Ruby - Properties of Ruby - Supplier Data from Goodfellow

Chemical Formula

The chemical formula of Ruby is Al2O3/Cr2O3/Si2O3

Background

Ruby exhibits identical properties to those of Sapphire. Small amounts of impurities give Ruby a red colouration.

Key Properties

The key properties of Ruby are tabulated below.

Table 1. Key properties

Chemical Resistance
Acids – concentrated Good
Acids – dilute Good
Alkalis Good
Halogens Good
Metals Good
Electrical Properties
Dielectric constant 7.5 - 11.5
Dielectric strength ( kV.mm-1 ) 15 - 50
Volume resistivity @ 25 °C ( Ohm.cm ) 1014
Mechanical Properties
Compressive strength ( MPa ) 2100
Hardness - Knoop ( kgf.mm-2 ) 2000
Hardness - Vickers ( kgf.mm-2 ) 2500 - 3000
Tensile modulus ( GPa ) 350 - 390
Tensile strength ( MPa ) 250 - 400
Physical Properties
Apparent porosity ( % ) 0
Density ( g.cm-3 ) 3.98
Useful optical transmission range 150 - 5500 nm
Water absorption - saturation ( % ) 0
Thermal Properties
Coefficient of thermal expansion, 20-1000 °C ( x10-6 K-1 ) 5.8
Melting point (°C ) 2050
Specific heat @ 25 °C ( J.K-1.kg-1 ) 750
Thermal conductivity @ 20 °C ( W.m-1.K-1 ) 35 - 40
Upper continuous use temperature ( °C ) 1800 - 1950

 

About Goodfellow

Goodfellow supplies metals, ceramics and other materials to meet the research, development and specialist production requirements of science and industry worldwide.

The Goodfellow group consists of four companies. The main administration, research laboratories and workshops are located at the Company's headquarters in Cambridge, England. The subsidiary offices in America, France and Germany provide an additional service.

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