Dear All,
I want to use non-conductively coated & programmable shape memory alloy.
However, to program SMA, I need to heat it up around 500 °C .
I'm thinking of 2 options:
1. find heat-resistant coating materials
2. find SMA which can be programmed in lower temperature.
Anyone who know something, please give me a help.
I'd love to study your references or links.
Thank you!
You could 'Google' the term "Accident Tolurant Fuel" for nuclear reactor based on coating of zirconium alloys. There are a lot of investigated heat resitant coating: Ti3SiC2, Ti3AlC2 , SiC, Fe-Cr-Al, TiO2, ZrO2, Cr-Ox, YSZ, NiZr, Al2O3, Al3Ti(Cr), TiN, ZrN, NiNх, CrN
dear nho Kang
I suggest Alumina powder coating by thermal plasma spray. it produces a hard, dense, high dielectric coat with high thermal resistance.
Inho Kang You want to store the shape of base structure and got to operate at 500C?
Just look at TiN or WC depending on the application. They work very good with M50 Steel and 100CrMn Mo8 materials for tooling purposes and they can sustain extreme load and pressure.
You may use diamond like nanocomposite thin film coating, it can withstand up to 600 degree.
dear Inho Kang;
DLC stand for Diamond-Like Carbon Coating it can be applied by : chemical vapour deposition (CVD) and physical vapour deposition (PVD).
Yes DLC may be used but thermal stability of DLN is much better than DLC.
Inho Kang
What is the purpose of this actuation device? There are some SMA with considerably lower transformation temperatures than 500°C. You should look for Ni-Ti alloys or NiTi with ternary additions, which usually have tunable transformation temperatures near to room temperature. I think you could find interesting information in Shape Memory Materials book, by Otsuka and Wayman. I don't know exactly the goal of your project but I think this book can guide you to your material choice.
In this book you might also find information about how to produce a shape that is recovered upon heating of your device. I did not understand what is your problem, whether if you want to produce an actuator that works at 500°C or if you want the temperature resistant material just for conformation of your SMA.
Regards
The HVOF thermal spray system utilizes high-pressure combustion (6–10 bars for the HVOF spray system of third generation [13]) of oxygen and gaseous fuels, such as hydrogen, propane, and propylene, or liquid fuels, such as kerosene. Combustion produces a flow of hot gas at supersonic or hypersonic velocity of approximately 2000 m/s [19, 22–24]. The flame achieves supersonic velocities in the process of expansion at the exit of the convergent-divergent nozzle with a diameter size from 8 to 9 mm [13, 22] and temperatures in the range of 2500–3200°C, depending on the type of the fuel, the fuel-to-oxygen ratio, and the combustion pressure.
link .Article Ni-Ti Shape Memory Alloy Coatings for Structural Application...
yes dr Saad, most conventional thermal barrier coating are non conducting and withstand high temperature
I think Zirconia will be the best. It will handle low to high pressure applications
Thank you everyone.
Saad Kariem Shather Thank you for the pdf link :)
Gabi Nehme Zirconia... I'm not used to it. May I ask whether it is stiff or not? I mean I need to bend when I shape-set NiTinol, and I'm worried that it may be cracked. I have no sense of this material. Thank you for the answers you've given to me.
Alisa Buchman Thank you for recommending me many materials. I will study about them. However, I'm looking for SMA coating material and I'm going to 1st coat and then 2nd shape set. So I'm afraid that ceramic coating may be cracked while I'm shape-setting. Can it be bent fairly well??
Jaafar Hadi Abboud I'll study about thermal barrier coating. Thank you.
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