NIST Structural Ceramics Database (SCD) Database

NIST Standard Reference Database 30

Last Update to Data Content: 2002

DOI: http://dx.doi.org/10.18434/T4F30D


SCD Citation Number: Z00635

Bibliographic Information

Reference:
"Microhardness of a Fine-Grain-Size Al2O3," S.D. Skrovanek and R.C. Bradt, Journal of the American Ceramic Society, Vol. 62 [3], pp. 215-216 (1979), published by American Ceramic Society.
Language: English

General Materials Processing Notes

"Commercial α-Al2O3 with 0.5% MgO, hot pressed at 1600 °C, was used. ... Specimens (about 1 cm cubes) were annealed at 1200 °C to 1800 °C, yielding a range of grain sizes which were measured by the linear intercept technique on fracture surfaces observed in an SEM."

Measurement Methods

Knoop indentation
"Microhardness was measured on diamond-polished surfaces, using a 400 g load on a Knoop indenter with a commercial microhardness tester. The load was applied automatically over a 15 s interval and allowed to remain on the sample for an additional 30 s. The 50 µm indentation traversed several grains and grain boundaries. Indentations were repeated until 20 distinct, symmetrical, uncracked indentations were achieved. Averages were calculated..."

Index of Materials and Properties

Material Number 1: Al2O3

Material Specification and Properties for Al2O3

Material number 1 of 1
in SCD Citation Number: Z00635
Chemical Class: Oxide
Chemical Family: Al-O
Formula: Al2O3
Informal Name: alumina
Structure Type: Polycrystalline
Manufacturer: In-House
Process: Hot Pressing

Al2O3

Material number 1 of 1
in SCD Citation Number: Z00635
Hardness
Annealing
Temperature
( °C )
Grain
Size
( µm )
Hardness
 
( GPa )
--- 1.9 19.7
1200 2.3 19.6
1200 2.1 19.5
1200 2.0 19.4
1300 2.3 19.4
1300 2.0 19.5
1300 1.9 19.5
1400 2.3 19.5
1400 2.1 19.4
1400 2.0 18.9
1500 2.3 19.4
1500 2.1 19.4
1600 5.6 18.1
1600 4.9 18.4
1600 4.5 18.6
1600 4.3 19.0
1600 4.0 19.1
1700 7.3 17.6
1700 6.5 17.9
1700 5.4 18.6
1750 6.1 17.5
1750 5.1 17.7
1800 8.4 16.2
1800 5.5 16.5

Measurement Method: Knoop indentation
Evaluation Status: Evaluated by acceptance criteria
Cautions:
Data were digitized from Fig. 2 of the reference.