First time here.

I'm seeking a cost-effective process to deposit Si onto SiC targets to a thickness of 50?. We are able to prepare the SiC targets to an Ra of 5nm, or if necessary rough lap with 6? diamond (for a rougher surface). Individual target pieces will be ?15mm up to ?300mm. Bond strength needs to be to MIL-C-48497A, but the thickness tolerance and surface quality are unimportant because we will then optically polish post-depostion, and then optically coat with a specialised high-reflectivity coating. Max polishing temps will be under 80C. Max optical coating chamber temps will be under 230C. Speed of deposition, cost of machinery and consumables are an issue (having said that we have experimented with ion-beam... which is astonomical), as is bonding strength. Ideally we are looking for a machinery manufacturer who could assist R&D, take sub-contract in the short-term, and then sell us the machinery and consumables, and provide training for our operator/s. We need to be processing 10,000 parts pa by 2010.

Sin

hi, may I know the temperature that should be maintain during spraying ID of a cylinder? Last time I plasma spray (I forgot use what powder) ID, maintain it around 90 degree C, but the whole coating come out from the base material when it cool down. It become my 'famous' product , the whole cylinder is made of coating material.

The ID I have machined thread before blast.

If I spray zirconia (Metco 204) or alumina (Metco 105) ID, what temperature should I maintain?

Dear Colleauges
I would be very pleased with an international expression concerning analysis. Witch is the most common way to express various analysys;
NiCrBSi or Ni-Cr-B-Si, or
WC+Co-Cr or WC-CoCr
and so on.
Looking and reading almosta all net-info in this business, doesn't give any help to my question.
br bjarne

hi, any recommended thermal spray related book ?

<The Science and Engineering of Thermal Spray Coatings> sold in Amazon.com is too expensive for me (USD 509).

This is because I'm quite confused in coating material selection. There are so many types of coating materials, and so many brands. I always blur I want to know how to choose the proper/right coating material (regardless of price and availability).

hi, recently i encounter a coating problem and don't know why it happened.

The base material is Aluminum 7075. The part was sent to machined and then underwent 'yellow chrome' (be informed by customer, he wanted yellow chrome as to prevent aluminum be oxidized. He said after yellow chrome, the part did not undergo any post treatment or heat treatment) and then sent to us for TBC. We used Amdry 962 as bond coat and Metco 204NS-G as top coat. After finish thermal spray, we wrapped it by stretch film (pallet film).

Customer said that after 3 or more months, the zirconia coating has many blistering and 'stain' on it, some of them have not yet unwrap.

What I know is after electroplating, the part must undergo heat treatment so as to release the chemicals or hydrogen inside. I suspect this is the reason cause it blistering.

What is you all opinions and suggestions ?

hi all, i have several questions that need to consult experts here,

1. Thermal spray coatings are sprayed layer by layer. If one small area of coating (e.g. TBC) cracks or no bonding due to poor surface preparation, can we re-spray that area instead of rework the whole work-piece? Can we say that the re-spray coating quality is low because of separation of splat (so splat cohesion low) & many porosities?

2. What's the difference between 3MB & 9MB gun?

3. What's the difference between diamond jet gun & HVOF? Can both share the powders?

4. What's difference between Aluminum oxide (e.g. Metco 105NS) and Zirconium oxide (e.g. Metco 204NS-G) in TBC? How to choose between them? If I not wrong, sevice temperature for alumina is 1650C while zirconia is 1010C. Alumina is dielectric.

5. What's difference between Metco 202NS (zirconia 80, yttria 20) & 204NS (zirconia 92, yttria 8)?

6. There are many bond coat, e.g. Amdry 962, Metco 443, Metco 404. How to choose among them?

7. How to choose sand grit (aluminum oxide) size? Depends on process (e.g. HVOF, wire, plasma) or on coating ?

When viewing in "threaded mode" it seems that not all posts are showing up.

see http://www.gordonengland.co.uk/sef/wc-co...t-226.html
viewed in threaded mode this post seems to be missing http://www.gordonengland.co.uk/sef/wc-co...tml#pid833
Viewed in linear mode everything seems right

Fergus

I have tried to spray AlSi-graphite abradable coating (Metco 313NS) for quiete a long time. However, the coating mostly was hard (HR15Y nearly 80). Can anyone offer an advice for me to reduce the hardness?

Thanks

Hello, I'm a newbie and I was wondering what is the significance of NiCr in Cr3C2 coatings. I came across one explanation but it was very short and I wanted to find out if there was anything more to it then that. Here is what I found:

"In thermal spray applications chromium carbide is combined with a metal matrix such as nickel chrome. There is typically a 3:1 ratio by weight of carbide to metal matrix. The metal matrix is present to bond the carbide to the substrate that has been coated and to provide a high degree of corrosion resistance. The combination of corrosion and wear resistance means that the thermally sprayed CrC-NiCr coatings are suitable as a barrier for high temperature wear. It is for this reason that they are finding increasing application in the aerospace market. Typical uses here are as coatings for rod mandrels, hot forming dies, hydraulic valves, machine parts, wear protection of aluminium parts and general applications with good corrosion and abrasion resistance at temperatures up to 700-800?C."

I found it here:
https://www.azom.com/details.asp?ArticleID=524


On a side note, what are the process parameters commonly used to make these Cr3C2 coatings using thermal spray (APS, HVOF, etc)? If there are any websites or specific publications which outline established methods of producing these coatings, please feel free to add!

Thank you

Hi,

could you recommend me the good (best) material against corrosion in sea water? The parts are without abrasive wear. Thickness of coating about 3mm.
I would like to use ARC spray by TAFA 9000.
Thanks for your answer.

Vladimir