CN1189475A - Process for mfg. non-lumps submicron alpha-Al2O3 powder and microlitic corundum ball - Google Patents

Abstract

A low-cst process for preparing non-aggregative submicron alpha-Al2O3 powder and micro-crystal corundum-ceramic balls includes preparing non-aggregative submicron alpha-Al2O3 powder with raw materials from market, proportional mixing the powder (85-97 Wt.%) with flux powder (3-15), ball grinding for 3-5 hr, spray drying, granulating, press shaping, cintering at 1400-1580 deg.C and keeping the temp for 1-3 hr. Its advantages are quick sintering and excellent performance of micro-crystal corundum-ceramic ball.

Description

The no reunion submicron alpha-Al of low-cost manufacturing 2O 3The method of powder and microcrystal fused alumina porcelain ball

The invention belongs to powder preparing and Al ₂O ₃The pottery preparation.

Alumina-ceramic because of its good electric property, physical strength height, advantage such as hardness is big, thermal expansivity is little, wear-resisting and thermal shock resistance is good, make it become a kind of most widely used pottery.Yet the sintering temperature of corundum porcelain is up to 1600～1700 ℃, and investment is big, energy consumption is high, adds the contradiction between its price and the performance, has limited its widespread use.

In order to address these problems, Chinese scholars had all been carried out number of research projects in recent years.The Japan scholar proposes to make 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; Norton Co adopts sol-gel method to prepare so-called SG material, produces microcrystal fused alumina, and its cost is higher than 6～7 times of traditional methods.Domestic scholars is also being made number of research projects aspect the sintering temperature that reduces alumina-ceramic.But all fundamentally do not solve the price of alumina-ceramic and the contradiction between the performance, the product of using as textile industry and the mill ball in the ceramic glaze fine grinding etc., the use price is 4000～5000 yuans/ton a common raw material, its sintering temperature height, the performance of product particularly wear resisting property do not satisfy user's requirement.And use price is 80000～200000 yuans/ton high pure and ultra-fine raw material, though can reduce sintering temperature and obtain the product of excellent property, its price is that user institute is unacceptable, and external situation is also like this.

Contradiction between the cost/performance ratio that the objective of the invention is to exist at present alumina-ceramic, adopt marketable material, low cost is prepared no reunion submicron alumina powder, select for use the technological process of optimization to make the microcrystal fused alumina porcelain of excellent performance, thereby realize the low-cost industrial preparation of high-performance ceramic.

Below in conjunction with Fig. 1 content of the present invention is specifically described.

Fig. 1. the no reunion submicron alpha-Al of low-cost manufacturing ₂O ₃The process flow sheet of powder and microcrystal fused alumina porcelain ball

1. there is not reunion submicron alpha-Al ₂O ₃The preparation of powder

With commercially available α-Al ₂O ₃α-Al that powder or modification bayer's process are produced ₂O ₃Powder, add the dispersion agent (as one or more of efficient dispersion agent such as polyether base, poly-hydroxy, many carboxyls) of 0.5～1.5wt%, traditional method ball milling (material: ball: water=1: 2: 1,24 hours), control the pH value (being generally 6～7) of slip well, adjust that the back is spray-dried to make no reunion submicron alpha-Al ₂O ₃Powder, its particle diameter are 0.1～1 μ m, median size 0.5 μ m.These powder can be single dispersion, not have soft-agglomerated attitude in an amount of water or organic solvent, the visible down isolated particle of polarizing microscope, and it is motion or vibrational state.

2. the preparation of flux

The chemical composition range of flux is (wt%): CaO15～30%, MgO15～25%, Al ₂O ₃0～5%, SiO ₂45～70%.It is to be made into by raw mineral materialss such as natural quartz, diopside, rhombspar, Wingdales, and ball milling mixes 5～10 hours, and (material: ball: water=1: 2: 1), 1200～1400 ℃ of insulations 1～3 hour, ball milling was to the ground flux of crossing 300 mesh sieves then.

