METHOD FOR STRENGTHENING GLASS SUBSTRATE AND ARTICLE MANUFACTURED BY THE SAME

A method for strengthening glass substrate includes: preheating a glass substrate; spraying a molted salt onto the substrate to form a ion exchange layer; forming a titanium dioxide layer on the ion exchange layer. The ion exchange layer infills some microcracks. The titanium dioxide layer reinforces the infilling of microcracks and applying further toughness. An article manufactured by the method is also provided.

DETAILED DESCRIPTION

Referring toFIG. 1, an exemplary method for strengthening glass substrate may include at least the following steps:

The glass substrate11is a sodium silicate glass substrate. The thickness of the glass substrate11is about 0.5 mm to about 3 mm. The glass substrate may have a plurality of micro cracks (not shown) defined on the surface of the glass substrate11caused by the annealing process during the manufacturing of the glass substrate or other causes. The glass substrate11may be a plain glass or a glass having a three-dimensional structure.

In the embodiment, the glass substrate11having a three-dimensional structure is made from a plain glass by hot bending treatment.

(2) The glass substrate11is polished to smoothen the inside and outside surfaces of the glass substrate11.

(3) The glass substrate11is strengthened to form an ion exchange layer13.

Referring toFIG. 2, a strengthening treatment device300is provided. The device300includes a strengthening furnace310, a bath330retained in the furnace310, and a horn-shaped spraying element350inserted into the bath330. The bath330contains salt solution370.

The strengthening process is carried out by the following steps: firstly, the glass substrate11is placed in the device300above the spraying element350, and the internal temperature of the furnace310is heated to about 200° C.-450° C. at a rate of about 2° C./min-12° C./min to pre-heat the glass substrate11; secondly, the internal temperature of the furnace310and the salt solution370is heated to about 450° C.-550° C. at a rate of about 5° C./min-10° C./min, thus melting the salt solution370; thirdly, the melted salt solution370is sprayed on the glass substrate11for about 90 min-240 min by the spraying element350, which facilitates an ion exchange between potassium ions included in the glass substrate11and potassium ions included in the salt solution370; fourthly, the internal temperature of the furnace310is decreased to room temperature at a rate of about 1° C./min-2° C./min.

In the embodiment, the salt solution370contains potassium nitrate, auxiliary substances (see below for description) and water, wherein the mass percentage of the potassium nitrate is about 54% to about 72%, the mass percentage of the auxiliary substances is about 4% to about 10%, the mass percentage of water is about 2.3% to about 7.5%. The auxiliary substances include corundum powder, potassium silicate and diatomite, wherein the mass percentage of the corundum powder is about 25% to about 35%, the mass percentage of the potassium silicate is about 25% to about 40%, and the mass percentage of diatomite is about 25% to about 50%.

During the strengthening process, sodium ions from the glass substrate11are exchanged with potassium ions included in the salt solution370to form an ion exchange layer13. Some of the micro cracks are filled and smoothed over by potassium ions, because the diameter of each potassium ion is larger than the diameter of the sodium ion. The ion exchange layer13has a thickness of about 10 μm to about 30 μm.

During the strengthening process, melted salt solution370is sprayed evenly on the surface of the glass substrate11, which makes the glass substrate11have a three-dimensional structure that is uniform in strength. Additionally, less of the salt solution370is consumed by the method compared to the consumption in the traditional chemical strengthening process.

(4) A titanium dioxide layer15is formed on the ion exchange layer13by thermal spraying.

A spraying solution is provided. The spraying solution includes carbon tetrachloride and organic solution, wherein the mass percentage of the carbon tetrachloride is about 58% to about 80%, and the mass percentage of the organic solution is about 20% to about 42%. The organic solution is an alcohol, such as ethanol or methanol.

The glass substrate11is positioned in a sealed chamber (not shown). The internal temperature of the chamber is heated to about 500° C.-700° C. The spraying solution is sprayed on the ion exchange layer13. Meanwhile, the carbon tetrachloride decomposes into titanium dioxide as a result of the high internal temperature of the chamber (500° C.-700° C)., which forms a titanium dioxide layer15on the ion exchange layer13. The titanium dioxide layer15consists of titanium dioxide. The thickness of the titanium dioxide layer15is about 15 μm-30 μm.

The titanium dioxide layer15is formed on the ion exchange layer13. Some of the titanium dioxide included in the titanium dioxide layer15is embedded in the micro cracks which are left unfilled by the potassium ions.

The above method not only strengthens the glass substrate11having a thickness less than 1.5 mm, but also strengthens the glass substrate11having a thickness about 1.5 mm to about 3 mm.

An article10manufactured by the above method is also provided. The article10includes a glass substrate11, an ion exchange layer13formed on the glass substrate11, and a titanium dioxide layer15formed on the ion exchange layer13.

The glass substrate11defines a plurality of micro cracks. The thickness of the glass substrate11is about 0.5 mm to about 3 mm.

The ion exchange layer13has sodium ions and potassium ions. Potassium ions are embedded in the glass substrate, partly filling any micro cracks. The ion exchange layer13has a thickness of about 10 μm to about 30 μm.

The titanium dioxide layer15is formed on the ion exchange layer13. Some of titanium dioxide included in the titanium dioxide layer15embeds in the micro cracks which are left unfilled by potassium ions. The titanium dioxide layer15consists of titanium dioxide. The thickness of the titanium dioxide layer15is about 15 μm-30 μm.

The ion exchanging layer13and the titanium oxide layer15are resistant to the propagation of existing micro cracks and the formation of new micro cracks due to impacts, thus improving the strength and toughness of the glass substrate11. Additionally, the titanium oxide layer15provides an enhanced resistance to abrasions and scratches.

It is believed that the exemplary embodiment and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its advantages, the examples hereinbefore described merely being preferred or exemplary embodiment of the disclosure.