CN101148352A - Tungsten corundum ceramic material and low temperature sintering method - Google Patents

Abstract

The present invention discloses one kind of tungsten corundum ceramic material and its low temperature sintering process. The tungsten corundum ceramic material has ingredients comprising alumina powder 85-99.5 wt%, tungsten oxide 0.1-3.0 wt%, clay 0.1-14.5 wt%, feldspar 0.1-14.5 wt%, calcium carbonate 0.1-14.5 wt%, talcum 0.1-14.5 wt%. It is prepared through mixing the materials through ball milling for 3 hr and drying in the air at 100 deg.c for 24 hr; cold isostatic formation at 200-300 MPa for 3 min; sintering in a Si-Mo furnace at 1350-1550 deg.c for 0.5-3 hr and cooling in the furnace. The preparation process has obviously lowered sintering temperature, low power consumption and low cost and is suitable for industrial production. The tungsten corundum ceramic material has bending strength up to 350-600MPa.

Description

A kind of tungsten corundum ceramic material and low-temperature sintering method

Technical field

The invention belongs to the alumina ceramic material technical field, particularly a kind of corundum ceramic material and low-temperature sintering method thereof that adds Tungsten oxide 99.999.

Background technology

Alumina-ceramic claims the corundum porcelain again, has excellent mechanical property, electrical property, thermal characteristics, very high specular reflectance excluded, erosion resistance, abundant raw material is inexpensive and than MgO, SiC, Si ₃N ₄Pottery is the characteristic of easy-sintering more, it is the base mateiral that is used for making multiple high strength, performance ceramic component such as wear-resistant, high temperature resistant, and demand is huge, thereby concern extremely both domestic and external, in modern industry and modern science and technology field, obtain application more and more widely, be present most widely used a kind of special cermacis, Application Areas relates to every field such as metallurgy, chemical industry, electromechanics, boats and ships, aerospace, military affairs.In alumina-ceramic is produced, all exist same problem both at home and abroad, promptly can not make the high-performance alumina-ceramic with existing industrial production technology, low cost.The sintering temperature of alumina ceramics is up to 1600～1700 ℃, and investment is big, the energy consumption height, and bending strength generally only is 250-350MPa.Quality product is difficult to further improve, and has limited applying of it.The alumina-ceramic sintering temperature is higher, easily causes grain growth, causes mechanical properties decrease generally to adopt the way that adds the liquid phase substance acceleration of sintering.By the difference of the mode of action, additive is by the sintering of two kinds of form promotes oxidn aluminium.The first, form liquid phase between additive system itself or additive and the alumina substrate, this class additive such as SiO ₂And MgO, GaO, SrO, BaO etc., the existence of liquid phase has made things convenient for the rearrangement of alumina particle, simultaneously by melting-the PRECIPITATION MECHANISM acceleration of sintering.The second, form sosoloid with alumina substrate,, make rate of diffusion become big by increasing the lattice distortion of aluminum oxide, thus acceleration of sintering.Additive such as TiO ₂, Cr ₂O ₃, Fe ₂O ₃, MnO ₂, Y ₂O ₃Deng.But, when add-on more after a little while, sintering temperature is still higher; When add-on increased, though help sintering, descending by a relatively large margin appearred in final material mechanical performance.

In order to address these problems, Chinese scholars had all been carried out number of research projects in recent years.Both at home and abroad impressive progress has been obtained about the research level of alumina-ceramic in the laboratory, and Japanese scientist develops bending strength in the nineties and reaches＞alumina sample of 1000MPa.Proposition is made raw material with superfine alumina powder, can prepare the excellent dense base substrate at 1400 ℃ of sintering, but its superfine alumina powder complicated process of preparation, cost is very high.There is similar problem at present equally in China, though domestic scholars is also being done number of research projects aspect the sintering temperature of alumina raw material preparation and reduction alumina-ceramic, all fundamentally do not solve the price of alumina-ceramic and the contradiction between the performance, the researchist of China also obtains bending strength 300～500MPa under laboratory condition, even＞alumina sample of 1000MPa, the raw material that adopts is that superfine nano aluminum oxide powder and nanometer silicon carbide compound material add spark plasma sintering or HIP sintering, its bending strength is greatly improved, but do not have industrial value, industrial production can't be promoted.

