Effect of critical plasma spray parameter on properties of hollow cathode plasma sprayed alumina coatings

S. Yugeswaran, V. Selvarajan, D. Seo, K. Ogawa

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

A 20 kW hollow cathode plasma spray torch was manufactured and its performances were examined by spraying alumina coatings on mild steel substrates with different critical plasma spray parameters (CPSP: 0.12, 0.24, 0.36, 0.48). CPSP is defined as the ratio between the torch input power and primary plasma forming gas flow rate. The effects of CPSP on the microstructure, porosity, microhardness, surface roughness, sliding wear and erosive wear properties of the coatings were investigated. The electrothermal efficiency and the excitation temperature of the plasma jet were also investigated for different CPSP. The microstructure and phase composition of the alumina coatings were examined using scanning electron microscope and X-ray diffraction (XRD) analysis respectively. XRD analysis revealed that alumina particles during plasma spraying reach sufficient melting state prior to the impact on the substrate with a velocity comparable to that of conventional plasma spraying. The experimental results have shown that the CPSP has significant influence on the microstructure and other properties of the deposited alumina coating. It also showed that the hollow cathode plasma spray torch is a suitable tool to coat the dense ceramic materials with low input power levels.

Original languageEnglish
Pages (from-to)129-136
Number of pages8
JournalSurface and Coatings Technology
Volume203
Issue number1-2
DOIs
Publication statusPublished - 2008 Nov 25

Keywords

  • Aluminium oxide
  • Hardness
  • Hollow cathode
  • Microscopy
  • Plasma spraying
  • Wear

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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