Chromium Nitride (CrN) PVD Coating Physical Properties

Physical Properties Chromium Nitride (CrN) PVD Coatings
Composition CrN. > 99 % purity.
Process PVD Vacuum Deposited Coating.
Appearance Chromium metallic silver color
Thickness Ranges from 0.25 to 15 microns. Typical applications are 1 to 5 microns. See the thickness conversion chart.
Uniformity Coating conforms uniformly to the substrate. No buildup occurs on corners (unlike plating operations). Coating “throws” well into features. In deep holes, coating tapers off from 1 to 7 diameters of depth.
Hardness, H Hardness > 1500 kg/mm2 Knoop or Vickers Microhardness. Values of 2000-2500 are typical. Equivalent to over 80 Rc. Twice as hard as hard chrome plating. 22 GPa.
Adhesion The coating forms a metallurgical bond to the substrate that will not flake, blister, chip or peel. In fact, the coating is actually implanted slightly into the surface layer of the substrate. Adhesion is superior to plating and other coating processes where mechanical adhesion occurs. Several adhesion test methods are possible, contact BryCoat for more info.
Adhesion, Scratch Adhesion Value > 3.0 kgf on hard steel substrates
Coefficient of Friction CrN generally provides low friction against steels, carbides, TiN, ceramics, platings, etc. Published values range from 0.05 to 0.90. A typical value is 0.4 for CrN against steel. The inert surface creates outstanding sliding wear performance.
Note: The coefficient of friction is a system property, not a material property. It is dependant on many factors such as material, counter-material, lubrication, temperature, speed, loading force, surface finish, surface finish of the counter-material, and type of motion (reciprocating, rotating). Published values can have large variations.
Non-stick CrN is an excellent non-stick surface against most other materials.
Toxicity Non-toxic. Meets FDA guidelines and has been approved for use in numerous medical/surgical devices. Meets requirements of FDA and USDA for food contact.
Temperature Resistance Begins to oxidize at 700° C. (1300° F.) in air. More resistant in an inert atmosphere.
Melting Temperature 1,500° C. (Decomposes to Cr2N at 1,050°C, which melts at 1,500°C)
Deposition Temperature Ranges from 200 to 450° C. Standard process is 400° C. and provides the toughest coating. See also the temperature reference page.
Electrical Resistivity >300 µOhm-cm. To determine resistance, multiply by length and divide by cross sectional area. (Literature values range widely from 300 to 600,000,000; 77,000 for single crystal CrN).
Chemical Resistance Highly inert to acids, bases, solvents, caustic, etc.
Thermal Expansion Coefficient xxx x 10-6 /°C.
Thermal Conductivity xxx Cal/sec.-cm-°C.
Density 5.9 g/cm3.
Crystal Structure Cubic.
Residual Compressive Stress 5.5 GPa
Young’s Modulus, Modulus of Elasticity, E 200 GPa.
Poisson’s Ratio 0.2
Heat of Formation 29,800 Cal/mole.
Band Gap xxx eV