Thermal Barrier Coating Aluminum Substrate for corrosion resistance

[alaskangrown]

Hello,

I've read this board here and there and did as much searching as one can do on the internet as well as on this forum. I was not lucky enough to find the answer that I am seeking. If I missed low hanging fruit, please excuse me for missing it.

I have a component made of aluminum that is experiencing accelerated corrosion as a result of the environment it lives. This component is used as an exhaust cone, yes I know... why Al?!, and operates at around 200F. The corrosion is likely the result of a few things but I am willing to guess at this point. I believe the exhaust gases, thermal cycling and anodized coating are all a factor. My hope is that someone here knows a little about using thermal barrier coatings (TBC) on internal combustion engine components made of aluminum.
I am aware of TBCs use in internal combustion engines but TBC coatings are not used, to my knowledge and research of multiple OEM manuals, on turbine engine aluminum components. All turbine section parts (except this exception!) are not made of aluminum.

I have to be slightly vague for obvious reasons for I'll sum it up again:
Aluminum substrate operating at 200F
Seeking TBC coating/method to protect the substrate surface exposed to hot exhaust gases.

Thank you for any thoughts you might have!

AG

[Vadim Verlotski]

Dear alaskangrown,

I propose a new thermal barrier and corrosion-proof coating for aluminum, designed to protect of pistons from internal combustion engines.

Properties of the coating:

Hardness (20°C): 350-380 HV0,2
Elastic modulus (20°C): 95-102 GPa
The strength of the four-point bending (20°C): 220-250 MPa
The strength of the four-point bending (550°C): 190-210 MPa
Bond strength to the Al-substrate (20°C): 100-150 MPa (corresponds to the strength of cast aluminum alloys Al-Si)
Specific heat (20°C): 0,57 J/gK
Thermal diffusivity (20°C): 1,9 mm2s-1
Thermal conductivity (20°C): 4,9 W/mK
Density (20°C): 4,8 g/cm3
Porosity: < 0,5%
The maximum temperature at the interface with the AlSi-substrate: 500°C
The maximum temperature on the surface of the coating: 800°C


The coating is applied by atmospheric plasma spraying (optimally at device - Axial III). Coating thickness can choose between 0,1-3 mm.

Coating intended to reduce the temperature on the surface of the piston and enhancing engine efficiency. Furthermore, the coating protects the surface of the piston against corrosion in combustion products comprising sulfur.

Regards

Vadim Verlotski
   

[alaskangrown]

Whom is the coating's manufacture and does it have a name?
What is the general chemical composition?

[Vadim Verlotski]

Whom is the coating's manufacture and does it have a name?
What is the general chemical composition?

The coating is produced by Märkisches Werk GmbH (patent 2008). The coating consists of three phases: nichrome, silicate glass and cristobalite.

  US20140302299A1.pdf (Size: 359.89 KB / Downloads: 631)
   

[alaskangrown]

Thank you Vadim