Hi I'm a student of Materials Science and Engeeniring, we (me and my group) have to solve problem: Why did table for PACVD cracked? We chekced chemical composition, its made for 99.9% Al with some Fe. Process was led on temperature about 500C, details were nitred, so the atmosphere contains N2, H2, and Ar. Process were led on underpressure. It taked 1 hour. Table was used only once. What else... after usage it looks like a mushroom, but it craked on surfuce, and near the "leg" on the top is a big round and deep fracture, and a lot of smal radiaire cracks. We checked chemical composition of sourface, obviously it contains a lot of nitrogen, and some argon. Could you help us? How does a pressure influence on the temperature of transformation solid-liquid. I though that it could creeps, but where did cracks come from. We also thought about influence of thermal stress between aluminium nitride and aluminium, when the chamber were cooling. A temperature was measureded by a thermocouple and pyrometer.

ps. I apologize for my English

Greetings, Michal from Poland

We are currently experiancing problems with spraying T800 HVOF using sultzer metcos DJ system. At the moment we have a set of spray parameters which we use, but when sectioning the test samples we will see a different oxide and porosity content with each application. We can generally meet any macro hardness figures and micro hardness figures. Our tensile strength properties can be a bit hit and miss ranging from 7500psi up to 1100 psi. Our main problem is the porosity content as when we machine the parts we tend to see the porosity in the machined surface.
Any help or tips would be much appreciated.

Hallo Everybody,
I am a new member to the forum.

We have laser cladded Stellite 6 on steel recently and the hardness was observed to be approx. 52 HRC. Unlike the PTA process where only a 42HRC is achieved, is this high hardness any problem? The coating was develped without any cracks and pores.

Regards,
Kedar

Gents

I am new to this forum, and have been out of the general machine shop industry for some 12 years. Back then it was generally accepted that Arc spray was a superior form of depositing a layer on a undersize/worn bearing journal/seat.

There were flame spray units utilising wire & powder but they didnt seem to give the same bond strength, and were prone to cracking.

Could you advise what is considered the most effective spraying process today for building undersize/worn bearing journals.

Cheers

Dan

Hello, Forum!
Sorry for my English!!!

I have question. Influence surface speed during HVOF, APS and Flame Spray on quality coatings (bond strength, porosity, residual stresses...). How choose surface speed for each technique?

Thank you.

Hi Gordon, have you got any chance to spray 45C and 45VF by SG-100 gun? What kind of parameter did you use to spray these powders? It seems that OEM's parameter is not perfect. My problem is for 45C we got too much oxide and for 45VF we got too much porosity.
I appreciate your help.

Hello,

I would like to know if there are any coating that can be used in hot forging dies. Can i use MCrAly coatings in order to prevent thermal fatigue? Is there any surface treatment that support/resist to stresses(thermal + mechanical) invoveld in hot forging process?

Apologies for bad english

Thanks a lot

Hello,
I am interested in portable coating thickness measurement instrument for thermal spray coating: all type cermet coatings WC/Co, CrC/NiCr; ceramic coatings Al2O3, Al2O3/TiO2; carbon steel; stainless steel, Mo ; self fluxing NiCrBSi coating and ?. on carbon steel, stainless steel and cast iron substrates. Can anyone to help?
Thanks

We spray TBC by SG-100 gun but there were too much metallic contaminations(approximately 2%) in the top coating. Does anyone can hlep me to solve this problem? How to adjust the spray parameters?

Thanks,

Can you explain to me please how does one go about editing a profile?

Thank you

ThermalMan