SU688271A1 - Suspension composition for making refractory ceramic moulds by the lost-wax method - Google Patents

Description

one

The invention relates to the field of foundry.

A known suspension for the manufacture of ceramic forms in melted models, containing ethyl silicate, solvent, water, inorganic acid, refractory filler and algae polysaccharides. The latter have been added to increase the gas permeability of the forms 1.

The introduction of this expensive organic additive into the suspension does not provide a stable gas permeability, and the marshalite is contained in the suspension as a refractory filler.

A suspension is also known for the manufacture of refractory ceramic forms, containing a refractory filler, ethyl silicate, hydrochloric and sulfuric acid, an organic solvent, water and a reinforcing additive, which uses a polyfunctional silicon-containing oligomer 2.

However, this suspension contains a large amount of water, which requires additional energy and material costs for drying.

The closest in technical essence and the achieved result is a suspension containing ethyl silicate 32,

alcohol, water, hydrochloric acid, and dystasillimanite 3.

Insufficient strength and gas permeability of the forms from the specified suspension limits its use due to significant losses in the rez one hundredth bo ceramics occurring during technological transitions.

In order to increase the gas permeability of the forms with their high strength and low cost, the suspension for the manufacture of ceramic forms, including ethyl silicate 32, water, hydrochloric acid, alcohol p distensilimite, additionally contains dibutyl phthalate or dibutyl sebacate in the following ratio of ingredients, %:

Ethyl silicate 3212-17

Alcohol15-19

Water2.4-3.6

Sol at acid 0.1-0.2

Dibutyl phthalate or

dibutyl sebacinate 0.5-1.0

DistensillimaniteOther

Preparation of refractory spzspn is carried out in the following way. The composition of ethyl silicate 32, hydrochloric acid (density 1.15 g / cm), alcohol (density 0.78 g / cm), water and refractory filler distensillimanite is mixed for 40 minutes. 10 min before the end of mixing, the addition of dibutyl phthalate or dibutyl sebacate is added.

Tests were carried out with an optimal suspension formulation with a different content of dibutyl phthalate or dibutyl sebacate, wt%: I-0; II-0,5; 111-1.0; IV-1.5.

Physico-mechanical and technological properties of these suspensions are given in table. one.

Table 1

The compositions of the mixtures with the addition of dibutyl phthalate

Properties and dibutyl sebacate

Gas permeability was determined for samples with a diameter of 50 mm at room temperature after calcination.

As can be seen from the table. 1 introduction to the composition of the suspension dibutyl phthalate or dibutyl sebacate leads to a significant increase in strength and gas permeability. At the same time, the greatest increase in the strength of the samples, both before calcination and after, is observed when the content of the additive is 0.5 wt. %

With the optimum content of dibutyl phthalate or dibutyl sebacate there is an increase in the gas permeability of the forms by 70.3%, and the strength of the ceramics in the raw and calcined state increases by 81.5 and 87.5%, respectively.

Along with the increase in strength, the stability of the properties is greatly improved. The relative property scattering index — the coefficient of variation of the strength of ceramics decreases by a factor of 2.6 for non-chilled and 3.0 times for calcined samples. The distribution parameters of the flexural strength of the samples are given in table. 2

As a result of the increase in mechanical and technological properties due to the addition of dibutyl phthalate or dibutyl sebacate additives to the refractory suspension, the waste of forms by

trash, inam and improved casting quality.

table 2