Research On Abrasive Wear And Corrosion-Resisting Property Of Coatings On The Pump Of Coal Water Slurry

Plasma sprayed coatings are effective to solve wear and corrosive problems in coal water slurry pump. The abrasive wear and corrosive-resisting properties of Al2O3/Cr ceramic composite coatings, Ni60 alloy composite coatings and WC-12wt%Co coatings have been investigated. By measuring wear volume loss, wear and corrosion-resisting coatings suitable for coal water slurry pumps service environment have been optimized. And the best parameters for plasma spraying sintering broken type WC-12wt%Co powders were optimized. Therefore the theoretic foundation has been formed for making plasma sprayed coatings in coal water slurry pump.In order to simulate the coal water slurry pumps service environment better, the self-designed and built multi-function wear test machine has been used in abrasive wear and corrosive wear experiments.Experiments were mainly undertaken in 3 aspects: abrasive wear, corrosion and corrosive wear. And wear mechanism is analyzed. In this paper, some important conclusions have been drawn as following:1. By testing the abrasive wear properties of Al2O3/Cr ceramic composite coatings, Ni60 alloy composite coatings and WC-12wt%Co coatings, the best abrasive wear-resistant material for plasma sprayed coatings is WC-12wt%Co sintering powders in the form of broken type.2. The best plasma spray parameters for WC-12wt%Co coatings are: spraying power 27kw, Ar current volume 51.6 dm3/min , spraying distance 80-110 mm3. Abrasive wear mechanism of WC-12wt%Co coatings is a blend of microscopic cutting, plough ditch plasticity deformation, microscopic rupture (flake off) wear and fatigue wear. And microscopic cutting, plough ditch plasticity deformation and microscopic rupture (flake off) wear are main abrasive wear mechanism in WC-12wt%Co coatings.4.WC-12wt%Co coatings have better corrosion-resistant to sparse HC1 and H2SO4 solution. The corrosion course of WC-12wt%Co coatings includes both coatings self corrosion, which matrix phase is mainly corroded and that between coatings and matrix interface. And matrix is mainly corroded while corroded with coatings, and the reason that causes corrosion is due to coatings connected pores.