Experimental Investigation of Displacement/Strain Fields in Metal Coatings Deposited on Ceramic Substrates by Thermal Spraying

Abstract

The paper presents the initial results of application of the high sensitivity grating interferometry (GI) method in order to measure the displacement and strain fields in copper and titanium coatings thermally sprayed onto alumina ceramic (Al2O3). The residual stresses had been relieved by iterative cutting method, which was applied twice. The displacement maps of u and v were measured after each cut and εxx and εyy maps were calculated. The results clearly show the presence of εxx strains relieved along the second cut. The comparison of both samples confirmed that residual strains in Ti/Al2O3 are more significant than in Cu/Al2O3 system. The result after relevant postprocessing had been supplemented with the sub-surface principal residual stresses measured in the selected point by the x-ray diffraction method and curvature measurements.

Structure and Selected Properties of Arc Sprayed Coatings Containing In-Situ Fabricated Fe-Al Intermetallic Phases

“…Specific to intermetallic phases is their high electrical resistance at room temperature. The materials owe their peculiar properties to an ordered crystal structure with strong chemical bonds, combined with a dense packing of atoms in space, which results in a reduced diffusion speed and increased resistance to creep, recrystallization and high-temperature corrosion, compared to traditional metal alloys [21][22][23][24][25][26][27][28][29][30]. The main issue that makes the use of Fe-Al coatings more difficult is due to their brittleness in surrounding temperature and the difficulty of shaping ready-made elements to desired dimensions via mechanical machining methods [31][32][33][34][35].…”

“…This is due to the interesting use properties and a structure that results from the regular, spatially centerd structure A2, thereby fulfilling the von Mises plasticity criterion. 30]. The main issue that makes the use of Fe-Al coatings more difficult is due to their brittleness in surrounding temperature and the difficulty of shaping ready-made elements to desired dimensions via mechanical machining methods [31][32][33][34][35].…”

Properties and Structure of Deposited Nanocrystalline Coatings in Relation to Selected Construction Materials Resistant to Abrasive Wear

“…Nanomaterials are classified as single or multiphase polycrystals characterized by a grain size on the order of 1 × 10 −9 m to 250 × 10 −9 m in diameter. At the upper limit of this range, the term “very fine” is used with respect to grain size on the order of 250–1000 nm in diameter [20,21,22,23,24,25,26,27]. Nanocrystalline materials are structurally characterized by a high volume fraction at the grain boundaries, which significantly changes their physical, chemical and mechanical properties in comparison to conventional coarse grains, whose grain size is usually on the order of 10–300 µm.…”

Testing of Flame Sprayed Al2O3 Matrix Coatings Containing TiO2

“…The aim of the study was to produce a ceramic coating on the base of Al 2 O 3 with a low content of TiO 2 by cold flame spraying (with minimal pre heating to the range of 40°C) to ensure high hardness and high adhesion. Formation of thin ceramic coatings by flame spraying with such characteristics is relatively difficult to obtain [7][8][9][10][11]. Parameter optimization of spraying and the use of the primer coating such as: Ni-Al-Mo, could minimize the stress level between the substrate material and the coating, at the same time ensuring its high resistance to abrasive wear, erosive wear and also to the cyclic heat stroke.…”