Material Product Data Sheet
Chromium Carbide – 25 % Nickel Chromium Powders
Thermal Spray Powder Products: Quick Facts
Woka 7201, Woka 7202, Woka 7203, Woka 7204,
Classification Carbide, chromium-based
Woka 7205, Woka 7207, Woka 7210, Woka 7215,
Chemistry Cr3C2 25(Ni 20Cr)
Woka 7218, Woka 7219
Manufacture Agglomerated and sintered
1 Introduction Morphology Spheroidal
When compared to coating materials containing tungsten Apparent Density 2.3 – 3.1 g/cm3
carbide, coating materials that contain chromium carbide are Service Temperature < 870 °C (1600 °F)
often used because they can withstand higher service tem- Purpose Corrosion and wear resistance
peratures up to 870 °C (1600 °F). Process HVOF or combustion powder
Thermospray™
Woka™ 7200 series of products are spheroidal, agglomerat-
ed and sintered powders for thermal spray that contain 75 %
chromium carbide as a hard, wear-resistant phase that has a
minimal tendency for decomposition during the thermal
spray process. A nickel-chromium (80 % / 20 %) matrix func-
tions as a binder for the carbides, and is also responsible for
the excellent corrosion and oxidation resistance of these
coatings.
Coatings of Woka 7200 series materials protect against
abrasion, various forms of erosion and tribo-corrosion at ele-
vated temperatures. They are well-known as an alternative to
hard chromium plating with better corrosion resistance in so-
dium chloride, acidic and alkaline environments. Environ-
ments with HCl as a corrosive medium should be avoided.
HVOF coatings of these materials are dense, show good
bond strength and are more homogeneous than coatings
applied using atmospheric plasma spray or combustion
powder flame sprayed coatings.
1.1 Typical Uses and Applications:
nn Hydraulic cylinders and piston rods
nn Valve stems
nn Boiler coatings
nn Chemical processing tooling
nn Turbine components
nn Sieves and cones
nn Ship engine valve spindles
nn Furnace rolls in metal production
nn Pump housings
SEM photomicrographs showing the morphology (top) and the microstructure
(bottom) of a Woka 7200 series materials.
DSMTS-0031.4 – Woka 7200 CrC-NiCr Series
© 2017 Oerlikon Metco 1
2 Material Information
2.1 Chemical Composition (all products)
Product Weight Percent (nominal)
Cr C (total) Ni Fe
Woka 7200 Series Balance 9.0 – 10.2 17.5 – 22.5 < 0.5
2.2 Particle Size Distribution
Product Nominal Range D95 D5 Primary Carbide Apparent Density
µm µm µm Size g/cm3
Woka 7201 –53 +20 53 20 Coarse 2.4 – 3.0
Woka 7202 –45 +15 45 15 Coarse 2.4 – 3.0
Woka 7203 –45 +11 45 11 Coarse 2.4 – 3.0
Woka 7204 –30 +10 30 10 Coarse 2.3 – 2.9
Woka 7205 –38 +10 38 10 Coarse 2.3 – 2.9
Woka 7207 –45 +20 45 20 Coarse 2.4 – 3.0
Woka 7210 –25 +5 25 5 Coarse 2.3 – 2.9
Woka 7215 –106 +45 106 45 Coarse 2.5 – 3.1
Woka 7218 –75 +45 75 45 Coarse 2.5 – 3.1
Woka 7219 –63 +20 63 20 Coarse 2.5 – 3.1
Size analysis using laser diffraction (Microtrac). Other particle size distributions are available on request.
2.3 Key Selection Criteria products (see datasheet DSMTS-0027) or plas-
Main selection criteria for choosing a Woka 7200 series ma- ma-densified chromium carbides such as Woka 73xx
terial are: series materials (see datasheet DSMTS-0058).
nn Particle size distributions are optimized for a variety of nn For better corrosion resistance in sulfuric acid (H2SO4) or
HVOF guns on the market today. See Section 2.5 for sodium chloride (NaCl) solutions choose materials that
recommendations. contain both chromium carbide and tungsten carbide,
nn Woka 7215 is suitable for application using combustion such as Woka 75xx or Woka 37xx series products (see
powder Thermospray™. datasheets DSMTS-0056, DSMTS-0059, respectively).
nn Desired as-sprayed surface roughness. For the smooth- nn For better resistance to acidic salt environments choose:
est possible surface, choose a product with the lowest nn A tungsten carbide materials with a cobalt-chromium
particle size distribution appropriate for the spray gun to matrix such as Woka 365x series products (see data-
be used. sheet DSMTS-0025) or Woka 360x series products
(see datasheet DSMTS-0051).
