997 Alumina Ceramics C799 Thermocouple Protection Tube Closed One End and Open Both End
Alumina ceramic-protection tubes are considered to have better mechanical strength and chemical resistance. With excellent gas tight, they can be primary as protection tubes for Noble Metal (Platinum based) thermocouples.
Chemical Composition and Physical Properties
95 Series |
99 Series |
997 Series |
Steatite |
Zr₂O Y-PSZ |
Al₂O₂+Zr₂O |
|
Al₂O₃(%) |
≥95 |
≥99 |
≥99.7 |
|||
SiO₂(%) |
≤2.3 |
＜0.2 |
＜0.04 |
＜0.2 |
＜0.04 |
|
Fe₂O3(%) |
＜0.1 |
＜0.1 |
＜0.05 |
＜0.1 |
＜0.05 |
|
Alkaline Substances(%) |
＜0.1 |
＜0.1 |
＜0.08 |
＜0.1 |
＜0.08 |
|
Density(g/cm³) |
3.7 |
3.87 |
3.89 |
2.7 |
3.87 |
3.89 |
Hardness(Mohs) |
8.8 |
9 |
9 |
9 |
9 |
|
Flexural strength(Mpa) |
300 |
340 |
390 |
150 |
1000 |
600 |
Compressive strength(Mpa） |
3400 |
3600 |
3900 |
900 |
3000 |
3600 |
Modulus of elasticity(Gpa) |
350 |
380 |
390 |
120 |
205 |
350 |
Impact resistance(Mpa m1/2) |
4.0 |
5.0 |
5.2 |
8 |
7.5 |
|
Webull modulus(m) |
10 |
10 |
12 |
22 |
18 |
|
Vickers hardness(HV0.5) |
1800 |
1900 |
2000 |
1300 |
1600 |
|
Thermal expansion coefficient(10-6k -1) |
5.0-8.3 |
5.4-8.3 |
5.5-8.4 |
6.0-9.0 |
10 |
6.0-8.6 |
Thermal conductivity(W.mK） |
24 |
27 |
28 |
2.0-2.5 |
＜2 |
18 |
Thermal shock resistance（T℃） |
250 |
270 |
280 |
100 |
270 |
320 |
Volume resistivity at 20℃（Ωcm） |
＞1014 |
＞1014 |
＞1015 |
＞1013 |
＞1010 |
＞1013 |
Dielectric strength(kv/mm) |
20 |
25 |
30 |
20 |
||
Operating temperature in short time(℃) |
1650 |
1800 |
1850 |
1450 |
||
Operating temperature in long time(℃) |
1530 |
1650 |
1700 |
1250 |
||
color |
pink,white |
white,ivory |
ivory |
white |
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