Summary of the invention

The objective of the invention is is exactly to adopt industrial raw material, by adding Tungsten oxide 99.999, utilize the atmospheric low-temperature sintering technology to prepare the high-strength alumina pottery of the big 300～600MPa of bending strength, can solve above-mentioned sintering temperature too high, adopt ultrafine powder or excessive, the problem that product cost is high with ionic discharge sintering or energy consumption that HIP sintering produced.

The raw material weight percent content is in the tungsten corundum ceramic material that the present invention relates to: aluminum oxide powder 85～99.5%, Tungsten oxide 99.999 0.1～3.0%, clay 0.1～14.5%, feldspar 0.1～14.5%, lime carbonate 0.1～14.5%, talcum 0.1～14.5%.

Concrete steps are:

(1) in aluminum oxide powder, add Tungsten oxide 99.999, with clay, feldspar, lime carbonate, talcum as sintering aid;

(2) mixing of above-mentioned raw materials ball milling was dried 24 hours in 100 ℃ in air after 3 hours;

(3) 3 minutes cold isostatic compactions of pressurize under 200～300MPa;

(4) 0.5～3 hour sintering of 1350～1550 ℃ of insulations in silicon molybdenum stove, furnace cooling, can obtain bending strength is that 300～600MPa sintered compact is a tungsten corundum ceramic material.

The present invention adopts general industry equipment, and technology is simple, helps the corundum ceramic suitability for industrialized production; Not only significantly reduce the sintering temperature of alumina-ceramic, bending strength can reach 350～600Mpa simultaneously; Can significantly reduce high temperature energy consumption and product cost in the high alumina ceramic production, obtain the high-strength alumina pottery simultaneously.

Description of drawings

Fig. 1 is a process flow sheet of the present invention.

Embodiment

Embodiment 1:

(1) raw material weight per-cent is: α-Al ₂O ₃Powder 90%, Tungsten oxide 99.999 1%, feldspar 3%, lime carbonate 2%, clay 3% and talcum 1%, batching according to the above ratio;

(2) mixing of above-mentioned raw materials ball milling was dried 24 hours in 100 ℃ in air after 3 hours;

(3) adopt cold isostatic compaction, pressurize is 3 minutes under 200MPa;

(4) in silicon molybdenum stove under 1430 ℃ of normal pressures sintering, be incubated 2 hours.

The bending strength of obtained product is 450MPa.

Embodiment 2:

(1) raw material weight per-cent is: α-Al ₂O ₃Powder 95%, Tungsten oxide 99.999 2%, feldspar 0.5%, lime carbonate 1%, clay 1% and talcum 0.5%, batching according to the above ratio;

(2) mixing of above-mentioned raw materials ball milling was dried 24 hours in 100 ℃ in air after 3 hours;

(3) adopt cold isostatic compaction, pressurize is 3 minutes under 300MPa;

(4) in silicon molybdenum stove under 1520 ℃ of normal pressures sintering, be incubated 2 hours.

The bending strength of obtained product is 550MPa.

Claims (2)

1. a tungsten corundum ceramic material is characterized in that the raw material weight percent content is in the tungsten corundum ceramic material: aluminum oxide powder 85～99.5%, Tungsten oxide 99.999 0.1～3.0%, clay 0.1～14.5%, feldspar 0.1～14.5%, lime carbonate 0.1～14.5%, talcum 0.1～14.5%.

2. the low-temperature sintering method of the described tungsten corundum ceramic material of claim 1 is characterized in that concrete steps are:

(1) in aluminum oxide powder, add Tungsten oxide 99.999, with clay, feldspar, lime carbonate, talcum as sintering aid;

(2) mixing of above-mentioned raw materials ball milling was dried 24 hours in 100 ℃ in air after 3 hours;

(3) adopt cold isostatic compaction, pressurize is 3 minutes under 200～300MPa pressure;

(4) 0.5～3 hour sintering of 1350～1550 ℃ of insulations in silicon molybdenum stove, furnace cooling, can obtain bending strength is that 300～600MPa sintered compact is a tungsten corundum ceramic material.

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