Materials Ceramics

Abrasives

Used to wear away other materials through sanding, grinding, lapping and pressure blasting. Rips away the softer material.

Friable

Materials form sharp edges when they break under stress from heat and pressure

Sandpaper

Hard particles bonded to a backing with resin. Most familiar abrasive product

Alumnia

Al2O3, most common abrasive, tough, hard, dense, and inexpensive

Garnet

A3B2(SiO4)3, not friable and less hard than alumina but produces a smoother surface and seals off the grain of wood

Silicon Carbide

Exceptional hard and friable material ideal for sanding metal, plaster, and fiberglass

Ceramic

Hardest and most expensive abrasive in which hard particles are deposited on a backing through sol-gel process

Powder Pressing

Particles are mixed with a binding agent that lubricates them during compaction and forced into a shape under pressure

Isotactic Powder Pressing

Ceramic material is placed in a rubber chamber and hydrostatic pressure is used to apply uniform pressure in all directions

Sintering

Particles are heated, causing the grain boundaries between them to coalesce

Silica Glasses

Non-crystalline material made from crystalline SiO2

Loose Networks

Tetrahedra form a with corner to corner contact

Network Modifiers

Metal oxides added to reduce the viscosity of loose networks

Intermediate Oxides

Used to enhance specific properties. Molecules incapable of forming their own network, but able to join the existing network

Cements

Any material capable of binding to other things

Hydraulic Cements

Requires water to form a solid

Non-Hydraulic Cements

Forms a solid without water

Portland Cement

The most common hydraulic Cement

A

AI2O3

C

CaO

F

Fe2O3

H

H2O

S

SiO

S^-

SO3

Evaporation

Dehydration in which excess water is driven off. 250-450C removes free water and 600C removes any other water

Capillary Pores

Open spaces between adjacent grains

Calcination

Calcium carbonate is converted to calcium oxide and carbon dioxide. 900C

Clinkering

Where calcium trisilicates form 1450C

Cooling

Heated materials return to room temperature

Gel Pores

Spaces working the C-S-H material

Refractories

Capable of withstanding high temperatures without melting, degrading, or reacting with other materials.

Refractory Types

Clays (12% Silica) and Non-clays

Fireclay

Most common refractory made from kaolinite

Recycling Ceramics

Unwanted Portland cement products are sometimes pulverized and used as aggregate for future materials

Cullet

Fine, ground glass powder used for recycling