Stay Black Stainless
Stayblack is a chemical conversion which modifies the passive oxide layer of the stainless steel fastener leaving the coated steel matt black. Stayblack is not electrolytic, it is a barrel or vat process, and there is no possibility of hydrogen embrittlement that can occur in both steel and stainless steel fasteners that are coated by an electrolytic process.
The surface coating will not chip, peel or flake. Stayblack fasteners can be delivered dry or lubricated. Stayblack is used more specifically in military applications where a black, matt, non-reflective surface is essential for stainless steel particular for fasteners which need to retain a consistent and durable black appearance.
Stayblack is specified for fastener components in medical, optical and scientific equipment as well as for many varied aerospace applications. Stayblack withstands hot water, atmospheric weathering, and temperatures up to 500°C without any change in appearance.
Stayblack coating is less than 1µm thick and so will not alter any tolerance fits or change the dimensions of the fastener to any significant amount. Stayblack does not affect the inherent corrosion resistance of the base stainless steel and will remain colour consistent longer than an untreated stainless steel fastener. The IMDS reference number for Stayblack coating is 3130589.