VITREOUS CARBON For laboratory and industrial applications TECHNIcal GUIDE
Applications Pièces standards Vitreous carbon is used in laboratory as: Fusion crucibles for setting into solution, Boats or capsules for evaporation, Rods or plates as electrodes for electrochemical analysis (flowmetry, potentiometry, polarography ). It is also used in industry, for example for the working and flowing of molten glass or manufacturing of binar components (Gallium-Arsenic, Cadmium Tellurium ) for electronics. Vitreous carbon is a form of pure carbon produced by the thermal decomposition of a three-dimensionally crosslinked polymer. It has a high flexural strength. Operating conditions Up to 600 C: From 600 to 2,500 C: Attacks by humid process: Fusion by dry process: In air In inert atmosphere (Nitrogen, Argon) or vacuum Acids and bases Sodium carbonate Pyrosulfate Meta and tetraborate of lithium Fusion by sodium peroxide: By addition of 5 % sodium carbonate (5 to 6 fusions) No memory effects: Cleaning is not necessary for another fusion Temperature ( C) Test duration (in hour) Vitreous carbon crucible 452 25 202 ( P%) Vitreous crucible 452 25 202 ( P%) Crucible / Sheath Graphite sheath 438 25 701 ( P%) 600 1 0.14 0.13 0.50 800 1 2.60 1.00 9.00 1,000 1 30.00 2.70 9.50 Comparative tests have been carried out in a muffle furnace between a crucible Ø 35 x 35 grade V25 (ref. 452 25 202) and the same size crucible in a graphite sheath (ref. 438 25 701). 2
Manufacture of Vitreous This material is obtained by carbonisation and subsequent thermal treatment of organic materials having very strong transverse molecular bonds which produce a coke. It belongs to the graphite crystalline family but with a very high crystallographic disorder and sub-microscopic spaces which explain its low density of 1.5 compared to 2.26 the theorical density of graphite. The characteristics of this type of graphite known as vitreous carbon are just like those of glass: fragility, closed microporosity, impervious to gases. The results of these characteristics is an exceptional resistance to corrosion and to general chemical agents. Only oxygen above 600 C and oxidants may attack vitreous carbon. Its resistance to thermal chocks is acceptable. Possible manufactured shapes are limited to a maximum thickness of 2-3 mm. Standard items In the following pages we describe the main standard items in vitreous carbon which can be used in laboratories. Special shapes and sizes can be provided after study. Items Crucibles Graphite shealth Graphite lid Boats Capsules Discs Square plates Rods References D D1 E E1 H L Capacity V10 V25 (mm) (mm) (mm) (mm) (mm) (mm) (ml) 452 10 201 452 25 201 12.5 12.5 1.2 452 25 206 25.0 25.0 10 452 10 202 452 25 202 35.0 2.0 35.0 30 452 25 207 39.0 to 40.0 50 452 10 203 453 25 203 50.0 2.5 50.0 100 453 10 204 454 25 204 70.0 70.0 250 454 25 205 100.0 250.0 1,900 438 25 701 45.0 5.0 45.0 453 30 267 50.0 5.0 50.0 438 25 702 45.0 30.0 10.0 5.0 452 10 101 452 25 101 12.5 100 452 10 102 452 25 102 19.5 125 452 10 103 452 25 103 50.0 340 452 10 221 452 25 221 50.0 18.0 452 10 311 452 25 311 15.0 452 10 312 452 25 312 40.0 2.0 452 10 313 452 25 313 55.0 to 452 10 314 452 25 314 78.0 2.5 452 10 315 452 25 315 100.0 452 10 301 452 25 301 25 452 10 302 452 25 302 100 452 10 601 452 25 601 3.0 150 3
D (mm) L maxi (mm) 12.5 19.5 23.3 25.0 35.0 49.6 50.0 54.6 60.0 70.4 77.7 100 750 750 450 750 740 600 700 450 750 700 700 1,000 GRAPHITE LID discs CRUCIBLE SQUARE PLATES BOATS tubes tube GRAPHITE SHEATH capsules FLAT BOTTOMED TUBE RODS FLAT BOTTOMED TUBE WITH FLANGE Data herein contained are provided for general information purpose only and are not binding. MERSEN shall have no liability whatsoever with respect to information contained herein. Duplication, reproduction or translation of any information contained herein, in whole or in part, is strictly prohibited without prior written consent of MERSEN. 4
Characteristics Caractéristiques Vitreous carbon is a micro porous material (approx. 1µ); it is chemically resistant even in the most aggressive solutions. Two variants are currently available which differ essentially in the temperature of the treatment used: V10 treated à 1,000 C V25 treated à 2,500 C This latter variant is more stable in the course of thermal cycle and is recommended when sharp variations in temperature occur or when operating temperature it to exceed Characteristics Units V10 Grades V25 Density 1.50 to 1.55 Open porosity % 0 0 Nitrogen tightness (5 bars) - at ambient temperature cm -2.s -1 < 10-10 < 10-8 - at 2,500 C cm -2.s -1 < 10-6 Shore hardness 120-125 120-125 Vickers micro-hardness (30 g) 225 150-175 Flexural strength MPa 100 60-80 Compressive strength MPa 300 150-200 Young s modulus kg.mm -2 2,850 2,200 Coefficient of expansion - at 1,000 C 10-6. C -1 3.2 3.5 Thermal conductivity W.cm -1. C -1 0.04 0.08 Resistivity µω.cm 5,500 4,500 Ash content % 0.04 0.04 Sulphur content ppm 50 50 Boron content ppm 2 Parts according to drawings On request MERSEN is able to manufacture various other parts from drawings: crucibles, flow parts, boats, grids, spheres Our materials are in conformity with the RoHS-Directive (Restriction of the use of certain Hazardous Substances in electrical and electronic equipment). Besides MERSEN guarantees the application of the European Community REACH-Regulation (Registration, Evaluation, Authorisation and Restriction of Chemical substances) to all its plants located in Europe. 5
Holytown, Scotland UK Chongqing, China St-Marys, USA V10 Gennevilliers, France Main production sites Industrial or commercial branch A WORLD EXPERT in materials and solutions for high temperature processes Global expert in materials and solutions for extreme environments as well as in the safety and reliability of electrical equipment Mersen designs innovative solutions to address its clients specific A GLOBAL PLAYER needs to enable them to optimize their manufacturing process in sectors such as energy, transportation, electronics, chemical, pharmaceutical and process industries. Contact in North America MERSEN USA BN Corp. Bay City Branch, 900 Harrison Street Bay City, MI 48708, USA Tel.: +1 989 894 29 11 Fax: +1 989 895 77 40 E-mail: semicon@mersen.com www.mersen.com Contact for Europe MERSEN France Gennevilliers SAS 41 rue Jean Jaurès - BP 148 F-92231 GENNEVILLIERS CEDEX FRANCE Tel: + 33 (0) 1 41 85 45 55 Fax: +33 (0) 1 41 85 43 53 HT7 GB 1240