A product engineer is tasked with selecting a solid material to fabricate the blades…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A product engineer is tasked with selecting a solid material to fabricate the blades of a household food processor. The blades must simultaneously (1) maintain a sharp cutting edge over repeated use, (2) resist corrosion when exposed to acidic foods, (3) avoid imparting metallic flavors, and (4) be manufactured at moderate cost. Four candidate solids are under consideration: • 440C martensitic stainless steel (metallic solid with high carbon content) • Sintered silicon nitride, Si3N4 (covalent network solid) • Cellulose-based bioplastic (molecular solid) • Sodium chloride single crystal (ionic solid) Relevant measured data supplied by the manufacturer are summarized in the table below.| Property | 440C Stainless | Si3N4 | Cellulose Bioplastic | NaCl Single Crystal |
|---|---|---|---|---|
| Vickers hardness (MPa) | 760 | 1550 | 35 | 20 |
| Density (g·cm⁻³) | 7.7 | 3.2 | 1.3 | 2.2 |
| Thermal conductivity (W·m⁻¹·K⁻¹) | 24 | 30 | 0.26 | 6.7 |
| Estimated raw material cost (USD·kg⁻¹) | 4.8 | 46 | 3.1 | 0.4 |
| Electrical conductivity | Excellent | Insulator | Insulator | Insulator |
| Chemical resistance to 1 M HCl | Very good | Excellent | Poor | Dissolves |