Non oxide ceramics - properties and applications.pptx

Non oxide ceramics

1. Non-oxide cerAMICS BY V.VIJAYA LAKSHMI

2. Silicon carbide Corrundum Natural mineral- Moissanite Properties Chemical formula S iC Molar mass 40.096 g·mol −1 Appearance Yellow to green to bluish-black, iridescent crystals Density 3.16 g⋅cm −3  (hex.) Melting point 2,830 °C (5,130 °F; 3,100 K)(decomposes) Solubility Insoluble in water, soluble in molten alkalis and molten iron

3. Manufacturing of SiC

4. Silicon Nitride(Si 3 N 4 ) Properties Chemical formula Si 3 N 4 Molar mass 140.283 g·mol −1 Appearance grey, odorless powder [1] Density 3.17 g/cm 3 [1] Melting point 1,900 °C (3,450 °F; 2,170 K) [1]  (decomposes) Solubility in water Insoluble [1] Refractive index  ( n D ) 2.016 [2]

5. Manufacturing of Silicon Nitride Si + N = Si 3 N 4 Carbothermal reduction SiO 2 +C+N 2 =Si 3 N 4 +CO

6. Uses of Silicon Nitride

7. Boron Carbide(B 4 C) Properties Chemical formula B 4 C Molar mass 55.255 g/mol Appearance dark gray or black powder, odorless Density 2.52 g/cm 3 , solid. Melting point 2,763 °C (5,005 °F; 3,036 K) Boiling point 3,500 °C (6,330 °F; 3,770 K) Solubility in water insoluble

8. Boron carbide is known as a robust material having extremely high hardness (about 9.5 up to 9.75 on  Mohs hardness scale ) high cross section for absorption of  neutrons  (i.e. good shielding properties against neutrons) stability to  ionizing radiation  and most chemicals. boron carbide is the third hardest substance known, after  diamond  and  cubic boron nitride , earning it the nickname "black diamond".

9. Manufacturing & uses Electric arc furnace 2 B 2 O 3  + 7 C → B 4 C + 6 CO Uses: Padlocks Personal and vehicle anti-ballistic  armor plating Grit blasting  nozzles High-pressure water  jet cutter nozzles Scratch and wear resistant coatings Cutting tools and dies Abrasives Neutron absorber  in  nuclear reactors Metal matrix composites In brake linings of vehicles

10. Boron Nitride(BN) Properties Chemical formula BN Molar mass 24.82 g·mol −1 Appearance Colorless crystals Density 2.1 (h-BN); 3.45 (c-BN) g/cm 3 Melting point 2,973 °C (5,383 °F; 3,246 K) sublimates (cBN) Solubility in water insolubl

11. Uses Electrical Insulators Crucible and reaction vessels Molds and evaporating boats Cutting tools and abrasive