Porcelain
Contents |
[edit] Introduction
Porcelain is a translucent, non-porous ceramic material. It is made by firing a mixture of kaolinite (a clay mineral present in kaolin), quartz and feldspar. Kaolinite is sometimes referred to as china clay or porcelain earth.
Hard porcelain is usually made from a mixture of 50% kaolinite, 25% quartz and 25% felspar. Soft porcelain is made from the same materials but with different proportions: 25% kaolinite, 45% quartz and 30% feldspar. Soft porcelain is generally less expensive to make because it is fired at lower temperatures.
[edit] Making porcelain
To make porcelain, kaolin is washed and screened to produce kaolinite. This is then mixed with finely ground quartz and felspar along with water, soda and other materials. Next, the substance is thoroughly kneaded and then it is moulded or cast into plaster moulds.
Once the moulds have dried, the material is placed in a kiln and fired at a temperature of approximately 900C. This produces a substance that is hard and water tight, but its surface is dull.
[edit] Glazing
To produce a glaze on the surface of the item, it is placed in a liquid of the same components, but this time the quartz and felspar are the dominant substances. The object is then placed in a kiln, where it is fired again at a temperature of about 1400C. In this heating treatment, which lasts from approximately 20 to 30 hours, the particles of the mixture become partially fused together to produce a continuous coating on the surface of the object.
Glazes can be painted with dyes to produce different colours or patterns. To make the substances melt and fuse, the painted objects are fired in an enamelling furnace to about 800C. The paint can also be applied before the glazing.
Porcelain is primarily known for its use in domestic applications, but it can also be used in laboratories and in industry as an insulating material. It is not degraded by liquids or gases, and it is somewhat unaffected by moderate variations in temperature.
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Investors in People: CIOB achieves gold
Reflecting a commitment to employees and members.
Scratching beneath the surface; a guide to selection.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
UK gov apprenticeship funding from April 2024
Brief summary the policy paper updated in March.
For the World Autism Awareness Month of April.
70+ experts appointed to public sector fire safety framework
The Fire Safety (FS2) Framework from LHC Procurement.
Project and programme management codes of practice
CIOB publications for built environment professionals.
The ECA Industry Awards 2024 now open !
Recognising the best in the electrotechnical industry.
Sustainable development concepts decade by decade.
The regenerative structural engineer
A call for design that will repair the natural world.
Buildings that mimic the restorative aspects found in nature.
CIAT publishes Principal Designer Competency Framework
For those considering applying for registration as a PD.
BSRIA Building Reg's guidance: The second staircase
An overview focusing on aspects which most affect the building services industry.
Design codes and pattern books
Harmonious proportions and golden sections.
Introducing or next Guest Editor Arun Baybars
Practising architect and design panel review member.
Quick summary by size, shape, test, material, use or bonding..