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15/03/53 1 Color in glazes and enamels

Color in glazes and enamels

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15/03/53 1

Color in glazes and enamels

15/03/53 2

Sources of color in glazes• Transition metal ions• The precipitation of crystal: titania and zirconia• Insoluble crystal or crystals that are colored

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Crystal chemistry of pigments

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• Lattice energy� determined almost totally by the nearest-neighbor cation-anion distances

• Coordination polyhedra� radius ratio• Electrostatic neutrality

Crystal chemistry of pigments

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Crystal chemistry of pigments

15/03/53 6

Crystal chemistry of pigments

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Crystal chemistry of pigments

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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

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Pigments design

Oxide A Oxide B

Oxide C

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Mixed-metal oxide pigments

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Mixed-metal oxide pigments

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Mixed-metal oxide pigments

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Black and grey pigments

• CoO, Mn2O3, NiO, Fe2O3, Cr2O3, FeO, CuO

• Black spinel pigments:– CuO-Cr2O3

– FeO-CoO– FeO-CoO-Cr2O3

– Mn2O3-Fe2O3

– Cr2O3-FeO-NiO

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Blue pigments• CoO• Spinal cobalt aluminate• Olivine cobalt silicate

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Green pigments• Chromium ion• Cobalt-zinc-alumina-

chromite bluegreenpigments

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Green pigments

Silica and a dichromate with calcium carbonate

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Green pigments

• Zircon vanadium blue

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Green pigments

• Copper compound

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Yellow pigments

• Zirconia vanadiayellow

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Yellow pigments

• Tin vanadium yellow

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Brown pigments

• Zinc-iron-chromitespinels

• Zinc-iron-chrome-aluminate

• Chrome-iron-tin-brown

• Iron-manganese brown

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Pink, purple and maroon pigments

• Chrome alumina pink

• Maganesealumina pink

• Zircon-iron system

• Chrome-tin system

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������������ก�����ก����ก �������

• Cr 3+ , Cr 6+

• Cr 3+ ����� ������ก � ����������� �������������������ก� ����ก� ��� �� ����!"��ก� #�$� SiO2 %$&��ก��' RO ��

• Cr 6+ #&��(��ก� ����(�!���)��� #*"���" )"�ก*+,��-�%. ������+ ก#�$�ก�$� ���

• Cr2O3 �'������ก� ������ ��

15/03/53 24

%* ������� ���ก� #�$�ก.� )"���!$��/�ก ��ก����

• Mn 2+ (�!� Mn 3+

• Mn 3+ �'������ก� #&��(��ก� ���� �� � �%��� )"�ก*+� �� � ����'-�.� ������+ ก#�$��0����1��'ก�+�����!�+�� �

• Mn 2+ �����!�+/'�(����"&�%��2�� ��'*ก3+ Mn 2+ �����!�+#�$�4��++��ก2.��-*$�

15/03/53 25

%* ������� ���ก� #�$�ก.� )"���!$��/�ก�(��ก

• Fe 2+ (�!� Fe 3+

• Fe 2+ /'#&��(��ก� ��0����"&���.�� �

• Fe 3+ /'#&��(��ก� ������ ��������%&��(�������������ก� ��'���ก2.�/������+ 4 %* /'�ก.����"&�%�� �%���������%&��(�����*+������!"��ก� ��'���ก2.�/������+ 6 %* /'�(���2���(�!���-3

• ��ก%.2.�.�ก%#�$��(��ก�'��������ก����/'�(���� �� �78�

• �ก� #�$��(��ก��.�9���ก����������������$��������ก��

15/03/53 26

�://*�#�$�4�%��ก������$������ �������!�+

• -�.� �����'�%�

• -�.� �����!�+ (���!�+�� ���� #)+��' *%���.+�����!�+)

• -�.� ����!"��.�

• ก���%������!�+ (�'�'� ����ก��+����!�+)

• � �(�� �����!�+

• ��9(=.��'+����ก�>ก���4� (%&��(��� �����%��4�)

15/03/53 27

%* �����ก��4����'�%������!�+

Zr

Ca,Pb,Sn

Zn, Zr

Zn, Zr

Zr

�(�'ก*+���!�+

Zn, B, alkali1250 OFZr-Si-Fe��� (Coral)

Zn,B1250 OFSn-Ca-Si-Cr��� (maroon)

1300 OF

1350 OF

Zn-Cr-Fe-Al-Sn

Zn-Cr-Fe�"&�%��

Pb, Zn,Ca,B

alkali

1400 OF-RF

1350 OF

Zr-V

Sn-V-Ti�(�!��

Zn,Sn,Mg1400,OF-RFCr-Si-Al� �� ���

���(�'ก*+���!�+��9(=.

