There are so many forms of corrosion that you have to go back to the basics in order to name them all.
Corrosion starts by two things the activity of the surface molecules and the presents of oxygen. If you take away one of these then you have stopped the corrosion process from occurring. TDZ, is a cathode to everything under zi-fe on the galvanic cycle chart with an OCP (open circuit potential) of -.820 to -.850mV. Everything has an electric current running to it and from it. The cross over of different metals being bonded, welded together only makes the situation worse for the less noble metals and can lead to total failure of the joining metals. TDZ, acts as a barrier after the Gamma phase and as a cathodic solution in the eta, zeta and delta phases of the alloy coating. It does not allow corrosion to reach the substrate and dis-allows the metal substrate to reach oxygen allowing the zinc-alloy to carry the current.
(TDZ) works well as a bolt, spring, tension metal protection. It also works well as an over lay on welds and cladding materials. The TDZ, acts as a barrier to H2S from reaching tensile metals and welded materials. Two substrates which absorb H2S, in their environment and become brittle.
With attributes such as a metallurgical bond with the substrate #1, a metal alloy itself. #2 you have an OCP = -.850mV, which is a lot closer to the substrate material it is trying to protect, but still anodic. #3 the surface alloy acts as a barrier and as a anode and can be applied thin or thick evenly over threads.
Having TDZ over threads protects the tension metal from hydrogen embrittlement, shear and tension, it works best when it is applied thick on the threads and replaces the internal threads. 2mils of TDZ would need to be over tapped by 20 mils. The TDZ would then replace the over tapped metal and should easily pass a proof load test. With a corrosion rate of 3100 salt spray hours til red rust, we should see a very long life. Never the less, the CoF will remain .13 constantly in the 2 mil thick surface alloy.
Corrosion starts by two things the activity of the surface molecules and the presents of oxygen. If you take away one of these then you have stopped the corrosion process from occurring. TDZ, is a cathode to everything under zi-fe on the galvanic cycle chart with an OCP (open circuit potential) of -.820 to -.850mV. Everything has an electric current running to it and from it. The cross over of different metals being bonded, welded together only makes the situation worse for the less noble metals and can lead to total failure of the joining metals. TDZ, acts as a barrier after the Gamma phase and as a cathodic solution in the eta, zeta and delta phases of the alloy coating. It does not allow corrosion to reach the substrate and dis-allows the metal substrate to reach oxygen allowing the zinc-alloy to carry the current.
(TDZ) works well as a bolt, spring, tension metal protection. It also works well as an over lay on welds and cladding materials. The TDZ, acts as a barrier to H2S from reaching tensile metals and welded materials. Two substrates which absorb H2S, in their environment and become brittle.
With attributes such as a metallurgical bond with the substrate #1, a metal alloy itself. #2 you have an OCP = -.850mV, which is a lot closer to the substrate material it is trying to protect, but still anodic. #3 the surface alloy acts as a barrier and as a anode and can be applied thin or thick evenly over threads.
Having TDZ over threads protects the tension metal from hydrogen embrittlement, shear and tension, it works best when it is applied thick on the threads and replaces the internal threads. 2mils of TDZ would need to be over tapped by 20 mils. The TDZ would then replace the over tapped metal and should easily pass a proof load test. With a corrosion rate of 3100 salt spray hours til red rust, we should see a very long life. Never the less, the CoF will remain .13 constantly in the 2 mil thick surface alloy.