Internship
09-27-2008, 03:09 AM,
#1
Internship
Hello! I am an intern at Vulcan GMS. We are a company that focuses on creating products that are shielded from radiation. My assignment has been to research new technologies for applying lead or tungsten onto steel cast pieces. I came across spraying and powder metallurgy, and I was wondering if i could get some insight from some professionals.

What i really want to know is with this spraying technology, how exactly does it work, and can any metal be used for coating. Also the thickness of the coat is important. And about how long does the process take on a 1'x1' surface, and how costly is it compared to other technologies.

Thank you all very much.

Sean Larson
Undergraduate of Industrial Engineering
Milwaukee School of Engineering
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09-29-2008, 12:57 PM,
#2
RE: Internship
(09-27-2008, 03:09 AM)larsons Wrote: Hello! I am an intern at Vulcan GMS. We are a company that focuses on creating products that are shielded from radiation. My assignment has been to research new technologies for applying lead or tungsten onto steel cast pieces. I came across spraying and powder metallurgy, and I was wondering if i could get some insight from some professionals.

What i really want to know is with this spraying technology, how exactly does it work, and can any metal be used for coating. Also the thickness of the coat is important. And about how long does the process take on a 1'x1' surface, and how costly is it compared to other technologies.

Thank you all very much.

Sean Larson
Undergraduate of Industrial Engineering
Milwaukee School of Engineering

Tungsten can be apply by thermal plasma spray coating under atmospheric and low pressure system (better results but really more expansive). Thickness possible are generally from 50 micrometers to 300 micrometers (more probably possible), and 1'x1' surface will take less of the minute (some seconds). If you search thickness around micron, you can use PVD (Physical Vapor Deposition) but this is not thermal spray ;-)
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09-30-2008, 03:10 PM,
#3
RE: Internship
Ho Sean

Sign0016 to the Surface Engineering Forum.

Both lead and molybdenum can be thermal sprayed, though health/safety/environmental concerns make spraying of lead more restrictive. Combustion wire spray (possibly arc but not sure with lead) method should be able to produce coatings ~ 1mm or may be more in thickness and will be the cheaper option of the thermal spray processes.

What thickness of coating do you require?
What properties do you want from the coatings?
What is the size and shape of part requiring coating? (Thermal spray is a line of sight process, like spraying paint)
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10-01-2008, 09:56 PM,
#4
RE: Internship
Hi,
Most of my industrial experience is in thermal spray. But years ago got a chance to work in cold spray technology with a company called SST, a division of Centerline in Windsor, ON Canada. This SST system uses 80 psi shop air as gas, very economical system. I am not posting ads for them. But my R&D experience with them told me that this will be an ideal process to coat soft materials like lead, Zn, and Al. Deposition rate of soft material like lead shoud be very high. I never sprayed pure lead at that time. But Deposition efficiency should be above 50%. The whole system cost only around $ 55K years ago. But spraying lead powder will address serious environmental and healthy issue.

Hong

(09-27-2008, 03:09 AM)larsons Wrote: Hello! I am an intern at Vulcan GMS. We are a company that focuses on creating products that are shielded from radiation. My assignment has been to research new technologies for applying lead or tungsten onto steel cast pieces. I came across spraying and powder metallurgy, and I was wondering if i could get some insight from some professionals.

What i really want to know is with this spraying technology, how exactly does it work, and can any metal be used for coating. Also the thickness of the coat is important. And about how long does the process take on a 1'x1' surface, and how costly is it compared to other technologies.

Thank you all very much.

