The mid-nineteenth century saw the conception of a conical shaped spring disc. This spring disc was subsequently termed a belleville washer after the name of its originator

Belleville Washers
Heavy Duty Belleville Washers to DIN 6796

Phosphating : A zinc phosphate coating usually with subsequent oil or wax treatment. This treatment is widely offered as 'standard' on most stock-range carbon steel disc springs. The protection offered is sufficient to prevent corrosion throughout storage and normal transit conditions. It is adequate also for those applications where the disc springs are not directly exposed to the elements. However, where the application involves a more hostile environment, i.e. disc springs open to weather or marine conditions, chemical or acid laden atmosphere, etc; then a superior treatment or material must be considered.

Mechanical Zinc Plating : This is a method of depositing substantial thicknesses of zinc on the surfaces of disc springs without the risk of 'hydrogen embrittlement' associated with normal electro-plating. The zinc is impacted onto the surfaces by way of tumbling the disc springs in a rotating barrel, together with glass beads, metal powder, and promoting chemicals. In addition to removing the risk of embrittlement, the 'peening' aspect of this process is beneficial in terms of some stress relieving of the components. There are two forms of subsequent passivation treatment.