Ceramic Alumina 96% vs. Steel

Compare Ceramic Alumina 96% vs. Steel strength, stiffness, weight and thermal properties.

Ceramic Alumina 96%Sintered ceramic (pressed and fired)

Mechanical	Ceramic Alumina 96%	Steel
Yield strength	none (brittle)	385MPa1
Ultimate tensile strength	221MPa2	505MPa12.29x stronger
Compressive strength	2,068MPa2	not sourced
Flexural strength	flexural strength358MPa2	not sourced
Elongation at break	none (brittle)	24.2%1
Young's modulus (stiffness)	303GPa2	design value200GPa3
Density	3,720kg/m³22.11x lighter	7,850kg/m³4
Strength to weight	59.4kN·m/kg21% higher	49kN·m/kg
Stiffness to weight	81.5MN·m/kg3.2x higher	25.5MN·m/kg
Poisson's ratio	0.212	design value0.33
Shear modulus	125GPa1.63x stiffer in shear	76.9GPa
Bulk modulus	174GPa4% higher	167GPa
Speed of sound	9,025m/s1.79x faster	5,048m/s

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Ceramic Alumina 96%	Steel
Thermal conductivity	24.7W/m·K2	48W/m·K41.94x more heat through a fin
Thermal expansion	mean8.2µm/m·K246% less	12µm/m·K4
100 mm part over a 50 °C swing	41µm growth46% less	60µm growth
Specific heat	880J/kg·K2	base material460–480J/kg·K5
Heats up and cools (diffusivity)	7.55mm²/s	13mm²/s1.72x faster
Thermal shock resistance	1,736W/m	5,390W/m3.11x more resistant

Thermal conductivity against densityHigher and further left: spreads more heat for its weight

Thermal expansion against thermal conductivityLower and further right: warps less when heated

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Sources5 documents: American Institute of Steel Construction, CoorsTek, bauforumstahl (ArcelorMittal), Ovako

Ceramic Alumina 96%: CoorsTek AD-96, nominal 96% Al2O3 sintered alumina, typical values; CoorsTek "Ceramic Seal Material Properties" (© 2018, 01899 F). AD-96 is the general 96% grade, not the ADS-96R substrate grade.
Steel: Generic structural steel, cited as ASTM A992 (the current US structural grade): ASTM A992 W-shapes; Fy/Fu specified minimums from AISC publications (AISC 360-16 Commentary; Modern Steel Construction); elastic constants AISC 360; physical constants from the bauforumstahl structural-steel EPD, which names A992 among covered product standards.

1
Updating Standard Shape Material Properties Database for Design and ReliabilityAmerican Institute of Steel Constructionarchived copySteel · Yield strength: typical: mean of 20,295 A992 flange mill-test coupons (1998 SSPC survey), as reported by AISCSteel · Ultimate tensile strength: typical: mean of 20,295 A992 flange mill-test coupons (1998 SSPC survey)Steel · Elongation at break: typical: mean of 24,847 A992 mill-test elongations, web and flange (1998 SSPC mill data), as reported by AISC
2
Ceramic Seal Material Properties (01899 F)CoorsTekarchived copyCeramic Alumina 96% · Ultimate tensile strength: typical tensile strength, 25 °C (ACMA Test #4)Ceramic Alumina 96% · Compressive strength: typical, 20 °C (ASTM-C773)Ceramic Alumina 96% · Flexural strength: flexural strength (MOR), 20 °C (ASTM-F417)Ceramic Alumina 96% · Young's modulus (stiffness): typical, 20 °C (ASTM-C848)Ceramic Alumina 96% · Density: typical (ASTM-C20)Ceramic Alumina 96% · Poisson's ratio: typical, 20 °C (ASTM-C848)Ceramic Alumina 96% · Thermal conductivity: typical, 20 °C (ASTM-C408)Ceramic Alumina 96% · Thermal expansion: mean, 25-1000 °C (ASTM-C372)Ceramic Alumina 96% · Specific heat: typical, 100 °C (ASTM-E1269)
3
ANSI/AISC 360-16 Specification for Structural Steel Buildings, with CommentaryAmerican Institute of Steel Constructionarchived copySteel · Young's modulus (stiffness): design value (AISC 360-16)Steel · Poisson's ratio: design value (AISC 360-16 Commentary)
4
Environmental Product Declaration: Structural Steel Sections and Merchant Bars (2023)bauforumstahl (ArcelorMittal)archived copySteel · Density: nominal (constructional data)Steel · Thermal conductivity: nominal at 20 °CSteel · Thermal expansion: nominal (constructional data, no temperature range stated)
5
S275JR Steel GradeOvakoSteel · Specific heat: base material: EN S275JR unalloyed structural steel (the EN counterpart of A36), typical, 50/100 °C

Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Mechanical

Is Ceramic Alumina 96% stronger than Steel?

Steel is stronger: its yield strength is 385 MPa against tensile strength 221 MPa for Ceramic Alumina 96% (1.74x).

Which is lighter, Ceramic Alumina 96% or Steel?

Ceramic Alumina 96% is lighter: 3,720 kg/m³ against 7,850 kg/m³ for Steel.

Which is stiffer, Ceramic Alumina 96% or Steel?

Ceramic Alumina 96% is stiffer: Young's modulus 303 GPa against 200 GPa for Steel, so the same part in Ceramic Alumina 96% deflects less under the same load.

Which is lighter for the same job, Ceramic Alumina 96% or Steel?

For the same stiffness or strength: Ceramic Alumina 96% is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.

Part that must be	Ceramic Alumina 96%	Steel
Stiff rod or tie (tension)	lighter	3.2x heavier
Stiff beam (bending)	lighter	2.6x heavier
Stiff panel or plate	lighter	2.42x heavier
Strong rod or tie	lighter	21% heavier
Strong beam	lighter	46% heavier
Strong panel or plate	lighter	1.6x heavier

For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).

Thermal

Which conducts heat better, Ceramic Alumina 96% or Steel?

Steel conducts heat better: 48 W/m·K against 24.7 W/m·K for Ceramic Alumina 96%.

Which expands less with temperature?

Ceramic Alumina 96% expands less: 8.2 µm/m·K against 12 µm/m·K for Steel.