Ceramic dining utensils are the most common, and are loved by consumers for their many advantages, such as easy cleaning, acid and alkali resistance, convenient high-temperature disinfection, and steaming, boiling, roasting, and roasting food. High-grade ceramic utensils with beautiful appearance and beautiful decoration are not only practical, but also artistic and ornamental, and are necessities of daily life.
1. Ceramic classification
(1) Classification according to the type of porcelain: At present, there are mainly daily-use porcelain, bone ashes porcelain, exquisite daily-use porcelain, underglaze (middle) color daily-use porcelain, daily-use fine pottery, ordinary ceramic cooking utensils and fine ceramic cooking utensils. device, etc. Daily-use ceramics (bone china has only one grade) are divided into multiple grades such as superior products, first-class products, and qualified products according to the number or extent of appearance defects.
(2) Classification according to the decoration method of the flower surface: According to the characteristics of the flower surface, it can be divided into on-glaze color, in-glaze color, under-glaze color and color-glazed porcelain and some uncolored white porcelain.
On-glaze ceramics are products made of on-glaze ceramic pigments that are pasted on the glaze or directly painted with pigments on the surface of the product, and then baked at 700-850°C. Because the baking temperature did not reach the melting temperature of the glaze layer and the non-glaze ceramic pigment was used, the flower surface could not sink into the glaze, but could only stick to the surface of the glaze layer. If you touch the surface of the product with your hand, there is a protruding feeling at the decoration, and you can observe the unevenness with the naked eye.
The firing temperature of in-glaze color ceramics is higher than that of on-glaze color, reaching the melting temperature of the product glaze. The ceramic pigment sinks into the glaze when the glaze is melted, and is covered by the glaze layer after cooling. The surface of the product is as smooth as glass when touched by hand, and there is basically no unevenness.
Underglaze ceramics is a traditional decoration method in my country. All the decorations of the products are carried out on the porcelain blanks. After glazing, they are fired at a high temperature. This product is the same as the underglaze color. The flower surface is covered by the glaze layer and the surface is bright. , flat, the surface of the product is smooth when you touch it by hand, and sometimes there is a concave feeling in the decoration.
For color-glazed porcelain, a high-temperature colorant is added to the ceramic glaze, so that the glazed surface of the fired product exhibits a certain color, such as yellow, blue, bean cyan, etc.
White porcelain usually refers to ceramics without any color decoration.
2. Precautions for purchase
(1) Appearance quality. Consumers can first check the product name and grade indicated on the product packaging box or the documents in the box; secondly, they can observe the physical quality of the product with the naked eye. When purchasing, they should try to choose products with no obvious defects on the surface and regular shapes. For plate and bowl products, you can stack several products of the same size and size together, and observe the distance between them. The distance is uneven, indicating that the shape of the device is irregular and the deformation is large. For a single product, it can be placed flat or buckled on the glass plate to see if it matches the glass plate to judge its deformation. For porcelain products, you can hold it on your hand and tap the edge of the mouth with your fingers. If there is a hoarse sound, it means that there is a crack.
(2) Dissolution of lead and cadmium: The dissolved lead and cadmium of in-glaze color products and under-glaze color products are very little or almost none, so you can buy with confidence. When purchasing on-glaze color products, you can refer to the following methods:
(1) For utensils containing food, products with less decorative patterns on the surface in contact with food should be selected.
(2) When purchasing, you should also pay attention to whether the color of the pattern is bright. If it is not bright, it may be that the temperature does not meet the requirements when baking the flower, and the amount of lead or cadmium dissolved in such products is often high.
(3) Special attention should be paid to those products whose patterns can be wiped off by hand. Most of these products have extremely high lead or cadmium dissolution and should not be purchased.
(4) For unreliable products, edible vinegar can be used (the concentration of acetic acid used in the inspection of lead dissolution and cadmium dissolution is basically the same as that of edible vinegar.) Soak for a few hours, if it is found that there is a significant change in color, it should be discarded. , Most of these products have high lead or cadmium dissolution.
(5) For products marked for decoration, do not use for food.
In addition, when purchasing products for microwave ovens, you should avoid products with metal decoration, such as products with gold edging, silver edging, or products with gold decals, metal wires, and metal wire inlaid patterns.