2.4 Related Products nn A material that contains both chromium carbide and
nn For better wear resistance or higher coating hardness tungsten carbide, such as Woka 75xx or Woka 37xx
choose: series products (see datasheets DSMTS-0056,
nn A tungsten carbide material when service temperatures DSMTS-0059, respectively).
are below 500 °C (930 °F). Metco offers an extensive nn Diamalloy 3007 is a clad material [Cr3C2 20(Ni 20Cr)].
portfolio of tungsten carbide materials. A few examples Coatings of Diamalloy 3007 show outstanding properties
are WC 12Co (see datasheet DSMTS-0044 and in applications with erosion, cavitation, heavy abrasion or
WC 17Co (see datasheet DSMTS-0030). Other prod- substantial friction wear at service temperatures between
ucts are available with corrosion resistance matrixes. 540 °C – 870 °C (1000 °F – 1600 °F) (see datasheet
nn Woka 75xx series products, which can be used at ser- DSMTS-0022).
vice temperatures up to 700 °C (1290 °F). nn Within Metco’s portfolio are various chromium carbide
nn At higher temperatures, chromium carbide materials blends such as Diamalloy 3004 and Metco 5255, as well
with higher carbide content such as Woka 71xx series as specialty products such as Amdry 5241.
DSMTS-0031.4 – Woka 7200 CrC-NiCr Series
© 2017 Oerlikon Metco 2
2.5 Recommended Spray Guns
Product HVOF Combustion
DiamondJet WokaJet / K2 Jet Kote Top Gun / CJS Powder
WokaStar / HV2000 Thermospray
JP5000
Woka 7201
Woka 7202
Woka 7203
Woka 7204
Woka 7205
Woka 7207
Woka 7210
Woka 7215
3 Coating Information
3.1 Key Thermal Spray Coating Information
Characteristic Typical Data a
Recommended Process HVOF
Microhardness HV0.3 850 – 1200
Macrohardness HR15N > 90
Wear Rate ASTM G65 B < 9 mm3 < 0.00055 in3
Porosity < 1 %
Corrosion Resistance Excellent in 1 M NaOH, very good in 1M NaCl, good in 0.5 M H2SO4
Maximum Service Temperature 870 °C 1600 °F
Deposition Efficiency 30 – 55 %
a epending on the HVOF spray gun used, parameter used and coating thickness applied. Please note that typical data is given for application using HVOF processes.
D
Woka 7215 is designed to be applied using Combustion Powder Thermospray™ and coating results can be expected to be significantly different.
3.2 Coating Parameters Recommended Spray Guns
Please contact your Oerlikon Metco Account Representative
HVOF Combustion Powder
for parameter availability. For specific coating application
DiamondJet series Metco 6P-II series
requirements, the services of Oerlikon Metco’s Coating
Solution Centers are available. WokaJet series
WokaStar series
DSMTS-0031.4 – Woka 7200 CrC-NiCr Series
© 2017 Oerlikon Metco 3
4 Commercial Information
4.1 Ordering Information and Availability
Product Order No. Package Size Availability Distribution
Woka 7201 1041120 5 kg (approx. 11 lb) Special Order Europe
1041074 10 lb (approx. 4.5 kg)
Woka 7202 1041121 5 kg (approx. 11 lb) Stock Europe
1041075 10 lb (approx. 4.5 kg) Americas
Woka 7203 1059066 5 kg (approx. 11 lb) Special Order Europe
1049664 10 lb (approx. 4.5 kg) Americas
Woka 7204 1041180 5 kg (approx. 11 lb) Special Order Europe
1041192 10 lb (approx. 4.5 kg) Americas
Woka 7205 1041122 5 kg (approx. 11 lb) Stock Europe
1041076 10 lb (approx. 4.5 kg) Americas
Woka 7207 1041123 5 kg (approx. 11 lb) Stock Europe
1041077 10 lb (approx. 4.5 kg) Americas
Woka 7210 1050159 5 kg (approx. 11 lb) Special Order Europe
1049657 10 lb (approx. 4.5 kg) Americas
Woka 7215 1075481 10 lb (approx. 4.5 kg) Special Order Americas
Woka 7218 1065672 5 kg (approx. 11 lb) Special Order Europe
1042908 10 lb (approx. 4.5 kg) Americas
Woka 7219 1065678 5 kg (approx. 11 lb) Special Order Europe
Note: For products available in both kg and lb weights, the kg package will be supplied to unspecified regions (Africa, Asia/Pacific, Japan and Middle East) unless the lb
package is specifically requested by the customer.
4.2 Handling Recommendations 4.3 Safety Recommendations
nn Store in the original container in a dry location. See SDS 50-880 (Safety Data Sheet) in the version localized
nn Tumble contents prior to use to prevent segregation. for the country where the material will be used. SDS are
nn Remove desiccant bag prior to use, where applicable. available from the Oerlikon web site at
nn Open containers should be stored in a drying oven to www.oerlikon.com/metco (Resources – Safety Data Sheets).
prevent moisture pickup.
Information is subject to change without prior notice.
DSMTS-0031.4 – Woka 7200 CrC-NiCr Series www.oerlikon.com/metco
© 2017 Oerlikon Metco info.metco@oerlikon.com4
