Effetto Mariposa® CarboCut Replacement Blades are available in packs of five. Composed of Tungsten Carbide, each blade is 10 inches long, 19mm (3/4") tall and has a cutting surface of 1.6 mm. These blades are designed to cut through the carbon matrix and resin while smoothing the fibers to be as clean and smooth as a factory carbon fiber cut.
What is Tungsten Carbide?
What is Tungsten Carbide?
Tungsten Carbide (WC) is a chemical compound containing tungsten and carbon. Like most ceramic materials (especially carbides) it has very high hardness, high thermal/chemical resistance but, compared to metals, it's very brittle.
Measuring its hardness on the Mohs scale (see **1, About the Hardness), WC rates 9 just below diamond (which rates 10 on the same scale, while titanium and steel rate respectively 6 and 6.5), making it a suitable material for cutting tools.
To reduce its brittleness WC is cemented: WC powder is "sintered" (see **2, About the Hardness) with Cobalt (a ductile metal) powder. The result is a metal-matrix composite, where cobalt (that enters the liquid stage during the process, unlike WC) embeds/cements WC grains. This composite has an higher shock resistance/toughness than WC alone, preserving most of its high hardness.
About the Hardness
**1: Mohs Scale (source: Wikipedia)
Friedrich Mohs (January 29, 1773 - September 29, 1839) was a German geologist/mineralogist. In 1812, using relatively common minerals, he created a hardness scale that is still used today, called the Mohs' scale of mineral hardness.
The hardness of a material is measured against the scale by finding the hardest material that the given material can scratch, and/or the softest material that can scratch the given material. The Mohs scale is a purely ordinal scale. For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is almost four times as hard as corundum. Table 1.1 shows comparison with absolute hardness.
| Mohs Hardness | Mineral | Absolute Hardness |
| 1 | Talc | 1 |
| 2 | Gypsum | 2 |
| 3 | Calcite | 9 |
| 4 | Fluorite | 21 |
| 5 | Apatite | 48 |
| 6 | Orthoclase | 72 |
| 7 | Quartz | 100 |
| 8 | Topaz | 200 |
| 9 | Corundum | 400 |
| 10 | Diamond | 1500 |
Table 1.1 - comparison between Mohs and Absolute hardness
On the Mohs scale, a pencil lead has a hardness of 1; a fingernail has hardness 2.5; a copper penny, about 3.5; a knife blade, 5.5; window glass, 5.5; steel file, 6.5. Using these ordinary materials of known hardness can be a simple way to approximate the position of a mineral on the scale. Table 1.2 incorporates additional substances that may fall between levels.
| Mohs Hardness | Substance or Mineral |
| 1 | Talc |
| 2 | Gypsum |
| 2.5 to 3 | Pure gold, silver, aluminum |
| 3 | Calcite, copper penny |
| 4 | Fluorite |
| 4 to 4.5 | Platinum |
| 4 to 5 | Iron |
| 5 | Apatite |
| 6 | Orthoclase |
| 6 | Titanium |
| 6.5 | Iron pyrite, steel |
| 6 to 7 | Glass, vitreous pure silica |
| 7 | Quartz |
| 7 to 7.5 | Garnet |
| 7 to 8 | Hardened steel |
| 8 | Topaz |
| 9 | Corundum |
| 9 to 9.5 | Carborundum (SiC) |
| < 10 | Ultrahard fullerite |
| 10 | Diamond |
| > 10 | Aggregated diamond nanorods |
Table 1.2 additional substances in Mohs scale
**2: Sintering
Sintering is a process that takes place at both high pressure and high temperature and is used to create solid parts starting from powders (usually ceramic, but a mix of ceramic and metals or metals alone can be used as well). Solid state sintering is when the heating temperature is below the melting point of the powders, liquid state sintering is when at least one (but not all) element melts during the process. Cemented WC is obtained from liquid state sintering.
