The Impact of Selected ESD Parameters on the Properties of Tungsten Layers

TL;DR

The study examines how different ESD parameters affect the properties of tungsten layers deposited on cast iron, focusing on layer thickness and wear resistance.

Contribution

A novel two-factor, five-level Hartley experimental design is applied to optimize ESD parameters for tungsten layer properties.

Findings

Higher voltages during ESD result in thicker tungsten layers and reduced sample wear.

Increased capacitor capacity leads to increased counter-sample wear during friction tests.

Tungsten layers significantly increase the hardness of cast iron by over 400 µHV.

Abstract

This article presents studies of surface layers produced by electro-spark deposition (ESD) on cast iron using a W-Ni-Co sintered electrode. To minimize the number of required experiments, a two-factor, five-level Hartley experimental design was chosen. The assessment involved observing the effect of voltage and capacitor capacity during the ESD process (on layer thickness and wear of the sample and counter-sample under technically dry friction conditions). Microscopic and tomographic observations were performed to analyze the thickness and structure of the layers. Image analysis methods were employed to examine the cross-section of the layers. ESD diffusion analyses were performed on the produced layer. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were performed to characterize the microstructure and composition of the coating. In addition, in order to evaluate the performance properties of tungsten coatings, the tribological tests were also conducted on a TRB3 Ball-on-Disc testing device. Hardness tests confirm an increase in the hardness of cast iron with a tungsten layer by over 400 µHV. The tests showed that higher voltages during the ESD process result in thicker layers and reduced wear of the sample with a tungsten layer at the expense of increased wear of the counter-sample (ball).

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