3. moulding

With the above-mentioned raw material powder that makes by Al ₂O ₃Powder 85～97wt%, ground flux 3～15wt% batching, ball milling 3～5 hours, spray-dried machine drying-granulating, axial pressure or cold isostatic compaction.

4. burn till

Above-mentioned base substrate was burnt till 1400～1580 ℃ of insulations in 1～3 hour.

Table 1 has been listed 95 porcelain of the present invention's preparation and the various salient featuress and the firing temperature of GB (GB-5593-85) 95 porcelain.

Table 2 has been listed the performance data of 90,95 corundum porcelain balls, commercially available 90,95 porcelain balls and the Japanese import porcelain ball of the present invention's preparation.

Fig. 2 is the grain-size of 90 alumina ceramics that make of the present invention.

Fig. 3 is the grain-size of 95 alumina ceramics that make of the present invention.

95 porcelain of table 1. the present invention preparation and GB 95 porcelain performances are relatively

	The present invention prepares 95 porcelain	GB A95 porcelain
			Volume density g/cm 3Bending strength MPa linear expansivity (* 10 -6/ ℃) 20～500 ℃ of 20～800 ℃ of dielectric loss 1MHz (* 10 -4) tangent value 10GHz (* 10 -4) specific inductivity 1MHz firing temperature ℃ Al 2O 3Content wt%	????＞3.70 ????377 ????7.12 ????7.01 ????2.3 ????5.4 ????3.12 ????1500 ????95	????＞3.60 ????280 ????6.2～7.5 ????6.5～8.0 ????≤4 ????≤?10 ????9～10 ????1650 ????95

The main performance index of the porcelain ball that table 2. the present invention makes

	The present invention's preparation		Commercially available		Japan's import
						????90	????95	????90	????95
	Alumina content wt% microhardness Hm ultimate compression strength MPa density g/cm 3Wear rate g/kgh water-intake rate % grain-size μ m	????88.75 ????＞1800 ????＞1500 ????＞3.50 ????＜0.16 ????0.23 ????1～6	????95 ??＞2000 ??＞2000 ??＞3.70 ??＜0.12 ????0.15 ????1～6	87～90 9.0 (hardness) 〉=1500 〉=3.45 0.8 2.39---						94～96 9.0 (hardness) 〉=2000 〉=3.60 0.7------	??—— ????1000 ??—— ????3.65 ??0.17 ??—— ????2.6

As can be seen from Table 1, every performance of 95 porcelain that the present invention makes reaches or is better than GB, and firing temperature is far below the temperature of stipulating in the GB, and the present invention burns till 95 alumina ceramics for 1500 ℃, the GB regulation then at 1650 ℃.

As can be seen from Table 2, every performance of the corundum porcelain ball that the present invention makes all is better than commercially available porcelain ball, particularly wear rate this represent the key index of abrading-ball to be much better than commercially available abrading-ball especially, even be better than Japanese import abrading-ball, 90 porcelain mill loss rate＜0.16g/kgh that the present invention makes, 95 porcelain mill loss rate＜0.12g/kgh, commercially available 90 porcelain mill loss rate≤0.8g/kgh, 95 porcelain mill loss rate≤0.7g/kgh, mouthful this import abrading-ball wear rate is 0.17g/kgh.

From Fig. 2, Fig. 3 as can be seen, with 90,95 porcelain that method of the present invention is prepared, all between 1～6 μ m, average grain size is a microlitic structure between 3～4 μ m to its grain-size.

Characteristics of the present invention are:

(1) makes no reunion submicron Al with commercially available low-cost raw material ₂O ₃Powder;

(2) produce ground flux with natural mineral with low cost;

(3) low temperature fast firing makes excellent property microcrystal fused alumina porcelain;

(4) to adopt cheap natural mineral and the commercial alumina have a large capacity and a wide range be raw material in the present invention, is particularly suitable for large-scale commercial production:

(5) realize the low cost manufacturing of high-performance ceramic, solved the contradiction between the price and performance during alumina-ceramic is produced.

