WC-CO- Cr coating
05-05-2014, 01:14 PM,
#1
WC-CO- Cr coating
Hi,

I need some recommendations for microstructure and quality coating of WC-Co-Cr. I sprayed by JP5000 and I want to reach porosity below 1% or better.

Is there anybody to help me or send good microstructure of this powder?

Meanwhile, I have concern for mounting of this kind of coatings. Is there any comment for best way of preparation of that? Is it cold mount or regualr for microstructure study?

Thank you for your taking time and consideration,

Regards,
Reply
08-16-2014, 04:28 PM,
#2
RE: WC-CO- Cr coating
Hi Ramin

Sorry for late reply. A contentious issue.

Easy one first
"Is it cold mount or regualr for microstructure study?"

I use hot mounting with bakelite with relatively few issues.

"I need some recommendations for microstructure and quality coating of WC-Co-Cr. I sprayed by JP5000 and I want to reach porosity below 1% or better."

If you want to achieve a below 1% or better apparent porosity by metallography then you should have no problem using some of the commonly recommended preparation procedures for these coatings. I believe most of these produce too much "smearing" to reveal true porosity. But are needed in many cases to pass quality specifications.

If on the other hand you want to help develop coatings which actually have less than 1% true porosity then this is a lot more difficult to reveal accurately in metallography.

Reply
09-26-2014, 06:23 PM,
#3
RE: WC-CO- Cr coating
I can share my scanning electron microscopy images of WC-Co-Cr powder and coating. And yes you can achieve porosity less than 1 % but there are other issues such as the coating may contain W2C, W, Co3W3C phases which are detrimental to coating performance. Spraying the powder at or near stoichiometric ratio can result in dense coating. For WC-Co-Cr coating with JP-5000, it is adviced to spray with oxygen rich atmosphere for cooling the flame and increased particle velocities which can reduce the decomposition of WC phase and porosity issues. And for analysing the porosity less than 1% it is good to capture the back scattered electron images and then process it with some image analysis software.
Reply
09-28-2014, 06:53 PM,
#4
RE: WC-CO- Cr coating
Hi Ramin,

We have a gun MJP-6000 which can produce a coating less than 0.7% porosity. This gun not only can coat inner bore but also very much popular for coating on external surface to produce excellent quality of coatings. You may please refer SEM pics generated fro mircostructure for WC-10Co-4Cr coating done be MJP-6000.

For more, please write to undersigned on marketing@mecpl.com

Thanks & Regards
Manish Choudhary
Metallizing Equipment Co. Pvt. Ltd, India
www.mecpl.ccom
M:- +91 98296 50571


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09-29-2014, 07:11 AM,
#5
RE: WC-CO- Cr coating
(05-05-2014, 01:14 PM)Ramin Wrote: Hi,

I need some recommendations for microstructure and quality coating of WC-Co-Cr. I sprayed by JP5000 and I want to reach porosity below 1% or better.

Is there anybody to help me or send good microstructure of this powder?

Meanwhile, I have concern for mounting of this kind of coatings. Is there any comment for best way of preparation of that? Is it cold mount or regualr for microstructure study?

Thank you for your taking time and consideration,

Regards,


Dear,

I know about regular mounting with heat treatment for mounting of these specimen, cleaning throughly should not be avoided. I have somewhere seen even better microstructure properties with lesser porosity with ST (Small Target) 5000 gun from Tafa.


Thanks

Ravi

Reply
12-27-2014, 02:42 PM, (This post was last modified: 12-27-2014, 03:00 PM by Joris Kraak.)
#6
RE: WC-CO- Cr coating
Hi Ramin,

A hot mounting procedure works fine, no need for cold mounting. You have to pay attention to the cutting process as a too high pressure generates excessive heat and may cause cracking. Also the cooling water and the cutting blade size are crucial! If you observe any cracks introduced by the cutting just remove 1-2mm by plane grinding which should remove your cracks!

In the attached samples one of our wccocr coatings where you can see some edge retention at the top and the influence of different light settings on the microstructure. The term <1% porosity is always discussable as many things in this industry. This is of course also the charm of the job, this certain "grey field" where no-one can give a real answer and where everyone is right, of course so am I ;-)

If you need any more advice on whatsoever you are always welcome

Kind regards,
Joris
Ramin,

An example below where 2 well known independent laboratories identified one of our wccocr coatings to have a porosity level of <0.1%. Initially that put a big smile on my face but of course that can't be true, that would mean it would be almost impenetrable for water. A salt spray test of 2000hrs it will easily survive but when you submerge it for long time in water you can measure a potential difference showing the water is penetrating. That to underline that "porosity level" is discussable.

