product of ZrSiO4, and therefore, the high wear resistant zirconium corundum composite material can be obtained. The wear resistant sintered zirconium corundum composite material and producing method thereof have the characteristics that the products of zirconium oxide and mullite have large strength and high density under normal temperature; the product of the zirconium oxide is uniformly diffused in a generated crystal phase; the adopted sintered method has the advantages of simple technological process and low product cost, the sintering temperature of the wear resistant sintered zirconium corundum composite material is 1580 DEG C, compared with the sintering temperature of 1650 DEG C to 1680 DEG C of a 95% of aluminum oxide wear resistant material with high aluminium, the sintering temperature of the wear resistant sintered zirconium corundum composite material is lowered by 70 to 100 DEG C, and compared with the wear resistance of the 95% of aluminum oxide material, the wear resistance of the wear resistant sintered zirconium corundum composite material is strengthened by about 25%.

Description

Wear-resistant sintered zirconia-corundum composite material and production method thereof

The invention relates to wear-resistant sintered Al₂O₃、ZrSiO₄Zirconium corundum composite material and its production method, it uses Al₂O₃、ZrSiO₄Is prepared from Al as main raw material, and additive₂O₃And ZrSiO₄Over-proportioning and high-temp in-situ reaction, using ZrSiO₄Decomposition product ZrO₄Toughening the reaction product-main crystal phase corundum to obtain the high wear-resistant zirconia-corundum composite material.

The grinding body is the main material for grinding ceramic slip. At present, the reserves of high-quality natural spherulites are gradually reduced and the exploitation is to be exhausted. The quality of ordinary natural pebbles has clearly failed to meet the demands of increasingly developed ceramic production. The price and quality of artificial marble have become the focus of attention. The high-alumina porcelain ball directly influences popularization and use due to reasons of overhigh price, poor wear resistance and the like. The development of a high wear-resistant and low-cost abrasive body is one of the problems that ceramic technologists strive to find at present.

The invention aims to provide wear-resistant sintered Al₂O₃、ZrSiO₄Zirconium corundum composite material and its production method, it uses Al₂O₃、ZrSiO₄The main raw material is added with certain additive and passes through Al₂O₃And ZrSiO₄Over-proportioning and high-temp in-situ reaction, using ZrSiO₄Decomposition product ZrO₄Toughening the reaction product, namely the main crystal phase steel, so as to obtain the high wear-resistant zirconia-corundum composite material.

The material and the production process thereof are characterized in that:

(1) the zirconium oxide and the mullite have high strength and high density at normal temperature;

(2) the zirconium oxide generated is uniformly dispersed in the generated crystalline phase;

(3) the adopted sintering method has simple process and low product cost, compared with the high-aluminum wear-resistant material, the sintering temperature of the product is 1580 ℃, which is reduced by 70-100 ℃ compared with the usual 95 percent alumina wear-resistant material 1650-1680 ℃, but the wear resistance of the product exceeds about 25 percent of the 95 percent alumina material.

The wear-resistant sintered Al is₂O₃、ZrSiO₄The zirconia corundum composite material (by weight) is prepared from：65～95％Al₂O₃And 5-35% of ZrSiO₄The additive is added in an amount of 1-6% of the total amount or 3-10% of the additive, and the additive is selected from 0-5% of TiO₂0 to 0.3 percent of CaO, 0 to 4 percent of MgO and 0 to 6 percent of active SiO₂The auxiliary agent is selected from 0-7% of ZrO₂And 0 to 4% of Y₂O₃。

The wear-resistant sintered Al is₂O₃、ZrSiO₄The production method of the corundum-zirconia composite material comprises the following steps:

(1) mixing the raw materials in proportion;

(2) carrying out wet or dry ultrafine grinding on the mixed raw materials, wherein the grinding particle size is less than 5 mu m;

(3) performing pressure spray granulation on the powder, wherein secondary granules are 40-80 meshes (equivalent to 420-171 mu m), and the water content is controlled to be 2-8%;

(4) semi-drying or dry-pressing the granulated powder, wherein the forming pressure is 40-150 Mpa, and the forming density is more than 2.2g/cm³；

(5) Carrying out manual or automatic blank finishing repair on the molded blank, wherein the drying temperature is 40-80 ℃, and the drying moisture of the blank is controlled to be less than 1%;

(6) and (3) placing the dried blank into a high-temperature pushed slab kiln or a high-temperature shuttle kiln for sintering, wherein the temperature rise speed is 150-200 ℃/h, the sintering temperature is 1550-1590 ℃, the heat preservation is carried out for 2-4 h at the highest temperature, and the cooling average speed is less than 300 ℃/h.

The main technical indexes of the product obtained by the invention are as follows:

the water absorption rate is less than 0.15 percent

Density>3.6g/cm³

Hardness (HRA)>80

Flexural strength>200MPa

The fracture toughness Kic is more than 8 MPa.m^1/2

The color is white or beige

α-Al₂O₃Is Al₂O₃One of the stable crystals is selected from the group consisting of,belongs to trigonal system, and has compact structure and density of 3.96-4.01 g/cm³The Mohs hardness is 9, the fired product has high strength and high hardness, the defects are poor plastic deformation capability and low wear resistance, and ZrSiO is utilized₄High temperature decomposition product ZrO₂Toughening the aluminum oxide ceramic is one of the main ways to improve the aluminum oxide ceramic.

