Chrome Oxide Hardness

[Neufeld]

Hi all,
Im trying to find out how hard(HV vickers) it is possible to spray chrome oxide.
I use Amperit 707.054 (99.5% chrome oxide) Grain size -45/+10
Spraying with an F4 plasma gun

I am able to get up to 1250-1290 vickers.
Testing is done per ASTM E384-17

I have a customer that wants us to achieve 1300+ vickers. We are struggling to reach this spec.

Parameters used are:
Argon: 80 schf
Hydrogren: 15-18 scfh
Carrier Gas (Argon): 5.5 scfh
Powder volume: 35-40 g/min
Amps: 625
Volts: 67
Gun Standoff: 4"
Using air nozzles on gun to keep flame clean and focused.

Does anyone have experience achieving 99.5% chrome-oxide coating at 1300+ vickers with F4 Plasma gun?

[Lemster68]

Have you seen this thread?

http://www.gordonengland.co.uk/sef/Threa...conversion