Coating applied in paper pulp filter?

[Garyn]

Dear Gordon,

I have a question about coating applied in paper pulp filter tray sprayed by arc spraying with wick wire material which is a kind of cermet compound.
The coating begins to be worn out at the edge of each hole because of the impact erosion of impurities adulterated in paper pulp.
I find this coating has a short service life.
Composition of wick wire (incl. core material): h-BN, Ni, Cr, Mo and rare earth elements.
Coating hardness: HV100 800~1100
Bonding strength: more than 58 MPa
Could you please tell me whether better wire materials recommended to use in the circumstance or not?
Thank you for your help!

RGDS
Garyn

[Gordon]

Hi Garyn

to the Surface Engineering Forum.

To be honest, I feel a little in the dark on this one.

Composition of wick wire (incl. core material): h-BN, Ni, Cr, Mo and rare earth elements.

h-BN or hexagonal boron nitride is a rather soft material unlike its other cubic form, a bit like graphite and diamond. Most coating I know containing h-BN are used as abradable coatings.

"wick wire" probably being thick could you expand?

More info on the wire and some detail on the desired function of the coating would be helpful in trying to answer your question.

Just a tip - I would address your opening post in your thread to all SEF members, as I am sure some of our other members may have the answer your looking for and may be put off from responding.

My son reminded me - quote " definition of an expert - a drip under pressure"

[Garyn]

Dear Gordon,

Thank you for your support.
I'm sorry I made a mistake. The crystal structure of BN should be cubic, c-BN.
Wick wire with a metal/alloy shell and a cermet powder core is a kind of wire material sprayed by arc spraying equipment.
The wire material is applied in the inner wall of fluidized bed boiler usually.
I used it in paper pulp filter against impact erosion as a possible method.
But now I find it not a good choice.

Application: paper pulp filter
Material form requirement: wire
Equipment: Arc spraying
Performance requirement: impact erosion resistance

PS. Someone recommends another material consisted of Cr, Ni, Cr3C2, B, Si, Mo, Mn, V, Fe to me.

RGDS
Garyn
------------

Hi Garyn

to the Surface Engineering Forum.

To be honest, I feel a little in the dark on this one.

Composition of wick wire (incl. core material): h-BN, Ni, Cr, Mo and rare earth elements.

h-BN or hexagonal boron nitride is a rather soft material unlike its other cubic form, a bit like graphite and diamond. Most coating I know containing h-BN are used as abradable coatings.

"wick wire" probably being thick could you expand?

More info on the wire and some detail on the desired function of the coating would be helpful in trying to answer your question.

Just a tip - I would address your opening post in your thread to all SEF members, as I am sure some of our other members may have the answer your looking for and may be put off from responding.

My son reminded me - quote " definition of an expert - a drip under pressure"

[Gordon]

Hi Garyn

OK that seems to make more sense, though I'm not familiar with that wire or coatings produced - so I would be interested if you have any additional info.

You say impact erosion, do you know what the predominant impact angle is with surface. Generally speaking angles lower than 45 degrees tend to be similar to abrasive wear and the very hard coatings usually do well. On the other hand angles above 45 degrees toughness becomes far more important.

Are you looking for arc spray coatings only?

[djewell]

I would look at some amorphous coatings, ie Armacor or Nanosteel. They are extremely hard and wear resistant, yet impact resistant. The coating is alloyed metal instead of composite (cer-met). Wire based coatings have a high percentage of filler material holding the wear resistant material, in your case BN, in place. By switching to an all metal coating, you pick up toughness without sacrificing hardness or wear resistance.