Manish is telling you he can reach 0.7% porosity but he just wants to sell his system, that is rule nr1 never believe a sales guy Big Grin

(that's a joke Manish, you are a good guy!)

regards,

Joris


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12-28-2014, 02:03 PM, (This post was last modified: 12-28-2014, 02:11 PM by Boris Eizner.)
#7
RE: WC-CO- Cr coating
(05-05-2014, 01:14 PM)Ramin Wrote: Hi,

I need some recommendations for microstructure and quality coating of WC-Co-Cr. I sprayed by JP5000 and I want to reach porosity below 1% or better.

Is there anybody to help me or send good microstructure of this powder?

Meanwhile, I have concern for mounting of this kind of coatings. Is there any comment for best way of preparation of that? Is it cold mount or regualr for microstructure study?

Thank you for your taking time and consideration,

Regards,

Dear Sir
Our set HVOF give real 0.3-0.8 % porosity for OD burner and 0.5-1.0% for ID one
Look attach.
a.termika@gmail.com

Reply
12-30-2014, 02:53 PM,
#8
RE: WC-CO- Cr coating
Hi Ravi,

A good laborant can give you any result you want. Nevertheless you should always question if this is the real coating or not. It all depends on polishing techniques used and experience.

regards,
Joris


(09-29-2014, 07:11 AM)RV_DMG Wrote:
(05-05-2014, 01:14 PM)Ramin Wrote: Hi,

I need some recommendations for microstructure and quality coating of WC-Co-Cr. I sprayed by JP5000 and I want to reach porosity below 1% or better.

Is there anybody to help me or send good microstructure of this powder?

Meanwhile, I have concern for mounting of this kind of coatings. Is there any comment for best way of preparation of that? Is it cold mount or regualr for microstructure study?

Thank you for your taking time and consideration,

Regards,


Dear,

I know about regular mounting with heat treatment for mounting of these specimen, cleaning throughly should not be avoided. I have somewhere seen even better microstructure properties with lesser porosity with ST (Small Target) 5000 gun from Tafa.


Thanks

Ravi

Reply
12-31-2014, 10:04 AM,
#9
RE: WC-CO- Cr coating
(12-27-2014, 02:42 PM)Joris Kraak Wrote: Hi Ramin,

A hot mounting procedure works fine, no need for cold mounting. You have to pay attention to the cutting process as a too high pressure generates excessive heat and may cause cracking. Also the cooling water and the cutting blade size are crucial! If you observe any cracks introduced by the cutting just remove 1-2mm by plane grinding which should remove your cracks!

In the attached samples one of our wccocr coatings where you can see some edge retention at the top and the influence of different light settings on the microstructure. The term <1% porosity is always discussable as many things in this industry. This is of course also the charm of the job, this certain "grey field" where no-one can give a real answer and where everyone is right, of course so am I ;-)

If you need any more advice on whatsoever you are always welcome

Kind regards,
Joris
Ramin,

An example below where 2 well known independent laboratories identified one of our wccocr coatings to have a porosity level of <0.1%. Initially that put a big smile on my face but of course that can't be true, that would mean it would be almost impenetrable for water. A salt spray test of 2000hrs it will easily survive but when you submerge it for long time in water you can measure a potential difference showing the water is penetrating. That to underline that "porosity level" is discussable.

Manish is telling you he can reach 0.7% porosity but he just wants to sell his system, that is rule nr1 never believe a sales guy Big Grin

(that's a joke Manish, you are a good guy!)

regards,

Joris

Hi Joris

Thanks for the commentToungueToungueToungueToungueToungueToungue

In fact the coating quality mentioned i.e 0.7% has been tested on SEM. We can test the coating as per your suggestion and will submit the proof. Please let me know the same.

Thanks & Regards
Manish Happy0193Happy0193Happy0193
Reply
01-01-2015, 02:00 PM,
#10
RE: WC-CO- Cr coating
Hi Manish,

How did you analyze the porosity and how did you classify it as 0.7%? Could you also please let me know which standard you have followed. As mentioned in my previous mails there is a difference how people analyze porosity. That is underlined by the fact that different laboratories showed us different porosity value for the same coating.

