DiffusionCoating:Powder Pack CementationCementation+and+TGA.pdf · Schematic of a TGA‐apparatus...
Transcript of DiffusionCoating:Powder Pack CementationCementation+and+TGA.pdf · Schematic of a TGA‐apparatus...
Thermogravimetric Analysis (TGA)
Argon
Micro balance
Counter weight
Computer based data collection
Gas outlet
TGA = M [mg]
M/A [mg/cm²]
M²/A4 t [mg²/cm4 s]
= kp (parabolic rate constant)
Furnace
Argon
Quartz glass tube
Sample
Quartz glass hanger
l
Gas supply
Diffusion Coating: Powder Pack Cementation
Schematic of a TGA‐apparatus
Gas inlet Gas flow controlling
Diffusion Coating: Powder Pack Cementation
M(s) + AX(s)MX(g) + A(g)
MX(g)
SubstrateTemperature: 600‐1200 CGases: Ar, Ar/H2
Cr‐diffusion on 9%‐chromium ferritic‐martensitic steel
Cr‐diffusion zone
Ni‐platingCr23C6
X(g) + M(s)
Solid state diffusion
Gas diffusion
M: Al, Si, Cr or TiX: F, Cl, Br or IA: NH4, Na or Al
inert filler activator diffusion element
Cr diffusion zone
P92
50 µm
Co‐diffusion of Al and Snon Alloy 600
0 15
0.20
Calculated activities of gaseous Al‐chloridesMixing + Sample
Al2O3, SiO2 NH4Cl, CoBr2, AlF3 Al, Mn, Cr, Ti, Sn,…
Co diffusion of Al and Snon Alloy 600
Ni3Sn2
NiAl
700 800 900 1000 1100 12000.00
0.05
0.10
0.15
Activity
Temperature [ C]
AlCl(g)AlCl3(g)
AlCl2(g)
Powder mixture (weight%):
“Out‐of‐Pack”‐Ti‐Al‐diffusion layer on TNM‐B1Filling
Closing
Setup of a powder pack experiment
Powder mixture (weight%):
5% Al, 0.5% NH4Cl, 94.5% Al2O3
Furnace