Would it be possible to delay the spread of fire from a failing battery module, by using a thermally protective coating?
Safety is a key aspect in lithium ion batteries. If the spread of fire could be delayed it would give longer time for people to evacuate. Is a thermally protective coating a viable solution or are there other better suited solutions to delay spread of fire? How could one simulate/modelling and then verify experimentally in a smaller scale?
How much heat dissipation can a thermally conductive interface tape offer and how can it be measured?
Thermally conductive interface tapes are used in certain electronic applications where it is important to have good heat dissipation throughout the lifetime of the application. Results from thermal conductivity measurements can vary significantly depending on method etc.
What polymeric coatings are available (besides Teflon) that can enhance the antifouling and anticorrosive properties of steel? And how to promote their interfacial adhesion?
Substrate – stainless steel. The mechanical properties of the coating will be very important to us, especially wear resistance.
How could it be studied the erosion resistance of metallic and polymer materials?
We would like to explore the possibility to set up database of erosion resistance of Alfa Laval presently used metallic and polymer materials. (We have worked with Ångström laboratory before studying our diamond composite and carbide/metal composites by use of your test rig).
What is the underlying mechanism that gives an exponential increases of the air conductance as a function of humidity under electrical stress ( 0.5 to 2.0 kV/mm): Electrochemical reaction including water at the electrode?
The conductivity of air is an important parameter when designing HVDC insulation systems. It is recently found that the conductivity of air (in the field range 0.5 to 2.0 kV/mm) have an exponential behavior of humidity as well as the electrical field. The earlier picture in the power industry was that the conductivity was limited by charges generated by background radiation and had a very week dependence of both electrical field and humidity. The strength of the humidity dependence increases with increased electrode surface roughness Indicates that the humidity dependence of air conductivity is an electrode surface effect.
High-strength cellulose-based materials
Is it possible to improve the mechanical performance (by a factor 5-10) of the current solid insulation materials? The other physical properties should remain unchanged (or be improved)
– Using additives
– Mixing with stiffer materials
Is it possible to study the interaction/adsorption of naphtenic, paraffinic and aromatic molecules on cellulose surfaces? The goal would be to study adsorption strength and charge transfer.
The electrical insulation of power transformers consists of mineral oil and impregnated cellulose. Mineral oil consists in the first placed of napthenic and paraffinic molecules. A better understanding of the properties of the oil cellulose interface could help to improve the electrical insulation.
As a first step an investigation of cellulose and the respective molecules could be done.
How to determine physical properties of narrow brazed joints that have a different microstructure and composition than the bulk brazing filler metal?
We see an increased use of computer assisted modelling as part of the design process of brazed components, and get requests for what physical properties such as thermal expansion and density that can be used for the brazed joints which connect the different base materials.
As an example, we consider Ni-base brazing filler metals which in addition to Ni are alloyed with other elements to either provide certain properties such as corrosion or oxidation resistance (Cr, Si, Mo etc.), or elements that depress the melting point of the alloy so that it melts at a lower temperature than the base materials to be joined (Si, P, B etc.)
The challenge in this case is that the brazing filler metal is relying on the capillary force to fill narrow joints (< 100-150 µm), and that the resulting "alloy" that fills the gap can have a different chemical composition to the bulk alloy by diffision of elements to/from the base material(s).
If a sample size sufficiently large to measure for example the thermal expansion would be prepared from the brazing filler metal, the microstructure of this would be a coarse casting microstructure and not representative for the “alloy” that is inside the joint.
Are there ways to approximate or determine the physical properties that can be representative for what is actually in the component?
Nickel diffusion into iron – How to control the diffusion to form a thin surface layer on irregular iron particles?
Metallic nickel deposited onto pure ferritic iron will form an austenitic phase some distance into the iron upon heating, forming a gradient of nickel. However, how can the composition and thickness of the obtained Ni-enriched iron surface be controlled to e.g. 2:1 and <1µm?
If successful, this surface-alloyed powder would have similar compressibility as pure iron but superior properties as a powder compact.
3097: Regarding W(Re) legeringar: hur påverkar K-doping och Re-halten materialegenskaperna?
3100: Concerning Volframtråd: finns det någon mikrostruktur som gynnar rakheten på tråden?
3097: • Hur påverkas mekaniska egenskaper från 0 Kelvin till smältpunkten?
• Tänkbar applikation: att W-Re tråden används i rymden eller i flygmotorn.
• Vad vi vet: duktiliteten blir bättre och resistiviteten blir högre jämfört med ren W.
3100: • Tråden blir ofta lockig efter dragningen och därför behöver sträckas, riktas och/eller värmebehandlas för att få den rak.
• Därför är det intressant om det finns någon mikrostruktur eller kornorientering som underlättar rak- dragning eller sträckning. Om det är fallet hur kan man då få den önskade mikrostrukturen/kornorienteringen?
• Vi vet att värme och riktning/sträckning fungerar oftast men inte alltid.
PTFE replacement as dustbinding compound
Today we add a small portion (<1 %) of PTFE in our alkaline battery active materials during the final manufacturing step of the powder/granulate (blending or granulation). It has a proven dust reduction effect, but it is from an electrochemical point of view dead. Are there polymers or other materials that have a dust binding effect but at the same time are electrically conductive?
Our battery techno is alkaline NiCd and today we use the active material in a powder (nickel cathode) or granulate (cadmium anode) form that are subsequently compacted to oblong briquettes put in between two perforated steel strips.
How are nitrides affected by chromium and silicon in the steel matrix?
In the engine there is a small shaft that previously had a hard chrome coating. That is not allowed anymore, since chrome six is formed during the process. The shafts are therefore now nitrided. The base material is a martensitic chromium steel with about 9 % chromium and 3 % silicon. We are interested in investigating the thin nitride layers in composition and crystallography. The thickness is just a few microns. We know when ordinary steels are nitrided, we get two kinds of nitrides, γ´and ε with different amount of nitrogen. But we don’t know how the nitrides are affected by chromium and silicon in the matrix. One difficulty is that the shafts are quite small and have a diameter of 10 mm. The investigation would probably be made in SEM and perhaps X-ray diffraction or if there is another investigation method at Uppsala University that is suitable.