1.Inclusion Stains
Inclusion stains are our principal products. The colors cover red, orange red, orange, yellow, golden yellow, green and violet.
Basic components and structure:
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The chromophore in inclusion stains is Cd-Se-S (Cd-S). It is encapsulated with Zirconium Silicate crystal which is transparent and chemically stable in high temperature. So the basic components are Cd-Se-S-Zr-Si(Cd-S-Zr-Si).
Corelation between components and colors:
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The color of inclusion stains is directly related to the content of Selenium . The higher the Se content , the more reddish of the color. On the contrary, the lower the Se content, the more yellowish the color. From red JH-189 to yellow JH-488A, there is Selenium of various content, while as the color ranges from red, to yellow, the content of Selenium decreases until in JH-488, there is not Selenium any more. In a word, in the structure, Selenium is in the position of Sulphur.
Item Codes VS performance:
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In inclusion stains, our standard item codes are:
Red: JH-189, JH-188A, JH-188, JH-188B, JH-186
Orange Red: JH-288
Orange: JH-388A, JH-388, JH-388B, JH-386
Yellow: JH-488A, JH-488, JH-488B
Green: JH-584, JH-586
Violet: JH-088
The first digit refers to the color group, i.e.: 1, 2, 3,4,5,0 indicates red, orange red, orange, yellow, green and violet respectively.
The second digit refers to different grade for each color. According to the market demand, we devided it into 3 different grades for each color, i.e. grade 9, grade 8 and grade 7.
The third digit or combination of a digit and a capital letter indicates the content of Selenium in each color group. From 9, to 8A, to 8, to 8B, to 6, the content of Se is lower and lower, so the color appears less reddish and becomes more yellowish.
For example: JH-189, 1 = red, 8 = the 8th grade, 9 = reddest; and for 376, 3= orange, 7 = the 7th grade， 6= the lowest Selenium content in orange group.
Applications of Inclusion stains:
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Inclusion stains are mainly used in ceramics (ceramics for daily use, building ceramics, etc.). Application methods mainly include in-glazing (also called colored glaze, i.e. finished ceramic products are obtained by applying the mixture of stains and glazes on the body and then firing), under-glazing (finished ceramic products are obtained by applying the mixture of stains and flux on the body , drying, covering with transparent glaze, and then firing), and on-glazing (covering the body with base glazes which are not limited to white color, applying stained glaze on base glaze, then firing). Inclusion stains are usually used in high temperature on-glazing process or with products having very strict standard of Cd release. Otherwise, ordinary cadmium pigments can be used instead. Inclusion stains are also used for coloring bodies of high grade ceramic articles.
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Temperature range:Below 1250 ℃, our inclusion stains are very stable. Most of our customers use inclusion stains at temperatures from 1030℃ to 1230℃. Other customers use them well at 1280-1300℃ with reducing atmosphere. Inclusion stains have good adaptability for frits (transparent, opaque, and matte). Generally speaking, they behave best in transparent frits at lower temperature, while in opaque or matte frits, the coloring strength is comparatively weaker. We usually test our stains at 1030℃ with transparent frits and at 1230℃ with matte frits. With transparent frits, the color and brilliance are easily determined while with matte frits the coloring strength is easily determined. So normally we test our stains with transparent frits; we use matte frits in case the coloring strength is not easily determined.
Instructions for application:
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Excessive grinding may destroy the encapsulated cover.
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Content of alkali metals in glaze should be low, otherwise the stability of zirconium silicate will be affected.
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Avoid adding ZnO to the glaze, otherwise it may cause pin hole.
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Avoid adding Barium to the glaze, otherwise it may affect the colorization.
Customer Feedback:
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Color differrence: For every batch of product delivered, we keep the pre-shipment sample for two years, and we keep ample stock to make sure that the customer get consistence in color.
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Black dots: black dots phenomenon, i.e. the brownish-black spots appeared on the surface of ceramic wares calcined with medium and high temperatures, is a weakness in the application of inclusion stains. Experiments have proven that this phenomenon is related to the ceramic body, frits as well as the pigments used. This problem can be solved by “Compensative encapsulation” and adjustment of frits.
