Why is argon gas used along with tungsten wire in an electric bulb?

Argon is an inert gas used in incandescent electric bulbs to significantly increase the life of the bulb. The primary function of filling the bulb with inactive gases like argon or nitrogen is to prevent the tungsten filament from coming into contact with oxygen, which would otherwise cause the filament to burn or oxidize rapidly [1]. In a vacuum, the tungsten filament evaporates quickly at high operating temperatures, leading to thinning and eventual breakage. The presence of argon provides an inert atmosphere that suppresses this evaporation and prevents oxidation [1]. By slowing down the degradation of the glowing thin wire known as the filament [2], the gas ensures the bulb remains functional for a much longer duration. While it does not reduce electricity consumption or change the light's color, it is essential for the structural longevity of the lamp.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Nitrogen > p. 272
2. [2] Science-Class VII . NCERT(Revised ed 2025) > Chapter 3: Electricity: Circuits and their Components > Incandescent Lamp > p. 26