��'+����ก�>

����������'++����

15/03/53 28

Stability range for body stains

15/03/53 29

Stability range for glaze colors

15/03/53 30

Stability range for underglaze colors

15/03/53 31

Stability range for overglaze colors

15/03/53 32

��#��

• ��� �4� ��#��,���� 11-12% ��'��#��������� �4� ��#�� 16-60%

• ����'��� ��#��������1��0� ���(� ���"&�%�� ����'�ก�.$�J�� ���#*$ ����� �4� ��+���2.�.�ก%7�.%��'+.#*��3!$�-� ��(�#���)�����+�4. ���!�+(�*��4������

• ��ก���4���#���กK�2ก&�'�*� (H2SO4) ��'�"&�*��� ��-� ���กก���4� �*��*"�� ��ก�����กK�2��'� �-!"���ก���4�

• ��9(=.�4� 440ºC �&�(�*+��#������ ��' 300ºC �&�(�*+#�� �

15/03/53 33

Enamels, Porcelain enamels and vitreous enamels

15/03/53 34

�.�����!�

• ��!"��ก� ���!�+�ก� #�$�ก�����!�+�3!$�%ก�%��(�!��3!$�ก���-���� ���!�+��+���('��'�ก�

• ��9(=.���!�+��ก �� 425ºC

• ���*�ก���/'���!�+��+� #����� #�� ��.�(�!�#���(�!�� ��'���3*L������!�++��(��ก(��� (�!��(��กก���

15/03/53 35

ก���&����!�+�.�������-���'��-�1

Tablewares

SinksChemical apparatusjewellry

Refrigerator, washing machines

15/03/53 36

Properties of enamels and coatings

• Mechanical properties– Elasticity– Tensile strength, compressive strength, bending strength, hardness

• Thermal properties – Thermal conductivity (�.����#�$��3��� /'�&�� �����%$&� #&��(�#�%��ก������$������

� �������)– Thermal expansion (�.����� �� COE %$&�ก ����('(�!�-."����#�$/'���!�+)– Thermal shock resistance,TSR (�.�������� TSR ���������� convex )

• Optical properties– Reflection – color

• Electrical properties– Insulator

15/03/53 37

Elasticity

• *���� ���(�!�� ��� ����$�����ก(�!������!$������)�(�!����ก�ก�'#&�%�� *����*"�

• ��� modulus %$&� /'� elasticity ��

• �!$� Elasticity �� �.����/'#�%�� strain ��

=∆

ES

Pll

∆ll

S P

E = modulus of elasticity

15/03/53 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 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 40

*%���.+��ก���ก.��ก� ���.����

• Acid oxides: Silica, boric oxide ����ก� Quartz, sand, boric oxide

• Basic oxides: alkalis and alkaline-earth metals) ����ก� (.�7:��� ��1 ZnO, MgO, PbO

• Amphoteric oxides: mainly alumina

• Acid+basic oxides (������ ก*�): Feldspar, clay and kaolin, borax

15/03/53 41

ก�'+ �ก��4�.%4�.%=*9N1�.����#&� frit-*$� *%���.+ 4�

)"�����('

#&�� ��'���4. ��('

+���O�ก(�!�+��(��

���!�+�.�����.+-*"���ก

���!�+�.����-*"�+�

�+�(��

�4� �+�(��

15/03/53 42

�&���#���+#

���'�%��!��'�����������4�)ก �����'�%���'��+��� �.�����!��'��Strain #�$�ก.� )"���-*"��.���� �ก.�/�ก���(%���