Also I am curious which material you have use for obtaining the 0.7%. Was it an agglomerated sintered or sintered crushed material.

regards,
Joris




(12-31-2014, 10:04 AM)Manish Choudhary Wrote:
(12-27-2014, 02:42 PM)Joris Kraak Wrote: Hi Ramin,

A hot mounting procedure works fine, no need for cold mounting. You have to pay attention to the cutting process as a too high pressure generates excessive heat and may cause cracking. Also the cooling water and the cutting blade size are crucial! If you observe any cracks introduced by the cutting just remove 1-2mm by plane grinding which should remove your cracks!

In the attached samples one of our wccocr coatings where you can see some edge retention at the top and the influence of different light settings on the microstructure. The term <1% porosity is always discussable as many things in this industry. This is of course also the charm of the job, this certain "grey field" where no-one can give a real answer and where everyone is right, of course so am I ;-)

If you need any more advice on whatsoever you are always welcome

Kind regards,
Joris
Ramin,

An example below where 2 well known independent laboratories identified one of our wccocr coatings to have a porosity level of <0.1%. Initially that put a big smile on my face but of course that can't be true, that would mean it would be almost impenetrable for water. A salt spray test of 2000hrs it will easily survive but when you submerge it for long time in water you can measure a potential difference showing the water is penetrating. That to underline that "porosity level" is discussable.

Manish is telling you he can reach 0.7% porosity but he just wants to sell his system, that is rule nr1 never believe a sales guy Big Grin

(that's a joke Manish, you are a good guy!)

regards,

Joris

Hi Joris

Thanks for the commentToungueToungueToungueToungueToungueToungue

In fact the coating quality mentioned i.e 0.7% has been tested on SEM. We can test the coating as per your suggestion and will submit the proof. Please let me know the same.

Thanks & Regards
Manish Happy0193Happy0193Happy0193

Reply
01-06-2015, 03:33 AM,
#11
RE: WC-CO- Cr coating
(01-01-2015, 02:00 PM)Joris Kraak Wrote: Hi Manish,

How did you analyze the porosity and how did you classify it as 0.7%? Could you also please let me know which standard you have followed. As mentioned in my previous mails there is a difference how people analyze porosity. That is underlined by the fact that different laboratories showed us different porosity value for the same coating.

Also I am curious which material you have use for obtaining the 0.7%. Was it an agglomerated sintered or sintered crushed material.

regards,
Joris




(12-31-2014, 10:04 AM)Manish Choudhary Wrote:
(12-27-2014, 02:42 PM)Joris Kraak Wrote: Hi Ramin,

A hot mounting procedure works fine, no need for cold mounting. You have to pay attention to the cutting process as a too high pressure generates excessive heat and may cause cracking. Also the cooling water and the cutting blade size are crucial! If you observe any cracks introduced by the cutting just remove 1-2mm by plane grinding which should remove your cracks!

In the attached samples one of our wccocr coatings where you can see some edge retention at the top and the influence of different light settings on the microstructure. The term <1% porosity is always discussable as many things in this industry. This is of course also the charm of the job, this certain "grey field" where no-one can give a real answer and where everyone is right, of course so am I ;-)

If you need any more advice on whatsoever you are always welcome

Kind regards,
Joris
Ramin,

An example below where 2 well known independent laboratories identified one of our wccocr coatings to have a porosity level of <0.1%. Initially that put a big smile on my face but of course that can't be true, that would mean it would be almost impenetrable for water. A salt spray test of 2000hrs it will easily survive but when you submerge it for long time in water you can measure a potential difference showing the water is penetrating. That to underline that "porosity level" is discussable.

Manish is telling you he can reach 0.7% porosity but he just wants to sell his system, that is rule nr1 never believe a sales guy Big Grin

(that's a joke Manish, you are a good guy!)

regards,

Joris

Hi Joris

Thanks for the commentToungueToungueToungueToungueToungueToungue

In fact the coating quality mentioned i.e 0.7% has been tested on SEM. We can test the coating as per your suggestion and will submit the proof. Please let me know the same.

Thanks & Regards
Manish Happy0193Happy0193Happy0193

Hi Joris,
We have taken the microstructure photographs on S.E.M. and Porosity analyzed by MIAS software. The software is referring ASTM B276 for porosity.

We used agglomerated sintered powder.

Thanks & Regards
Manish
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