Silicon Carbide Bonding – Nitride Bonded SiC

Silicon carbide is frequently employed for applications that require it to resist corrosion, abrasion and high temperatures as well as for its strength and toughness, particularly under impact conditions.

Numerous techniques exist for bonding molded silicon carbide parts with metal or other silicon carbide parts. Unfortunately, however, these costly and complicated methods have yet to find extensive technological applications.

Nitride Bonded

Nitride Bonded SiC is an ultra-strong material that combines the excellent wear and impact resistance of silicon carbide with superior thermal shock resistance, making it an excellent choice for applications involving rapid temperature or thermal cycling changes, alkali erosion and abrasion resistance, alkaline resistance as well as alkali corrosion protection. This material can be produced by nitriding a mixture of silicon powder (Si) and silicon carbide particles (SiC); when exposed to nitrogen the reaction forms silicon nitride which bonds to all particles for strong composite strength resulting in dense composite structure.

This refractory material can be produced to near-net shape, saving both time and money in its manufacture by eliminating grinding operations or other finishing operations. It’s particularly useful in applications requiring high abrasion resistance such as mining cyclones and coal plants; for lining work; corrosion protection is provided as part of its properties; it also features excellent thermal shock resistance as it’s non-wetting to metal melts making it suitable for aluminum reduction cells or waste incinerator plants.

Reaction-bonded silicon nitride can be produced by carefully nitriding an SiC ‘dough’ or compact at elevated temperatures, bonding its particles to various metal nitrides such as those made up of boron, vanadium, titanium and tantalum nitrides to form a strong ceramic that resists abrasion, impact and thermal shock as well as being inert to acids and alkalis making it suitable for corrosion resistant environments.

SiC is coated with various metal nitrides deposited as layers on its surface, creating an extremely hard and resistant to abrasion surface that also boasts excellent thermal shock resistance and is non-wetting refractory for specific industrial applications.

Nitride-bonded refractories come in various shapes, sizes, and gradings to meet various firing needs. Commonly produced as cast ingots, larger shelves with expansion joints installed are equipped to help relieve stress during firing. Please keep in mind that any time nitride-bonded shelves are hot to touch they must be unloaded/loaded carefully with care to prevent an electrical shock occurring while loading or unloading it from its shelf.

Reaction Bonded

Reaction Bonded Aluminum Oxide (RBAO) reaction bonding provides a means for creating highly customized ceramic products, ideal for unique shapes and larger sizes as well as industrial uses like mining cyclones that require high wear resistance. Reaction bonded silicon carbide ceramics offer excellent thermal stability at lower temperatures; both manufacturing processes provide exceptional strength, durability, and abrasion resistance across multiple industries.

Reaction bonding is a grafting method that combines organosilane reagent with silica gel to form an impervious material that resists most fluids (including moderately caustic and acidic solutions ) while also remaining resistant to abrasion and oxidation, making it suitable for tribological components.

Reacting with organosilanes, silica gel’s surface can form new chemical bonds with organic molecules and this new material can be identified using surface-enhanced Raman spectroscopy (SERS), an advanced technique providing information about surface morphology in oxide materials [1].

SERS spectrum analysis of a silica surface with molecules attached indicates several peaks indicative of their presence, with broad bands at 4000 cm-1 being caused by polymeric condensation of silicic acid, while sharp peaks around 3700 cm-1 are due to silicon-oxygen bending and stretching modes.

SERS can detect other peaks as well, including those of molecules bound to surfaces via bonds. Methylene and methyl groups appear at approximately 0.8 and 1.2 ppm, and their distinct peaks indicate high bonding density for these groups.

SERS spectra of bonded phases produced through the reaction of tetraethoxysilane with silica gel reveal two unique peaks. One near -90ppm represents silicon atoms connected by three siloxane linkages to carbon (commonly referred to as geminai silanols), while 13ppm indicates carbon-13 CP-MAS NMR peaks due to attachment of methanol or acetone groups to an hydroxyl group (Si-CH2-CH3).