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Treatment of glazed surface: problems such as pin holes, glaze flowing, bubbles, chill etc, can be solved by adjusting glaze formula or firing temperature.
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Particle Size & impurity:Particle size becomes more and more impotant with the application of inclusion stains in screen printing. Some customers require that the particle size to be above 250 mesh, but currently our specification is 250 mesh. The problem can be solved by adding extra screening equipment and keeping more strict control of production process.
2.Cadmium Pigments
Brief introduction:
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Cadmium pigments are similar to inclusion stains in color spectrum. There are red, orange red, orange and yellow. Our standard products are as follows:
Cadmium Violet: JHT-171, JHT-173
Cadmium Red: JHT-160, JHT-161, JHT-165.
Cadmium Orange Red: JHT-151
Cadmium Orange: JHT-141
Cadmium Yellow: JHT-101, JHT-1015, JHT-1040, JHT-1050, JHT-1015B, JHT-102
Cadmium Lemon Yellow: JHT-088
The chromophore of Cadmium pigments is the same as inclusion stains. It is Cd-Se-S in violet, red, orange red, orange; and Cd-S in yellow. The content of Selenium is directly related to the change of color , as it is in inclusion stains.
Application of Cadmium Pigments:
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Mainly used in ceramics (glaze, on-glazing, and decal), enamel (glaze, decal), glass (body, surface), plastics and paints. Heat resistance is below 900℃. Cadmium pigments are easily oxidized and decomposed at high temperature, so we usually use them under comparatively lower temperature, preferably below 850℃. Nevertheless when used together with certain glaze which can provide protection to pigments, cadmium pigments can also be used at relatively high temperature.. When Cadmium pigments are used in body glass, the heat resistance is better. In practical application, customers may choose the proper items of the same color from different types based on various factors such as price and product quality.
Customer Feedback:
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Dull and foggy: this happens in enamels when the firing temperature is low, i.e. below 820℃. By raising the firing temperature or lowering the melting point of enamel frits can solve such problem.
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Black Spots:Pigment decomposing or impurity may cause black spots on enamel. The problem can be solved by adding extra screening equipment and keeping more strict control of production process.
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Glaze Flowing: It happens when using high viscosity frits. The problem can be solved by adding appropriate amount of electrolyte i.e. water glass or sodium humate.
3.Other Colors
We produce other stains, such as black series, Cobalt series (blue, green), brown series, Zr-Si series, and Sn series.
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Black series: there are Co black (JHT-132, JHT-133, JHT-134), which can be well used in ceramics, and non-Co black (JHT-131, JHT-130), which can be well used in enamel. Non-Co black or low-Co black are normally not used in ceramics, because Cr in black stains may react with Zn in frits, which lead to brownish red.
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Co Series (blue, green): Such as: Sky-Blue, Co-Blue, Sea-Blue, Bluish Green, Green, Co-Si Blue, etc. They can be widely used in ceramics, enamel and glass.
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Brown series (Fe-Cr-Zn): they are Brown, Coffee, and Dark Brown, Reddish Brown. They are used in ceramics, enamel and glass.
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Creamy Yellow: used in enamel, low temperature on-glaze ceramics and glass surface.
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Zr-Si series: Coral Pink, Pr-Yellow, V-Blue, V-Zr Yellow, Apple-Green. They are used in colored glaze for ceramics and glass surface; while in glaze for enamel, they may appear light and turbid in color and therefore not recommended for use.
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Cr-Sn series: They are Maroon, Pink, Rose, can be used in ceramics, enamel and glass. Not suitable for use in reducing atmosphere because of the instability of Cr.
Feedback from customers focuses on color difference and problems in glazed surface Such problems can be solved with the same methods as in inclusion stains.
4.Dispersion series pigments
They are dispersion Cadmium series which are our matured products, mainly used in plastics, paints and coatings. We are also developing other dispersion pigments in our MMO research project.
5.Colored Glaze
On-glaze pigments for ceramics, with heat resistance 760℃-840℃.
Colored glaze on glass surface: with heat resistance 550℃-620℃, 660℃-720℃.
Crystalline Glaze (also named Special Effect Glaze): with heat resistance 1200℃-1230℃.
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