Views:153 Author:Site Editor Publish Time: 2021-01-13 Origin:Site
K9 crystal is also called K9 glass, can also refer to glass products made of K9 material, used for optical coating and other fields, the price of 10-15 yuan per kilogram (only for reference, the actual according to different levels have a certain big difference). The transmittance, refractive effect, hardness and texture are far higher than resin material. The main molding is cutting polishing and polishing and pressure casting (need furnace). K9 material belongs to optical glass, crystal clear, so derived a lot of K9 material as the processing object of the factory, they process the products, known as crystal glass products in the market.
30% lead crystal glass
The grade of natural crystal is not as obvious as Mohres hardness grading, at present there is no unified strict distinction in the world, only some early actively develop the market by common agreement and now the market is general, the following is the natural white crystal in without the help of a magnifying glass to the naked eye observation down the classification:
1. AA level [market commonly known as AAA level] : All-American level, that is, the whole crystal inside and outside are transparent and flawless, the surface is not artificial scratch caused by.
2. Grade A- [market commonly known as Grade 2A] : one level below AA, with subtle blemishes, such as natural inclusions, cloud or cotton material not more than two to three centimeters, or artificial bruises that cannot be felt and must be noticed only when you scratch lightly with your fingernails.
3. Grade A: One level below A-. Slight blemishes, such as clouds, cotton wool, or surface bruises caused by human impacts, are easily visible to the naked eye.
4. Class AB: one step lower than Class A, with distinct inclusions, long strips of misty, cotton-wool material, with small ice cracks inside, or obvious man-made impact scars, but no significant large ice cracks.
5. Grade B: one level lower than grade AB, more than half of the whole natural crystal is fog-like, cotton wool or have obvious large ice cracks and can be felt with fingernails.
6. Grade C: The lowest level, most of the whole is translucent or opaque like cotton wool or has very large ice cracks, it feels as if it will break at any time.
Product performance: density: 3.17/ cubic centimeter
Refractive index: 1.545
Metal oxides: PBO greater than or equal to 30%
Expansion coefficient: 9.8*10 to the minus 6 /K
Softening temperature: 613 degrees
The annealing temperature of lead crystal glass is generally between 330 degrees C and 430 degrees C, and the annealing time is 10 days.
Silica 51.46% boron trioxide 1.46% ferric trioxide 8.14*10 minus 3 %
Zinc oxide 1.02% sodium oxide 1.64% potassium oxide 11.52% lead oxide 31.12% lithium oxide 0.40%.
Some domestic crystals on the market are even made of plastic or resin, lightweight, without cutting.