The reaction principle is as follows:

the method is characterized in that:

1) the zirconia and the mullite have high strength and high density at normal temperature.

2) The adopted sintering method has simple process and low product cost.

Based on the principle, the invention finds Al through a large number of experiments₂O₃And ZrSiO₄The proper proportion between the components, thereby obtaining more ideal hardness and toughness,

based on the feasibility of the reaction, the method adopts the excess Al₂O₃On the one hand, excess of Al₂O₃The formation of a portion of the corundum crystalline phase ensures sufficient hardness of the product, while on the other hand an excess of Al₂O₃The influence of mullite puffing reaction on preventing density increase is also weakened.

The invention will now be further described with reference to specific embodiments, which are not intended to limit the invention in any way.

Example 1

1. Range of ingredients

The components: al (Al)₂O₃80％ ZrSiO₄17％ TiO₂0.4％

CaO 0.3% active SiO₂0.3 Mg 2％

2. Ultra-fine grinding

Placing the ingredients into a wet stirring mill, and performing ultrafine grinding to obtain powder with particle size less than 3 μm

3. Spray granulation

The ultrafine crushed material slurry was subjected to spray granulation, and the secondary particle size was 40 mesh (equivalent to 420 μm) and the moisture was 6%.

4. Press forming

And (3) performing ball molding with the diameter of 40mm on an isostatic press at the pressure of 150 MPa.

5. Fettling and drying

Removing burrs in the middle of the blank, polishing, drying at 55-65 deg.C with drying water less than 1%

6. Firing into

The grinding balls are put into a high-temperature shuttle kiln, the heating rate is 170 ℃/h, the cooling rate is 200 ℃/h, and the high-sintering temperature is 1580 ℃ multiplied by 2 h.

7. Examination of

Performing product inspection

The main technical indexes of the product obtained by the invention are as follows:

the water absorption rate is less than 0.10 percent

Density>3.7g/cm³

Hardness (HRA)>83

Flexural strength>200MPa

Fracture toughness KIC is greater than 9.5Mpa^1/2

The color is white

The composition of its crystalline phase is corundum 62%, zircon 13% and mullite 25%.

The relative and bulk densities and abrasion resistance were 94,3.60 and 0.154, respectively.

Wherein: 1. relative density = bulk density/theoretical density x 100% (same applies below)

2. Abrasion resistance = weight loss of abrasive body/initial weight of abrasive body × 100% (1 kg force applied to polishing equipment-grinder, grinding for 40 minutes, abrasive sand added with 149 μm, 200g of SiC added 4 times on average) (the same applies below)

Example 2

The same procedure as in example 1 above was followed, except that the following ingredients were used and the sintering was carried out at 1550 ℃ for 2 hours:

the components: al (Al)₂O₃65％ ZrSiO₄35 percent of additive MgO 2.5 percent and TiO₂0.5％,CaO 0.2％

The main technical indexes of the product obtained by the invention are as follows:

the water absorption rate is less than 0.15 percent

Density>3.63g/cm³

Hardness (HRA)>80

Flexural strength>200MPa

The fracture toughness Kic is more than 8.5 MPa.m^1/2

The color is beige

The composition of its crystal phase is corundum 34%, zircon 23% and mullite 43%.

The relative and bulk densities and abrasion resistance were 92,3.39 and 0.205, respectively.

Example 3

The procedure was as in example 1, except that the following ingredients were used and the sintering was carried out at 1590 ℃ for 2.5 hours:

the components: al (Al)₂O₃90％ ZrSiO₄The total amount of the 10 percent of the additive is 2.5percent

The main technical indexes of the product obtained by the invention are as follows:

the water absorption rate is less than 0.10 percent

Density>3.75g/cm³

Hardness (HRA)>85

Flexural strength>220MPa

The fracture toughness Kic is more than 8.0 MPa.m^1/2

The color is white

The crystal phase composition of the corundum-mullite brick comprises 81 percent of corundum, 6.5 percent of zircon and 12.5 percent of mullite.

The results of the above 3 examples show that the relative density, the bulk density and the wear resistance are regularly changed along with the change of the crystal phase composition, and the wear resistance and the density are in an increasing trend.

This indicates that the composition of the corundum crystal phase in excess will weaken mulliteAdverse factors of puffing, right amount of ZrO₂The volume fraction will serve as a toughening effect. Too high ZrO₂The content will also lead to coalescence of microcracks, reducing the toughening effect. An excess of corundum crystal phase, i.e. too little ZrO₂It will not have toughening effect.

Obtaining compact product pair Al by complete solid phase diffusion₂O₃And ZrSiO₄Ceramic materials are difficult. If appropriate additives are added to form a glassy phase and other liquid phases, a dense product can be obtained and the sintering temperature can be reduced due to the rearrangement and viscous flow of the particles in the liquid phase.

