First, analyze the reasons for the cracking of some porcelain glazes.

From the perspective of the product itself, the glaze layer on the surface of today's porcelain is basically impervious to water, so most of the cracking of the glaze surface after the porcelain is laid on the wall is caused by the water absorption and expansion of the brick, especially for the high-absorption products with high potassium and sodium content in the brick, the water absorption and expansion will be more serious. At this time, the body expands greatly after absorbing water, but the expansion coefficient of the glaze layer on the surface of the porcelain is small, and the glaze surface will crack.

The flatness of the brick is also a key factor. Since the tiles generally need to absorb water before paving, if the flatness of the brick is not good and the water absorption rate is too large, too much water absorption will flatten the originally sunken place and cause glaze cracks.

It can be said that due to the difference in the expansion coefficient between the adobe and the surface glaze layer, the cracking of the glaze surface after the porcelain sheet is laid is an unavoidable problem. Among them, water absorption and flatness are two important quality indicators. If the flatness of the porcelain sheet is poor and the water absorption rate is too high, the problem of glaze cracking will easily occur. For glaze cracks caused by product quality problems, general cracks will show an attitude from the inside to the outside, and there are many cracks.

However, it should be noted that on the basis of the same excellent product quality, affected by various factors such as paving method, application site and environment, the time and specific performance of the cracking problem of the glaze surface of the porcelain will also show great differences.

The first is to pay attention to leaving seams for paving. Another common reason for cracking the glaze surface of the porcelain sheet is that there are no seams left when paving. Later, due to thermal expansion and contraction due to temperature changes, the glaze surface will crack due to extrusion. The cracking of the glaze surface caused by this reason generally shows the characteristics of more peripheral cracks and fewer intermediate cracks.

The second is the seam treatment of the porcelain. As mentioned above, the glaze layer on the surface of the porcelain sheet is impermeable to water, but water will penetrate into the blank from the gap left when the porcelain sheet is laid. Therefore, if the traditional seam agent and white cement are used for seam treatment, or even no treatment, the water absorption speed of the porcelain sheet will be particularly fast. However, if a sealant with better sealing performance is used in the jointing treatment of the porcelain, the water seepage speed will be much slower, or even not penetrate. If the porcelain only relies on the bottom of the blank in contact with the wall to absorb water naturally, the glaze will crack. The time will be greatly delayed, and the service life will be longer.

In addition, the inappropriate ratio of cement will also lead to cracking of the glaze surface. If the ratio of cement, sand and water is not appropriate, the stress generated by the volume change during the curing process will exceed the bearing capacity of the glazed brick, resulting in cracking of the glaze surface. At this time, cement and fine sand can be used when paving, and some coarse sand can be used appropriately, which can improve the speed of water volatilization and reduce the shrinkage and tension during curing.

The temperature difference is also a major reason for the cracking of the glaze surface of the porcelain, especially in the northerly area with a large temperature difference. Generally, the glaze surface of the porcelain will crack in about 2 to 3 years. The main reason is that the porcelain will absorb water and freeze again in winter., thermal expansion and contraction, the glaze is easy to crack.

In general, since the porcelain is a product with high water absorption, the humid environment with more moisture in the air or on the wall will reduce the service life of the porcelain. Therefore, in general, in the space and occasion where the porcelain is pasted, it is necessary to maintain a relatively dry environment, and at the same time pay attention to the details of the above paving, which will prolong the service life of the product. Otherwise, even the best quality porcelain will soon appear glaze cracks.

At present, there are a batch of low-absorption porcelain pieces on the market. Relatively speaking, the situation of glaze cracks of such porcelain pieces will be better. But it is also necessary to be vigilant. According to reports, due to the different processes used, some companies will choose to increase the content of potassium and sodium in order to achieve the effect of low absorption and do not want to increase the firing temperature. The method of changing the ratio of raw materials to produce low-absorption porcelain pieces, but in fact, the increase of potassium and sodium content is very likely to be counterproductive, making porcelain pieces more prone to glaze cracks.