The High Temperature, High Pressure, In Situ Atomic Force Microscope

Mar 7, 2017

Objective

Existing AFMs operate largely in laboratory temperature and pressure environments. A number of heated stage options exist for samples in a gas environment - this way a small sample area (since the sample itself is small) is heated to the desired temperature with the rest of the microscope operating as normal since it is not significantly heated up. On the high pressure front, pressurized gaseous environment chambers have been explored (still at a fraction of our desired pressure of 17MPa) as well as pressurized supercritical CO2 devices. The purpose of our AFM is to explore the previously inaccessible region of materials in high temperature (350C) high pressure (17MPa) water and steam (air would also be possible - but for high temperature air other existing designs could be used). These conditions - water approaching the critical point - are relevant to power plants where water is used as a heat transfer fluid (which includes non-gas fossil fuel plants, geothermal plants, and nuclear plants) since thermodynamically the highest efficiency of energy generation occurs at the highest temperature difference - so these industries have an incentive to use as high a water temperature as reasonable (and have already taken steps to do so - opposing factors include materials degradation at high temperature and safety concerns). There are a number of existing problems that this AFM will enable us to explore directly - corrosion of materials under these extreme conditions, interparticle forces, and fouling processes.

Photos


An interferometric test apparatus to prove the concept of nanoscale actuation through a pressure boundary, using sealing elements as flexures.

Results

Presented at 2017 EUSPEN international conference (upcoming)