Micro-nanojauges design to monitor surface mechanical state during high temperature oxidation of metals with application to 17-4PH stainless steel

Nanoparticles fabrication from RIE etching combined with a mask done by EBL technique. Oxide stress determination from nanoparticles displacement, during oxidation of 17-4PH stainless steel. • Nanogauges are designed for applications to high temperature oxidation. • Nanofabrication is explored through different deposition techniques to test and optimize different gauges materials. • Design and choice of materials is performed under specific criteria. • Uncertainties for stress determination within oxide layers by use of nanogauges are calculated. • Application for 17-4PH steel is performed, with identification of thermomechano-chemical parameters for oxidation at 480°C. Determination of mechanical state of thermal oxide growing during high temperature oxidation is a challenge. Fabrication of nanogauges for monitoring during high temperature oxidation was presently investigated up to 1000 °C. Several materials were tested in terms of mechanical behaviour and maximum working temperature for gauges used as markers during thermal loading under air. The experimental determination of the optimized gauges material for high temperature oxidation was validated. SiO 2 offers particularly interesting features for gauges to determine the mechanical state of metal/oxide system. In this article, a special attention has also been paid to two nano-fabrication processes, as well as their limits. The standard electron beam lithography process is well suited to build gauges for oxidation applications, and can be improved by use of reactive ion etching process. The gauges can eventually reach several micrometers height such that the oxidation layer does not cover the gauges during thermal loading for relevant monitoring at short oxidation times. To illustrate, an application to a 17-4PH stainless steel oxidized at 480 °C is proposed and stress kinetics are deduced and related to an advanced thermomechano-chemical model, as well as identification of the numerical values of different thermomechano-chemical parameters associated to mechanisms of growth or relaxation.