Sean Larson
Undergraduate of Industrial Engineering
Milwaukee School of Engineering
Reply
10-02-2008, 01:42 AM,
#5
RE: Internship
Hi

(10-01-2008, 09:56 PM)mehongbo Wrote: Hi,
Most of my industrial experience is in thermal spray. But years ago got a chance to work in cold spray technology with a company called SST, a division of Centerline in Windsor, ON Canada. This SST system uses 80 psi shop air as gas, very economical system. I am not posting ads for them. But my R&D experience with them told me that this will be an ideal process to coat soft materials like lead, Zn, and Al. Deposition rate of soft material like lead shoud be very high. I never sprayed pure lead at that time. But Deposition efficiency should be above 50%. The whole system cost only around $ 55K years ago. But spraying lead powder will address serious environmental and healthy issue.

Hong

(09-27-2008, 03:09 AM)larsons Wrote: Hello! I am an intern at Vulcan GMS. We are a company that focuses on creating products that are shielded from radiation. My assignment has been to research new technologies for applying lead or tungsten onto steel cast pieces. I came across spraying and powder metallurgy, and I was wondering if i could get some insight from some professionals.

What i really want to know is with this spraying technology, how exactly does it work, and can any metal be used for coating. Also the thickness of the coat is important. And about how long does the process take on a 1'x1' surface, and how costly is it compared to other technologies.

Thank you all very much.

Sean Larson
Undergraduate of Industrial Engineering
Milwaukee School of Engineering

Cold spray should technically be very good for lead coating and using air, relatively cheap Sign0184, though probably useless for spraying molybdenum.
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10-02-2008, 01:56 AM,
#6
RE: Internship
Thanks everyone! As to the earlier post, We currently use 1/8" thick lead sheets, cut and formed into a steel cast. The cast is like a hollowed box, except with some ridges inside. I am not sure if 1/8" is neccasary, I've been trying to figure out how much radiation, MeVs the machine puts out that is being housed in this cast. The purpose of this lead spray is shielding.

Cold spraying sounds like a something i should put some time into researching. thank you again, if i have any questions about the process I will ask.
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10-02-2008, 03:29 PM,
#7
RE: Internship
(10-02-2008, 01:42 AM)Gordon Wrote: Hi

(10-01-2008, 09:56 PM)mehongbo Wrote: Hi,
Most of my industrial experience is in thermal spray. But years ago got a chance to work in cold spray technology with a company called SST, a division of Centerline in Windsor, ON Canada. This SST system uses 80 psi shop air as gas, very economical system. I am not posting ads for them. But my R&D experience with them told me that this will be an ideal process to coat soft materials like lead, Zn, and Al. Deposition rate of soft material like lead shoud be very high. I never sprayed pure lead at that time. But Deposition efficiency should be above 50%. The whole system cost only around $ 55K years ago. But spraying lead powder will address serious environmental and healthy issue.

Hong

(09-27-2008, 03:09 AM)larsons Wrote: Hello! I am an intern at Vulcan GMS. We are a company that focuses on creating products that are shielded from radiation. My assignment has been to research new technologies for applying lead or tungsten onto steel cast pieces. I came across spraying and powder metallurgy, and I was wondering if i could get some insight from some professionals.

What i really want to know is with this spraying technology, how exactly does it work, and can any metal be used for coating. Also the thickness of the coat is important. And about how long does the process take on a 1'x1' surface, and how costly is it compared to other technologies.

Thank you all very much.

Sean Larson
Undergraduate of Industrial Engineering
Milwaukee School of Engineering

Cold spray should technically be very good for lead coating and using air, relatively cheap Sign0184, though probably useless for spraying molybdenum.

That's true. The "hardest material" I successfully sprayed was pure Ni using that SST system. D.E was very low. But was able to spray materials like Zn and Al with very high, and Cu with OK deposition rate.
However, here I only mean the materials were deposited. Further treatment, say, coating diffusion, or annealing may be needed to releas stress and increase cohesive/bond strength for some application.
A researcher told me that he was able to cold spray MCrAlY alloy using a gun works like a D-gun but powered by high pressurized air, instead of combustion. I am very negative on cold spray of hard materials. That's why I walked out. However, I have to say, this SST one is really amazing tool to deposit soft metal like lead, zn, Al.

Hong
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