Research into Morphology and Properties of TiO2 – NiAl Atmospheric Plasma Sprayed Coating

Abstract

Titania (TiO 2 ) based coatings are ceramic products with unique properties that make them widely applicable (e.g. in automotive industry, optoelectronics, chemical processing or medicine). Atmospheric plasma spray process enables to deposit TiO 2 with addition of NiAl feedstock material which has an influence on coating cohesion and adhesion to substrate. However, the literature and technical notes give little information about parameters of spraying of TiO 2 -10 wt.% NiAl feedstock powders enables producing coating without nonuniformities including cracks and delamination form substrate. The aim of the work was to verify the parameters of plasma spraying by evaluation of the morphology and properties of manufactured the TiO 2 -10 wt.% NiAl coatings. Titania based coatings were deposited by means of atmospheric plasma sprayed on steel substrate using TiO 2 -10 wt.% NiAl feedstock powders. Morphology and microstructure were examined using light optical microscope (LOM) and scanning electron microscope (SEM). Coating chemical composition were analysed by means of SEM-EDS method. Coating surface topography and Knoop microhardness were determined. Porosity and thickness were evaluated by using quantities image analysis programme. Plasma spraying parameters used in our research allow to obtain uniform coating without cracks and delamination at coating-substrate interface. It acknowledges that uniformity of coating technological properties as well manufactured coatings can be put to wear tests, such as high temperature oxidation, corrosion, erosion or cavitation erosion resistance evaluation.

Impact of Atmospheric Plasma Spray Parameters on Cavitation Erosion Resistance of Al2O3-13% TiO2 Coatings

“…Nowadays thermal spraying of coatings is a relevant issue in the surface industry [1]. A lot of attention is paid to the complex deposits, derived from powders which are composed of different metals, hardmetals, and/or oxides [1][2][3]. One of those intensively studied powders are Al 2 O 3 + TiO 2 powders, most commonly sprayed with the Atmospheric Plasma Spraying (APS) method [1].…”

Effect of Atmospheric Plasma Sprayed TiO2-10% NiAl Cermet Coating Thickness on Cavitation Erosion, Sliding and Abrasive Wear Resistance

“…The two main phases in the structure were recognized as ceramic and metallic. The previous SEM-EDS studies [8] conducted for the as-sprayed coating structure, acknowledged that the phase, visible in the gray colour in Fig. 1, was mainly formed from TiO 2 ceramics and the lamellas visible in the white colour derives from metallic NiAl material.…”

“…TiO 2 -10 wt% NiAl coatings were deposited using atmospheric plasma spray (APS) by means of a Plamotron PN-200 facility onto the workpiece surface made of low alloy steel grade 40Cr4. The coating thicknesses equalled approximately 50 µm, 100 µm, and 200 µm and the deposition parameters were given in our earlier paper [8]. The coating microstructure was analyzed using a light optical microscopy (Axiovert 25, Carl Zeiss) and a scanning electron microscope (SEM, JSM-6610LV, JEOL).…”

“…containing: [2,[4][5][6][7]) or metallic (e.g. FeCrC, * corresponding author; e-mail: m.szala@pollub.pl CoCrW, NiAl, NiCrBSi [3,4,8,9]) based coatings, it also enables deposition of the composite system of ceramics and metallic phases which are known as cermets [10]. In addition, the deposition of cermet coatings is beneficial especially in the cases where ceramic coatings improvement of bond strength, impact strength, or shock resistance are needed.…”

“…Plasma sprayed TiO 2 -containing composite coatings have been used to resist abrasive, fretting, cavitation, and erosive wear [6,11]. TiO 2 -10 wt% NiAl cermet coatings have a unique composition and limited information is available in the literature [8]. However, the structure of the coating produced as cermet, that contains TiO 2 and NiAl, was not completely examined.…”