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After coating by SS 321 by arc spray, we have to apply high temp. sealant. Can anybody suggest any heating blower, please? Being a confined space, only 24 V or 110 V machines are allowed for safety reasons.

Hi all,

First of all I would like to say this is a very interesting and useful forum. It would be great to have such a forum for every discipline of (mechanical) engineering.

My questions are about the surface roughness of TBC for industrial gas turbines.

-What roughness (Ra, Rz, Rmax, ...) values are used for turbine vanes and blades?
-Which processes are used to reach these values (grinding, blasting, vibratory finishing...)?
-Is efficiency the only reason to decrease the roughness? Or are there other (material) characteristics (like life cycle) positively influenced by lowering the roughness?

Many thanks for your replies.

Best regards,

Rogier Vermeulen
Student mechanical engineering

I work actually on spin coating, and I would like to make thin film of CuInS2 using this technique.
I'd like to use binder to improve my process, but I don't where to start.
So, can somebody help me? It'd be very nice
Thanks

Hi,

I am working at a university lab. We have a magnetron sputtering chamber, we generally coat Titanium Nitride, occasionally other coatings. We use both turbo and mechanical pump. We achive 5x10-6 torr when we wait overnight. But during the coating I can smell what we are coating. Because everything is under vacuum this shouldn't come from the chamber. How atoms escape from the chamber and what should we do about that?

Thanks,

For sale:

Sulzer Metco special purpose semi-automatic thermal spray system. Was used to molybdenum coat synchromesh rings for gear boxes. This equipment is about 10 years old and said to be in good condition and little used.

The system comprises of 2 type 5K guns with type 6CE control units, booths, automatic handling and grit blasting equipment, complete except for extraction/filtration equipment.

The seller is based in Poland. Please see links to some photographs below. For more information please email.

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Hi All,

I am testing T800 coating (Praxair Co-111 POWDER)with 3MB and 9MB.

I found 3 MB is not able to get qualfied coating as the oxide level is much higher than expected.

So i want to turn to 9MB.is there anyone who has the qualfied spraying parameter for this coating for GE-Aviation?THe coating shall meet GE F50TF45 CL-A.

Urgent!!

Thanks.

Good evening? or morning? or day
Does anybody have experience in plasma, (not HVOF) coating of WC-17%Co?
We obtain very brittle coating: the cross- section shows transverse cracks, originated from thermal stresses, I think. At the same time microhardness results are about 700HV, that is below the Spec. requirements: 800-1000 HV
We use the METCO powder 73FNS-1, spray distance- 80 mm, gases helium and hydrogen, deposition rate 20 mkm per pass, total thickness about 250 mkm.
Thank you, volf

Hello,
My name is Şevket from Turkey. I am a production manager in a factory which manufactures engine valves. My problem is about the hard chrome plating for the surfaces of valves. We are plating hard chrome for ten years. And now we improved our technology with a new system. In this system first of all we are sinking the valves to clean the surfaces from oil and the other unwanted materials in the caustic bath with the opposite current. And then sinking to the other two baths including water. After that we send them to the chrome bath which includes chromic acid and sulfuric acid. I see that the stem part of the valve is burned and there is no clear appearing on the surface. If i decrease the current then it doesn't clear valve. When i use normal current for caustic bath the same problems repeat. Expecially the tips are burning, the middle of the stem surfaces are clouded or mat. which amper must i work for cleaning and chrome plating. What are the suitable chemical materials for the plating.
The temperature is nearly 45 for cleaning and the current is 1000 A for 96 valves and their area is 0,2 dm2 for each valve cleaning ın 180 seconds.Redresor voltage is 5,5-6V.
For the chrome tank the temperature is 65 and the current 1200 for 96 valve and the surface area is 0,2 dm2 for each valve. The time is 10 minutes. Redresor voltage is 4V
Is my method suitable for chrome plating or not and what must i do?