SU1237646A1 - Solution for treating glass articles before ion-exchange hardening - Google Patents

Description

The invention relates to the pretreatment of glass products and can be used prior to the strengthening of glass products by the method of low-temperature ion exchange.

The aim of the invention is to increase the tensile strength of glass.

Introduction to the solution of potassium salts KNOj and in amounts of 1.0-5.0 wt.% Each contributes to an increase in the K content in the surface of glass reinforcement due to the introduction of K ions into the solution. At the same time, the degree of exchange K after treatment in the melt increases, which leads to an increase in the compressive stress and strain of the stress zone and, consequently, to an increase in the resistance to tensile loads. The introduction of HNO J into the solution is necessary to change the structure and density of microcracks on the glass surface, which leads to an increase in the strength of the glass, and especially in the case of tensile forces.

The content in the amount of 2.5 to 4.0 wt.% Contributes to the chemical modification of the surface layer of glass and changes in its structure. As a result of the hydrolysis of a part of the HSi-0-Sis bonds and the removal of Na from the Si-O-Na groups during

ion exchange H;

f-fa

Na Art. the formation on the surface of the glass-, la depolarized, hydrated layer, an enriched group

five

0

five

0

five

MH5Si.-OH. This layer with high molecular mobility has an enhanced relaxation capacity, which leads to a rise in glass strength. The presence in the surface layers of an increased proton content, in turn, intensifies ion exchange hardening due to the flow of diffuse H exchange for ions from the melt.

In the proposed solution, the action of all components reduces the defectiveness of the glass being processed and the formation of a hydrated layer on its surface with partial replacement of Na by K, which substantially intensifies ion-exchange hardening in the melt tCNOj. As a result, an additional increase in tensile strength of glass and an increase in the service life of hardened products is achieved.

The composition of the solution dp processing glass before ion-exchange pack-, rochnenie are given in table. 1, the properties of hardened glass - in Table. 2

The manufacturability of the proposed solution and the possibility of combining pretreatment with glass washing make it possible, at no additional cost to strengthen, to significantly improve the technical and economic indicators of the strengthening process.

Table 1

94.0 22 ° С - 1 h 420 ° С - 2 h 87.0 22 s - 1 h 420 ° С - 2 h 80.0 22 С - 1 h 420 С - 2 h

SL, 0 40.0 32.0

11.0 12.0 10.5

3, 0 3.4 3.0

1237646

table 2

Claims (1)

A SOLUTION FOR PROCESSING GLASSWARE BEFORE ION EXCHANGE STRENGTH, including H ₂ SO ₄ , H ₂ O, characterized in that, in order to increase the tensile strength of the glass, it additionally contains HN0 _? , KNO ₅ , K ₂ SO ₄ in the following ratio of components, wt.%: H ₂ so ₄ 2.5-4.0 Hno _? 1,5-6,0 Kno ₃ 2-5 k ₂ so ₄ 1-5 h ₂ o Rest boo w • m (X &