Composite material

A composite material is a material made by combining two or more different materials so that the product has better properties than any of the individual components on its own. Malay: bahan komposit · Chinese: 复合材料.

The point of a composite is to take the useful property of each material and leave its weakness behind. One material usually acts as a matrix that holds everything together, while a second material, often a fibre or a rod, is embedded in it to add strength. The finished composite can be stronger, lighter, stiffer or more corrosion-resistant than either starting material, which is why composites are chosen for demanding jobs in building, transport and electronics. Because the improvement comes from the combination itself, describing a composite always means naming both parts and the property each contributes.

Example. Reinforced concrete combines concrete with steel bars to be strong under both squeezing and stretching forces. Fibreglass combines glass fibre with plastic resin to be light, strong and corrosion-resistant, so it is used for boat and car bodies. Fibre optic cable and photochromic glass are further examples of engineered materials with tailored properties.

Confusion to avoid. Do not confuse a composite with an alloy. An alloy is a mixture of metals in which the main element is a metal, whereas a composite combines whole materials of different kinds, such as a metal with a ceramic or a glass with a plastic.

When you describe any composite, use the same two-part pattern every time: name the matrix material and the reinforcing material, then state the improved property that results. Following that pattern makes it easy to answer about a composite you have not seen before, because the structure of the answer stays the same even when the materials change.

Being able to define a composite and give a named example with its two components is a reliable one- or two-mark answer in SPM Chemistry.