23.12/2022
Merry Christmas and Happy New Year 2023!
27.06/2022
POLEMA’s QMS confirmed its compliance with ISO 9001:20015
POLEMA JSC confirmed the compliance of the current QMS with the requirements of ISO 9001:2015.
03.06/2011
Progressive materials for multi-functional vacuum coatings
Application fields of materials for multi-functional vacuum coatings, characteristics of sputtering targets and evaporable sources used for technologies of physical deposition of hardening, protective, decorative and light-reflecting coatings, resistive, switching and transparent electro conductive films.
24.05/2011
Molybdenum and tungsten products for production of leucosapphires
POLEMA JSC is the leading global manufacturer of chromium, molybdenum, tungsten products, metal powders and composite materials.
Electrolytic chromium flakes
Since 1964, POLEMA has been actively refining its production of electrolytic refined chromium. Developed as the leading method in 1854 by Bunsen, the electrolytic method now makes it possible to obtain high-grade chromium on an industrial scale.
JSC POLEMA's unique methods for refining electrolytic chromium allow it to eliminate any oxygen, sulphur, nitrogen and hydrogen contained in the «raw» product.
The product of electrolysis – primary ECr chromium – comes in thin layers of a dark gray color, flakey in shape, with a thickness of up to 2.5 mm. ECr contains 0.5-0.55% oxygen. High-temperature hydrogen processing of ECr produces refined ERCr chromium, primarily in the form of light gray, shiny layers (flakes) with extremely low amounts of interstitial impurities (C, O, N, S, H).
Use
Electrolytic refined chromium in the form of flakes is traditionally used in vacuum metallurgy when producing heat-resistant Ni-Cr superalloys. Flake chromium is widely used for other purposes as well: in electronics it is used for vaporizing and depositing thin films in units with involving electron-beam heating. Using thermal processing in a pure nitrogen atmosphere, flakey ERCr chromium can be turned into chromium nitride (Cr2N) or nitrided products with other compositions for use in doping special steels and alloys.
Using mechanical grinding, electrolytic refined chromium flakes can be turned into powder and grit with various chemical compositions and dispersibility.
Powder made from pure electrolytic refined chromium is intended for use in manufacturing.
Electrolytic chromium flakes (unrefined)
Electrolytic chromium flakes (refined)
ECr electrolytic unrefined chromium
| Grade | Base | Impurities content, % (mass), maximum | |||||||||
| O | N | C | S | Fe | Si | Ni | Al | Cu | Pb | ||
| ECr | Cr | 0.55 | 0.013 | 0.01 | 0.02 | 0.008 | 0.01 | 0.005 | 0.006 | 0.003 | 0.001 |
ERCr electrolytic refined chromium
| Grades | Cr, %, minimum | Impurities, ppm, maximum | ||||||||
| O | N | C | S | Fe | Si | Ni | Al | Cu | ||
| ERCr-0 | 99.99* | 50 | 50 | 80 | 20 | ∑ Ni, Mo, W, Al, Ca, Co, Cu, Fe, Mg, Mn, Si, Ti, V, K, Li, Na and others 100 ppm, maximum | ||||
| ERCr-1 | 99.95* | 50 | 50 | 80 | 20 | 80 | 100 | 50 | 60 | 30 |
* Mass percentage of chromium, not including the gas-forming impurities C, O, N, S, H, F, Cl.
