Thin coatings by plasma spraying on thin substrates

AGEORGES HELENE; GONG HAOCHEN; CADUS LUIS E.

Limoges

Congreso; 7th Les Rencontres Internationales sur la Projection Thermique; 2015

In order to reduce the consumption of energy and the size of components, these last years,new nanomaterials and nanotechnicshave been developed to various applications.It is the case of the SuspensionPlasma Spraying (SPS) process which had been developed to spray nanometric powders in a plasma to manufacture coatings with nanometric structure.This process is used in this work to obtainthin coatings with a nanometric structure on thin substrates in order to use to realize a micro-reactor.The purpose of the study is to perform alumina layer by suspension plasma spraying on of a fifty micronin thickness substratemade of 316L stainless steel.The alumina powders used is AKP30 with an average particle size of 300 nm. Two kinds of substrates are used: flat and wavy substrates.A mixture of argon and hydrogen is used as plasma forming gas and current intensity varies from 500 to 700 A. The spray distance is adjusted according to the plasma for not damaged the substrates.The coatings obtained show a uniform layer ofabout forty microns, with a slightly smaller thickness on the wavy substrate (cf. Figure 1). The microstructure is a combination of melted granular and porous particles. The crystalline phases are α-alumina and γ-alumina. The adhesion of the coating on the substrates depends on the plasma conditions.