HVOF alternative to Detonation flame method
12-18-2014, 11:09 AM, (This post was last modified: 12-18-2014, 11:11 AM by texnicar.)
#1
HVOF alternative to Detonation flame method
Hello,
is there anyone who try to compare this two proces? I must achive with HVOF next parameters:
microhardness 55-64 HRC
phorosity <1%
surface roughness 2.5-5 micro m
service temperature 1100 C

I found Diamalloy 3007 (80%Cr3C2/20%NiCr) with similar carasteristic but problem is service temperature.

Can i use powder for detonation flame method 9507/306 (65%Cr3C2/35%NiCr) on HVOF DiamondJet?

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12-18-2014, 04:21 PM, (This post was last modified: 12-18-2014, 04:22 PM by Vadim Verlotski.)
#2
RE: HVOF alternative to Detonation flame method
(12-18-2014, 11:09 AM)texnicar Wrote: Hello,
is there anyone who try to compare this two proces? I must achive with HVOF next parameters:
microhardness 55-64 HRC
phorosity <1%
surface roughness 2.5-5 micro m
service temperature 1100 C

I found Diamalloy 3007 (80%Cr3C2/20%NiCr) with similar carasteristic but problem is service temperature.

Can i use powder for detonation flame method 9507/306 (65%Cr3C2/35%NiCr) on HVOF DiamondJet?

Hello texnicar,

Unfortunately, to date there are no coatings with an service temperature of 1100 °C. There are only two-layer thermal barrier coating for turbine blades from nickel alloys, consisting of a metal bondcoat (usually NiCrCoAlReY) and a porous ceramic topcoat ZrO2/Y2O3. Bondcoat stand in air not more than 900°C, and the surface temperature of topcoat may reach 1100°C.

All coating systems Cr3C2-NiCr are not used at high temperatures, and in any case can not withstand more than 800°C.

Regards
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12-19-2014, 07:53 AM, (This post was last modified: 12-19-2014, 07:59 AM by texnicar.)
#3
RE: HVOF alternative to Detonation flame method
Thank`s for the answer Vadim Verlotski,
i found a data in technical bulletin for powder (Cr3C2/35%NiCr) (9507/306) which used for detonation flame method that the service temperature is 1100 C and that powder with detonation flame method was used for coating on turbine blades 1st stage.
Particle size of the powder is the same with powders which used for HVOF and my question is can i use that powder for detonation flame method on HVOF (DiamonJet)? In that case i suppose that i will achice satisfactory results.

I think that the service temperature dictate a procent of Ni in the powder in this powder 9507/306 procent is 15% more than Diamalloy 3007 which used for HVOF.

Best regards, Sasa Golubovic.

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12-19-2014, 04:42 PM,
#4
RE: HVOF alternative to Detonation flame method
Hi Sasa,

It is not necessary to believe what they write about the powder in the manuals. It's not important about which way to spray the powder. Importantly, none of the nickel alloy can withstand 1100°C a long time in air.
As I said earlier, most scale resistant are NiCrCoAlReY-alloys , but they can not withstand more than 900°C. Of course, you can try sprayed powder Cr3C2/35%NiCr with HVOF method, but I can guarantee that this coating rebound from the substrate after prolonged exposure at 900°C. In 1100°C it was not only rebound but also oxidizes the entire thickness.

Regards

Vadim

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12-22-2014, 01:28 PM,
#5
RE: HVOF alternative to Detonation flame method
HVOF - High Velocity Oxygen Fuel Thermal Spray Coating
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12-22-2014, 01:46 PM, (This post was last modified: 12-22-2014, 01:48 PM by texnicar.)
#6
RE: HVOF alternative to Detonation flame method
Hi Vadim,
Then i don`t understand why is the Cr3C2/NiCr powder (in standard) purphosed to use on turbine blades 1st where is the service temperature 1100 C. Main function of coating is to provide wear and standard said that the coting applicated by detonation flame metod with Cr3C2/NiCr.

Regards

Sasa.
Reply
12-22-2014, 02:58 PM,
#7
RE: HVOF alternative to Detonation flame method
Hi Sasa,

There is a very big difference between what they write in a variety of scientific articles and that is used in the real technic. Let me give a couple of examples:
1. Detonation spraying method appears in a large number of scientific papers, but in fact, hardly used, since there is no сommercial detonation spraying devices.
2. Many scientific works devoted to the application of high temperature of coatings Cr3С2-NiCr, whereas in reality they use only at normal temperatures to protect from abrasion and friction pairs.
3. Dozens of scientific papers discuss the use of thermal barrier coatings to the blades of the first stage gas turbines at temperatures above 1300°C, whereas in reality, the temperature never exceeds 1000°C.

One can cite thousands of such examples. Just think of a more critical of what they write and try to learn that there is more to reality.

Regards

Vadim
Reply
12-23-2014, 12:52 PM,
#8
RE: HVOF alternative to Detonation flame method
I was reading some scientific articles on warm spraying in which in-flight powder particles travel with high velocity and reduced surface temperature. There is an extra shroud with continuous supply of nitrogen is attached to the barrel of JP-5000 torch.
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