Correct option is A
Solid (pack) carburizing: The components are enclosed by a carburizing medium (compound) and mounted in a sealed box in solid or pack carburizing.
Barium carbonate is used as an
energizer in the
pack carburizing process. In this process, carbon is diffused into the surface of low-carbon steel to improve its hardness and wear resistance.
· The energizer, such as barium carbonate, decomposes during heating and releases carbon dioxide, which reacts with the solid carburizing agent (like charcoal) to form carbon monoxide.
· The carbon monoxide delivers carbon to the steel surface.
