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Effect of Methyl Silicone Oil to Moisture Resistance of Sodium Silicate Sands by Microwave Hardening

Wang Huafang, Gao Xiang, Yang Lei, He Wei, Lu Jijun

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 1

43--47

EN

The sodium silicate sands hardened by microwave have the advantages of high strength, fast hardening speed and low residual strength with the lower addition of sodium silicate. However, the sodium ion in the sands will absorb moisture from the atmosphere, which would lead to lower storing strength, so the protection of a bonding bridge of sodium silicate between the sands is crucial. Methyl silicone oil is a cheap hydrophobic industrial raw material. The influence of the addition amount of methyl silicone oil modifier on compressive strength and moisture absorption of sodium silicate sands was studied in this work. The microscopic analysis of modified before and after sodium silicate sands has been carried on employing scanning electron microscopy(SEM) and energy spectrum analysis(EDS). The results showed that the strength of modified sodium silicate sands was significantly higher than that of unmodified sodium silicate sands, and the best addition of methyl silicone oil in the quantity of sodium silicate was 15%. It was also found that the bonding bridge of modified sodium silicate sands was the density and the adhesive film was smooth, and the methyl silicone oil was completely covered on the surface of the sodium silicate bonding bridge to protect it.

2

Microwave-Hardened Moulding Sands with Hydrated Sodium Silicate for Modified Ablation Casting

Puzio S., Kamińska J., Major-Gabryś K., Angrecki M., Hosadyna-Kondracka M.

Archives of Foundry Engineering

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2019

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iss. 2

91--96

EN

The aim of this study is to demonstrate the possibility of using moulds made from the environmentally friendly sands with hydrated sodium silicate in modified ablation casting. The ablation casting technology is primarily intended for castings with diversified wall thickness and complex shapes made in sand moulds. The article presents the effect of binder content and hardening time on the bending strength Rgu of moulding sands with binders based on hydrated sodium silicate hardened by microwave technology. The aim of the research was to develop an optimal sand composition that would provide the strength necessary to make a mould capable of withstanding the modified ablation casting process. At the same time, the sand composition should guarantee the susceptibility of the mould to the destructive action of the ablation medium, which in this case is water. Tests have shown that microwave hardening provides satisfactory moulds’ strength properties even at a low binder content in the sand mixture.

3

Effect of bentonite addition on residual strength of microwave-hardened waterglass-containing moulding sands

Stachowicz M., Granat K., Nowak D.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3 spec.

199--204

EN

The paper presents results of a preliminary research of the effect of bentonite addition on residual strength of microwave-hardened moulding sands, containing sodium waterglass. Strength was determined at ambient temperature, on cylindrical specimens baked in an oven. Moulding sands for examinations were based on high-silica sand with addition of 2.5 % of non-modified, domestic-made waterglass grade 145. The prepared standard cylindrical specimens were hardened using the innovative microwave heating process and next baked for 30 minutes at temp eratures between 100 and 1200 °C. Strength parameters of the specimens were determined on the specimens cooled-down to ambient temperature. The obtained results were compared with literature data to evaluate the effect of the applied hardening method and of the special additive on residual strength as a function of baking temperature. A favourable effect was found of both the innovative heating process and the applied bentonite addition.