top                                                           Ceramics from  KERANOVA  AB

Remark
This compilation is based upon a large selection of product brochures, data sheets, professional literature, etc. The information in the tables is given as mean value ± standard deviation whenever this has been possible, based on the available material. This information undergoes continuous revision and should be used for guidance only.

Note 1:
Density values at upper/lower limits usually offer similar positions for other table data.

Note 2:
Closed porosity is most often between 0 or 2%, sometimes even 5% by volume. Normally, only hot-pressed materials are fully dense.

Note 3:
Hardness values show a large spread between different manufacturers. The data are probably correct, even though the large spread makes comparisons difficult between different materials. Knoop 100g values are approx. 20-40% higher than the 1000g value; Vickers 50g values are approx. 5-15% higher than when using a 500g test load. Temperature: 20°C.

Note 4:
Available data often do not indicate the load method adopted. A 3-point load may result in 30% higher values than a 4-point load, but also a wider spread in the strength data (which is seen as a lower Weibull modulus). For load tests with a widely distributed load (e.g. in case of bending), the lower values should act as guidance, while for local loads, the higher strength values could be used. 

Note 5:
The Weibull modulus is a statistical measurement of the properties spread, often used with bend strength (MOR) values. A high value indicates uniform measurement data and, as such, better reliability for strength calculations. The modulus is primarily affected by the material properties, such as a uniform microstructure, etc.

Note 6:
Poisson’s ratio gives the relationship between the modulus of elasticity and that of shearing (E and G, respectively). The ratio equals 0.5 for ideal elastic solids where its volume remains constant under elongation.

Note 7:
The friction coefficient is usually based on unlubricated materials in contact with identical material in air at low relative contact speed. Surface finish: lapped or polished to Ra<= 0,1 mm.

Note 8:
In reducing atmosphere, lower values often apply, e.g. for TiO2 and MgO. Al2O3 is a highly stable oxide and withstands reducing conditions well.

Note 9:
The value is highly dependent on the size and shape of the product. Generally, ceramics withstand "up-shocks", at increasing temperature, better than cooling.

Note 11:
Commercial data often confuse tand and e_r^.tand, which we have tried to compensate for in this compilation. T=20°C.

Note 12:
Values are based on weight loss per year (365 days). This corrosion often attac the binder phase first, possibly leading to severe weakening of the ceramic, at even a minute weight loss.

Note 13:
Index 100 corresponds to dense sintered, unmachined 99.6% pure Al2O3, exclusive of tooling expenses, etc. Production lots: 100 - 10,000 pcs. Easiest way to find out current prices, applicable to your requirements, is to contact us.

Macor: ® Corning Glass

© KERANOVA AB 1995-2006. Tables revision: January 2006