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|Balance||H2O and trace elements|
Special low chloride product
Dalfratex products with a lower level of chlorides are available by special arrangement.
They find application when temperature and humidity conditions conducive to stress corrosion cracking of stainless steel are likely to be encountered.
Maximum Continuous Use Temperature: 1000 deg C
Progressive devitrification eventually leading to brittleness will occur above this temperature.
Maximum Short Term Use Temperature
Dalfratex products can be used up to the softening point if the exposure is of limited duration. The actual duration of exposure is a function of temperature and mode of use. Advice on the suitability of a Dalfratex product for a given application may be obtained from Ceramisis. Some examples of this type of use are: Manufacture of flexible fire barriers and curtains. Fire stopping of pipe penetrations through rigid fire walls. Protection of personnel and plant from liquid metal splash.
Softening Point: approx 1600 deg C.
Thermal Shock Resistance : excellent
Standard products have an initial high rate of shrinkage which is irreversible, and occurs when they are first heated. The following graph is given for guidance only, and is based on measured values for broadcloth.
For certain applications, shrinkage of Dalfratex in-situ during the first heating may be undesirable. For these applications, most Dalfratex products are available in a pre-shrunk form. Further limited shrinkage may still occur in use, depending upon the temperature and time conditions prevailing, but typically will be less than 2% at 1000 deg C.
The following values of thermal conductivity shown on the graph, below, were determined using the water calorimeter procedure described in BS 874: 1973, paragraph 4.2.5. Units are Wm/m2 °C.
The thermal conductivity values of ball in a slightly compressed condition (density 96kg/rn3) are reported, being the most common application form. In the fully relaxed, as supplied, condition the thermal conductivity is 10% to 15% higher at elevated temperatures.
250 C= 0.80 j/g deg C, 500 C= 0.88, 750 C= 0.96, 1000 C= 1.09
Dalfratex fibre is a good electrical insulator, with high electric strength and low electrical conductivity.
For most design purposes it may be assumed that the electrical breakdown strength of a region filled with Dalfratex, is essentially that of atmospheric air.
The dielectric properties of Dalfratex at room temperature are adversely affected by the presence of associated water. This can substantially be removed by heating the material to 100 deg C to 200 deg C, when the losses are significantly reduced.
The electrical properties of Dalfratex have been measured by an independent testing laboratory, and their report is available upon request from Ceramisis Limited.
The chemical properties of Dalfratex are similar to those of vitreous silica (silica glass).
In general Dalfratex is compatible with mineral acids except phosphoric and hydrofluoric and is also compatible with a wide range of substances including air, chloride, carbon monoxide, ammonia, sulphur dioxide.
Dalfratex products are compatible with silica refractories at high temperatures. As there is no possibility of forming a SiOz’Al203 eutectic, Dalfratex can safely be used in conjunction with silica
refractories in coke ovens, glass melt tanks etc.
Dalfratex products are not recommended for use in contact with bases such as sodium and calcium hydroxides or substances giving the reaction of these, e.g. sodium silicate.
This data set out in this publication are for information purposes only and their accuracy is not warranted or guaranteed. These particulars do not constitute an offer or any part of an offer.
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