Color in glazes and enamels 15/03/53 1

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1 Color in glazes and enamels 15/03/53 1

2 Sources of color in glazes Transition metal ions The precipitation of crystal: titania and zirconia Insoluble crystal or crystals that are colored 15/03/53 2

3 Crystal chemistry of pigments 15/03/53 3

4 Crystal chemistry of pigments Lattice energy determined almost totally by the nearest-neighbor cation-anion distances Coordination polyhedra radius ratio Electrostatic neutrality 15/03/53 4

5 Crystal chemistry of pigments 15/03/53 5

6 Crystal chemistry of pigments 15/03/53 6

7 Crystal chemistry of pigments 15/03/53 7

8 Oxide pigments Opacifiers = white pigments Tin oxide (refractive index 2.04) Zirconia (refractive index 2.40) Zircon (refractive index 1.85) Titania (R.I =2.5, 2.7 for anatase and rutite) Color pigments / stains 15/03/53 8

9 Pigments design Oxide C Oxide A Oxide B 15/03/53 9

10 Mixed-metal oxide pigments 15/03/53 10

11 Mixed-metal oxide pigments 15/03/53 11

12 Mixed-metal oxide pigments 15/03/53 12

13 Black and grey pigments CoO, Mn 2 O 3, NiO, Fe 2 O 3, Cr 2 O 3, FeO, CuO Black spinel pigments: CuO-Cr 2 O 3 FeO-CoO FeO-CoO-Cr 2 O 3 Mn 2 O 3 -Fe 2 O 3 Cr 2 O 3 -FeO-NiO 15/03/53 13

14 CoO Spinal cobalt aluminate Olivine cobalt silicate Blue pigments 15/03/53 14

15 Chromium ion Cobalt-zinc-aluminachromite bluegreen pigments Green pigments 15/03/53 15

16 Green pigments 15/03/53 16 Silica and a dichromate with calcium carbonate

17 Green pigments Zircon vanadium blue 15/03/53 17

18 Green pigments Copper compound 15/03/53 18

19 Yellow pigments Zirconia vanadia yellow 15/03/53 19

20 Yellow pigments Tin vanadium yellow 15/03/53 20

21 Brown pigments Zinc-iron-chromite spinels Zinc-iron-chromealuminate Chrome-iron-tinbrown Iron-manganese brown 15/03/53 21

22 Pink, purple and maroon pigments Chrome alumina pink Maganese alumina pink Zircon-iron system Chrome-tin system 15/03/53 22

23 ก ก ก Cr 3+, Cr 6+ Cr 3+ ก ก ก ก SiO 2 ก RO Cr 6+ ก ก ก ก Cr 2 O 3 ก 15/03/53 23

24 ก ก ก ก Mn 2+ Mn 3+ Mn 3+ ก ก ก ก ก Mn 2+ ก Mn 2+ ก 15/03/53 24

25 ก ก ก ก Fe 2+ Fe 3+ Fe 2+ ก Fe 3+ ก ก ก 4 ก ก ก 6 ก ก ก ก ก ก ก ก 15/03/53 25

26 ก ( ) ก ( ก ) ก ก ( ) 15/03/53 26

27 ก ก ก ก Cr-Si-Al 1400,OF-RF Zn,Sn,Mg Zr-V 1400 OF-RF Pb, Zn,Ca,B Sn-V-Ti 1350 OF Zr alkali Zn-Cr-Fe-Al-Sn 1300 OF Zn, Zr Zn-Cr-Fe 1350 OF Zn, Zr (maroon) Sn-Ca-Si-Cr 1250 OF Ca,Pb,Sn Zn,B (Coral) Zr-Si-Fe 1250 OF Zr Zn, B, alkali 15/03/53 27

28 Stability range for body stains 15/03/53 28

29 Stability range for glaze colors 15/03/53 29

30 Stability range for underglaze colors 15/03/53 30

31 Stability range for overglaze colors 15/03/53 31

32 11-12% 16-60% ก ก ก ก ก (H 2 SO 4 ) กก ก ก ก 440ºC 300ºC 15/03/53 32

33 Enamels, Porcelain enamels and vitreous enamels 15/03/53 33

34 ก ก ก ก ก ก ก 425ºC ก ก กก 15/03/53 34

35 ก Tablewares jewellry Sinks Chemical apparatus Refrigerator, washing machines 15/03/53 35

36 Properties of enamels and coatings Mechanical properties Elasticity Tensile strength, compressive strength, bending strength, hardness Thermal properties Thermal conductivity ( ก ) Thermal expansion ( COE ก ) Thermal shock resistance,tsr ( TSR convex ) Optical properties Reflection color Electrical properties Insulator 15/03/53 36

37 Elasticity ก ก ก modulus elasticity Elasticity strain l l = S l Pl ES P E = modulus of elasticity 15/03/53 37

38 Strains in the enamel layer Bonding between metal and enamel Shape of surface and radius of curvature COE Softening temperature of enamels Thickness of enamel Elasticity of enamel and metal 15/03/53 38

39 ก ก ก ก ก ก ก ก ก ก ก ( ) ( CuO, MnO, pigments) ก ก ก ก ( CoO, NiO, MoO) ก ( fluoride, tin oxide, Arsenic, titanium, zirconium) 15/03/53 39

40 ก ก ก Acid oxides: Silica, boric oxide ก Quartz, sand, boric oxide Basic oxides: alkalis and alkaline-earth metals) ก ZnO, MgO, PbO Amphoteric oxides: mainly alumina Acid+basic oxides ( ก ): Feldspar, clay and kaolin, borax 15/03/53 40

41 ก ก frit ก ก 15/03/53 41

42 ก Strain ก ก ก 15/03/53 42