Embodiment 1:

(1) no reunion submicron alpha-Al ₂O ₃The preparation of powder

With commercially available α-Al ₂O ₃α-Al that powder or modification bayer's process are produced ₂O ₃Powder adds compound many carboxyls high molecular polymer (PAA: NH of 1wt% ₄PAA=1: 1) dispersion agent, (material: ball: water=1: 2: 1) 24 hours, the pH value of regulating slip was between 6～7 to ball milling, and spraying drying makes no reunion submicron alpha-Al then ₂O ₃Powder.

(2) preparation of flux

(wt%) composed as follows of flux: diopside 89.4%, natural quartz 0.2%, rhombspar 10.4%.With above-mentioned raw materials earlier respectively ball milling cross mixing behind 200 mesh sieves, in the corundum crucible of packing into, 1200 ℃ of calcinings 1 hour, ball milling was to the ground flux of crossing 300 mesh sieves then.

(3) easy fired

Ceramic formula is (wt%): no reunion submicron alpha-Al ₂O ₃Powder 85%, ground flux 15%, ball milling (material: ball: water=1: 2: 1) 3 hours mixings, slip send the spray-drier drying-granulating, and cold isostatic compaction is sent into low temperature fast firing in the Si-Mo rod stove then, and 1400 ℃ of insulations promptly made the porcelain ball in 1 hour.Embodiment 2:

(1) no reunion submicron alpha-Al ₂O ₃Powder, preparation method thereof is identical with embodiment one;

(2) preparation method of flux is identical with embodiment one;

(3) easy fired

Ceramic formula is (wt%): no reunion submicron alpha-Al ₂O ₃Powder 90%, ground flux 10%.Manufacturing process is identical with embodiment one, and firing temperature is 1450 ℃, is incubated 1 hour and makes the porcelain ball.

(4) salient features of the porcelain ball of Huo Deing

Microhardness Hm:2081

Ultimate compression strength MPa:＞1500

Density g/cm ³: 3.52

Wear rate g/kgh:0.159

Water-intake rate %: 0.23

Grain-size μ m:1～6 embodiment 3:

(1) no reunion submicron alpha-Al ₂O ₃Powder, preparation method thereof is identical with embodiment one;

(2) preparation method of flux is identical with embodiment one;

(3) easy fired

Ceramic formula is (wt%): no reunion submicron alpha-Al ₂O ₃Powder 95%, ground flux 5%.Manufacturing process is identical with embodiment one, and firing temperature is 1500 ℃, is incubated 1 hour and makes the porcelain ball.

(4) salient features of the porcelain ball of Huo Deing

Microhardness Hm:2254

Ultimate compression strength MPa:＞2000

Density g/cm ³: 3.74

Wear rate g/kgh:0.113

Water-intake rate %:0.15

Grain-size μ m:1～6

Claims (1)

1. no reunion submicron alpha-Al ₂O ₃Powder 85～97wt%, ground flux 3～15wt% proportioning, ball milling 3～5 hours, spray-dried granulation, axial pressure or cold isostatic compaction, 1400～1580 ℃ of insulations were burnt till in 1～3 hour, and the low-cost method of making alumina-ceramic is characterized in that:

(1) no reunion submicron alpha-Al ₂O ₃The preparation of powder

With commercially available α-Al ₂O ₃α-Al that powder or modification bayer's process are produced ₂O ₃Powder, add the dispersion agent (as one or more of efficient dispersion agent such as polyether base, poly-hydroxy, many carboxyls) of 0.5～1.5wt%, traditional method ball milling (material: ball: water=1: 2: 1,24 hours), control the pH value (being generally 6～7) of slip well, adjust the back drying and make no reunion submicron alpha-Al ₂O ₃Powder, its particle diameter are 0.1～1 μ m, median size 0.5 μ m;

(2) preparation of flux

The chemical composition range of flux is (wt%): CaO15～30%, MgO15～25%, Al ₂O ₃0～5%, SiO ₂45～70%.It is to be made into by raw mineral materialss such as natural quartz, diopside, rhombspar, Wingdales, and ball milling mixes 5～10 hours, and (material: ball: water=1: 2: 1), 1200～1400 ℃ of insulations 1～3 hour, ball milling was to the ground flux of crossing 300 mesh sieves then.

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