As we know gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression.
Typically used flat materials to create gaskets include:

paper
rubber
silicone
metal
cork
felt
neoprene
nitrile rubber
fiberglass
PTFE
plastic polymers

Metallic gaskets are made from a single metal or a combination of metals, which allows for surface sealing of a higher-quality as compared to their non-metallic counterparts. These  
gaskets are ideal for medium- and high-pressure applications, and are designed to resist extreme temperatures and pressures, as well as chemical exposure.

Available in regular and custom configurations, metal gaskets are produced in a wide range of material combination to accommodate all types of applications such as use in heat exchangers, compressors, condensers, pumps, valves, and turbines.

Some examples of metallic & semi-metallic gaskets are:

Camprofile or grooved gaskets - These are perfect solutions for sealing of media under extreme operating conditions, such as high operating pressures and temperatures. They combine the specific properties of soft material gaskets? i.e. great alignment onto the flange sealing surface and metal gaskets i.e. high stability and rupture strength.

Metal jacketed gaskets - These consist of a metallic outer shell with either metallic or non- metallic compressed fiber filler, that gives the gasket resilience, while the metal jacket  
protects the filler and resists pressures, temperatures, and corrosion.

Ring joints - Ring-type-joint (RTJ) gaskets are commonly used in offshore oil and gas pipelines where high-pressure conditions are prevalent.There exists apassage hole in these that permits pressure equalization on both sides of the sealing surfaces. 

Spiral wound gaskets - This is the perfect solution for flanged joints, heat exchangers, boiler handholes, manholes, and other high-temperature, high-pressure applications—providing resistance to precisely every known corrosive and toxic element.

Corrugated metal gaskets - Corrugated metal gaskets are manufactured from corrugated metallic rings in a wide range of materials. They are a universal gasket for a range of applications but are particularly suited to applications involving narrow flanges or where bolt loads are low.

NewAge Scaffolding has been a reliable source of high quality metallic gaskets in Delhi and entire North India.