The microstructure, hardness and wear properties of atmospheric plasma spray coating of TiO2 and Al2O3-13TiO 2 with incremental hydrogen fractions (11·1-23·8%) in primary gas have been investigated in this work. TiO2 coating shows a fine bead-like surface structure, while Al2O3- 13TiO 2 predominantly exhibits a splat-like morphology. The microstructure shows a slight refinement in the structure for the highest hydrogen content possibly due to the higher specific enthalpy of the plasma plume. Both coatings show the highest hardness for samples coated with the highest hydrogen content possibly due to the refined structure. The roughness shows a mild decreasing trend for TiO2 coating, while the reverse trend is observed for Al2O3-13TiO2 coating. The wear loss and friction coefficient show a flat trend (0·4-0·6) for all the hydrogen contents. The worn tracks show a compacted mixture of ceramic, graphite and metallic particles. © 2013 Institute of Materials, Minerals and Mining.

M. Kamaraj

Department of Metallurgical and Materials Engineering

Aluminum

Friction

Hard coatings

Hardness

microstructure

Plasma spraying

Titanium dioxide

TITANIUM PLATING

Wear of materials

ALUMINA-TITANIA COATINGS

ATMOSPHERIC PLASMA SPRAY

COMPACTED MIXTURES

Friction coefficients

Hydrogen contents

METALLIC PARTICLES

REFINED STRUCTURES

SPECIFIC ENTHALPY

Aluminum coatings

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Microstructure and dry sliding wear behaviour of titania and alumina-titania coatings

Surface Engineering

The influence of Cu and Ni nanoparticle suspensions (2 wt-%) in commercially available engine oil (15W40) has been investigated on friction and wear behaviour of Al2O3-13TiO2 coatings. Lab synthesised nano-Cu and Ni suspensions have been compared with one commercially available nano-Cu suspension. Results show that lab synthesised Cu and Ni increases the oil viscosity by 12 and 20% for Ni and Cu respectively. However, the commercially available nano-Cu has reduced the viscosity by 8%. Lab synthesised Cu and Ni showed slightly reduced friction coefficient with significantly higher mass loss compared to virgin base oil and commercially available nano-Cu. The abrasive nature of these particles may possibly predominate in higher viscosity medium generating steady wear particles from the softer counterpart. Commercially available nano-Cu shows higher and irregular friction profile with mass loss equal to base oil possibly due to reduced viscosity. © 2013 Institute of Materials, Minerals and Mining.

Lubricated sliding wear behaviour of Al2O3–13TiO2coatings

Fretting damage is normally expected in biomedical implants due to body movements. Titanium alloys are most commonly used for biomedical devices and surface modified alloys have superior tribological properties to virgin materials. In the present study, the fretting wear resistance of physical vapour deposition (PVD) TiN coated, ion implanted and thermally oxidised biomedical alloys have been investigated and compared. PVD TiN coating has shown the best fretting wear resistance with minimum friction coefficient, less wear scar depth and diameter, and minimum wear rate compared to other coatings. The ion implanted specimen has undergone fretting assisted electrochemical dissolution to give higher wear loss after the modified layer has eroded away. Thermal oxidation has shown intermediate response to fretting. Fretting resistance can be improved with layers of high hardness and thickness. © 2007 Institute of Materials, Minerals and Mining.

Fretting wear studies on PVD TiN coated, ion implanted and thermally oxidised biomedical titanium alloys

This paper reports on the sliding wear performance of the nanostructured Al2O3-13TiO2, ZrO2 and the bilayered (ZrO2/Al2O3-13TiO2) coated biomedical Ti-13Nb-13Zr alloy in simulated body fluid condition. The nanopowders were sprayed using an atmospheric plasma spray technique and the reciprocatory sliding wear behavior of all the above coatings was evaluated using wear testing machine. The bilayered (ZrO2/Al2O3-13TiO2) coating which has not been reported hitherto exhibited two hundred and five hundred fold increase in the wear resistances when compared with that of the nanostructured Al2O3-13TiO2 (AT) and ZrO2 (YSZ) coatings. This substantial improvement in the wear resistance of the bilayered coating is attributed to its lower porosity and higher adhesion strength when compared to the AT and YSZ coatings. This study suggests that this new type of bilayered coating may be a preferred approach to be tried for obtaining much higher wear resistant coatings. © 2011 Elsevier B.V.

Wear

Sliding wear behavior of plasma sprayed nanoceramic coatings for biomedical applications

Journal of Materials Processing Technology

Scratch induced damage in alumina splats deposited on bond coats

Variation of splat shape with processing conditions in plasma sprayed alumina coatings

Materials & Design

A study on sliding and erosive wear behaviour of atmospheric plasma sprayed conventional and nanostructured alumina coatings

Journal	Surface Engineering
Publisher	Maney Publishing
ISSN	02670844
Open Access	No