1.Alumina ceramic is the most mature of the engineering ceramics, offering excellent electrical insulat Good insulator/alumina tube furnace for metallurgical melting/innovacera ion properties together with high hardness and good wear resistance but relatively low strength and fracture toughness.Alumina has a high melting point, high hardness,although mechanical strength is reduced at temperatures above 1000 C. Due to the relatively large coefficient of thermal expansion, thermal shock resistance is reduced.Good chemical stability of alumina leads to high corrosion resistance. It is insoluble in water and only slightly soluble in strong acid and alkaline solutions. Testing has shown that the low chemical solubility of alumina ceramics components makes them highly resistant to chemical corrosion. This is what makes high purity alumina the material of choice for components in a wide range of industrial applications.
2. Alumina ceramics features:
1).Excellent electrical insulation
2).High hardness
3).Relatively low strength and fracture toughness
4).Resistance to wear and corrosive
5).Excellent thermal stability
6).Resistance to high temperatures
7).High electrical resistivity
8).Good chemical stability and resistance
9).High corrosion resistance
10).Excellent thermal shock resistance
11).High thermal insulation
12).A Low Young’s modulus
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Alumina Ceramic Property
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Property
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Unit
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92% Alumina Ceramic
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95% Alumina Ceramic
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99% Alumina Ceramic
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Density
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g/cm3
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≥3.63
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≥3.68
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≥3.83
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Water absorption
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%
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O
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O
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O
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Sintering temperature
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°C
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1500-1700
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1600-1800
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1700-1800
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Hardness
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HV
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≥1400
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≥1500
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≥1650
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Flexural strength
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Kgf/cm2
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3000
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3000
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3000
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Compressive strength
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Kgf/cm2
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24000
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25000
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26000
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Fracture toughness
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Map.m3/2
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3~4
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3~4
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4~5
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Maximum temperature
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°C
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1600
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1700
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1800
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Coefficient of thermal expansion
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/°C
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8*10-6
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8*10-6
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8*10-6
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Heat shock
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T(°C)
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220
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220
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220
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Thermal conductivity
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W/m.k(25-300°C)
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25 14
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25 14
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25 14
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20°C
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>1012
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>1012
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>1012
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Advantage:
1.Purity:92%, 95%, 96%, 99%, 99.7%2.Good mechanical strength
3.Excellent electrical insulation
4.High-frequency loss
5.Good thermal conductivity
6.Heat, wear and corrosion resistance.
