An Experimental Approach to Gain Insight Into Cold Gas Spraying of Ceramics

Abstract

In this study, an experimental approach to investigate basic dependencies on impact and bonding of agglomerated ceramic particles in cold spraying is presented. Single impact morphologies of ceramic particles obtained from wipe tests are correlated with data obtained from powder compression experiments with a modified nanoindenter. Different feedstock powders of agglomerated TiO2-nanoparticles were used and also partially heat treated. The powder shapes and sizes prior and after the compression tests were analyzed by confocal microscopy. The single particle impacts were characterized by SEM. Besides the expected influence of substrate material, substrate temperature, and spray conditions, the deformation and bonding of ceramic particles to metal substrates critically depend on the powder properties. To which degree particles fracture or contribute to layer formation upon the high-energy impact is highly correlated to their individual deformation behaviour in quasi-static compression tests.

Features of ceramic nanoparticle deformation in aerosol deposition explored by molecular dynamics simulation

“…Examples include application of finite element method (FEM) [26][27], molecular dynamics (MD) [35][36][37][38], smoothed particle hydrodynamics (SPH) [31] and nonlinear transient FEM [39,40] in the study of particle impact in AD. Based on these studies, various bonding mechanisms have been proposed for AD [26][27][31][32][33][34][35][36][37][38][39][40]. The main proposed mechanisms are (1) room temperature impact consolidation (RTIC) [26][27][35][36][37][38][39][40], (2) fragmentation and packing [31], (3) interlocking along with creation of highly activated surfaces [32,33], and (4) 'shear localization' [41].…”