Drill string elements, used in the oil & gas industry commonly employ rotary shouldered connections. These connections are either standard API connections or connections that are developed proprietarily to provide increased torque capacity, fatigue performance and higher connection reliability. A wide variety of alloy families are used for drillstring components, and they exhibit very different galling behavior during make up. The non-magnetic austenitic stainless-steel drillstring components from the CrNiMo family or the nickel alloy family are prone to galling at the connection. This study focuses on thermally diffused zinc (TDZ) as an effective solution to galling issues seen on rotary shouldered connection. The effectiveness of the coating was studied by performing both multi-cycle, lab-scale galling tests as well as full-scale connection testing. Its corrosion performance was studied using electrochemical methods such as open circuit potential and cyclic potentiodynamic polarization, along with high temperature immersion testing. Its corrosion and fatigue impact on the different substrate materials were evaluated using rotating bending fatigue testing and stress corrosion cracking tests. Finally, metallurgical characterization tests were performed to understand the diffusion process and phase formation at the interface on the different alloy substrates. The results from this study established that TDZ is an effective gall resistant coating for CrNiMo austenitic stainless steel-based drill string components.