Phosphate Surface Treatment for Improving the Corrosion Resistance of the C45 Carbon Steel Used in Carabiners Manufacturing

Abstract

This study approaches the issues which appear during carabiner use and analyses the possibility to eliminate them. Therefore, to improve the corrosion resistance of carbon steel, used in carabiners manufacturing, three different insoluble phosphate layers were deposited on the samples’ surface. The layers were obtained by immersion in zinc-based phosphate solution, zinc/iron-based phosphate solution and manganese-based phosphate solution, Afterwards, to protect against mechanical shocks, a layer of elastomer-based paint was deposited. Furthermore, to reduce rope wear by decreasing the value of the coefficient of friction, the samples were impregnated in molybdenum disulfide-based lubricant. This study aims to analyse the corrosion behaviour of the layers deposited on the carbon steel surface in three of the most common corrosive environments (rainwater, seawater and fire extinguishing solution) by linear and cyclic polarisation. The overall results show that all types of deposited layers increase the corrosion resistance of C45 steel. The experimental results revealed that the samples coated with a phosphate layer obtained by immersion in the zinc-based phosphate solution possess the highest corrosion resistance among the phosphate samples.

Immersion Behavior of Carbon Steel, Phosphate Carbon Steel and Phosphate and Painted Carbon Steel in Saltwater

“…Thus, the samples were immersed in the solution for 30 min at a temperature of 95 °C ± 2 °C. At the end of the phosphating process, the samples were dried for 4 h in an oven at 120 °C [ 17 ].…”

“…According to previous studies [ 15 , 16 , 17 , 18 ], phosphating is one of the most widely used methods of protection against corrosion in metals [ 19 ]. The phosphating process consists of, with the help of a phosphating solution, a layer of zinc, iron, or manganese phosphate (depending on the major constituent of the phosphating solution) on the surface of the metal [ 20 ].…”

“…However, to our knowledge, there is no study which approaches the corrosion behavior evaluation of the carbon steel coated with Zn/Fe phosphate layer and phosphate-painted carbon steel immersed in a natural saltwater environment. Based on previous preliminary studies [ 17 , 26 ], the goal of this study is to analyze the influence of immersion time in saltwater of three types of samples: carbon steel, phosphate carbon steel, and phosphate and painted carbon steel, while a new phosphating solution suitable for carbon steel coating was introduced. Moreover, the corrosion mechanism and parameters for different immersion times were analyzed using EIS, SEM, and EDS.…”

Phosphating Depositions for Equipment’s Used in Explosive Atmospheres

“…According to the results obtained from previous tests [16], it was considered that 3 types of tests should be used for the impact test, these being presented in Table 1. The phosphating process included several steps aimed at preparing the material for the deposition of the phosphate layer, as well as its actual deposition by immersion for 30 minutes in the phosphating solution, followed by drying the samples [15].…”

Investigation on the Surface Quality of Böhler S290 Powder Metallurgical Tool Steel After Wedm Machining

“…On the material surface are developing a heat affected zone with different surface morphology. This surface consists white layer with hollow cavities, micro-cracks and craters [4][5][6]. White layer is a hard skin on the WEDM machined material surface formed due the resolidification of melted residual material which was not completely flushed by the dielectric liquid [7].…”