Ruby Balls

Ruby Balls – High Hardness and Wear Resistance

REDHILL supplies ruby balls for parts that need high hardness and low wear. Synthetic ruby uses aluminum oxide with a small amount of chromium. This gives it its red color. As a result, engineers can see and handle tiny ruby balls more easily. In addition, ruby suits many measuring tools and optical parts.

Key Technical Facts

The values below give a general guide. However, temperature and crystal direction can affect some properties. Therefore, confirm the required material data when ordering.

• Structure: Single-crystal corundum.
• Composition: Aluminum oxide with chromium, Al₂O₃:Cr.
• Density: About 3.99 g/cm³.
• Mohs hardness: 9.
• Knoop hardness: About 1,800–2,200, depending on crystal direction.
• Stiffness (Young’s modulus): About 440 GPa, depending on crystal direction.
• Melting point: About 2,050°C.
• Thermal conductivity: About 40 W/(m·K) at 300 K.
• Expansion with heat: The value changes with crystal direction and temperature.
• Electrical resistivity: Typically above 10¹² Ω·cm near room temperature.
• Dielectric constant: About 8.6–10.6, depending on crystal direction and test conditions.

However, the melting point does not define the safe working temperature. In addition, agree on the chromium content and base material purity for the order.

Benefits of Ruby Balls

Ruby’s hard surface resists scratches and wear. As a result, the balls can hold their size and shape over long periods.

In addition, ruby resists many chemicals and acts as an electrical insulator. However, the fluid and working temperature must suit the material.

Ruby can also pass light in some wavelength ranges. However, chromium absorbs some light, so optical use depends on the wavelength.

Common Uses for Ruby Balls

• Measuring tools: For example, probes use ruby balls as hard contact tips.
• Flow control: In addition, designers use ruby balls in flow meters and some check valves.
• Optical systems: Engineers use ruby ball lenses in fiber links, scanners and sensors.
• Bearings: Ruby suits selected precision bearing designs in instruments.

Available Grades and Sizes

Choose the grade and size to match your design. For example, our range includes:

• Grades: G1, G2, G3, G5, G10 and up to G25.
• Sizes: Diameters from 0.16 mm to 10 mm. In addition, ask us about custom sizes.

Finally, send us your drawing, quantity and working conditions. We can then check the size, grade and finish for your project.