One of the typical results of a certain Al/Zr comparative experiment (in this case 65% for alumina and 35% for zirconium silicate) is given in the following table:

external dosage property 01% 3% 6% abrasion resistance 0.1810.1330.1420.143 relative density 82888990

The typical data statistics show that the density and the wear resistance of the corundum zirconium material can be obviously improved by a proper amount of the additive, and meanwhile, the density of the corundum zirconium material cannot be highly compact by means of adding the additive only.

The method has the advantages of reducing the powder granularity, increasing the solid-phase reaction area, being an important measure for promoting sintering and reducing the sintering temperature of the current special ceramics, being economical and economical, changing the product performance, being beneficial to generating fine and uniform crystals, and improving the densification speed and the wear resistance. The zirconia corundum material is mainly subjected to solid-phase reaction, and the powder granularity and activity are particularly important. Experiments show that the ultrafine grinding is favorable for promoting the density of the corundum-zirconia material to be improved, and the influence degree of the ultrafine grinding exceeds the use effect of the additive.

The following table shows the usage of the ultrafine grinding (in this case, 80% of alumina, 20% of zirconium silicate, and 3% of additive):

relative density of powder particle size%

88<5 μm

94<3 μm

96<2 μm

The zirconia-corundum material is mainly divided into two parts in the heat treatment process, and the densification process is carried out at 1370-1450 ℃. The mullite puffing reaction and sintering stage is at about 1550 ℃, the chemical reaction is the puffing reaction and sintering stage on one hand, the chemical reaction is the puffing process on the other hand, secondary air holes are easily generated, the end point sintering process on the other hand, the contradiction between the two results in that the end point sintering temperature is important, the reaction cannot be fully performed due to too low temperature, the primary air holes cannot be exhausted, the temperature is too high, crystals grow up, and the generation of the secondary air holes influences the densification degree of the mullite.

By combining the X-diffraction result and the electron microscope picture of the product, the invention can be seen that the zirconite is completely decomposed to generate the products of crystalline corundum, mullite and baddeleyite, the crystal structure takes round grains or cylindrical corundum as the main crystal phase, the baddeleyite and the mullite are embedded in the crystal structure in a pinning mode, and most of the baddeleyite and the mullite are in solid solution in a grain boundary. Baddeleyite is in the form of round particles or clusters with significant microcracks around the baddeleyite. Fracture analysis shows that ZrO₂And mullite has a pull-out effect, namely intergranular fracture, and the fracture mode effectively improves the strength and the wear resistance of the material.

According to the general grinding ball abrasion test method provided by the national building institute, the abrasion test is carried out on the corundum zirconium grinding ball obtained by the method, and the abrasion rate is 3.4%. (provided by national building institute, the best 95 percent of alumina in China currently has the wear rate of 3-4 percent)

The test conditions are as follows: 1L alumina pot

20 balls with diameter of 20

400ml of water

Running time 24h

The rotating speed is 140 turns

In addition, in the quick grinding process, the ball stones of different manufacturers are added, the comparison experiment is carried out, and the experimental results are shown in the following table

95% of alumina 2.12%

95% of alumina 1.78%

The zirconia corundum grinding body of the invention is 1.42 percent

Obviously, the above embodiments are only examples of the present invention, and do not limit the scope of the present invention, including wear liners, nozzles, textile wire loops, etc., and the thermal shock properties specific to the products of the present invention, and the applications of spark plugs, etc., on heat engines, can be produced according to the process provided by the present invention, and the application prospects are very broad.

Claims (2)

1. Wear-resistant sintered Al₂O₃、ZrSiO₄Zirconia-corundum composite material, characterized by consisting of (by weight): 65-95% Al₂O₃And 5-35% of ZrSiO₄The additive is added in an amount of 1-6% of the total amount or 3-10% of the additive, and the additive is selected from 0-5% of TiO₂0 to 0.3 percent of CaO, 0 to 4 percent of MgO and 0 to 6 percent of active SiO₂The auxiliary agent is selected from 0-7% of ZrO₂And 0 to 4% of Y₂O₃。

2. The wear-resistant sintered Al of claim 1₂O₃、ZrSiO₄The production method of the corundum-zirconia composite material comprises the following steps:

(1) mixing the raw materials in proportion;

(2) carrying out wet or dry ultrafine grinding on the mixed raw materials, wherein the grinding particle size is less than 5 mu m;

(3) carrying out pressure spray granulation on the powder, wherein the secondary particles are 420-171 mu m, and the water content is controlled to be 2-8%;

(4) semi-drying or dry-pressing the granulated powder, wherein the forming pressure is 40-150 Mpa, and the forming density is more than 2.2g/cm³；

(5) Carrying out manual or automatic blank finishing repair on the molded blank, wherein the drying temperature is 40-80 ℃, and the drying moisture of the blank is controlled to be less than 1%;

(6) and (3) placing the dried blank into a high-temperature pushed slab kiln or a high-temperature shuttle kiln for sintering, wherein the temperature rise speed is 150-200 ℃/h, the sintering temperature is 1550-1590 ℃, the heat preservation is carried out for 2-4 h at the highest temperature, and the cooling average speed is less than 300 ℃/h.