SU531619A1 - Conductive slurry for making casting ceramic molds - Google Patents

Description

salt, melted during calcination, fills cracks, micropores, arising during calcination, and upon cooling the shells crystallizes with hardening of the shells. Quartz sand also increases the strength of the ceramic form. The specified amount of a 28-35% aqueous solution of sodium chloride is optimal, since it provides the required electrical conductivity of the suspension of 0.6-0.8 ohm cm. Just 28-35% of the concentration of the aqueous sodium chloride solution makes it possible to obtain a saturated solution that provides required conductivity. Less concentration does not give the indicated electrical conductivity, a greater concentration is impractical from an economic point of view. The described ceramic slurry has an acidic medium. The chromium oxide contained in the slurry composition is oxidized and gives a high-temperature compound ICp O -tiSiO fNoljO, which melts at 1900 ° C and contributes to the formation of a smooth film on the casting that prevents burning. Examples of the compositions of the described conductive suspension (No. 1-3) and the prototype suspension (No. 4) are given in Table. 1, the physicomechanical and technological properties of the suspension are given in table. 2. The proposed conductive slurry is prepared in the hydrolyser as follows. The following components are poured into the broomstick: an aqueous solution of sodium chloride and water glass (M 2.2-3.2; from 1.42-1.52 g / cm), mixed thoroughly, then quartz sand and pulverized quartz are added. and the components are moved for 15-20 minutes until a homogeneous suspension is obtained, followed by the introduction of chromium oxide, and then stirred for 2-3 minutes. The application of the suspension is carried out directly on the block of models, followed by fixing the layer with quartz sand. A ceramic sheath is formed on the resulting conductor wire through electrophoresis. The use of the described conductive slurry to obtain casting ceramic forms allows: to obtain high-quality castings from ferrous and non-ferrous alloys, including magnesium; increase the strength of ceramic shells; to improve the quality of the surface of the casting to V 5 tb Cl, with the thickness of the ceramic mold mm; reduce the cost of making ceramic shells; improve the cleaning of castings from ceramics. Table 1.

Quartz sand

Liquid glass (M 2.2-3.2; 1.42-1.52 g / cm3)

28-35% aqueous solution of salt 10

Chromium Oxide Marshalite Bentonite Clay

Converter Vanadium Slag

28

25

20

ten

20

15

20

15

3

4 31

40 1O 47

ten

Flexural strength of the calcined ceramic form to geplosmeny, kgf / cm

Flexural strength of calcined samples after heat shift, kgf / cm

Sedimentation stability, days

Viscosity by viscometer, VZ-1O

Heat resistance of ceramic forms (by loss of strength after heat exchange),%

Claims (1)

Density, g / cm. Formula of the Invention. A conductive slurry for the manufacture of casting ceramic forms of fused or burnable models, including quartz sand, marshalite, liquid glass, characterized in that, in order to enable the pouring of ferrous and non-ferrous alloys, strength ceramic foundry 6 Table 2. 150 130 100 90 90 7O 7 7 25 22 20 30.7 30.7 30.7 1.95 2.0 1.9 forms, the suspension additionally contains a 28-35% aqueous solution of sodium chloride and chromium oxide in the following ratio of ingredients, wt.%: Quartz sand 10.0-2 5.0 Liquid glass O, 0-2O, 0 28-35 % aqueous solution of sodium chloride 10.0-20.0 Chromium oxide1.0-4.0 Marshalite Else,