Ceramic balls are mainly used in harsh environments. Their main advantages on steel is that they have a density 40% lower than steel, have 29% lower thermal expansion and are 150% harder. In certain high-speed applications their life is extended hundred times. It is also used as grinding media. There are three main types.
| Alumina Oxide - ceramic balls |
| Composition |
99.5% Al2O3 / 0.5% other |
| Hardness |
1700 Hv |
| Ultimate Tensile Strength |
31,000 psi |
| Ultimate Compressive Strength |
>300,000 psi |
| Modulus of Elasticity |
53 x106 psi |
| Maximum Working Temperature |
1400oC |
| Corrosion Resistance |
Inert except for hydruofluric, hydrochloric acid and
hot concentrated sulphuric acids. Inert to most substances, not recommended for environments of strong alkaline solutions |
| Zirconia Oxide - ceramic balls |
| Composition |
97% ZrO2 / 3% MgO |
| Hardness |
80 - 84 Ra |
| Ultimate Tensile Strength |
60,000 psi |
| Ultimate Compressive Strength |
285,000 psi |
| Modulus of Elasticity |
29 x106 psi |
| Maximum Working Temperature |
2400oC |
| Corrosion Resistance |
Inert to most substances, not recommended for environments of hydrochloric or strong alkaline solutions |
| Silicon Nitride - ceramic balls |
| Composition |
87% Si3N4 / 13% other |
| Hardness |
1400 - 1700 Hv |
| Ultimate Tensile Strength |
/ |
| Ultimate Compressive Strength |
>570,000 psi |
| Modulus of Elasticity |
44-45 x106 psi |
| Maximum Working Temperature |
1000oC |
| Corrosion Resistance |
Inert to most substances. |
