Department of Industrial Chemistry, KMUTNB

Degradation of Ceramics

By : Kotchawan Srimala : Supa Sunthornvatin : Kanokwun Meesuntud : Varinya Panusuvat

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DEGRADATION OF CERAMICSoDegradation of an object occurs as a result of the interaction

between the environment or with the materials that form the object however, in the case of ceramics, environmental factors are the major cause. There are several ways in which ceramics break down physically and chemically.

o It is in the nature of all the materials used for construction to eventually degrade and deteriorate

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TYPES OF DEGRADATIONPHYSICAL DEGRADATION

Due to their fragility, damage to ceramics typically comes from mishandling and packing. However, other factors such vandalism, frost, mold, and other similar occurrences can also inflect harm.

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• Also known as inherent vice, the intrinsic instability of the fabric and components of an objects can lead to its own physical degradation.• This is difficult to prevent because it occurs within the fabric of the

material and therefore is a natural occurrence. • Deterioration of an object can happen even before the object is used.

How the piece is created can instill manufacturing defects in the piece This means that objects can be damaged even before they are used

PHYSICAL DEGRADATIONMANUFACTURING DEFECTS

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PHYSICAL DEGRADATIONMANUFACTURING DEFECTS• This would include a body that contains inadequate qualities of (filler

(materials)). A second typical defect is from poor design and construction. An example of this would be a ceramic piece with a handle that is too thin to support the weight of the cup. A third manufacturing defect includes careless firing. A ceramic piece that has been fired too rapidly or allowed to dry too fast will crack or break.

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PHYSICAL DEGRADATIONIMPACT AND ABRASION• With its delicate nature, ceramics that have been used over a period

of time will sustain cracks, nicks, and blemishes. Additionally in a museum environment, damages can occur from packing storing, and handling of objects.

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PHYSICAL DEGRADATIONFROST• Damage can occur when ceramics are exposed to freezing

temperatures and frost. The problem occurs when ice crystals form inside of the pores of the ceramic piece. The frost inside of the pores will exert pressure onto the fabric of the pottery and cause the material to crack and break.

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PHYSICAL DEGRADATIONMOLD GROWTH• Opposite of frost is heat and humidity. When the humidity is

high molds can begin to form on ceramic, particularly ones in which there is no glaze. Spores of molds are found throughout the atmosphere and will attached to any organic residues nearby, such as ceramics. Earthenware ceramics are frequently affected due to their porosity and lack of glaze.

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TYPES OF DEGRADATIONCHEMIAL DEGRADATION• Chemical degradation of objects occurs not in the physical structure

of the object but rather in at the chemical or compound level.• The degradation of the chemical component of an object will hinder

or weaken the stability of the object when exposed to environmental factors such as water, air, pollution, heat, humidity, and the like.

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CHEMICAL DEGRADATIONWATER• Water can dissolve or deform ceramics that have been low fired, i.e.

temperatures around 600 °C. Ceramic fired in high temperatures may also be susceptible to water if their mineral particles are soluble in water, for example Gypsum or calcite.

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CHEMICAL DEGRADATIONSOLUBLE SALTS• A common degradation issue in ceramics involves soluble salts.

Soluble salts can either enter the clay body from the environment, for example from being buried underground for decades, or they are already naturally occurring due to the components of the materials or clay used.

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CAUSES OF DEGRADATION o Life span of ceramics can be increased by controlling the

environment they are exposed to; operational load sand temperatures; altering the component design.

o Factors effecting life of ceramic components include: temperature, external loads, vibrations, environment, etc.

o In high humidity salts become soluble and in low humidity they crystallize. The changing from soluble to crystallization and back damages the surface of the ceramic because salt crystals are larger than liquid salt and therefore will shrink and expand the ceramic body. Overtime the physical component of the body will crumble until it is completely destroyed.

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HOW TO PREVENT DEGRADATION OF CERAMICS?o In the realm of conservation there are two distinct practices: non-

interventive and active conservation. Non-interventive types of conservation are used to control the surrounding environment such as light, humidity, and temperature. Active conservation is when a conservator practices treatments to alleviate physical problems in the object such as fading, chipping, or breaks.

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HOW TO PREVENT DEGRADATION OF CERAMICS?• Ceramics are utilitarian, some pieces are made to be artwork and

therefore displayed. Displaying an object improperly can cause damages either physical or chemically from the environment. One of the most common causes for damages is a ceramic piece falling over or off a shelf. To prevent this issue, many historic houses will line storage and display shelves with a thin layer of ethafoam (polyethylene foam) or bubble wrap.

DISPLAY

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HOW TO PREVENT DEGRADATION OF CERAMICS?• A blue board box with an acrylic plastic lid. The ring is laid upon a

layer of carved ethafoam to prevent it from shifting during handling.• The most common way in which ceramics become damaged is when

they are stacked one inside the other. Unless this is part of the original design, this will typically cause nicks, cracks, or breaks.

STORAGE

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HOW TO PREVENT DEGRADATION OF CERAMICS?• One of the cardinal rules in object handling is to treat every object as

if it is fragile and easily breakable.

HANDLING

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SUMMARY

o The Degradation of ceramics as a result of the interaction between the environment or with the materials that form the object however, in the case of ceramics, environmental factors are the major cause. There are several ways in which ceramics break down physically and chemically.

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REFERENCES

owww.conservationregister.com/downloads/ceramic.pdfowww.liverpoolmuseums.org.uk/conservation/departments/

ceramics/questions.aspxo en.wikipedia.org/wiki/

Conservation_and_restoration_of_ceramic_objects