Study On The Corrosion Behaviours Of Electrodeposited Tungsten Alloys In H₂s Environment And The Properties Of Pulse Electrodeposited Tungsten Alloy

The gas field in our country had high concentrations of hydrogen sulfide, energy needs in the gas or solution phase can attack oilfield equipment aggressively, and it causes great finan-cial losses. During the process of Oil extraction, the corrosion behavior of steel in the field containing H₂S is a most pressing problem. With the growth in energy needs in China,The safety exploration in H₂S field,especially in high concentrations, is very important for us. Studying how to effectivly in the prevention eroding in hydrogen sulfide solution is a top pri-ority.For decades, tungsten alloys had been studies wildly for their excellent properties, such as appearances, hardness, wear resistance, and et al, and their corrosion resistance is con-cerned extensivly. In recent years, most reserachers get the tungsten alloys by direct current and study their corrosion behaviors. So for the first time, we think the electrodeposition tech-nology of tungsten alloys may have great potential values in gas industrial applica-tion.Direct-current palting has many weakness during electrodeposition, for example, the sin-gleness of electrodeposition parameter, the unstabilization of electrolyte, unsmooth surface, and et al. Pulse electrodeposition can be used as a means to produce a unique structure, i.e. coatings with properties not obtained by direct current (dc) plating. Pulse electrodeposition yields a finer grained and more homogeneous surface appearance of the deposit, because a higher instantaneous current density is possible during deposition. Pulse plating also yields uniformity in alloy composition and grain structure, smoother and denser deposits with negli-gible porosity. In this paper, following researches were studied in detail.1. We obtained four tungsten alloys by direct-current plating under the same electrolyte and researched the corrosion properties in saturated hydrogen sulfide solution.2. We study the corrosion-resistence of sucker rods eroded in saturated hydrogen sul-fide solution through some methods, and compared to direct-current deposite.We want to prove that the protection of tungsten alloys is effectively.3. We reaserched the mechanism corrosion-resistence of the double Ni-Fe/Ni-W-P al-loy.4. Obtained tungsten alloy by pulse plated under the same condition to direct-current electroposition. The influence of pulse electrodeposition parameters on the texture , element and microhardness of tungsten electrodeposit was inspected particularly.